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+The Project Gutenberg eBook, Freshwater Sponges, Hydroids & Polyzoa, by
+Nelson Annandale
+
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+
+
+
+Title: Freshwater Sponges, Hydroids & Polyzoa
+
+
+Author: Nelson Annandale
+
+
+
+Release Date: June 24, 2011  [eBook #36504]
+
+Language: English
+
+Character set encoding: ISO-8859-1
+
+
+***START OF THE PROJECT GUTENBERG EBOOK FRESHWATER SPONGES, HYDROIDS &
+POLYZOA***
+
+
+E-text prepared by Bryan Ness, Carol Brown, Sharon Joiner, and
+the Online Distributed Proofreading Team (http://www.pgdp.net)
+from page images generously made available by Internet Archive
+(http://www.archive.org)
+
+
+
+Note: Project Gutenberg also has an HTML version of this
+      file which includes the original illustrations.
+      See 36504-h.htm or 36504-h.zip:
+      (http://www.gutenberg.org/files/36504/36504-h/36504-h.htm)
+      or
+      (http://www.gutenberg.org/files/36504/36504-h.zip)
+
+
+      Images of the original pages are available through
+      Internet Archive. See
+      http://www.archive.org/details/freshwatersponge00anna
+
+
+
+
+
+The Fauna of British India, Including Ceylon and Burma.
+
+Published Under the Authority of the Secretary of
+State for India in Council.
+
+Edited by A. E. Shipley, M.A., Sc.D., HON. D.Sc., F.R.S.
+
+
+FRESHWATER SPONGES, HYDROIDS & POLYZOA.
+
+by
+
+N. ANNANDALE, D.SC.,
+
+Superintendent and Trustee (_Ex Officio_) of the Indian Museum,
+Fellow of the Asiatic Society of Bengal and of the Calcutta University.
+
+
+
+
+
+
+
+London:
+Taylor and Francis, Red Lion Court, Fleet Street.
+
+Calcutta:
+Thacker, Spink, & Co.
+
+Bombay:
+Thacker & Co., Limited.
+
+Berlin:
+R. Friedl�nder & Sohn, 11 Carlstrasse.
+
+August, 1911.
+
+Printed at Today & Tomorrow's Printers & Publishers, Faridabad
+
+
+
+
+CONTENTS.
+
+                                                                   Page
+
+  EDITOR'S PREFACE                                                    v
+
+  SYSTEMATIC INDEX                                                  vii
+
+  GENERAL INTRODUCTION                                                1
+    Biological Peculiarities                                          2
+    Geographical Distribution                                         5
+    Geographical List                                                 7
+    Special Localities                                               13
+    Nomenclature and Terminology                                     17
+    Material                                                         20
+
+  INTRODUCTION TO PART I. (_Spongillid�_)                            27
+    The Phylum Porifera                                              27
+    General Structure                                                29
+    Skeleton and Spicules                                            33
+    Colour and Odour                                                 35
+    External Form and Consistency                                    37
+    Variation                                                        39
+    Nutrition                                                        41
+    Reproduction                                                     41
+    Development                                                      45
+    Habitat                                                          47
+    Animals and Plants commonly associated with Freshwater Sponges   49
+    Freshwater Sponges in relation to Man                            50
+    Indian Spongillid� compared with those of other Countries        51
+    Fossil Spongillid�                                               52
+    Oriental Spongillid� not yet found in India                      52
+    History of the Study of Freshwater Sponges                       54
+    Literature                                                       55
+
+  GLOSSARY OF TECHNICAL TERMS USED IN PART I.                        61
+
+  SYSTEMATIC LIST OF THE INDIAN SPONGILLID�                          63
+
+  INTRODUCTION TO PART II. (_Hydrida_)                              129
+    The Phylum Coelenterata and the Class Hydrozoa                  129
+    Structure of Hydra                                              130
+    Capture and Ingestion of Prey: Digestion                        133
+    Colour                                                          134
+    Behaviour                                                       135
+    Reproduction                                                    136
+    Development of the Egg                                          139
+    Enemies                                                         139
+    Coelenterates of Brackish Water                                 139
+    Freshwater Coelenterates other than Hydra                       141
+    History of the Study of Hydra                                   142
+    Bibliography of Hydra                                           143
+
+  GLOSSARY OF TECHNICAL TERMS USED IN PART II.                      145
+
+  LIST OF THE INDIAN HYDRIDA                                        146
+
+  INTRODUCTION TO PART III. (_Ctenostomata_ and _Phylactol�mata_)   163
+    Status and Structure of the Polyzoa                             163
+    Capture and Digestion of Food: Elimination of Waste Products    166
+    Reproduction: Budding                                           168
+    Development                                                     170
+    Movements                                                       172
+    Distribution of the Freshwater Polyzoa                          173
+    Polyzoa of Brackish Water                                       174
+    History of the Study of Freshwater Polyzoa                      177
+    Bibliography of the Freshwater Polyzoa                          178
+
+  GLOSSARY OF TECHNICAL TERMS USED IN PART III.                     181
+
+  SYNOPSIS OF THE CLASSIFICATION OF THE POLYZOA                     183
+
+  SYNOPSIS OF THE SUBCLASSES, ORDERS, AND SUBORDERS                 183
+
+  SYNOPSIS OF THE LEADING CHARACTERS OF THE DIVISIONS OF
+    THE SUBORDER CTENOSTOMATA                                       185
+
+  SYSTEMATIC LIST OF THE INDIAN FRESHWATER POLYZOA                  187
+
+  APPENDIX TO THE VOLUME                                            239
+    Hints on the Preparation of Specimens                           239
+
+  ADDENDA                                                           242
+    Part I.                                                         242
+    Part II.                                                        245
+    Part III.                                                       245
+
+  ALPHABETICAL INDEX                                                249
+
+  EXPLANATION OF PLATES.
+
+
+
+
+EDITOR'S PREFACE.
+
+
+Dr. N. Annandale's volume on the Freshwater SPONGES, POLYZOA, and
+HYDRIDA contains an account of three of the chief groups of freshwater
+organisms. Although he deals mainly with Indian forms the book contains
+an unusually full account of the life-history and bionomics of
+freshwater Sponges, Polyzoa, and Hydrozoa.
+
+I have to thank Dr. Annandale for the great care he has taken in the
+preparation of his manuscript for the press, and also the Trustees of
+the Indian Museum, Calcutta, for their kindness in placing material at
+the disposal of the Author.
+
+                   A. E. SHIPLEY.
+  Christ's College, Cambridge,
+  March 1911.
+
+
+
+
+  SYSTEMATIC INDEX.
+
+
+                                            Page
+  PORIFERA.
+
+  Order HALICHONDRINA                         65
+
+  Fam. 1. SPONGILLID�                         65
+
+  1. Spongilla, _Lamarck_                     67
+    1A. Euspongilla, _Vejdovsky_              69
+      1.     lacustris, _auct._               69
+      1_a_.  reticulata, _Annandale_     71, 241
+      2.     proliferens, _Annandale_         72
+      3.     alba, _Carter_                   76
+      3_a_.  cerebellata, _Bowerbank_         76
+      3_b_.  bengalensis, _Annandale_         77
+      4.     cinerea, _Carter_           79, 241
+      5.     travancorica, _Annandale_        81
+      6.     hemephydatia, _Annandale_        82
+      7.     crateriformis (_Potts_)          83
+    1B. Eunapius, _J. E. Gray_                86
+      8.     carteri, _Carter_           87, 241
+      8_a_.  mollis, _Annandale_              88
+      8_b_.  cava, _Annandale_                88
+      9.     fragilis, _Leidy_                95
+      9_a_.  calcuttana, _Annandale_          96
+      9_b_.  decipiens, _Weber_               97
+     10.    gemina, _Annandale _              97
+     11.    crassissima, _Annandale_          98
+     11_a_. crassior, _Annandale_             98
+    1C. Stratospongilla, _Annandale_         100
+     12.    indica, _Annandale_              100
+     13.    bombayensis, _Carter_       102, 241
+     13_a_. pneumatica, _Annandale_          241
+     14.    ultima, _Annandale_              104
+  2. Pectispongilla, _Annandale_             106
+     15.     aurea, _Annandale_              106
+     15 _a_.  subspinosa, _Annandale_        107
+  3. Ephydatia, _Lamouroux_                  108
+     16.     meyeni (_Carter_)               108
+             fluviatilis, _auct._            242
+  4. Dosilia, _Gray_                         110
+     17.     plumosa (_Carter_)              111
+  5. Trochospongilla, _Vejdovsky_            113
+     18.     latouchiana, _Annandale_        115
+     19.     phillottiana, _Annandale_       117
+     20.     pennsylvanica (_Potts_)         118
+  6. Tubella, _Carter_                       120
+     21.     vesparioides, _Annandale_       120
+  7. Corvospongilla, _Annandale_             122
+     22.     burmanica (_Kirkpatrick_)       123
+             caunteri, _Annandale_           243
+     23.     lapidosa (_Annandale_)          124
+
+  HYDROZOA.
+
+  Order ELEUTHEROBLASTEA                     147
+
+  Fam. 1. HYDRID�                            147
+
+  1. Hydra, _Linn�_                          147
+     24.     vulgaris, _Pallas_              148
+     25.     oligactis, _Pallas_        158, 245
+
+  POLYZOA.
+
+  Order CTENOSTOMATA                         189
+
+  Div. 1.    Vesicularina                    189
+
+  Fam. 1. VESICULARID�                       189
+
+  1. Bowerbankia, _Farre_                    189
+         caudata, _Hincks_                   189
+         bengalensis, _Annandale_            189
+
+  Div. 2. Paludicellina                      190
+
+  Fam. 1. PALUDICELLID�                      191
+
+  1. Paludicella, _Gervais_                  192
+  2. Victorella, _Kent_                      194
+     26.     bengalensis, _Annandale_        195
+
+  Fam. 2. HISLOPIID�                         199
+
+  1. Hislopia, _Carter_                      199
+     27.     lacustris, _Carter_             202
+     27 _a_.  moniliformis, _Annandale_      204
+
+  Order PHYLACTOL�MATA                       206
+
+  Div. 1. Plumatellina                       206
+
+  Fam. 1. FREDERICELLID�                     208
+
+  1. Fredericella, _Gervais_                 208
+     28.     indica, _Annandale_        210, 245
+
+  Fam. 2. PLUMATELLID�                       211
+
+  Subfam. A. _Plumatellin�_                  212
+
+  1. Plumatella, _Lamarck_                   212
+     29.     fruticosa, _Allman_             217
+     30.     emarginata, _Allman_       220, 245
+     31.     javanica, _Kraepelin_           221
+     32.     diffusa, _Leidy_           223, 245
+     33.     allmani, _Hancock_         224, 246
+     34.     tanganyik�, _Rousselet_    225, 246
+     35.     punctata, _Hancock_             227
+  2. Stolella, _Annandale_                   229
+     36.     indica, _Annandale_             229
+             himalayana, _Annandale_         246
+
+  Subfam. B. _Lophopin�_                     231
+
+  1. Lophopodella, _Rousselet_               231
+     37.     carteri (_Hyatt_)               232
+     37 _a_.  himalayana (_Annandale_)       233
+  2. Pectinatella, _Leidy_                   235
+     38.     burmanica, _Annandale_          235
+
+
+
+
+GENERAL INTRODUCTION TO THE VOLUME.
+
+
+Although some zoologists have recently revived the old belief that the
+sponges and the coelenterates are closely allied, no one in recent times
+has suggested that there is any morphological relationship between
+either of these groups and the polyzoa. Personally I do not think that
+any one of the three groups is allied to any other so far as anatomy is
+concerned; but for biological reasons it is convenient to describe the
+freshwater representatives of the three groups in one volume of the
+"Fauna."
+
+Indeed, I originally proposed to the Editor that this volume should
+include an account not only of the freshwater species, but of all those
+that have been found in stagnant water of any kind. It is often
+difficult to draw a line between the fauna of brackish ponds and marshes
+and that of pure fresh water or that of the sea, and this is
+particularly the case as regards the estuarine tracts of India and
+Burma.
+
+Pelseneer[A] has expressed the opinion that the Black Sea and the
+South-east of Asia are the two districts in the world most favourable
+for the study of the origin of a freshwater fauna from a marine one. The
+transition in particular from the Bay of Bengal, which is much less salt
+than most seas, to the lower reaches of the Ganges or the Brahmaputra is
+peculiarly easy, and we find many molluscs and other animals of marine
+origin in the waters of these rivers far above tidal influence.
+Conditions are unfavourable in the rivers themselves for the development
+and multiplication of organisms of many groups, chiefly because of the
+enormous amount of silt held in suspension in the water and constantly
+being deposited on the bottom, and a much richer fauna exists in ponds
+and lakes in the neighbourhood of the rivers and estuaries than in
+running water. I have only found three species of polyzoa and three of
+sponges in running water in India, and of these six species, five have
+also been found in ponds or lakes. I have, on the other hand, found
+three coelenterates in an estuary, and all three species are essentially
+marine forms, but two have established themselves in ponds of brackish
+water, one (the sea-anemone _Sagartia schilleriana_) undergoing in so
+doing modifications of a very peculiar and interesting nature. It is not
+uncommon for animals that have established themselves in pools of
+brackish water to be found occasionally in ponds of fresh water; but I
+have not been able to discover a single instance of an estuarine species
+that is found in the latter and not in the former.
+
+     [Footnote A: "L'origine des animaux d'eau douce," Bull. de
+     l'Acad. roy. de Belgique (Classe des Sciences), No. 12,
+     1905, p. 724.]
+
+For these reasons I intended, as I have said, to include in this volume
+descriptions of all the coelenterates and polyzoa known to occur in
+pools of brackish water in the estuary of the Ganges and elsewhere in
+India, but as my manuscript grew I began to realize that this would be
+impossible without including also an amount of general introductory
+matter not justified either by the scope of the volume or by special
+knowledge on the part of its author. I have, however, given in the
+introduction to each part a list of the species found in stagnant
+brackish water with a few notes and references to descriptions.
+
+
+BIOLOGICAL PECULIARITIES OF THE SPONGES, COELENTERATES, AND POLYZOA OF
+FRESH WATER.
+
+There is often an external resemblance between the representatives of
+the sponges, coelenterates, and polyzoa that causes them to be classed
+together in popular phraseology as "zoophytes"; and this resemblance is
+not merely a superficial one, for it is based on a similarity in habits
+as well as of habitat, and is correlated with biological phenomena that
+lie deeper than what are ordinarily called habits. These phenomena are
+of peculiar interest with regard to difficult questions of nutrition and
+reproduction that perhaps can only be solved by a close study of animals
+living together in identical conditions and exhibiting, apparently in
+consequence of so living, similar but by no means identical tendencies,
+either anatomical or physiological, in certain directions.
+
+One of the most important problems on which the study of the sponges,
+coelenterates, and polyzoa of stagnant water throws light is that of the
+production of resting buds and similar reproductive bodies adapted to
+withstand unfavourable conditions in a quiescent state and to respond to
+the renewal of favourable conditions by a renewed growth and activity.
+
+Every autumn, in an English pond or lake, a crisis takes place in the
+affairs of the less highly organized inhabitants, and preparations are
+made to withstand the unfavourable conditions due directly or indirectly
+to the low winter temperature of the water: the individual must perish
+but the race may be preserved. At this season _Hydra_, which has been
+reproducing its kind by means of buds throughout the summer, develops
+eggs with a hard shell that will lie dormant in the mud until next
+spring; the phylactol�matous polyzoa produce statoblasts, the
+ctenostomatous polyzoa resting-buds ("hibernacula"), and the sponges
+gemmules. Statoblasts, hibernacula, and gemmules are alike produced
+asexually, but they resemble the eggs of _Hydra_ in being provided with
+a hard, resistant shell, and in having the capacity to lie dormant until
+favourable conditions return.
+
+In an Indian pond or lake a similar crisis takes place in the case of
+most species, but it does not take place at the same time of year in the
+case of all species. Unfortunately the phenomena of periodic
+physiological change have been little studied in the freshwater fauna of
+most parts of the country, and as yet we know very little indeed of the
+biology of the Himalayan lakes and tarns, the conditions in which
+resemble those to be found in similar masses of water in Europe much
+more closely than they do those that occur in ponds and lakes in a
+tropical plain. In Bengal, however, I have been able to devote
+considerable attention to the subject, and can state definitely that
+some species flourish chiefly in winter and enter the quiescent stage at
+the beginning of the hot weather (that is to say about March), while
+others reach their maximum development during the "rains" (July to
+September) and as a rule die down during winter, which is the driest as
+well as the coolest time of year.
+
+The following is a list of the forms that in Bengal are definitely known
+to produce hard-shelled eggs, gemmules, resting-buds, or statoblasts
+only or most profusely at the approach of the hot weather and to
+flourish during winter:--
+
+     _Spongilla carteri._
+     _Sponging alba._
+     _Spongilla alba_ var. _bengalensis_.
+     _Spongilla crassissima._
+     _Hydra vulgaris._
+     _Victorella bengalensis._
+     _Plumatella fruticosa._
+     _Plumatella emarginata._
+     _Plumatella javanica._
+
+The following forms flourish mainly during the "rains":--
+
+     _Spongilla lacustris_ subsp. _reticulata_.
+     _Trochospongilla latouchiana._
+     _Trochospongilla phillottiana._
+     _Stolella indica._
+
+The following flourish throughout the year:--
+
+     _Spongilla proliferens._
+     _Hislopia lacustris._
+
+It is particularly interesting to note that three of the species that
+flourish in the mild winter of Bengal, namely _Hydra vulgaris_,
+_Plumatella emarginata_, and _P. fruticosa_, are identical with species
+that in Europe perish in winter. There is evidence, moreover, that the
+statoblasts of the genus to which two of them belong burst more readily,
+and thus give rise to new colonies, after being subjected to a
+considerable amount of cold. In Bengal they only burst after being
+subjected to the heat of the hot weather. Does extreme heat have a
+similar effect on aquatic organisms as extreme cold? There is some
+evidence that it has.
+
+The species that flourish in India during the rains are all forms which
+habitually live near the surface or the edge of ponds or puddles, and
+are therefore liable to undergo desiccation as soon as the rains cease
+and the cold weather supervenes.
+
+The two species that flourish all the year round do not, properly
+speaking, belong to one category, for whereas _Hislopia lacustris_
+produces no form of resting reproductive body but bears eggs and
+spermatozoa at all seasons, _Spongilla proliferens_ is a short-lived
+organism that undergoes a biological crisis every few weeks; that is to
+say, it begins to develop gemmules as soon as it is fully formed, and
+apparently dies down as soon as the gemmules have attained maturity. The
+gemmules apparently lie dormant for some little time, but incessant
+reproduction is carried on by means of external buds, a very rare method
+of reproduction among the freshwater sponges.
+
+The facts just stated prove that considerable specific idiosyncrasy
+exists as regards the biology of the sponges, hydroids, and polyzoa of
+stagnant water in Bengal; but an even more striking instance of this
+phenomenon is afforded by the sponges _Spongilla bombayensis_ and
+_Corvospongilla lapidosa_ in Bombay. These two sponges resemble one
+another considerably as regards their mode of growth, and are found
+together on the lower surface of stones. In the month of November,
+however, _C. lapidosa_ is in full vegetative vigour, while _C.
+bombayensis_, in absolutely identical conditions, is already reduced to
+a mass of gemmules, having flourished during the "rains." It is thus
+clear that the effect of environment is not identical in different
+species. This is more evident as regards the groups of animals under
+consideration in India (and therefore probably in other tropical
+countries) than it is in Europe. The subject is one well worthy of study
+elsewhere than in India, for it is significant that specimens of _S.
+bombayensis_ taken in November in S. Africa were in a state of activity,
+thus contrasting strongly with specimens taken at the same time of year
+(though not at the same season from a climatic point of view) in the
+Bombay Presidency.
+
+
+GEOGRAPHICAL DISTRIBUTION OF THE INDIAN SPECIES.
+
+The geographical distribution of the lower invertebrates of fresh and of
+stagnant water is often an extremely wide one, probably because the
+individual of many species exists at certain seasons or in certain
+circumstances in a form that is not only resistant to unfavourable
+environment, but also eminently capable of being transported by wind or
+currents. We therefore find that some genera and even species are
+practically cosmopolitan in their range, while others, so far as our
+knowledge goes, appear to have an extraordinarily discontinuous
+distribution. The latter phenomenon may be due solely to our ignorance
+of the occurrence of obscure genera or species in localities in which
+they have not been properly sought for, or it may have some real
+significance as indicating that certain forms cannot always increase and
+multiply even in those localities that appear most suitable for them. As
+an example of universally distributed species we may take the European
+polyzoa of the genus _Plumatella_ that occur in India, while of species
+whose range is apparently discontinuous better examples could not be
+found than the sponges _Trochospongilla pennsylvanica_ and _Spongilla
+crateriformis_, both of which are only known from N. America, the
+British Isles, and India.
+
+My geographical list of the species of sponges, coelenterates, and
+polyzoa as yet found in fresh water in India is modelled on Col.
+Alcock's recently published list of the freshwater crabs (Potamonid�) of
+the Indian Empire[B]. I follow him in accepting, with slight
+modifications of my own, Blanford's physiographical rather than his
+zoogeographical regions, not because I think that the latter have been
+or ought to be superseded so far as the vertebrates are concerned, but
+rather because the limits of the geographical distribution of aquatic
+invertebrates appear to depend on different factors from those that
+affect terrestrial animals or even aquatic vertebrates.
+
+     [Footnote B: Cat. Ind. Dec. Crust. Coll. Ind. Mus., part i,
+     fasc. ii (Potamonid�), 1910.]
+
+"Varieties" are ignored in this list, because they are not considered to
+have a geographical significance. The parts of India that are least
+known as regards the freshwater representatives of the groups under
+consideration are the valley of the Indus, the lakes of Kashmir and
+other parts of the Himalayas, the centre of the Peninsula, and the basin
+of the Brahmaputra. Those that are best known are the districts round
+Bombay, Calcutta, Madras and Bangalore, Travancore and Northern
+Tenasserim. Little is known as regards Ceylon, and almost nothing as
+regards the countries that surround the Indian Empire, a few species
+only having been recorded from Yunnan and the Malay Peninsula, none from
+Persia, Afghanistan, or Eastern Turkestan, and only one from Tibet.
+Professor Max Weber's researches have, however, taught us something as
+regards Sumatra and Java, while the results of various expeditions to
+Tropical Africa are beginning to cast light on the lower invertebrates
+of the great lakes in the centre of that continent and of the basin of
+the Nile.
+
+It is not known to what altitude the three groups range in the Himalayas
+and the hills of Southern India. No sponge has been found in Indian
+territory at an altitude higher than that of Bhim Tal in Kumaon (4,500
+feet), and _Hydra_ is only known from the plains; but a variety of _H.
+oligactis_ was taken by Capt. F. H. Stewart in Tibet at an altitude of
+about 15,000 feet. _Plumatella diffusa_ flourishes at Gangtok in Sikhim
+(6,100 feet), and I have found statoblasts of _P. fruticosa_ in the
+neighbourhood of Simla on the surface of a pond situated at an altitude
+of about 8,000 feet; Mr. R. Kirkpatrick obtained specimens of the genus
+in the Botanical Gardens at Darjiling (6,900 feet), and two species have
+been found at Kurseong (4,500-5,000 feet) in the same district.
+
+
+GEOGRAPHICAL LIST OF THE FRESHWATER SPONGES, HYDROIDS, AND POLYZOA OF
+INDIA, BURMA, AND CEYLON.
+
+[A * indicates that a species or subspecies has only been found in one
+physiographical region or subregion so far as the Indian Empire is
+concerned; a ! that the species has also been found in Europe, a $ in
+North America, a + in Africa, and a @ in the Malay Archipelago.]
+
+1. Western Frontier Territory[C].
+
+(Baluchistan, the Punjab, and the N.W. Frontier Province.)
+
+     [Footnote C: I include Baluchistan in this territory largely
+     for climatic reasons.]
+
+  SPONGES:--
+    1. _Spongilla_ (_Eunapius_) _carteri_!@ (Lahore).
+
+  HYDROIDS:--
+    1. _Hydra oligactis_!$ (Lahore).
+
+  POLYZOA:--
+    1. _Plumatella fruticosa_!$ (Lahore).
+    2. _Plumatella diffusa_!$ (Lahore).
+
+
+2. Western Himalayan Territory.
+
+(Himalayas from Hazara eastwards as far as Nepal.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Eunapius_) _carteri_!@ (Bhim Tal).
+    2. _Ephydatia meyeni_@ (Bhim Tal).
+
+  HYDROIDS:--None known (_Hydra oligactis_ recorded from Tibet).
+
+  POLYZOA:--
+    1. _Plumatella allmani_! (Bhim Tal).
+    2. _Plumatella fruticosa_!$ (Simla).
+    3. _Lophopodella carteri_+ (Bhim Tal).
+
+
+3. North-Eastern Frontier Territory.
+
+(Sikhim, Darjiling and Bhutan, and the Lower Brahmaputra
+Drainage-System.)
+
+  SPONGES:--
+    _Spongilla proliferens_@ (Assam).
+
+  HYDROIDS:--None known.
+
+  POLYZOA:--
+    1. _Plumatella fruticosa_! (Kurseong and Assam).
+    2. _Plumatella diffusa_!$ (Sikhim).
+    3. _Plumatella javanica_@ (Kurseong).
+
+
+4. Burma Territory.
+
+(Upper Burma, Arrakan, Pegu, Tenasserim.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _proliferens_@ (Upper Burma, Pegu).
+    2. _Spongilla_ (_Euspongilla_) _crateriformis_!$ (Tenasserim).
+    3. _Spongilla_ (_Eunapius_) _carteri_!@ (Upper Burma, Pegu,
+         Tenasserim).
+    4. _Trochospongilla latouchiana_ (Tenasserim).
+    5. _Trochospongilla phillottiana_ (Tenasserim).
+    6. _Tubella vesparioides_* (Tenasserim).
+    7. _Corvospongilla  burmanica_* (Pegu).
+
+  HYDROIDS:--
+    1. _Hydra vulgaris_!$ (Upper Burma and Tenasserim).
+
+  POLYZOA:--
+    1. _Plumatella emarginata_!$ (Pegu, Upper Burma).
+    2. _Plumatella allmani_! (Tenasserim).
+    3. _Pectinatella burmanica_ (Tenasserim).
+    4. _Hislopia lacustris_ (Pegu).
+
+
+5 _a._ Peninsular Province--Main Area.
+
+(The Peninsula east of the Western Ghats.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _lacustris_ subsp. _reticulata_
+         (Orissa, Madras).
+    2. _Spongilla_ (_Euspongilla_) _proliferens_@ (Madras).
+    3. _Spongilla_ (_Euspongilla_) _alba_+ (N. Madras, Orissa, Hyderabad).
+    4. _Spongilla_ (_Euspongilla_) _hemephydatia_* (Orissa).
+    5. _Spongilla_ (_Euspongilla_) _crateriformis_!$.
+    6. _Spongilla_ (_Eunapius_) _carteri_!@.
+    7. _Spongilla_ (_Eunapius_) _gemina_* (Bangalore).
+    8. _Spongilla_ (_Stratospongilla_) _bombayensis_+ (Mysore).
+    9. _Dosilia plumosa_ (N. Madras).
+
+  HYDROIDS:--
+    1. _Hydra vulgaris_!$.
+
+  POLYZOA:--
+    1. _Plumatella fruticosa_! (Madras, Bangalore).
+    2. _Lophopus_ (?_Lophopodella_), sp. (Madras).
+    3. _Pectinatella burmanica_ (Orissa).
+    4. _Victorella bengalensis_ (Madras).
+    5. _Hislopia lacustris_ (Nagpur).
+
+
+5b. Peninsular Province--Malabar Zone.
+
+(Western Ghats from Tapti R. to Cape Comorin and eastwards
+to the sea.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _lacustris_ subsp. _reticulata_
+         (W. Ghats).
+    2. _Spongilla_ (_Euspongilla_) _proliferens_@ (Cochin).
+    3. _Spongilla_ (_Euspongilla_) _alba_+.
+    4. _Spongilla_ (_Euspongilla_) _cinerea_*.
+    5. _Spongilla_ (_Euspongilla_) _travancorica_* (Travancore).
+    6. _Spongilla_ (_Euspongilla_) _crateriformis_!$ (Cochin).
+    7. _Spongilla_ (_Eunapius_) _carteri_!@.
+    8. _Spongilla_ (_Stratospongilla_) _indica_* (W. Ghats).
+    9. _Spongilla _ (_Stratospongilla_) _bombayensis_+ (Bombay, W. Ghats).
+   10. _Spongilla_ (_Stratospongilla_) _ultima_* (Travancore).
+   11. _Pectispongilla aurea_* (Travancore, Cochin).
+   12. _Ephydatia meyeni_@ (Bombay, Travancore).
+   13. _Dosilia plumosa_ (Bombay).
+   14. _Trochospongilla pennsylvanica_*!$ (Travancore).
+   15. _Corvospongilla lapidosa_* (W. Ghats).
+
+  HYDROIDS:--None recorded.
+
+  POLYZOA:--
+    1. _Fredericella indica_* (W. Ghats and Travancore).
+    2. _Plumatella fruticosa_! (Bombay).
+    3. _Plumatella javanica_@ (Travancore).
+    4. _Plumatella tanganyik�_*+ (W. Ghats).
+    5. _Lophopodella carteri_+ (Bombay, W. Ghats).
+
+
+6. Indo-Gangetic Plain.
+
+(From Sind to the Brahmaputra.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _lacustris_ subsp. _reticulata_
+         (Gangetic delta).
+    2. _Spongilla_ (_Euspongilla_) _proliferens_@ (Lower Bengal, etc.).
+    3. _Spongilla_ (_Euspongilla_) _alba_+ (Lower Bengal).
+    4. _Spongilla_ (_Euspongilla_) _crateriformis_!$.
+    5. _Spongilla_ (_Eunapius_) _carteri_!@ (Lower Bengal, etc.).
+    6. _Spongilla_ (_Eunapius_) _fragilis_ subsp. _calcuttana_* (Lower
+         Bengal).
+    7. _Spongilla_ (_Eunapius_) _crassissima_ (Bengal).
+    8. _Ephydatia meyeni_@ (Lower Bengal).
+    9. _Trochospongilla latouchiana_ (Lower Bengal).
+   10. _Trochospongilla phillottiana_ (Lower Bengal).
+
+  HYDROIDS:--
+    1. _Hydra vulgaris_!$.
+
+  POLYZOA:--
+    1. _Plumatella fruticosa_!.
+    2. _Plumatella emarginata_!$.
+    3. _Plumatella javanica_@ (Lower Bengal).
+    4. _Plumatella diffusa_!$.
+    5. _Plumatella allmani_!.
+    6. _Plumatella punctata_!$ (Lower Bengal).
+    7. _Stolella indica_* (Lower Bengal, United Provinces).
+    8. _Victorella bengalensis_ (Lower Bengal).
+    9. _Hislopia lacustris_ (United Provinces, N. Bengal).
+    9a. _Hislopia lacustris_ subsp. _moniliformis_* (Lower Bengal).
+
+
+7. Ceylon.
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _proliferens_@.
+    2. _Spongilla_ (_Eunapius_) _carteri_!@.
+
+  HYDROIDS:--
+    1. _Hydra vulgaris_!$.
+
+  POLYZOA:--
+    1. ? _Plumatella emarginata_!$.
+    2. _Pectinatella burmanica._
+
+The most striking feature of this list is the evidence it affords as to
+the distinct character of the fauna of the Malabar Zone, a feature that
+is also remarkably clear as regards the Potamonid�, one genus of which
+(_Gecarcinucus_) is peculiar, so far as India is concerned, to that
+zone. As regards the sponges we may note the occurrence of no less than
+three species of the subgenus _Stratospongilla_, which has not been
+found elsewhere in India except on one occasion in Mysore, and of a
+species of the genus _Corvospongilla_, which is unknown from the rest of
+Peninsular India and from the Himalayas. The genus _Pectispongilla_ is
+only known from the Malabar Zone. Among the polyzoa the genus
+_Fredericella_[D] appears to be confined, so far as the Indian and
+Burmese fauna is concerned, to the Malabar Zone, and the same is true as
+regards the group of species to which _Plumatella tanganyik�_, an
+African form, belongs.
+
+     [Footnote D: Mr. S. W. Kemp recently obtained at Mangaldai,
+     near the Bhutan frontier of Assam, a single specimen of what
+     may be a species of _Fredericella_.]
+
+A further examination of the list of Malabar species and a consideration
+of allied forms shows that the majority of the forms restricted to the
+Malabar Zone are either African or else closely allied to African forms.
+The genus _Corvospongilla_, except for one Burmese species, is otherwise
+peculiar to Tropical Africa; while _Stratospongilla_, although not
+confined to Africa, is more prolific in species in that continent than
+in any other. _Spongilla (Stratospongilla) bombayensis_ has only been
+found in Bombay, the Western Ghats, Mysore, and Natal, and _Plumatella
+tanganyik�_ only in the Western Ghats and Central Africa. The genus
+_Fredericella_ (which also occurs in Europe, N. America, and Australia)
+is apparently of wide distribution in Africa, while _Lophopodella_
+(which in India is not confined to the Malabar Zone) is, except for a
+Japanese race of the Indian species, restricted outside India, so far as
+we know, to East Africa.
+
+A less definite relationship between the sponges and polyzoa of the
+Malabar Zone and those of countries to the east of India is suggested by
+the following facts:--
+
+     (1) The occurrence of the genus _Corvospongilla_ in Burma;
+
+     (2) the occurrence of the subgenus _Stratospongilla_ in
+     Sumatra, China, and the Philippines;
+
+     (3) the occurrence of a race of _Lophopodella carteri_ in
+     Japan;
+
+     (4) the occurrence of a species allied to _Plumatella
+     tanganyik�_ in the Philippines.
+
+It will be noted that in each of these instances the relationship
+extends to Africa as well as to the Eastern countries, and is more
+marked in the former direction. The species of _Stratospongilla_,
+moreover, that occurs in Sumatra (_S. sumatrensis_) also occurs in
+Africa, while those that have been found in China and the Philippines
+are aberrant forms.
+
+At first sight it might appear that these extra-Indian relationships
+might be explained by supposing that gemmules and statoblasts were
+brought to the Malabar Coast from Africa by the a�rial currents of the
+monsoon or by marine currents and carried from India eastwards by the
+same agency, this agency being insufficient to transport them to the
+interior and the eastern parts of the Peninsula. The work of La
+Touche[E] on wind-borne foraminifera in Rajputana is very suggestive in
+this direction; but that the peculiar sponge and polyzoon fauna of
+Malabar is due to the agency either of wind or of marine currents may be
+denied with confidence, for it is a striking fact that most of the
+characteristic genera and subgenera of the Zone have resting
+reproductive bodies that are either fixed to solid objects or else are
+devoid of special apparatus to render them light. The former is the case
+as regards all species of _Corvospongilla_ and all Indian and most other
+species of _Stratospongilla_, the gemmules of which not only are
+unusually heavy but also adhere firmly; while the statoblasts of
+_Fredericella_ have no trace of the air-cells that render the free
+statoblasts of all other genera of phylactol�matous polyzoa peculiarly
+light and therefore peculiarly liable to be transported by wind.
+
+     [Footnote E: See Mem. Geol. Surv. Ind. XXXV (1), p. 39
+     (1902).]
+
+A true geographical or geological explanation must therefore be sought
+for the relationship between the sponges and polyzoa of Malabar, of
+Africa, and of the Eastern countries--a relationship that is well known
+to exist as regards other groups of animals. No more satisfactory
+explanation has as yet been put forward than that of a former land
+connection between Africa and the Malaysia through Malabar at a period
+(probably late Cretaceous) when the Western Ghats were much higher than
+they now are[F].
+
+     [Footnote F: See Ortmann, "The Geographical Distribution of
+     Freshwater Decapods and its bearing upon Ancient Geography,"
+     Proc. Amer. Phil. Soc. xli, p. 380, fig. 6 (1902); also
+     Suess, "The Face of the Earth" (English ed.) i, p. 416
+     (1904).]
+
+There is little to be said as regards the distribution of the sponges,
+hydroids, and polyzoa of fresh water in other parts of India. It may be
+noted, however, that the species known from the Punjab are all widely
+distributed Pal�arctic forms, and that the genus _Stolella_ is
+apparently confined to the Indo-Gangetic Plain. Two species of sponge
+are peculiar to Lower Burma, one of them (_Corvospongilla burmanica_)
+representing the geographical alliance already discussed as regards the
+Malabar Zone, the other (_Tubella vesparioides_) closely related to a
+Malaysian species (_T. vesparium_ from Borneo) and perhaps representing
+the northern limit of the Malaysian element well known in the fauna of
+Lower Burma. Of the sponges and polyzoa of Ceylon we know as yet too
+little to make it profitable to discuss their affinities. All that have
+as yet been discovered occur also in Peninsular India; nor do they
+afford any evidence of a connection with the Malabar Zone.
+
+The question of the geographical range of the sponges, hydroids, and
+polyzoa of brackish water may be considered briefly, for it is of
+importance in considering that of those which are confined to fresh
+water. Some of these species from brackish water (e. g., _Membranipora
+lacroixii_) are identical with others (e. g., _Victorella bengalensis_
+and _Bowerbankia caudata_ subsp. _bengalensis_) closely related to
+European forms. Others again (e. g., _Loxosomatoides colonialis_ and
+_Sagartia schilleriana_) are known as yet from the Ganges delta only. In
+our ignorance of the Indian representatives of the groups to which they
+belong, it is impossible to assert that their distribution is actually
+so restricted as it seems.
+
+
+SOME SPECIAL LOCALITIES.
+
+In order to avoid constant repetition as regards the conditions that
+prevail at the places most frequently mentioned in this volume, a few
+details as regards them may be conveniently stated here.
+
+_Lower Bengal._
+
+CALCUTTA is situated on the River Hughli at a point about 90 miles from
+the open sea. The water of the river is practically fresh, but is
+strongly affected by the tides; it is always turbid and of a brownish
+colour. The river, however, is not a good collecting ground for sponges,
+coelenterates, and polyzoa, and none of the species described in this
+volume have been obtained from it. It is in the Calcutta "tanks" that
+most of my investigations have been made. These tanks are ponds, mostly
+of artificial origin, very numerous, of varying size but never very
+large or deep. Most of them contain few solid objects to which sedentary
+organisms can fix themselves, and such ponds are of course poor in
+sponges and polyzoa. Others, however, support a prolific growth of weeds
+such as _Pistia stratiotes_, _Lemna_, and _Limnanthemum_, and a few have
+brickwork or artificial stonework at their sides. In those parts of the
+town that approach the Salt Lakes (large lagoons and swamps of brackish
+water connected with the sea by the Mutlah River) the water of the ponds
+is slightly brackish and permits few plants except alg� to flourish. Few
+of the bigger tanks ever dry up. The best of the tanks from the
+sponge-collector's point of view, so far as I have been able to
+discover, is the one in the compound of the Indian Museum. It enjoys all
+the advantages of light and shade, solid supports, prolific aquatic
+vegetation, considerable depth, and the vicinity of human dwellings that
+seem to be favourable to the growth of sponges, no less than nine
+species of which, representing three genera and two subgenera, grow
+abundantly in it. _Hydra_ also flourishes in this pond, but for some
+reasons there are few polyzoa. The phylactol�matous species of the
+latter group, however, are extraordinarily abundant in one of the tanks
+in the Zoological Gardens at Alipore. In this tank, which unlike the
+Museum tank is directly connected with the river, no less than six
+species and varieties of the genus _Plumatella_ have been found growing
+together on sticks, floating seeds, and water-plants. Except _Hislopia_,
+which is common on _Vallisneria_ in one tank on the Maidan (opposite the
+Bengal Club), the ctenostomes of stagnant water are only found in the
+tanks near the Salt Lakes.
+
+PORT CANNING is situated on the Mutlah River about 30 miles from
+Calcutta and about 60 from the open sea. The Mutlah is really a tidal
+creek rather than a river, in spite of the fact that it runs for a
+considerable number of miles, and its waters are distinctly brackish.
+Water taken from the edge at Port Canning in March was found to contain
+25.46 per thousand of saline residue. The interesting feature of Port
+Canning, however, is from a zoological point of view not the Mutlah but
+certain ponds of brackish water now completely separated from it, except
+occasionally when the river is in flood, but communicating regularly
+with it in the memory of living persons. These ponds, which were
+apparently not in existence in 1855, have on an average an area of about
+half an acre each, and were evidently formed by the excavation of earth
+for the construction of an embankment along the Mutlah. They are very
+shallow and lie exposed to the sun. The salinity differs considerably in
+different ponds, although the fauna seems to be identical; the water of
+one pond was found to contain 22.88 per thousand of saline residue in
+May, 20.22 per thousand in March, and 12.13 in December. A second pond
+in the neighbourhood of the first and apparently similar to it in every
+way contained only 9.82 per thousand in July, after the rains had
+broken. The fauna of these ponds includes not only a freshwater sponge
+(_Spongilla alba_ var. _bengalensis_) but also many aquatic insects
+(_e. g._, larv� of mosquitos and of _Chironomus_ and several species of
+beetles and Rhynchota); while on the other hand essentially marine
+coelenterates (_Irene ceylonensis_, etc.) and worms (_e. g._, the
+gephyrean _Physcosoma lurco_[G]) form a part of it, together with forms
+of intermediate habitat such as _Bowerbankia caudata_ subsp.
+_bengalensis_, _Victorella bengalensis_, and several fish and crustacea
+common in brackish water.
+
+     [Footnote G: I am indebted to Mr. W. F. Lanchester for the
+     identification of this species.]
+
+_Orissa._
+
+Orissa may be described in general terms as consisting of the coastal
+area of Bengal south of the Gangetic delta. It extends in inland,
+however, for a considerable distance and includes hilly tracts. There is
+no geographical boundary between it and the north-eastern part of the
+Madras Presidency or the eastern part of the Central Provinces.
+
+CHILKA LAKE.--This marine lake is a shallow lagoon measuring about 40
+miles in length and 10 miles in breadth, and formed in geologically
+recent times by the growth of a narrow sand-bank across the mouth of a
+wide bay. At its northern end it communicates with the sea by a narrow
+channel, and throughout its length it is strongly affected by the tides.
+At its south end, which is actually situated in the Ganjam district of
+Madras, the water is distinctly brackish and is said to be nearly fresh
+at certain times of year. At this end there are numerous small
+artificial pools of brackish water somewhat resembling those of Port
+Canning as regards their fauna.
+
+SUR (or SAR) LAKE.--A shallow, freshwater lake of very variable size
+situated a few miles north of Puri on the Orissa coast. In origin it
+probably resembled the Chilka Lake, but it is now separated from the sea
+by about 3 miles of barren sand dunes, among which numerous little pools
+of rain-water are formed during the rains. These dry up completely in
+winter, and even the lake itself is said sometimes almost to disappear,
+although when it is full it is several miles in length. The fauna is
+essentially a freshwater one, but includes certain Mysid� and other
+crustacea usually found in brackish water.
+
+_Bombay Presidency._
+
+BOMBAY.--The town of Bombay, built on an island near the mainland, is
+situated close to swamps and creeks of brackish water not unlike those
+that surround Calcutta. Its "tanks," however, differ from those of
+Calcutta in having rocky bottoms and, in many cases, in drying up
+completely in the hot weather. Of the fauna of the swamps extremely
+little is known, but so far as the sponges and polyzoa of the tanks are
+concerned the work undertaken by Carter was probably exhaustive.
+
+IGATPURI.--Igatpuri is situated at an altitude of about 2000 feet, 60
+miles north-east of Bombay. Above the town there is a lake of several
+square miles in area whence the water-supply of several stations in the
+neighbourhood is obtained. The water is therefore kept free from
+contamination. The bottom is composed of small stones and slopes
+gradually up at the edges. During the dry weather its level sinks
+considerably. Several interesting sponges and polyzoa have been found in
+this lake, most of them also occurring in a small pond in the
+neighbourhood in which clothes are washed and the water is often full of
+soap-suds.
+
+_Southern India._
+
+MADRAS.--The city of Madras is built by the sea, straggling over a large
+area of the sandy soil characteristic of the greater part of the east
+coast of India. In wet weather this soil retains many temporary pools of
+rain-water, and there are numerous permanent tanks of no great size in
+the neighbourhood of the town. The so-called Cooum River, which flows
+through the town, is little more than a tidal creek, resembling the
+Mutlah River of Lower Bengal on a much smaller scale. The sponges and
+polyzoa as yet found in the environs of Madras are identical with those
+found in the environs of Calcutta.
+
+BANGALORE.--Bangalore (Mysore State) is situated near the centre of the
+Madras Presidency on a plateau about 3000 feet above sea-level. The
+surrounding country is formed of laterite rock which decomposes readily
+and forms a fine reddish silt in the tanks. These tanks are numerous,
+often of large size, and as a rule at least partly of artificial origin.
+Their water supports few phanerogamic plants and is, as my friend Dr.
+Morris Travers informs me, remarkably free from salts in solution. The
+sponge fauna of the neighbourhood of Bangalore appears to be
+intermediate between that of Madras and that of Travancore.
+
+THE BACKWATERS OF COCHIN AND TRAVANCORE.--The "backwaters" of Cochin and
+Travancore were originally a series of shallow lagoons stretching along
+the coast of the southern part of the west coast of India for a distance
+of considerably over a hundred miles. They have now been joined together
+by means of canals and tunnels to form a tidal waterway, which
+communicates at many points directly with the sea. The salinity of the
+water differs greatly at different places and in different seasons, and
+at some places there is an arrangement to keep out sea-water while the
+rice-fields are being irrigated. The fauna is mainly marine, but in the
+less saline parts of the canals and lakes many freshwater species are
+found.
+
+_Shasthancottah._--There are two villages of this name, one situated on
+the backwater near Quilon (coast of Travancore), the other about three
+miles inland on a large freshwater lake. This lake, which does not
+communicate with the backwater, occupies a narrow winding rift several
+miles in length at a considerable depth below the surrounding country.
+Its bottom is muddy and it contains few water-plants, although in some
+places the water-plants that do exist are matted together to form
+floating islands on which trees and bushes grow. The fauna, at any rate
+as regards mollusca and microscopic organisms, is remarkably poor, but
+two species of polyzoa (_Fredericella indica_ and _Plumatella
+fruticosa_) and one of sponge (_Trochospongilla pennsylvanica_) grow in
+considerable abundance although not in great luxuriance.
+
+_The Himalayas._
+
+BHIM TAL[H] is a lake situated at an altitude of 4500 feet in that part
+of the Western Himalayas known as Kumaon, near the plains. It has a
+superficial area of several square miles, and is deep in the middle. Its
+bottom and banks are for the most part muddy. Little is known of its
+fauna, but two polyzoa (_Plumatella allmani_ and _Lophopodella carteri_)
+and the gemmules of two sponges (_Spongilla carteri_ and _Ephydatia
+meyeni_) have been found in it.
+
+     [Footnote H: The fauna of this lake and of others in the
+     neighbourhood has recently been investigated by Mr. S. W.
+     Kemp. See the addenda at the end of this volume.--_June
+     1911._]
+
+       *     *     *     *     *
+
+NOMENCLATURE AND TERMINOLOGY.
+
+The subject of nomenclature may be considered under four heads:--(I.)
+the general terminology of the various kinds of groups of individuals
+into which organisms must be divided; (II.) the general nomenclature of
+specimens belonging to particular categories, such as types, co-types,
+etc.; (III.) the nomenclature that depends on such questions as that of
+"priority"; and (IV.) the special terminology peculiar to the different
+groups. The special terminology peculiar to the different groups is
+dealt with in the separate introductions to each of the three parts of
+this volume.
+
+
+(I.)
+
+No group of animals offers greater difficulty than the sponges,
+hydroids, and polyzoa (and especially the freshwater representatives of
+these three groups) as regards the question "What is a species?" and the
+kindred questions, "What is a subspecies?" "What is a variety?" and
+"What is a phase?" Genera can often be left to look after themselves,
+but the specific and kindred questions are answered in so many different
+ways, if they are even considered, by different systematists, especially
+as regards the groups described in this volume, that I feel it necessary
+to state concisely my own answers to these questions, not for the
+guidance of other zoologists but merely to render intelligible the
+system of classification here adopted. The following definitions should
+therefore be considered in estimating the value of "species," etc.,
+referred to in the following pages.
+
+_Species._--A group of individuals differing in constant characters of a
+definite nature and of systematic[I] importance from all others in the
+same genus.
+
+     [Footnote I: "What characters are of systematic importance?"
+     is a question to which different answers must be given in
+     the case of different groups.]
+
+_Subspecies._--An isolated or local race, the individuals of which
+differ from others included in the same species in characters that are
+constant but either somewhat indefinite or else of little systematic
+importance.
+
+_Variety._--A group of individuals not isolated geographically from
+others of the same species but nevertheless exhibiting slight, not
+altogether constant, or indefinite differences from the typical form of
+the species (_i. e._, the form first described).
+
+_Phase._--A peculiar form assumed by the individuals of a species which
+are exposed to peculiarities in environment and differ from normal
+individuals as a direct result.
+
+There are cases in which imperfection of information renders it
+difficult or impossible to distinguish between a variety and a
+subspecies. In such cases it is best to call the form a variety, for
+this term does not imply any special knowledge as regards its
+distribution or the conditions in which it is found.
+
+I use the term "form" in a general sense of which the meaning or
+meanings are clear without explanation.
+
+
+(II.)
+
+The question of type specimens must be considered briefly. There are two
+schools of systematists, those who assert that one specimen and one only
+must be the type of a species, and those who are willing to accept
+several specimens as types. From the theoretical point of view it seems
+impossible to set up any one individual as the ideal type of a species,
+but those who possess collections or are in charge of museums prefer,
+with the natural instinct of the collector, to have a definite single
+type (of which no one else can possibly possess a duplicate) in their
+possession or care, and there is always the difficulty that a zoologist
+in describing a species, if he recognizes more than one type, may
+include as types specimens that really belong to more than one species.
+These difficulties are met by some zoologists by the recognition of
+several specimens as paratypes, all of equal value; but this, after all,
+is merely a terminological means of escaping from the difficulty,
+calculated to salve the conscience of a collector who feels unwilling to
+give up the unique type of a species represented by other specimens in
+his collection. The difficulty as regards the confounding of specimens
+of two or more species as the types of one can always be adjusted if the
+author who discovers the mistake redescribes one of the species under
+the original name and regards the specimen that agrees with his
+description as the type, at the same time describing a new species with
+another of the specimens as its type. Personally I always desire to
+regard the whole material that forms the basis of an original
+description of a species as the type, but museum rules often render this
+impossible, and the best that can be done is to pick out one specimen
+that seems particularly characteristic and to call it the type, the rest
+of the material being termed co-types. A peculiar difficulty arises,
+however, as regards many of the sponges, coelenterates, and polyzoa,
+owing to the fact that they are often either compound animals, each
+specimen consisting of more than one individual, or are easily divisible
+into equivalent fragments. If the single type theory were driven to its
+logical conclusion, it would be necessary to select one particular polyp
+in a hydroid colony, or even the part of a sponge that surrounded a
+particular osculum as the type of the species to which the hydroid or
+the sponge belonged. Either by accident or by design specimens of
+Spongillid�, especially if kept dry, are usually broken into several
+pieces. There is, as a matter of fact, no reason to attribute the
+peculiarly sacrosanct nature of a type to one piece more than another.
+In such cases the biggest piece may be called the type, while the
+smaller pieces may be designated by the term "schizotype."
+
+The more precise definition of such terms as topotype, genotype, _et
+hujus generis omnis_ is nowadays a science (or at any rate a form of
+technical industry) by itself and need not be discussed here.
+
+
+(III.)
+
+In 1908 an influential committee of British zoologists drew up a
+strenuous protest against the unearthing of obsolete zoological names
+(see 'Nature,' Aug. 1908, p. 395). To no group does this protest apply
+with greater force than to the three discussed in this volume. It is
+difficult, however, to adopt any one work as a standard of nomenclature
+for the whole of any one of them. As regards the Spongillid� it is
+impossible to accept any monograph earlier than Potts's "Fresh-Water
+Sponges" (P. Ac. Philad., 1887), for Bowerbank's and Carter's earlier
+monographs contained descriptions of comparatively few species. Even
+Potts's monograph I have been unable to follow without divergence, for
+it seems to me necessary to recognize several genera and subgenera that
+he ignored. The freshwater polyzoa, however, were dealt with in so
+comprehensive a manner by Allman in his "Fresh-Water Polyzoa" (London,
+1856) that no difficulty is experienced in ignoring, so far as
+nomenclature is concerned, any earlier work on the group; while as
+regards other divisions of the polyzoa I have followed Hincks's "British
+Marine Polyzoa" (1880), so far as recent researches permit. In most
+cases I have not attempted to work out an elaborate synonymy of species
+described earlier than the publication of the works just cited, for to
+do so is a mere waste of time in the case of animals that call for a
+most precise definition of species and genera and yet were often
+described, so far as they were known earlier than the dates in question,
+in quite general terms. I have been confirmed in adopting this course by
+the fact that few of the types of the earlier species are now in
+existence, and that a large proportion of the Indian forms have only
+been described within the last few years.
+
+
+MATERIAL.
+
+The descriptions in this volume are based on specimens in the collection
+of the Indian Museum, the Trustees of which, by the liberal manner in
+which they have permitted me to travel in India and Burma on behalf of
+the Museum, have made it possible not only to obtain material for study
+and exchange but also to observe the different species in their natural
+environment. This does not mean to say that specimens from other
+collections have been ignored, for many institutions and individuals
+have met us generously in the matter of gifts and exchanges, and our
+collection now includes specimens of all the Indian forms, named in
+nearly all cases by the author of the species, except in those of
+species described long ago of which no authentic original specimens can
+now be traced. Pieces of the types of all of the Indian Spongillid�
+described by Carter have been obtained from the British Museum through
+the kind offices of Mr. R. Kirkpatrick. The Smithsonian Institution has
+sent us from the collection of the United States National Museum
+specimens named by Potts, and the Berlin Museum specimens named by
+Weltner, while to the Imperial Academy of Sciences of St. Petersburg we
+owe many unnamed but interesting sponges. Dr. K. Kraepelin and Dr. W.
+Michaelsen have presented us with specimens of most of the species and
+varieties of freshwater polyzoa described by the former in his great
+monograph and elsewhere. We owe to Dr. S. F. Harmer, formerly of the
+Cambridge University Museum and now Keeper in Zoology at the British
+Museum, to Professor Max Weber of Amsterdam, Professor Oka of Tokyo, and
+several other zoologists much valuable material. I would specially
+mention the exquisite preparations presented by Mr. C. Rousselet.
+Several naturalists in India have also done good service to the Museum
+by presenting specimens of the three groups described in this volume,
+especially Major H. J. Walton, I.M.S., Major J. Stephenson, I.M.S., Dr.
+J. R. Henderson and Mr. G. Matthai of Madras, and Mr. R. Shunkara
+Narayana Pillay of Trivandrum.
+
+The following list shows where the types of the various species,
+subspecies, and varieties are preserved, so far as it has been possible
+to trace them. I have included in this list the names of all species
+that have been found in stagnant water, whether fresh or brackish, but
+those of species not yet found in fresh water are enclosed in square
+brackets.
+
++-----------------------------------------------------------------------+
+|                       INDIAN SPONGILLID�.                             |
+|                                                                       |
++---------------------------------+----------------------+--------------+
+|         NAME.                   |   TYPE IN COLL.      |  MATERIAL    |
+|                                 |                      |  EXAMINED.   |
++---------------------------------+----------------------+--------------+
+| _Spongilla lacustris_ subsp.    | Ind. Mus.            |    Type.     |
+| _reticulata_                    |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla proliferens_         |   "   "              |       "      |
++---------------------------------+----------------------+--------------+
+| _Spongilla alba_                | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| [_Spongilla alba_ var.          | Ind. Mus.            |     Type     |
+| _bengalensis_]                  |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla alba_ var.           | Brit. Mus.           | {Specimens   |
+| _cerebellata_                   |                      | {compared    |
+|                                 |                      | {with type.  |
++---------------------------------+----------------------+--------------+
+| _Spongilla cinerea_             | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| [_Spongilla travancorica_]      | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Spongilla hemephydatia_        |   "     "            |      "       |
++---------------------------------+----------------------+--------------+
+| _Spongilla crateriformis_       | U.S. Nat. Mus.       |   Co-type.   |
++---------------------------------+----------------------+--------------+
+| _Spongilla carteri_             | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| _Spongilla carteri_ var.        | Ind. Mus.            |    Type.     |
+| _mollis_                        |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla carteri_ var.        |  "     "             |      "       |
+| _cava_                          |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla carteri_ var.        |  "     "             |      "       |
+| _lobosa_                        |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla fragilis_ subsp.     |  "     "             |      "       |
+| _calcuttana_                    |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla fragilis_ subsp.     | Amsterdam Mus.       |   Co-type.   |
+| _decipiens_                     |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla gemina_              | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Spongilla crassissima_         |  "     "             |      "       |
++---------------------------------+----------------------+--------------+
+| _Spongilla crassissima_ var.    |  "     "             |      "       |
+| _crassior_                      |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla bombayensis_         | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| _Spongilla indica_              | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Spongilla ultima_              |  "    "              |      "       |
++---------------------------------+----------------------+--------------+
+| _Pectispongilla aurea_          |  "    "              |      "       |
++---------------------------------+----------------------+--------------+
+| _Ephydatia meyeni_              | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| _Dosilia plumosa_               |  "   "  "   "        |      "       |
++---------------------------------+----------------------+--------------+
+| _Trochospongilla latouchiana_   | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Trochospongilla phillottiana_  |  "    "              |      "       |
++---------------------------------+----------------------+--------------+
+| _Trochospongilla pennsylvanica_ | U.S. Nat. Mus.       |   Co-type.   |
++---------------------------------+----------------------+--------------+
+| _Tubella vesparioides_          | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Corvospongilla burmanica_      | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| _Corvospongilla lapidosa_       | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+|               INDIAN COELENTERATES OF STAGNANT WATER.                 |
++---------------------------------+----------------------+--------------+
+|          HYDROZOA.              |                      |              |
++---------------------------------+----------------------+--------------+
+| _Hydra oligactis_               | Not in existence.    |              |
++---------------------------------+----------------------+--------------+
+| _Hydra vulgaris_                |  "    "              |              |
++---------------------------------+----------------------+--------------+
+| [_Syncoryne filamentata_]       | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| [_Bimeria vestita_]             | ? Not in existence.  |              |
++---------------------------------+----------------------+--------------+
+| [_Irene ceylonensis_]           |  {Hydroid in Ind.}   | Hydroid type |
+|                                 |  {Mus.,  Medusa}     |              |
+|                                 |  {in Brit. Mus.}     |              |
++---------------------------------+----------------------+--------------+
+|         ACTINIARIA.             |                      |              |
++---------------------------------+----------------------+--------------+
+| [_Sagartia schilleriana_]       | Ind. Mus.            |    Types.    |
++---------------------------------+----------------------+--------------+
+| [_Sagartia schilleriana_        |  "    "              |      "       |
+| subsp. _exul_]                  |                      |              |
++---------------------------------+----------------------+--------------+
+|                   INDIAN POLYZOA OF STAGNANT WATER.                   |
++---------------------------------+----------------------+--------------+
+|       ENTOPROCTA.               |                      |              |
++---------------------------------+----------------------+--------------+
+| [_Loxosomatoides colonialis_]   | Ind. Mus.            |    Types.    |
++---------------------------------+----------------------+--------------+
+|   ECTOPROCTA CHEILOSTOMATA.     |                      |              |
++---------------------------------+----------------------+--------------+
+| [_Membranipora lacroixii_]      | ? Paris Mus.         |              |
++---------------------------------+----------------------+--------------+
+| [_Membranipora bengalensis_]    | Ind. Mus.            |    Types.    |
++---------------------------------+----------------------+--------------+
+|   ECTOPROCTA STENOSTOMATA.      |                      |              |
++---------------------------------+----------------------+--------------+
+| [_Bowerbankia caudata_ subsp.   | Ind. Mus.            |    Types.    |
+| _bengalensis_]                  |                      |              |
++---------------------------------+----------------------+--------------+
+| _Victorella bengalensis_        |  "    "              |      "       |
++---------------------------------+----------------------+--------------+
+| _Hislopia lacustris_            | ? Not in existence.  |              |
++---------------------------------+----------------------+--------------+
+| _Hislopia lacustris_ subsp.     | Ind. Mus.            |      "       |
+| _moniliformis_                  |                      |              |
++---------------------------------+----------------------+--------------+
+|   ECTOPROCTA PHYLACTOL�MATA.    |                      |              |
++---------------------------------+----------------------+--------------+
+| _Fredericella indica_           | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Plumatella fruticosa_          | Not in existence.    |              |
++---------------------------------+----------------------+--------------+
+| _Plumatella diffusa_            |?Philadelphia Acad.[J]|              |
++---------------------------------+----------------------+--------------+
+| _Plumatella allmani_            | Not in existence.    |              |
++---------------------------------+----------------------+--------------+
+| _Plumatella emarginata_         |  "        "          |              |
++---------------------------------+----------------------+--------------+
+|                                 | {Hamburg and}        | One of the   |
+| _Plumatella javanica_           | {Ind.  Mus. }        | types.       |
++---------------------------------+----------------------+--------------+
+|                                 | {Brit. and Ind.}     | One of the   |
+| _Plumatella tanganyik�_         | {Mus.          }     | types.       |
++---------------------------------+----------------------+--------------+
+| _Stolella indica_               | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Lophopodella carteri_          | Brit. Mus.           |      "       |
++---------------------------------+----------------------+--------------+
+| _Lophopodella carteri_ var.     | Ind. Mus.            |      "       |
+| _himalayana_                    |                      |              |
++---------------------------------+----------------------+--------------+
+| _Pectinatella burmanica_        | Ind. Mus.            |       "      |
++---------------------------------+----------------------+--------------+
+
+     [Footnote J: I have failed to obtain from the Philadelphia
+     Academy of Science a statement that the type of this species
+     is still in existence.]
+
+
+The literature dealing with the various groups described in the volume
+is discussed in the introductions to the three parts. Throughout the
+volume I have, so far as possible, referred to works that can be
+consulted in Calcutta in the libraries of the Indian Museum, the
+Geological Survey of India, or the Asiatic Society of Bengal. The names
+of works that are not to be found in India are marked with a *. The
+rarity with which this mark occurs says much for the fortunate position
+in which zoologists stationed in Calcutta find themselves as regards
+zoological literature, for I do not think that anything essential has
+been omitted.
+
+It remains for me to express my gratitude to those who have assisted me
+in the preparation of this volume. The names of those who have
+contributed specimens for examination have already been mentioned. I
+have to thank the Trustees of the Indian Museum not only for their
+liberal interpretation of my duties as an officer of the Museum but also
+for the use of all the drawings and photographs and some of the blocks
+from which this volume is illustrated. Several of the latter have
+already been used in the "Records of the Indian Museum." From the Editor
+of the "Fauna" I have received valuable suggestions, and I am indebted
+to Dr. Weltner of the Berlin Museum for no less valuable references to
+literature. Mr. F. H. Gravely, Assistant Superintendent in the Indian
+Museum, has saved me from several errors by his criticism.
+
+The majority of the figures have been drawn by the draftsmen of the
+Indian Museum, Babu Abhoya Charan Chowdhary, and of the Marine Survey of
+India, Babu Shib Chandra Mondul, to both of whom I am much indebted for
+their accuracy of delineation.
+
+No work dealing with the sponges of India would be complete without a
+tribute to the memory of H. J. Carter, pioneer in the East of the study
+of lower invertebrates, whose work persists as a guide and an
+encouragement to all of us who are of the opinion that biological
+research on Indian animals can only be undertaken in India, and that
+even systematic zoological work can be carried out in that country with
+success. I can only hope that this, the first volume in the official
+Fauna of the Indian Empire to be written entirely in India, may prove
+not unworthy of his example.
+
+Indian Museum, Calcutta      Oct. 23rd, 1910.
+
+
+
+
+PART I.
+
+FRESHWATER SPONGES
+
+(SPONGILLID�).
+
+
+
+
+INTRODUCTION TO PART I.
+
+
+I.
+
+THE PHYLUM PORIFERA.
+
+The phylum Porifera or Spongi� includes the simplest of the Metazoa or
+multicellular animals. From the compound Protozoa its members are
+distinguished by the fact that the cells of which they are composed
+exhibit considerable differentiation both in structure and in function,
+and are associated together in a definite manner, although they are not
+combined to form organs and systems of organs as in the higher Metazoa.
+Digestion, for instance, is performed in the sponges entirely by
+individual cells, into the substance of which the food is taken, and the
+products of digestion are handed on to other cells without the
+intervention of an alimentary canal or a vascular system, while there is
+no structure in any way comparable to the nervous system of more highly
+organized animals.
+
+The simplest form of sponge, which is known as an olynthus, is a hollow
+vase-like body fixed at one end to some solid object, and with an
+opening called the osculum at the other. The walls are perforated by
+small holes, the pores, from which the name Porifera is derived.
+
+Externally the surface is protected by a delicate membrane formed of
+flattened cells and pierced by the pores, while the interior of the vase
+is covered with curious cells characteristic of the sponges, and known
+as choanocytes or collar-cells. They consist of minute oval or
+pear-shaped bodies, one end of which is provided with a rim or collar of
+apparently structureless membrane, while a flagellum or whip-like lash
+projects from the centre of the surface surrounded by the collar. These
+collar-cells are practically identical with those of which the Protozoa
+known as Choanoflagellata consist; but it is only in the sponges[K] that
+they are found constantly associated with other cells unlike themselves.
+
+     [Footnote K: Except in "_Proterospongia_," an organism of
+     doubtful affinities but not a sponge. It consists of a mass
+     of jelly containing ordinary cells, with collar-cells
+     _outside_.]
+
+In addition to the collar-cells, which form what is called the gastral
+layer, and the external membrane (the derma or dermal membrane), the
+sponge contains cells of various kinds embedded in a structureless
+gelatinous substance, through which they have the power of free
+movement. Most of these cells have also the power of changing their form
+in an "amoeboid" manner; that is to say, by projecting and withdrawing
+from their margin mobile processes of a more or less finger-like form,
+but unstable in shape or direction. The protoplasm of which some of the
+cells are formed is granular, while that of others is clear and
+translucent. Some cells, which (for the time being at any rate) do not
+exhibit amoeboid movements, are glandular in function, while others
+again give rise in various ways to the bodies by means of which the
+sponge reproduces its kind. There is evidence, however, that any one
+kind of cell, even those of the membrane and the gastral layer, can
+change its function and its form in case of necessity.
+
+Most sponges possess a supporting framework or skeleton. In some it is
+formed entirely of a horny substance called spongin (as in the
+bath-sponge), in others it consists of spicules of inorganic matter
+(either calcareous or siliceous) secreted by special cells, or of such
+spicules bound together by spongin. Extraneous objects, such as
+sand-grains, are frequently included in the skeleton. The spongin is
+secreted like the spicules by special cells, but its chemical structure
+is much more complicated than that of the spicules, and it is not
+secreted (at any rate in most cases) in such a way as to form bodies of
+a definite shape. In the so-called horny sponges it resembles the chitin
+in which insects and other arthropods are clothed.
+
+       *     *     *     *     *
+
+In no adult sponge do the collar-cells completely cover the whole of the
+internal surface, the olynthus being a larval form, and by no means a
+common larval form. It is only found in certain sponges with calcareous
+spicules. As the structure of the sponge becomes more complicated the
+collar-cells are tucked away into special pockets or chambers known as
+ciliated chambers, and finally the approach to these chambers, both from
+the external surface and from the inner or gastral cavity, takes the
+form of narrow tubes or canals instead of mere pores. With further
+complexity the simple internal cavity tends to disappear, and the sponge
+proliferates in such a way that more than one osculum is formed. In the
+class Demospongi�, to which the sponges described in this volume belong,
+the whole system is extremely complicated.
+
+The skeleton of sponges, when it is not composed wholly of spongin,
+consists of, or at any rate contains, spicules that have a definite
+chemical composition and definite shapes in accordance with the class,
+order, family, genus, and species of the sponge. Formerly sponges were
+separated into calcareous, siliceous, and horny sponges by the nature of
+their skeleton; and although the system of classification now adopted
+has developed into a much more complex one and a few sponges are known
+that have both calcareous and siliceous spicules, the question whether
+the spicules are formed of salts of lime or of silica (strictly speaking
+of opal) is very important. All Demospongi� that have spicules at all
+have them of the latter substance, and the grade Monaxonida, in which
+the freshwater sponges constitute the family Spongillid�, is
+characterized by the possession of spicules that have typically the form
+of a needle pointed at both ends. Although spicules of this simple form
+may be absent in species that belong to the grade, the larger spicules,
+which are called megascleres, have not normally more than one main axis
+and are always more or less rod-like in outline. They are usually
+arranged so as to form a reticulate skeleton. Frequently, however, the
+megascleres or skeleton-spicules are not the only spicules present, for
+we find smaller spicules (microscleres) of one or more kinds lying loose
+in the substance of the sponge and in the external membrane, or, in the
+Spongillid� only, forming a special armature for the reproductive bodies
+known as gemmules.
+
+All sponges obtain their food in the same way, namely by means of the
+currents of water set up by the flagella of the collar-cells. These
+flagella, although apparently there is little concerted action among
+them, cause by their rapid movements changes of pressure in the water
+contained in the cavities of the sponge. The water from outside
+therefore flows in at the pores and finally makes its way out of the
+oscula. With the water minute particles of organic matter are brought
+into the sponge, the collar-cells of which, and probably other cells,
+have the power of selecting and engulfing suitable particles. Inside the
+cells these particles undergo certain chemical changes, and are at least
+partially digested. The resulting substances are then handed on directly
+to other cells, or, as some assert, are discharged into the common
+jelly, whence they are taken up by other cells.
+
+Sponges reproduce their kind in more ways than one, _viz._, by means of
+eggs (which are fertilized as in other animals by spermatozoa), by means
+of buds, and by means of the peculiar bodies called gemmules the
+structure and origin of which is discussed below (p. 42). They are of
+great importance in the classification of the Spongillid�. Sponges can
+also be propagated artificially by means of fission, and it is probable
+that this method of reproduction occurs accidentally, if not normally,
+in natural circumstances.
+
+
+GENERAL STRUCTURE OF THE SPONGILLID�.
+
+It would be impracticable in this introduction to give a full account of
+the structure of the Spongillid�, which in some respects is still
+imperfectly known. Students who desire further information should
+consult Professor Minchin's account of the sponges in Lankester's
+'Treatise on Zoology,' part ii, or, if a less technical description is
+desired, Miss Sollas's contribution to the 'Cambridge Natural History,'
+vol. i, in which special attention is paid to _Spongilla_.
+
+The diagram reproduced in fig. 1 gives a schematic view of a vertical
+section through a living freshwater sponge. Although it represents the
+structure of the organism as being very much simpler than is actually
+the case, and entirely omits the skeleton, it will be found useful as
+indicating the main features of the anatomy.
+
+[Illustration: Fig. 1.--Diagram of a vertical section through a
+freshwater sponge (_modified from K�kenthal_).
+
+A=pores; B=subdermal cavity; C=inhalent canal; D=ciliated chamber;
+E=exhalent canal; F=osculum; G=dermal membrane; H=eggs; J=gemmule.]
+
+It will be noted that the diagram represents an individual with a single
+osculum or exhalent aperture. As a rule adult Demospongi� have several
+or many oscula, but even in the Spongillid� sponges occur in which there
+is only one. New oscula are formed by a kind of proliferation that
+renders the structure still more complex than it is when only one
+exhalent aperture is present.
+
+The little arrows in the figure indicate the direction of the currents
+of water that pass through the sponge. It enters through small holes in
+the derma into a subdermal cavity, which separates the membrane from the
+bulk of the sponge. This space differs greatly in extent in different
+species. From the subdermal space the water is forced by the action of
+the flagella into narrow tubular canals that carry it into the ciliated
+chambers. Thence it passes into other canals, which communicate with
+what remains of the central cavity, and so out of the oscula.
+
+The ciliated chambers are very minute, and the collar-cells excessively
+so. It is very difficult to examine them owing to their small size and
+delicate structure. Fig. 2 D represents a collar-cell of a sponge seen
+under a very high power of the microscope in ideal conditions.
+
+[Illustration: Fig. 2.--Sponge cells.
+
+A=bubble-cells of _Ephydatia m�lleri_, � 350 (_after Weltner_).
+B=gemmule-cell of _Spongilla lacustris_ containing green corpuscles
+(shaded dark), � 800 (_after Weltner_). C=gemmule-cell of _Ephydatia
+blembingia_ showing "tabloids" of food-material, � 1150 (_after Evans_).
+D=collar-cell of _Esperella �gagrophila_, � 1600 (_after Vosmaer and
+Pekelharing_). E=three stages in the development of a gemmule-spicule of
+_E. blembingia_ (_after Evans_), � 665. F=outline of porocytes of _S.
+proliferens_, � ca. 1290: _e_=dermal cell; _n_=nucleus; _p_=pore;
+_p.c._=pore-cell.]
+
+The nature of the inhalent apertures in the external membrane has been
+much discussed as regards the Demospongi�, but the truth seems to be
+that their structure differs considerably even in closely allied
+species. At any rate this is the case as regards the Indian _Spongill�_.
+In all species the membrane is composed of flattened cells of irregular
+shape fitted together like the pieces of a puzzle-picture. In some
+species (e. g., _Spongilla carteri_) the apertures in the membrane
+consist merely of spaces between adjacent cells, which may be a little
+more crowded together than is usual. But in others (e. g., _Spongilla
+proliferens_ and _Spongilla crassissima_) in which the pores are
+extremely small, each pore normally pierces the middle of a flat,
+ring-shaped cell or porocyte. Occasionally, however, a pore may be found
+that is enclosed by two narrow, crescent-shaped cells joined together at
+their tips to form a ring. The porocytes of sponges like _Spongilla
+carteri_ are probably not actually missing, but instead of being in the
+external membrane are situated below the derma at the external entrance
+to the canals that carry water to the flagellated chambers or even at
+the entrance to the chambers themselves[L]. Some authors object on
+theoretical grounds to the statement that porocytes exist in the
+Demospongia, and it is possible that these cells have in this grade
+neither the same origin as, nor a precisely similar function to, the
+porocytes of other sponges. When they occur in the dermal membrane no
+great difficulty is experienced in seeing them under a sufficiently high
+power of the microscope, if the material is well preserved and mounted
+and stained in a suitable manner[M]. In most sponges the porocytes can
+contract in such a way that the aperture in their centre is practically
+closed, but this power appears to be possessed by the porocytes of
+_Spongilla_ only to a very limited extent, although they closely
+resemble the porocytes of other sponges in appearance.
+
+     [Footnote L: _Cf._ Weltner, "Spongillidenstudien, V," Arch.
+     Naturg. Berlin, lxxiii (i), p. 273 (1907).]
+
+     [Footnote M: It is difficult to see any trace of them in
+     thin microtome sections. A fragment of the membrane must be
+     mounted whole.]
+
+The external membrane in many Spongillid� is prolonged round and above
+the oscula so as to form an oscular collar. This structure is highly
+contractile, but cannot close together. As a rule it is much more
+conspicuous in living sponges than in preserved specimens.
+
+It is not necessary to deal here with most of the cells that
+occur in the parenchyma or gelatinous part of the sponge. A full
+list of the kinds that are found is given by Dr. Weltner in his
+"Spongillidenstudien, V," p. 276 (Arch. Naturg. Berlin, lxxiii (i),
+1907). One kind must, however, be briefly noticed as being of some
+systematic importance, namely the "bubble-cells" (fig. 2 A) that are
+characteristic of some species of _Ephydatia_ and other genera. These
+cells are comparatively large, spherical in form; each of them contains
+a globule of liquid which not only occupies the greater part of the
+cell, but forces the protoplasm to assume the form of a delicate film
+lining the cell-wall and covering the globule. In optical section
+"bubble-cells" have a certain resemblance to porocytes, but the cell is
+of course imperforate and not flattened.
+
+
+SKELETON AND SPICULES.
+
+[Illustration: Fig. 3.--Radial sections of fragments of the skeletons of
+_Spongill�_.
+
+A, _S. crassissima_ var. _crassior_ (from Rajshahi); B, _S. carteri_
+(from Calcutta); _a_=transverse, _b_=radiating fibres; _e_=external
+surface of the sponge.]
+
+In the Spongillid� the spicules and the skeleton are more important as
+regards the recognition of genera and species than the soft parts. The
+skeleton is usually reticulate, but sometimes consists of a mass of
+spicules almost without arrangement. The amount of spongin present is
+also different in different species. The spicules in a reticulate
+skeleton are arranged so as to form fibres of two kinds--radiating
+fibres, which radiate outwards from the centre of the sponge and
+frequently penetrate the external membrane, and transverse fibres, which
+run across from one radiating fibre to another. The fibres are composed
+of relatively large spicules (megascleres) arranged parallel to one
+another, overlapping at the ends, and bound together by means of a more
+or less profuse secretion of spongin. In some species they are actually
+enclosed in a sheath of this substance. The radiating fibres are usually
+more distinct and stouter than the transverse ones, which are often
+represented by single spicules but are sometimes splayed out at the ends
+so as to assume in outline the form of an hour-glass (fig. 3 B). The
+radiating fibres frequently raise up the membrane at their free
+extremities just as a tent-pole does a tent.
+
+Normal spicules of the skeleton are always rod-like or needle-like, and
+either blunt or pointed at both ends; they are either smooth, granular,
+or covered with small spines. Sometimes spicules of the same type form a
+more or less irregular transverse network at the base or on the surface
+of the sponge.
+
+[Illustration: Fig. 4.--Part of an oscular collar of _Spongilla
+lacustris_ subsp. _reticulata_, showing arrangement of microscleres in
+the derma (magnified).]
+
+From the systematist's point of view, the structure of the free spicules
+found scattered in the substance and membrane of the sponge, and
+especially of those that form the armature of the gemmules, is of more
+importance than that of the skeleton-spicules. Free spicules are absent
+in many species; when present they are usually needle-like and pointed
+at the tips. In a few species, however, they are of variable or
+irregular form, or consist of several or many shafts meeting in a common
+central nodule. In one genus (_Corvospongilla_) they resemble a double
+grappling-iron in form, having a circle of strongly recurved hooks at
+both ends. The free microscleres, or flesh-spicules as they are often
+called, are either smooth, granular, or spiny.
+
+Gemmule-spicules, which form a characteristic feature of the
+Spongillid�, are very seldom absent when the gemmules are mature. They
+are of the greatest importance in distinguishing the genera. In their
+simplest form they closely resemble the free microscleres, but in
+several genera they bear, either at or near one end or at or near both
+ends, transverse disks which are either smooth or indented round the
+edge. In one genus (_Pectispongilla_) they are provided at both ends not
+with disks but with vertically parallel rows of spines resembling combs
+in appearance.
+
+The simpler spicules of the Spongillid� are formed in single cells (see
+fig. 2 E), but those of more complicated shape are produced by several
+cells acting in concert. Each spicule, although it is formed mainly of
+hydrated silica (opal), contains a slender organic filament running
+along its main axis inside the silica. This filament, or rather the tube
+in which it is contained, is often quite conspicuous, and in some
+species (e. g., _Spongilla crassissima_) its termination is marked at
+both ends of the megasclere by a minute conical protuberance in the
+silica.
+
+Unless sponges are alchemists and can transmute one element into
+another, the material of which the spicules are made must ultimately
+come from the water in which the sponges live, or the rocks or other
+bodies to or near which they are attached. The amount of water that must
+pass through a large specimen of such a sponge as _Spongilla carteri_ in
+order that it may obtain materials for its skeleton must be enormous,
+for silica is an insoluble substance. I have noticed, however, that this
+sponge is particularly abundant and grows with special luxuriance in
+ponds in which clothes are washed with soap, and my friend Mr. G. H.
+Tipper has suggested to me that possibly the alkali contained in the
+soap-suds may assist the sponge in dissolving out the silica contained
+in the mud at the bottom of the ponds. The question of how the mineral
+matter of the skeleton is obtained is, however, one about which we know
+nothing definite.
+
+The spongin that binds the skeleton-spicules together takes the form of
+a colourless or yellowish transparent membrane, which is often
+practically invisible. When very abundant it sometimes extends across
+the nodes of the skeleton as a delicate veil. In some sponges it also
+forms a basal membrane in contact with the object to which the sponge is
+attached, and in some such cases the spongin of the radiating fibres is
+in direct continuity with that of the basal membrane.
+
+
+COLOUR AND ODOUR.
+
+Most freshwater sponges have a bad odour, which is more marked in some
+species than in others. This odour is not peculiar to the Spongillid�,
+for it is practically identical with that given out by the common marine
+sponge _Halichondria panicea_. Its function is probably protective, but
+how it is produced we do not know.
+
+The coloration of freshwater sponges is usually dull and uniform, but
+_Pectispongilla aurea_ is of the brilliant yellow indicated by its name,
+while many species are of the bright green shade characteristic of
+chlorophyll, the colouring matter of the leaves of plants. Many species
+are brown or grey, and some are almost white.
+
+These colours are due to one of three causes, or to a combination of
+more than one of them, viz.:--(1) the inhalation of solid inorganic
+particles, which are engulfed by the cells; (2) the presence in the
+cells of coloured substances, solid or liquid, produced by the vital
+activities of the sponge; and (3) the presence in the cells of peculiar
+organized living bodies known as "green corpuscles."
+
+Sponges living in muddy water are often nearly black. This is because
+the cells of their parenchyma are gorged with very minute solid
+particles of silt. If a sponge of the kind is kept in clean water for a
+few days, it often becomes almost white. An interesting experiment is
+easily performed to illustrate the absorption and final elimination of
+solid colouring matter by placing a living sponge (small specimens of
+_Spongilla carteri_ are suitable) in a glass of clean water, and
+sprinkling finely powdered carmine in the water. In a few hours the
+sponge will be of a bright pink colour, but if only a little carmine is
+used at first and no more added, it will regain its normal greyish hue
+in a few days.
+
+The colouring matter produced by the sponge itself is of two
+kinds--pigment, which is probably a waste product, and the substances
+produced directly by the ingestion of food or in the process of its
+digestion. When pigment is produced it takes the form of minute granules
+lying in the cells of the parenchyma, the dermal membrane being as a
+rule colourless. Very little is known about the pigments of freshwater
+sponges, and even less about the direct products of metabolism. It is
+apparently the latter, however, that give many otherwise colourless
+sponges a slight pinkish or yellowish tinge directly due to the presence
+in cells of the parenchyma of minute liquid globules. In one form of
+_Spongilla carteri_ these globules turn of a dark brown colour if
+treated with alcohol. The brilliant colour of _Pectispongilla aurea_ is
+due not to solid granules but to a liquid or semi-liquid substance
+contained in the cells.
+
+The green corpuscles of the Spongillid� are not present in all species.
+There is every reason to think that they represent a stage in the
+life-history of an alga, and that they enter the sponge in an active
+condition (see p. 49).
+
+A fourth cause for the coloration of freshwater sponges may be noted
+briefly. It is not a normal one, but occurs commonly in certain forms
+(e. g., _Spongilla alba_ var. _bengalensis_). This cause is the growth
+in the canals and substance of the sponge of parasitic alga�, which turn
+the whole organism of a dull green colour. They do not do so, however,
+until they have reduced it to a dying state. The commonest parasite of
+the kind is a filamentous species particularly common in brackish water
+in the Ganges delta.
+
+
+EXTERNAL FORM AND CONSISTENCY.
+
+[Illustration: Fig. 5.--Part of a type-specimen of _Spongilla lacustris_
+subsp. _reticulata_ (nat. size).]
+
+The external form of sponges is very variable, but each species,
+subspecies, or variety of the Spongillid� has normally a characteristic
+appearance. The European race of _Spongilla lacustris_, for example,
+consists in favourable circumstances of a flattened basal part from
+which long cylindrical branches grow out; while in the Indian race of
+the species these branches are flattened instead of being cylindrical,
+and anastomose freely. The structure of the branches is identical with
+that of the basal part. Many other species (for instance, _Spongilla
+bombayensis_ and _S. ultima_) never produce branches but always consist
+of lichenoid or cushion-shaped masses. The appearance of _Spongilla
+crateriformis_, when it is growing on a flattened surface which allows
+it to develop its natural form, is very characteristic, for it consists
+of little flattened masses that seem to be running out towards one
+another, just as though the sponge had been dropped, spoonful by
+spoonful, in a viscous condition from a teaspoon. Some species, such as
+_Trochospongilla phillottiana_, cover large areas with a thin film of
+uniform thickness, while others (e. g., _Spongilla alba_ and _Ephydatia
+meyeni_) consist of irregular masses, the surface of which bears
+numerous irregular ridges or conical, subquadrate, or digitate
+processes. In a few forms (e. g., _Corvospongilla burmanica_) the
+surface is covered with small turret-like projections of considerable
+regularity, and some (e. g., _Spongilla crassissima_) naturally assume a
+spherical or oval shape with an absolutely smooth surface.
+
+The production of long branches is apparently rare in tropical
+freshwater sponges.
+
+The form of the oscula is characteristic in many cases. No other Indian
+species has them so large, or with such well-defined margins as
+_Spongilla carteri_ (Pl. II, fig. 1). In many species (Pl. II, fig. 3)
+they have a stellate appearance owing to the fact that grooves in the
+substance of the sponge radiate round them beneath the external
+membrane. In other species they are quite inconspicuous and very small.
+
+[Illustration: Fig. 6.--Radial section through part of a dried sponge of
+_Spongilla crassissima_ (from Calcutta), � 5.]
+
+Spongillid� differ greatly in consistency. _Spongilla crassissima_ and
+_Corvospongilla lapidosa_ are almost stony, although the former is
+extremely light, more like pumice than true stone. Other species (e. g.,
+_Trochospongilla latouchiana_) are hard but brittle, while others again
+are soft and easily compressed, as _Spongilla lacustris_, the variety
+_mollis_ of _S. carteri_, and _S. crateriformis_. The consistency of a
+sponge depends on two factors--the number of spicules present, and the
+amount of spongin. In _Corvospongilla lapidosa_ the number of spicules
+is very large indeed. They are not arranged so as to form a reticulate
+skeleton but interlock in all directions, and there is hardly any
+spongin associated with them. In _Spongilla crassissima_, on the other
+hand, the number of spicules although large is not unusually so; but
+they form a very definitely reticulate skeleton, and are bound together
+by an unusually profuse secretion of spongin. In _S. carteri_ var.
+_mollis_ both spicules and spongin are reduced to a minimum, and the
+parenchyma is relatively more bulky than usual.
+
+
+VARIATION.
+
+Sponges are very variable organisms, and even a slight change in the
+environment of the freshwater species often produces a considerable
+change in form and structure. Some species vary in accordance with the
+season, and others without apparent cause. Not only have many given rise
+to subspecies and "varieties" that possess a certain stability, but most
+if not all are liable to smaller changes that apparently affect both the
+individual and the breed, at any rate for a period.
+
+(a) _Seasonal Variation._
+
+Weltner has shown in a recent paper (Arch. Natg. Berlin, lxxiii (i), p.
+276, 1907) that in Europe those individuals of _Ephydatia_ which are
+found (exceptionally) in an active condition in winter differ
+considerably both as regards the number of their cells and their anatomy
+from those found in summer. In Calcutta the majority of the individuals
+of _Spongilla carteri_ that are found in summer have their external
+surface unusually smooth and rounded, and contain in their parenchyma
+numerous cells the protoplasm of which is gorged with liquid. These
+cells give the whole sponge a faint pinkish tinge during life; but if it
+is plunged in spirit, both the liquid in the cells and the spirit turn
+rapidly of a dark brown colour. Specimens of _Spongilla crateriformis_
+taken in a certain tank in Calcutta during the cold weather had the
+majority of the skeleton-spicules blunt, while the extremities of the
+gemmule-spicules were distinctly differentiated. Specimens of the same
+species taken from the same tank in July had the skeleton-spicules
+pointed, while the extremities of the gemmule-spicules were much less
+clearly differentiated. I have been unable to confirm this by
+observations made on sponges from other tanks, but it would certainly
+suggest that at any rate the breed of sponges in the tank first
+investigated was liable to seasonal variation.
+
+(b) _Variation due directly to Environment._
+
+The characteristic external form of freshwater sponges is liable in most
+cases to be altered as a direct result of changes in the environment.
+The following are two characteristic instances of this phenomenon.
+
+Certain shrubs with slender stems grow in the water at the edge of
+Igatpuri Lake. The stems of these shrubs support many large examples of
+_Spongilla carteri_, which are kept in almost constant motion owing to
+the action of the wind on those parts of the shrubs that are not under
+water. The surface of the sponges is so affected by the currents of
+water thus set up against it that it is covered with deep grooves and
+high irregular ridges like cockscombs. Less than a hundred yards from
+the lake there is a small pond in which _Spongilla carteri_ is also
+abundant. Here it grows on stones at the bottom and has the
+characteristic and almost smooth form of the species.
+
+My second instance also refers in part to Igatpuri Lake. _Corvospongilla
+lapidosa_ is common in the lake on the lower surface of stones, and also
+occurs at Nasik, about thirty miles away, on the walls of a conduit of
+dirty water. In the latter situation it has the form of large sheets of
+a blackish colour, with the surface corrugated and the oscula
+inconspicuous, while in the clear waters of the lake it is of a pale
+yellowish colour, occurs in small lichenoid patches, and has its oscula
+rendered conspicuous, in spite of their minute size, by being raised on
+little conical eminences in such a way that they resemble the craters of
+volcanoes in miniature.
+
+Both the European and the Indian races of _Spongilla lacustris_ fail to
+develop branches if growing in unfavourable conditions. In specimens
+obtained from the River Spree near Berlin these structures are sometimes
+many inches in length; while in mature specimens taken under stones in
+Loch Baa in the Island of Mull the whole organism consisted of a minute
+cushion-shaped mass less than an inch in diameter, and was also
+deficient in spicules. Both these breeds belong to the same species, and
+probably differ as a direct result of differences in environment.
+
+(c) _Variation without apparent cause._
+
+Plate I in this volume illustrates an excellent example of variation in
+external form to which it is impossible to assign a cause with any
+degree of confidence. The three specimens figured were all taken in the
+same pond, and at the same season, but in different years. It is
+possible that the change in form, which was not peculiar to a few
+individuals but to all those in several adjacent ponds, was due to a
+difference in the salinity of the water brought about by a more or less
+abundant rainfall; but of this I have been able to obtain no evidence in
+succeeding years.
+
+Many Spongillid� vary without apparent cause as regards the shape, size,
+and proportions of their spicules. This is the case as regards most
+species of _Euspongilla_ and _Ephydatia_, and is a fact to which careful
+consideration has to be given in separating the species.
+
+
+NUTRITION.
+
+Very little is known about the natural food of freshwater sponges,
+except that it must be of an organic nature and must be either in a very
+finely divided or in a liquid condition. The cells of the sponge seem to
+have the power of selecting suitable food from the water that flows past
+them, and it is known that they will absorb milk. The fact that they
+engulf minute particles of silt does not prove that they lack the power
+of selection, for extraneous matter is taken up by them not only as food
+but in order that it may be eliminated. Silt would soon block up the
+canals and so put a stop to the vital activity of the sponge, if it were
+not got rid of, and presumably it is only taken into the cells in order
+that they may pass it on and finally disgorge it in such a way or in
+such a position that it may be carried out of the oscula. The siliceous
+part of it may be used in forming spicules.
+
+It is generally believed that the green corpuscles play an important
+part in the nutrition of those sponges in which they occur, and there
+can be no doubt that these bodies have the power peculiar to all
+organisms that produce chlorophyll of obtaining nutritive substances
+direct from water and carbonic oxide through the action of sunlight.
+Possibly they hand on some of the nourishment thus obtained to the
+sponges in which they live, or benefit them by the free oxygen given out
+in the process, but many Spongillid� do well without them, even when
+living in identical conditions with species in which they abound.
+
+
+REPRODUCTION.
+
+Both eggs and buds are produced by freshwater sponges (the latter rarely
+except by one species), while their gemmules attain an elaboration of
+structure not observed in any other family of sponges.
+
+Probably all Spongillid� are potentially monoecious, that is to say,
+able to produce both eggs and spermatozoa. In one Indian species,
+however, in which budding is unusually common (viz. _Spongilla
+proliferens_), sexual reproduction takes place very seldom, if ever. It
+is not known whether the eggs of sponges are fertilized by spermatozoa
+from the individual that produces the egg or by those of other
+individuals, but not improbably both methods of fertilization occur.
+
+The egg of a freshwater sponge does not differ materially from that of
+other animals. When mature it is a relatively large spherical cell
+containing abundant food-material and situated in some natural cavity of
+the sponge. In the earlier stages of its growth, however, it exhibits
+amoeboid movements, and makes its way through the common jelly. As it
+approaches maturity it is surrounded by other cells which contain
+granules of food-material. The food-material is apparently transferred
+by them in a slightly altered form to the egg. The egg has no shell, but
+in some species (e. g. _Ephydatia blembingia_[N]) it is surrounded,
+after fertilization, by gland-cells belonging to the parent sponge,
+which secrete round it a membrane of spongin. Development goes on within
+the chamber thus formed until the larva is ready to assume a free life.
+
+     [Footnote N: Rec. Ind. Mus. i, p. 269 (1907).]
+
+The spermatozoon is also like that of other animals, consisting of a
+rounded head and a lash-like tail, the movements of which enable it to
+move rapidly through the water. Spermatozoa are produced in _Spongilla_
+from spherical cells not unlike the eggs in general appearance. The
+contents of these cells divide and subdivide in such a way that they
+finally consist of a mass of spermatozoa surrounded by a single covering
+cell, which they finally rupture, and so escape.
+
+[Illustration: Fig. 7.--Diagram of a vertical section through the
+gemmule of _Spongilla proliferens_.
+
+A=cellular contents; B=internal chitinous layer; C=external chitinous
+layer; D=pneumatic coat; E=gemmule-spicule; F=external membrane;
+G=foraminal tubule.]
+
+Gemmules are asexual reproductive bodies peculiar to the sponges, but
+not to the Spongillid�. They resemble the statoblasts of the
+phylactol�matous polyzoa in general structure as well as in function,
+which is mainly that of preserving the race from destruction by such
+agencies as drought, starvation, and temperatures that are either too
+high or too low for its activities. This function they are enabled to
+perform by the facts that they are provided with coverings not only very
+hard but also fitted to resist the unfavourable agencies to which the
+gemmules are likely to be exposed, and that they contain abundant
+food-material of which use can be made as soon as favourable conditions
+occur again.
+
+Internally the gemmule consists of a mass of cells containing
+food-material in what may be called a tabloid form, for it consists of
+minutely granular plate-like bodies. These cells are enclosed in a
+flask-like receptacle, the walls of which consist of two chitinous
+layers, a delicate inner membrane and an outer one of considerable
+stoutness. The mouth of the flask is closed by an extension of the inner
+membrane, and in some species is surrounded by a tubular extension of
+the external membrane known as the foraminal tubule. Externally the
+gemmule is usually covered by what is called a "pneumatic coat," also of
+"chitin" (spongin), but usually of great relative thickness and
+honeycombed by spaces which contain air, rendering the structure
+buoyant. The pneumatic coat also contains the microscleres
+characteristic of the species; it is often limited externally by a third
+chitinous membrane, on which more gemmule-spicules sometimes lie
+parallel to the surface.
+
+The cells from which those of the gemmules are derived are akin in
+origin to those that give rise to eggs and spermatozoa. Some zoologists
+are therefore of the opinion that the development of the gemmule is an
+instance of parthenogenesis--that is to say of an organism arising from
+an egg that has not been fertilized. But some of the collar-cells,
+although most of them originate from the external ciliated cells of the
+larva, have a similar origin. The building-up of the gemmule affords an
+excellent instance of the active co-operation that exists between the
+cells of sponges, and of their mobility, for the food-material that has
+to be stored up is brought by cells from all parts of the sponge, and
+these cells retire after discharging their load into those of the young
+gemmule.
+
+The formation of the gemmule of _Ephydatia blembingia_, a Malayan
+species not yet found in India, is described in detail by Dr. R. Evans
+(Q. J. Microsc. Sci. London, xliv, p. 81, 1901).
+
+Gemmules are produced by the freshwater sponges of Europe, N. America
+and Japan at the approach of winter, but in the tropical parts of India
+they are formed more frequently at the approach of the hot weather (p.
+4). After they are fully formed the sponge that has produced them dies,
+and as a rule disintegrates more or less completely. In some species,
+however, the greater part of the skeleton remains intact, if it is not
+disturbed, and retains some of the gemmules in its meshwork, where they
+finally germinate. Other gemmules are set free. Some of them float on
+the surface of the water; others sink to the bottom. In any case all of
+them undergo a period of quiescence before germinating. It has been
+found that they can be kept dry for two years without dying.
+
+The function of the special spicules with which the gemmules of the
+Spongillid� are provided appears to be not only to protect them but more
+especially to weight them to the extent suitable to the habits of each
+species. Species that inhabit running water, for example, in some cases
+have heavier gemmule-spicules than those that live in stagnant water,
+and their gemmules are the less easily carried away by the currents of
+the river. The gemmules of sponges growing in lakes are sometimes
+deficient in spicules. This is the case as regards the form of
+_Spongilla lacustris_ found in Lake Baa, Isle of Mull, as regards _S.
+helvetica_ from the Lake of Geneva, _S. moorei_ from Lake Tanganyika,
+and _S. coggini_ from Tali-Fu in Yunnan; also as regards the species of
+_Spongilla_ and _Ephydatia_ found in Lake Baikal, many of the sponges of
+which are said never to produce gemmules.
+
+Except in the genus _Corvospongilla_ and the subgenus _Stratospongilla_,
+in both of which the air-spaces of the gemmules are usually no more than
+cavities between different chitinous membranes, the pneumatic coat is
+either "granular" or "cellular." Neither of these terms, however, must
+be understood in a physiological sense, for what appear to be granules
+in a granular coat are actually minute bubbles of air contained in
+little cavities in a foam-like mass of chitin (or rather spongin), while
+the cells in a cellular one are only larger and more regular air-spaces
+with thin polygonal walls and flat horizontal partitions. The walls of
+these spaces are said in some cases to contain a considerable amount of
+silica.
+
+The gemmules with their various coverings are usually spherical in
+shape, but in some species they are oval or depressed in outline. They
+lie as a rule free in the substance of the sponge, but in some species
+adhere at its base to the object to which it is attached. In some
+species they are joined together in groups, but in most they are quite
+free one from another.
+
+Reproductive buds[O] are produced, so far as is known, by very few
+Spongillid�, although they are common enough in some other groups of
+sponges. In the only freshwater species in which they have been found to
+form a habitual means of reproduction, namely in _Spongilla
+proliferens_, they have much the appearance of abortive branches, and it
+is possible that they have been overlooked for this reason in other
+species, for they were noticed by Laurent in _Spongilla lacustris_ as
+long ago as 1840 (CR. S�. Acad. Sci. Paris, xi, p. 478). The buds
+noticed by Laurent, however, were only produced by very young sponges,
+and were of a different nature from those of _S. proliferens_, perhaps
+representing a form of fission rather than true budding (see 'Voyage de
+la Bonite: Zoophytologie,' Spongiaires, pl. i (Paris, 1844)).
+
+     [Footnote O: Proliferation whereby more than one osculum is
+     produced is really a form of budding, but in most sponges
+     this has become no longer a mode of reproduction but the
+     normal method by which size is increased, and must therefore
+     be considered merely as a vegetative process.]
+
+In _Spongilla proliferens_, a common Indian species, the buds arise as
+thickenings of the strands of cells accompanying the radiating
+spicule-fibres of the skeleton, which project outwards from the surface
+of the sponge. The thickenings originate beneath the surface and
+contain, at the earliest stage at which I have as yet examined them, all
+the elements of the adult organism (_i. e._ flesh-spicules, ciliated
+chambers, efferent and afferent canals, parenchyma-cells of various
+sorts) except skeleton fibres, gemmules, and a dermal membrane. A
+section at this period closely resembles one of an adult sponge, except
+that the structure is more compact, the parenchyma being relatively
+bulky and the canals of small diameter.
+
+Laurent observed reproduction by splitting in young individuals of
+_Spongilla_, but I have not been able to obtain evidence myself that
+this method of reproduction occurs normally in Indian species. In
+injured specimens of _Spongilla carteri_, however, I have observed a
+phenomenon that seems to be rather an abnormal form of budding, little
+rounded masses of cells making their way to the ends of the radiating
+skeleton fibres and becoming transformed into young sponges, which break
+loose and so start an independent existence. Possibly the buds observed
+by Laurent in _S. lacustris_ were of a similar nature.
+
+
+DEVELOPMENT.
+
+
+(a) _From the Egg._
+
+After fertilization, the egg, lying in its cavity in the sponge,
+undergoes a complete segmentation; that is to say, becomes divided into
+a number of cells without any residuum remaining. The segmentation,
+however, is not equal, for it results in the formation of cells of two
+distinct types, one larger and less numerous than the other. As the
+process continues a pear-shaped body is produced, solid at the broader
+end, which consists of the larger cells, but hollow at the other.
+Further changes result in the whole of the external surface becoming
+ciliated or covered with fine protoplasmic lashes, each of which arises
+from a single small cell; considerable differentiation now takes place
+among the cells, and spicules begin to appear. At this stage or earlier
+(for there seem to be differences in different species and individuals
+as to the stage at which the young sponge escapes) the larva makes its
+way out of the parent sponge. After a brief period of free life, in
+which it swims rapidly through the water by means of its cilia, it fixes
+itself by the broad end to some solid object (from which it can never
+move again) and undergoes a final metamorphosis. During this process the
+ciliated cells of the external layer make their way, either by a
+folding-in of the whole layer or in groups of cells, into the interior,
+there change into collar-cells and arrange themselves in special
+cavities--the ciliated chambers of the adult. Finally an osculum, pores,
+&c., are formed, and the sponge is complete.
+
+This, of course, is the merest outline of what occurs; other changes
+that take place during the metamorphosis are of great theoretical
+interest, but cannot be discussed here. The student may refer to Dr. R.
+Evans's account of the larval development of _Spongilla lacustris_ in
+the Q. J. Microsc. Sci. London, xlii, p. 363 (1899).
+
+(b) _From the Gemmule._
+
+The period for which the gemmule lies dormant probably depends to some
+extent upon environment and to some extent on the species to which it
+belongs. Carter found that if he cleaned gemmules with a handkerchief
+and placed them in water exposed to sunlight, they germinated in a few
+days; but in Calcutta gemmules of _Spongilla alba_ var. _bengalensis_
+treated in this way and placed in my aquarium at the beginning of the
+hot weather, did not germinate until well on in the "rains." Even then,
+after about five months, only a few of them did so. Zykoff found that in
+Europe gemmules kept for two years were still alive and able to
+germinate.
+
+Germination consists in the cellular contents of the gemmule bursting
+the membrane or membranes in which they are enclosed, and making their
+way out of the gemmule in the form of a delicate whitish mass, which
+sometimes issues through the natural aperture in the outer chitinous
+coat and sometimes through an actual rent in this coat. In the latter
+case the development of the young sponge is more advanced than in the
+former.
+
+The fullest account of development from the gemmule as yet published is
+by Zykoff, and refers to _Ephydatia_ in Europe (Biol. Centralbl. Berlin,
+xii, p. 713, 1892).
+
+His investigations show that the bursting of the gemmule is not merely a
+mechanical effect of moisture or any such agency but is due to
+development of the cellular contents, which at the time they escape have
+at least undergone differentiation into two layers. Of the more
+important soft structures in the sponge the osculum is the first to
+appear, the ciliated chambers being formed later. This is the opposite
+of what occurs in the case of the bud, but in both cases the aperture
+appears to be produced by the pressure of water in the organism. The
+manner and order in which the different kinds of cells originate in the
+sponge derived from a gemmule give support to the view that the
+primitive cell-layers on which morphologists lay great stress are not of
+any great importance so far as sponges are concerned.
+
+(c) _Development of the Bud._
+
+As the bud of _Spongilla proliferens_ grows it makes its way up the
+skeleton-fibre to which it was originally attached, pushing the dermal
+membrane, which expands with its growth, before it. The skeleton-fibre
+does not, however, continue to grow in the bud, in which a number of
+finer fibres make their appearance, radiating from a point approximately
+at the centre of the mass. As the bud projects more and more from the
+surface of the sponge the dermal membrane contracts at its base, so as
+finally to separate it from its parent. Further details are given on p.
+74.
+
+
+HABITAT.
+
+Mr. Edward Potts[P], writing on the freshwater sponges of North America,
+says:--"These organisms have occasionally been discovered growing in
+water unfit for domestic uses; but as a rule they prefer pure water, and
+in my experience the finest specimens have always been found where they
+are subjected to the most rapid currents." True as this is of the
+Spongillid� of temperate climates, it is hardly applicable to those of
+tropical India, for in this country we find many species growing most
+luxuriantly and commonly in water that would certainly be considered
+unfit for domestic purposes in a country in which sanitation was treated
+as a science. Some species, indeed, are only found in ponds of water
+polluted by human agency, and such ponds, provided that other conditions
+are favourable, are perhaps the best collecting grounds. Other
+favourable conditions consist in a due mixture of light and shade, a
+lack of disturbance such as that caused by cleaning out the pond, and
+above all in the presence of objects suitable for the support of
+sponges.
+
+     [Footnote P: P. Ac. Philad. 1887, p. 162.]
+
+I do not know exactly why light and shade must be mixed in a habitat
+favourable for the growth of sponges, for most species prefer shade, if
+it be not too dense; but it is certainly the case that, with a few
+exceptions, Indian Spongillid� flourish best in water shaded at the
+edges by trees and exposed to sunlight elsewhere. One of the exceptions
+to this rule is the Indian race of _Spongilla lucustris_, which is found
+in small pools of water in sand-dunes without a particle of shade.
+Several species are only found on the lower surface of stones and roots
+in circumstances which do not suggest that their position merely
+protects them from mud, which, as Mr. Potts points out, is their "great
+enemy." A notable instance is _Trochospongilla pennsylvanica_, which is
+found hiding away from light in America and Europe as well as in India.
+
+It is curious that it should be easy to exterminate the sponges in a
+pond by cleaning it out, for one would have thought that sufficient
+gemmules would have remained at the edge, or would have been brought
+rapidly from elsewhere, to restock the water. Mr. Green has, however,
+noted that _Spongilla carteri_ has disappeared for some years from a
+small lake at Peradeniya in which it was formerly abundant, owing to the
+lake having been cleaned out, and I have made similar observations on
+several occasions in Calcutta.
+
+The question of the objects to which sponges attach themselves is one
+intimately connected with that of the injury done them by mud. The delta
+of the Ganges is one of the muddiest districts on earth. There are no
+stones or rocks in the rivers and ponds, but mud everywhere. If a sponge
+settles in the mud its canals are rapidly choked, its vital processes
+cease, and it dies. In this part of India, therefore, most sponges are
+found fixed either to floating objects such as logs of wood, to vertical
+objects such as the stems of bulrushes and other aquatic plants, or to
+the tips of branches that overhang the water and become submerged during
+the "rains." In Calcutta man has unwittingly come to the assistance of
+the sponges, not only by digging tanks but also by building
+"bathing-ghats" of brick at the edge, and constructing, with �sthetic
+intentions if not results, masses of artificial concrete rocks in or
+surrounding the water. There are at least two sponges (the typical form
+of _Spongilla alba_ and _Ephydatia meyeni_) which in Calcutta are only
+found attached to such objects. The form of _S. alba_, however, that is
+found in ponds of brackish water in the Gangetic delta has not derived
+this artificial assistance from man, except in the few places where
+brick bridges have been built, and attaches itself to the stem and roots
+of a kind of grass that grows at the edge of brackish water. This sponge
+seems to have become immune even to mud, the particles of which are
+swallowed by its cells and finally got rid of without blocking up the
+canals.
+
+Several Indian sponges are only found adhering to stones and rocks.
+Among these species _Corvospongilla lapidosa_ and our representatives of
+the subgenus _Stratospongilla_ are noteworthy. Some forms (e. g.
+_Spongilla carteri_ and _S. crateriformis_) seem, however, to be just as
+much at home in muddy as in rocky localities, although they avoid the
+mud itself.
+
+There is much indirect evidence that the larv� of freshwater sponges
+exercise a power of selection as regards the objects to which they affix
+themselves on settling down for life.
+
+Few Spongillid� are found in salt or brackish water, but _Spongilla
+alba_ var. _bengalensis_ has been found in both, and is abundant in the
+latter; indeed, it has not been found in pure fresh water. _Spongilla
+travancorica_ has only been found in slightly brackish water, while _S.
+lacustris_ subsp. _reticulata_ and _Dosilia plumosa_ occur in both fresh
+and brackish water, although rarely in the latter. The Spongillid� are
+essentially a freshwater family, and those forms that are found in any
+but pure fresh water must be regarded as aberrant or unusually tolerant
+in their habits, not as primitive marine forms that still linger halfway
+to the sea.
+
+
+ANIMALS AND PLANTS COMMONLY ASSOCIATED WITH
+FRESHWATER SPONGES.
+
+
+(a) _Enemies._
+
+Freshwater sponges have few living enemies. Indeed, it is difficult to
+say exactly what is an enemy of a creature so loosely organized as a
+sponge. There can be little doubt, in any case, that the neuropteroid
+larva (_Sisyra indica_) which sucks the cells of several species should
+be classed in this category, and it is noteworthy that several species
+of the same genus also occur in Europe and N. America which also attack
+sponges. Other animals that may be enemies are a midge larva (_Tanypus_
+sp.) and certain worms that bore through the parenchyma (p. 93), but I
+know of no animal that devours sponges bodily, so long as they are
+uninjured. If their external membrane is destroyed, they are immediately
+attacked by various little fish and also by snails of the genera
+_Limn�a_ and _Planorbis_, and prawns of the genus _Pal�mon_.
+
+Their most active and obvious enemy is a plant, not an animal,--to wit,
+a filamentous alga that blocks up their canals by its rapid growth (p.
+79).
+
+(b) _Beneficial Organisms._
+
+The most abundant and possibly the most important organisms that may be
+considered as benefactors to the Spongillid� are the green corpuscles
+that live in the cells of certain species (fig. 2, p. 31), notably
+_Spongilla lacustris_, _S. proliferens_, and _Dosilia plumosa_. I have
+already said that these bodies are in all probability alg� which live
+free in the water and move actively at one stage of their existence, but
+some of them are handed on directly from a sponge to its descendants in
+the cells of the gemmule. In their quiescent stage they have been
+studied by several zoologists, notably by Sir Ray Lankester[Q] and Dr.
+W. Weltner[R], but the strongest light that has been cast on their
+origin is given by the researches of Dr. F. W. Gamble and Mr. F. Keeble
+(Q. J. Microsc. Sci. London, xlvii, p. 363, 1904, and li, p. 167, 1907).
+These researches do not refer directly to the Spongillid� but to a
+little flat-worm that lives in the sea, _Convoluta roscoffiensis_. The
+green corpuscles of this worm so closely resemble those of _Spongilla_
+that we are justified in supposing a similarity of origin. It has been
+shown by the authors cited that the green corpuscles of the worm are at
+one stage minute free-living organisms provided at one end with four
+flagella and at the other with a red pigment spot. The investigators are
+of the opinion that these organisms exhibit the essential characters of
+the alg� known as Chlamydomonad�, and that after they have entered the
+worm they play for it the part of an excretory system.
+
+     [Footnote Q: Q. J. Microsc. Sci. London, xxii. p. 229
+     (1882).]
+
+     [Footnote R: Arch. Naturg. Berlin, lix (i), p. 260 (1893).]
+
+As they exist in the cells of _Spongilla_ the corpuscles are minute oval
+bodies of a bright green colour and each containing a highly refractile
+colourless granule. A considerable number may be present in a single
+cell. It is found in European sponges that they lose their green colour
+if the sponge is not exposed to bright sunlight. In India, however,
+where the light is stronger, this is not always the case. Even when the
+colour goes, the corpuscles can still be distinguished as pale images of
+their green embodiment. They are called _Chlorella_ by botanists, who
+have studied their life-history but have not yet discovered the full
+cycle. See Beyerinck in the Botan. Zeitung for 1890 (vol. xlviii, p.
+730, pl. vii; Leipzig), and for further references West's 'British
+Freshwater Alg�,' p. 230 (1904).
+
+The list of beneficent organisms less commonly present than the green
+corpuscles includes a _Chironomus_ larva that builds parchment-like
+tubes in the substance of _Spongilla carteri_ and so assists in
+supporting the sponge, and of a peculiar little worm (_Ch�togaster
+spongill�_[S]) that appears to assist in cleaning up the skeleton of the
+same sponge at the approach of the hot weather and in setting free the
+gemmules (p. 93).
+
+     [Footnote S: Journ. As. Soc. Beng. n. s. ii, 1906, p. 189.]
+
+(c) _Organisms that take shelter in the Sponge or adhere to it
+externally._
+
+There are many animals which take shelter in the cavities of the sponge
+without apparently assisting it in any way. Among these are the little
+fish _Gobius alcockii_, which lays its eggs inside the oscula of _S.
+carteri_, thus ensuring not only protection but also a proper supply of
+oxygen for them (p. 94); the molluscs (_Corbula_, spp.) found inside _S.
+alba_ var. _bengalensis_ (p. 78); and the Isopod (_Tach�a
+spongillicola_) that makes its way into the oscula of _Spongilla
+carteri_ and _S. crateriformis_ (pp. 86, 94).
+
+In Europe a peculiar ciliated Protozoon (_Trichodina spongill�_) is
+found attached to the external surface of freshwater sponges. I have
+noticed a similar species at Igatpuri on _Spongilla crateriformis_, but
+it has not yet been identified. It probably has no effect, good or bad,
+on the sponge.
+
+
+FRESHWATER SPONGES IN RELATION TO MAN.
+
+In dealing with _Spongilla carteri_ I have suggested that sponges may be
+of some hygienic importance in absorbing putrid organic matter from
+water used both for ablutionary and for drinking purposes, as is so
+commonly the case with regard to ponds in India. Their bad odour has
+caused some species of Spongillid� to be regarded as capable of
+polluting water, but a mere bad odour does not necessarily imply that
+they are insanitary.
+
+Unless my suggestion that sponges purify water used for drinking
+purposes by absorbing putrid matter should prove to be supported by
+fact, the Spongillid� cannot be said to be of any practical benefit to
+man. The only harm that has been imputed to them is that of polluting
+water[T], of blocking up water-pipes by their growth--a very rare
+occurrence,--and of causing irritation to the human skin by means of
+their spicules--a still rarer one. At least one instance is, however,
+reported in which men digging in a place where a pond had once been were
+attacked by a troublesome rash probably due to the presence of
+sponge-spicules in the earth, and students of the freshwater sponges
+should be careful not to rub their eyes after handling dried specimens.
+
+     [Footnote T: See Potts, Proc. Ac. Philad. 1884, p. 28.]
+
+
+INDIAN SPONGILLID� COMPARED WITH THOSE OF OTHER COUNTRIES.
+
+In Weltner's catalogue of the freshwater sponges (1895) seventy-six
+recent species of Spongillid� (excluding _Lubosmirskia_) are enumerated,
+and the number now known is well over a hundred. In India we have
+twenty-nine species, subspecies, and varieties, while from the whole of
+Europe only about a dozen are known. In the neighbourhood of Calcutta
+nine species, representing three genera and a subgenus, have been found;
+all of them occur in the Museum tank. The only other region of similar
+extent that can compare with India as regards the richness of its
+freshwater sponge fauna is that of the Amazon, from which about twenty
+species are known. From the whole of North America, which has probably
+been better explored than any other continent so far as Spongillid� are
+concerned, only twenty-seven or twenty-eight species have been recorded.
+
+The Indian species fall into seven genera, one of which (_Spongilla_)
+consists of three subgenera. With one exception (that of
+_Pectispongilla_, which has only been found in Southern India) these
+genera have a wide distribution over the earth's surface, and this is
+also the case as regards the subgenera of Spongilla. Four genera
+(_Heteromeyenia_, _Acalle_, _Parmula_, and _Uruguaya_) that have not yet
+been found in India are known to exist elsewhere.
+
+Five of the Indian species are known to occur in Europe, viz.,
+_Spongilla lacustris_, _S. crateriformis_, _S. carteri_, _S. fragilis_,
+_Trochospongilla pennsylvanica_; while _Ephydatia meyeni_ is
+intermediate between the two commonest representatives of its genus in
+the Holarctic Zone, _Ephydatia fluviatilis_ and _E. m�lleri_. Of the
+species that occur both in India and in Europe, two (_Spongilla
+lacustris_ and _S. fragilis_) are found in this country in forms
+sufficiently distinct to be regarded as subspecies or local races.
+Perhaps this course should also be taken as regards the Indian forms of
+_S. carteri_, of which, however, the commonest of the Indian races would
+be the typical one; but _S. crateriformis_ and _T. pennsylvanica_ seem
+to preserve their specific characters free from modification, whether
+they are found in Europe, Asia, or America.
+
+The freshwater sponges of Africa have been comparatively little studied,
+but two Indian species have been discovered, _S. bombayensis_ in Natal
+and _S. alba_ var. _cerebellata_ in Egypt. Several of the species from
+the Malabar Zone are, moreover, closely allied to African forms (p. 11).
+
+
+FOSSIL SPONGILLID�.
+
+The Spongillid� are an ancient family. Young described a species
+(_Spongilla purbeckensis_) from the Upper Jurassic of Dorset (Geol. Mag.
+London (new series) v, p. 220 (1878)), while spicules, assigned by
+Ehrenberg to various genera but actually those of _Spongilla lacustris_
+or allied forms, have been found in the Miocene of Bohemia (see
+Ehrenberg's 'Atlas f�r Micro-Geologie,' pl. xi (Leipzig, 1854), and
+Traxler in F�ldt. K�zl., Budapest, 1895, p. 211). _Ephydatia_ is also
+known in a fossil condition, but is probably less ancient than
+_Spongilla_.
+
+Ehrenberg found many sponge spicules in earth from various parts of the
+Indian Empire (including Baluchistan, Mangalore, Calcutta, the Nicobars
+and Nepal) and elsewhere, and it might be possible to guess at the
+identity of some of the more conspicuous species figured in his 'Atlas.'
+The identification of sponges from isolated spicules is, however, always
+a matter of doubt, and in some cases Ehrenberg probably assigned
+spicules belonging to entirely different families or even orders to the
+same genus, while he frequently attributed the different spicules of the
+same species to different genera. Among his fossil (or supposed fossil)
+genera that may be assigned to the Spongillid� wholly or in part are
+_Aphidiscus_, _Spongolithis_, _Lithastericus_ and _Lithosph�ridium_,
+many of the species of these "genera" certainly belonging to _Spongilla_
+and _Ephydatia_.
+
+
+ORIENTAL SPONGILLID� NOT YET FOUND IN INDIA.
+
+Few freshwater sponges that have not been found in India are as yet
+known from the Oriental Region, and there is positive as well as
+negative evidence that Spongillid� are less abundant in Malaysia than in
+this country. The following list includes the names of those that have
+been found, with notes regarding each species. It is quite possible that
+any one of them may be found at any time within the geographical
+boundaries laid down for this 'Fauna.' I have examined types or co-types
+in all cases except that of _Ephydatia fortis_, Weltner.
+
+I. _Spongilla_ (_Euspongilla_) _microsclerifera_*, Annandale
+(Philippines). P. U.S. Mus. xxxvii, p. 131 (1909).
+
+This sponge is closely related to _S. lacustris_, but apparently does
+not produce branches. It is remarkable for the enormous number of
+microscleres in its parenchyma.
+
+II. _S._ (_Euspongilla_) _philippinensis_*, Annandale (Philippines). P.
+U.S. Mus. xxxvi, p. 629 (1909).
+
+Related to _S. alba_ and still more closely to _S. sceptrioides_ of
+Australia. From the former it is readily distinguished by having
+minutely spined megascleres, green corpuscles, slender gemmule-spicules
+with short spines and no free microscleres.
+
+III. _S._ (? _Euspongilla_) _yunnanensis_*, Annandale (W. China). Rec.
+Ind. Mus. v, p. 197 (1910).
+
+Apparently allied to _S. philippinensis_ but with smooth
+skeleton-spicules and a more delicate skeleton.
+
+IV. _S._ (_Stratospongilla_) _sinensis_*, Annandale (Foochow, China). P.
+U.S. Mus. xxxviii, p. 183 (1910).
+
+This species and _S. clementis_ are referred to _Stratospongilla_ with
+some doubt. Their gemmules are intermediate in structure between those
+of that subgenus and those of _Euspongilla_.  In _S. sinensis_ the
+gemmules are packed together in groups at the base of the sponge, and
+their spicules are smooth, stout, and gradually pointed.
+
+V. _S._ (_Stratospongilla_) _clementis_*, Annandale (Philippines). P.
+U.S. Mus. xxxvi, p. 631 (1909).
+
+The gemmules are single and closely adherent at the base of the sponge.
+Their spicules are very slender and minutely spined.
+
+VI. _S._ (? _Stratospongilla_) _coggini_*, Annandale (W. China). Rec.
+Ind. Mus. v, p. 198 (1910).
+
+The gemmules apparently lack microscleres. They resemble those of _S.
+clementis_, to which the species is probably related, in other respects.
+The skeleton-spicules are spiny and rather stout, the species being
+strongly developed at the two ends.
+
+VII. _S._ (_Stratospongilla_) _sumatrana_*, Weber (Malay Archipelago).
+Zool. Ergebnisse einer Reise in Niederl�ndisch Ost-Indien, i. p. 38
+(1890).
+
+Closely allied to _S. indica_ (p. 100) but with pointed
+skeleton-spicules.
+
+VIII. _Ephydatia fortis_, Weltner (Philippines). Arch. Naturgesch.
+lxi(i), p. 141 (1895).
+
+This species is remarkable for the great development of the spines on
+the shaft of the gemmule-spicules.
+
+IX. _Ephydatia bogorensis_*, Weber (Malay Archipelago). Zool. Ergebnisse
+einer Reise in Niederl�ndisch Ost-Indien, i, p. 33 (1890).
+
+The gemmule-spicules have rather narrow flattish disks, the edge of
+which is feebly but closely serrated.
+
+X. _E. blembingia_*, Evans (Malay Peninsula). Q. J. Microsc. Sci.
+London, xliv, p. 81 (1901).
+
+The gemmules resemble those of _Dosilia plumosa_ but are spherical.
+There are no free microscleres.
+
+XI. _Tubella vesparium_*, v. Martens (Borneo). Arch. Naturg.
+
+Berlin, xxxiv, p. 62 (1868).
+
+Closely related to _T. vesparioides_ (p. 189), but with spiny
+megascleres.
+
+As regards _Spongilla decipiens_*, Weber, from the Malay Archipelago,
+see p. 97.
+
+
+II.
+
+HISTORY OF THE STUDY OF FRESHWATER SPONGES.
+
+The bath-sponge was known to the Greeks at an early date, and Homer
+refers to it as being used for cleansing furniture, for expunging
+writing, and for ablutionary purposes. He also mentions its peculiar
+structure, "with many holes." "Many things besides," wrote the English
+naturalist Ray in his 'Historia Plantarum' (1686), "regarding the powers
+and uses of sponges have the Ancients: to them refer." Ray himself
+describes at least one freshwater species, which had been found in an
+English river, and refers to what may be another as having been brought
+from America. In the eighteenth century Linn�, Pallas and other authors
+described the commoner European Spongillid� in general terms, sometimes
+as plants and sometimes as animals, more usually as zoophytes or
+"plant-animals" partaking of the nature of both kingdoms. The gemmules
+were noted and referred to as seeds. The early naturalists of the
+Linn�an Epoch, however, added little to the general knowledge of the
+Spongillid�, being occupied with theory in which theological disputes
+were involved rather than actual observation, and, notwithstanding the
+fact that the animal nature of sponges was clearly demonstrated by
+Ellis[U] in 1765, it was not until the nineteenth century was well
+advanced that zoologists could regard sponges in anything like an
+impartial manner.
+
+          [Footnote U: Phil. Trans. Roy. Soc. lv, p. 280.]
+
+One of the pioneers in the scientific study of the freshwater forms was
+the late Dr. H. J. Carter, who commenced his investigations, and carried
+out a great part of them, in Bombay with little of the apparatus now
+considered necessary, and with a microscope that must have been grossly
+defective according to modern ideas. His long series of papers
+(1848-1887) published in the 'Annals and Magazine of Natural History' is
+an enduring monument to Indian zoology, and forms the best possible
+introduction to the study of the Spongillid�. Even his earlier mistakes
+are instructive, for they are due not so much to actual errors in
+observation as to a faithful transcription of what was observed with
+faulty apparatus.
+
+Contemporary with Carter were two authors whose monographs on the
+freshwater sponges did much to advance the study of the group, namely,
+J. S. Bowerbank, whose account of the species known at the time was
+published in the 'Proceedings of the Zoological Society of London' in
+1882, and the veteran American naturalist Mr. Edward Potts, whose study
+of the freshwater sponges culminated in his monograph published in the
+'Proceedings of the Academy of Natural Sciences of Philadelphia' in
+1887. Carter's own revision of the group was published in the 'Annals
+and Magazine of Natural History' in 1881. The names of Vejdovsky, who
+prefaced Potts's monograph with an account of the European species, and
+of Dybowsky, who published several important papers on classification,
+should also be mentioned, while Weltner's catalogue of the known species
+(1895) is of the greatest possible value to students of the group.
+
+Many authors have dealt with the physiology, reproduction and
+development of the Spongillid�, especially in recent years; Dr. R.
+Evans's description of the larva of _Spongilla lacustris_ (1899), and
+his account of the development of the gemmule in _Ephydatia blembingia_
+(1901), Zykoff's account of the development of the gemmule and of the
+sponge from the gemmule (1892), and Weltner's observations on colour and
+other points (1893, 1907), may be mentioned in particular. Laurent's
+observations on development (1844), which were published in the 'Voyage
+de la Bonite,' and especially the exquisite plates which accompany them,
+have not received the notice they deserve, probably on account of their
+method of publication.
+
+
+LITERATURE.
+
+The fullest account of the literature on the Spongillid� as yet
+published will be found in the first of Weltner's 'Spongillidenstudien'
+(Archiv f�r Naturgeschichte, lix (i), p. 209, 1893). Unfortunately it
+contains no references of later date than 1892. The following list is
+not a complete bibliography, but merely a list of books and papers that
+should prove of use to students of the Oriental Spongillid�.
+
+(a) _Works of Reference._
+
+1863. BOWERBANK, "A Monograph of the Spongillid�," P. Zool. Soc. London,
+1863, pp. 440-472, pl. xxxviii.
+
+1867. GRAY, J. E., "Notes on the arrangement of Sponges, with the
+description of some new genera." _ibid._ 1867, pp. 492-558.
+
+1881. CARTER, "History and classification of the known species of
+_Spongilla_," Ann. Nat. Hist. (5) vii, pp. 77-107, pls. v, vi.
+
+1883. VEJDOVSKY, "Die S�sswasserschw�mme B�hmens," Abh. K�n. B�hm. Ges.
+Wiss. (math.-natur. Classe), xii, pp. 1-43, pls. i-iii.
+
+1887. VOSMAER, "Spongien (Porifera)," in Bronn's Thier-Reichs.
+
+1887. POTTS, "Contributions towards a synopsis of the American forms of
+Fresh-Water Sponges, with descriptions of those named by other authors
+and from all parts of the world," P. Ac. Philad. pp. 158-279, pls.
+v-xii.
+
+1887. VEJDOVSKY, "Diagnosis of the European Spongillid�," _ibid._ pp.
+172-180.
+
+1888. WIERZEJSKI, "Beitrag zur Kenntnis der S�sswasserschw�mme," Verh.
+k.-k. zool.-bot. Ges. Wien, xxxviii, pp. 529-536, pl. xii.
+
+1891. WELTNER, in Zacharias's Die Tier- und Pflanzenwelt des
+S�sswassers: I, Die S�sswasserschw�mme.
+
+1895. WELTNER, "Spongillidenstudien, III," Arch. Naturg. Berlin, lxi
+(i), pp. 114-144.
+
+1895. KORSCHELT and HEIDER, Text-book of the Embryology of
+Invertebrates: English edition, prepared by E. L. Mark and W. McM.
+Woodworth, Vol. I, chap. i.
+
+1900. MINCHIN, Sponges--Phylum Porifera in Lankester's "Treatise on
+Zoology," ii.
+
+1905. K�KENTHAL, W., Leitfaden f�r das Zoologische Praktikum (3rd Ed.,
+Jena), 2. Kursus: Porifera, Schw�mme, p. 31.
+
+1906. SOLLAS, I. B. J., Cambridge Natural History--I. Porifera
+(Sponges).
+
+1909. WELTNER, "Spongillid�, S�sswasserschw�mme," in Brauer's "Die
+S�sswasserfauna Deutschlands," Heft xix, pp. 177-190.
+
+1910. LLOYD, An Introduction to Biology for Students in India.
+
+(b) _Special Memoirs on Anatomy, Physiology, and Development._
+
+1844. LAURENT, "Recherches sur l'Hydre et l'Eponge d'eau douce," Voyage
+de la Bonite, ii, pp. 113-276.
+
+1854. CARTER, "Zoosperms in _Spongilla_," Ann. Nat. Hist. (2) xiv, pp.
+334-336, pl. xi, figs. 1-6.
+
+1857. CARTER, "On the ultimate structure of _Spongilla_, and additional
+notes on Freshwater Infusoria," Ann. Nat. Hist. (2) xx, pp. 21-41, pl.
+i, figs. 1-11.
+
+1859. CARTER, "On the identity in structure and composition of the
+so-called 'seed-like body' of _Spongilla_ with the winter-egg of the
+Bryozoa, and the presence of starch-granules in each," Ann. Nat. Hist.
+(3) iii, pp. 331-343, pl. viii.
+
+1859. LIEBERK�HN, "Neue Beitr�ge zur Anatomie der Spongien," Arch. Anat.
+Phys. J. M�ller, pp. 374-375, 526-528.
+
+1871. CARTER, "Discovery of the animal of the Spongiad� confirmed," Ann.
+Nat. Hist. (4) vii, p. 445.
+
+1871. HAECKEL, "Ueber die sexuelle Fortpflanzung und das nat�rliche
+System der Schw�mme," Jenaische Zeitschr. f. Naturw. vi, pp. 643, 645.
+
+1874. CARTER, "On the nature of the seed-like body of _Spongilla_; on
+the origin of the mother-cell of the spicule; and on the presence of
+spermatozoa in the _Spongida_," Ann. Nat. Hist. (4) xiv, pp. 97-111.
+
+1874. LANKESTER, E. RAY, "The mode of occurrence of chlorophyll in
+_Spongilla_," Q. J. Micr. Sci. xiv, pp. 400-401.
+
+1875. SORBY, H., "On the Chromatological relations of _Spongilla
+fluviatilis_," Q. J. Micr. Sci. xv, pp. 47-52.
+
+1878. GANIN, "Zur Entwickelung der _Spongilla fluviatilis_," Zool. Anz.
+I, pp. 195-199.
+
+1882. CARTER, "Spermatozoa, polygonal cell-structure, and the green
+colour in _Spongilla_, together with a new species," Ann. Nat. Hist. (5)
+x, pp. 362-372, pl. 16.
+
+1882. GEDDES, "Further researches on animals containing chlorophyll,"
+Nature, xxv, pp. 303-305, 361-362.
+
+1882. LANKESTER, E. RAY, "On the chlorophyll-corpuscles and amyloid
+deposits of _Spongilla_ and _Hydra_," Q. J. Micr. Sci. xxii (n. s.), pp.
+229-254, pl. xx.
+
+1883. MARSHALL, W., "Einige vorl�utige Bemerkungen �ber die Gemmul� der
+S�sswasserschw�mme," Zool. Anz. vi, pp. 630-634, 648-652.
+
+1884. CARTER, "The branched and unbranched forms of the Freshwater
+Sponges considered generally," Ann. Nat. Hist. (5) xiii, pp. 269-273.
+
+1884. MARSHALL, W., "Vorl�utige Bemerkungen �ber die
+Fortpflanzungsverh�ltnisse von _Spongilla lacustris_," Ber. Naturf. Ges.
+Leipzig,* pp. 22-29.
+
+1884. POTTS, "Freshwater Sponges as improbable causes of the pollution
+of river-water," P. Ac. Philad. pp. 28-30.
+
+1885. SCHULZE, F. E., "�ber das Verh�ltniss der Spongien zu den
+Choanoflagellaten," SB. preuss. Akad. Wiss. Berlin, pp. 179-191.
+
+1886. GOETTE, Untersuchungen zur Entwickelungsgeschichte von _Spongilla
+fluviatilis_*, Hamburg und Leipzig (5 plates).
+
+1886. WIERZEJSKI, "Le d�veloppement des Gemmules des Eponges d'eau douce
+d'Europe," Arch. Slaves Biologie, i, pp. 26-47 (1 plate).
+
+1887. CARTER, "On the reproductive elements of the _Spongida_," Ann.
+Nat. Hist. (5) xix, pp. 350-360.
+
+1889. MAAS, "Zur Metamorphose der Spongillalarve," Zool. Anz. xii, pp.
+483-487.
+
+1890. MAAS, "Ueber die Entwickelung des S�sswasserschw�mmes," Zeitschr.
+Wiss. Zool. 1, pp. 527-554, pls. xxii, xxiii.
+
+1890. WEBER, M. et Mme. A., "Quelques nouveau cas de Symbiose," Zool.
+Ergebn. einer Reise Niederl�nd. Ost-Indien, i, pp. 48-72, pl. v.
+
+1892. ZYKOFF, "Die Entwicklung der Gemmul� der _Ephydatia fluviatilis_
+auct.," Zool. Anz. xv, pp. 95-96.
+
+1892. ZYKOFF, "Die Bildung der Gemmul� bei _Ephydatia Fluviatilis_," Revue
+Sc. Nat. Soc. St. P�tersbourg,* pp. 342-344.
+
+1892. ZYKOFF, "Die Entwicklung der Gemmul� bei _Ephydatia fluviatilis_
+auct.," Bull. Soc. Imp. Natur. Moscou, n. s. vi, pp. 1-16, pl. i, ii.
+
+1892. ZYKOFF, "Entwickelungsgeschichte von _Ephydatia m�lleri_, Liebk.
+aus den Gemmul�," Biol. Centralbl. xii, pp. 713-716.
+
+1893. WELTNER, "Spongillidenstudien, II," Arch. Naturg. Berlin, lix (1),
+pp. 245-282, pls. viii, ix.
+
+1899. EVANS, R., "The structure and metamorphosis of the larva of
+_Spongilla lacustris_," Q. J. Micr. Sci. xlii, pp. 363-476, pls.
+xxxv-xli.
+
+1901. EVANS, R., "A description of _Ephydatia blembingia_, with an
+account of the formation and structure of the gemmule," Q. J. Micr. Sci.
+xliv, pp. 71-109, pls. i-iv.
+
+1907. WELTNER, "Spongillideustudien, V.: Zur Biologie von _Ephydatia
+fluviatilis_ and die Bedeutung der Am�bocyten f�r die Spongilliden,"
+Arch. Naturg. Berlin, lxxiii (i), pp. 273-286.
+
+1907. ANNANDALE, "The buds of _Spongilla proliferens_, Annand.," Rec.
+Ind. Mus. i, pp. 267, 268.
+
+1907. ANNANDALE, "Embryos of _Ephydatia blembingia_, Evans," _ibid._ p.
+269.
+
+1907. ANNANDALE, "The nature of the pores in _Spongilla_," _ibid._ pp.
+270-271.
+
+(c) _Descriptions of Asiatic Species[V] and of Animals associated with
+them._
+
+     [Footnote V: Descriptions of Siberian sponges are not
+     included in these references.]
+
+1847-1848. CARTER, "Notes on the species, structure, and animality of
+the Freshwater Sponges in the tanks of Bombay (Genus _Spongilla_),"
+Trans. Bombay Med. & Phys. Soc., 1847, and Ann. Nat. Hist. (2) i, pp.
+303-311, 1848.
+
+1849. CARTER, "A descriptive account of the Freshwater Sponges (Genus
+_Spongilla_) in the Island of Bombay, with observations on their
+structure and development," Ann. Nat. Hist. (2) iv, pp. 81-100, pls.
+iii-v.
+
+1868. MARTENS, E. VON, "Ueber einige �stasiatische S�sswasserthiere,"
+Arch. Naturg. Berlin, xxxiv, pp. 1-67: IV., Ein S�sswasserschwamm aus
+Borneo, pp. 61-64, pl. i, fig. 1.
+
+1881. CARTER, "On _Spongilla cinerea_," Ann. Nat. Hist. (5) vii, p. 263.
+
+1890. WEBER, M., "Zoologische Ergebnisse einer Reise in Niederl�ndisch
+Ost-Indien," i, pp. 30-47, pl. iv.
+
+1901. EVANS, R., "A description of _Ephydatia blembingia_, with an
+account of the formation and structure of the gemmule," Q. J. Micr. Sci.
+xliv, pp. 71-109, pls. i-iv.
+
+1901. WELTNER, "S�sswasserspongien von Celebes (Spongillidenstudien,
+IV.)," Arch. Naturg. Berlin, lxvii (1) (Special Number), pp. 187-204,
+pls. vi, vii.
+
+1906. ANNANDALE, "A variety of _Spongilla lacustris_ from brackish water
+in Bengal," J. As. Soc. Bengal, (n. s.) ii, pp. 55-58.
+
+1906. ANNANDALE, "Some animals found associated with _Spongilla carteri_
+in Calcutta," _ibid._ pp. 187-196.
+
+1907. WILLEY, "Freshwater Sponge and Hydra in Ceylon," Spolia Zeylanica,
+iv, pp. 184-185.
+
+1907. ANNANDALE, "On Freshwater Sponges from Calcutta and the
+Himalayas," J. As. Soc. Bengal, (n. s.) iii, pp. 15-26.
+
+1907. ANNANDALE, "Gemmules of _Trochospongilla phillottiana_, Annand.,"
+Rec. Ind. Mus. i, p. 269.
+
+1907. ANNANDALE, "Description of two new Freshwater Sponges from Eastern
+Bengal, with remarks on allied forms," _ibid._ pp. 387-392.
+
+1908. ANNANDALE, "Preliminary notice of a collection of Sponges from W.
+India, with descriptions of two new species," Rec. Ind. Mus. ii, pp.
+25-28.
+
+1908. KIRKPATRICK, "Description of a new variety of _Spongilla
+loricata_, Weltner," _ibid._ pp. 97-99.
+
+1908. ANNANDALE, "Preliminary notice of a collection of Sponges from
+Burma, with the description of a new species of _Tubella_," _ibid._ pp.
+157-158.
+
+1909. ANNANDALE, "Report on a small collection of Sponges from
+Travancore," Rec. Ind. Mus. iii, pp. 101-104, pl. xii.
+
+1909. NEEDHAM, "Notes on the Neuroptera in the collection of the Indian
+Museum," _ibid._ pp. 206-207.
+
+1909. ANNANDALE, "Description of a new species of _Spongilla_ from
+Orissa," _ibid._ p. 275.
+
+1909. ANNANDALE, "Beitr�ge zur Kenntnis der Fauna von S�d-Afrika: IX.
+Freshwater Sponges," Zool. Jahrb. (Syst.) xxvii, pp. 559-568.
+
+1909. ANNANDALE, "Report on a collection of Freshwater Sponges from
+Japan," Annot. Zool. Japon, vii, pp. 105-112, pl. ii.
+
+1909. ANNANDALE, "Freshwater Sponges in the collection of the United
+States National Museum: Part I. Specimens from the Philippines and
+Australia," P. U.S. Mus. xxxvi, pp. 627-632.
+
+1909. ANNANDALE, "Freshwater Sponges collected in the Philippines by the
+'Albatross' Expedition," _ibid._ xxxvii, pp. 131-132.
+
+1909. ANNANDALE, "Freshwater Sponges in the collection of the United
+States National Museum: Part II. Specimens from North and South
+America," _ibid._ pp. 401-406.
+
+1910. ANNANDALE, "Freshwater Sponges in the collection of the United
+States National Museum: Part III. Description of a new species of
+_Spongilla_ from China," _ibid._ xxxviii, p. 183.
+
+1910. ANNANDALE, "Description of a new species of Sponge from Cape
+Comorin," Rec. Ind. Mus. v, p. 31.
+
+1910. STEPHENSON, "On some aquatic Oligoch�te worms commensal in
+_Spongilla carteri_," _ibid._ pp. 233-240.
+
+1910. ANNANDALE, "Note on a Freshwater Sponge and Polyzoon from Ceylon,"
+Spolia Zeylanica, vii. p. 63, pl. i.
+
+
+
+
+GLOSSARY OF TECHNICAL TERMS USED IN PART I.
+
+
+  _Amphioxi_ (adj.               Rod-like spicules sharp at both ends.
+  _amphioxous_)
+
+  _Amphistrongyli_ (adj.         Rod-like spicules blunt at both ends.
+  _amphistrongylous_)
+
+  _Basal membrane_               A horny, structureless membrane found
+                                 at the base of some sponges.
+
+  _Birotulate_ (subst. or adj.)  Spicule with a transverse disk at both
+                                 ends.
+
+  _Bubble-cells_                 Spherical cells of the parenchyma the
+                                 contents of which consist of a drop of
+                                 liquid covered by a thin film of
+                                 protoplasm.
+
+  _Ciliated_ (or _flagellated_)  A cavity lined with collar-cells.
+  _chamber_
+
+  _Collar-cell_ (_choanocyte_)   Cell provided at one end with a
+                                 membranous collar and a vibratile lash
+                                 or flagellum that springs from within
+                                 the collar.
+
+  _Derma_ or _ectodermal layer_  A layer of flat cells arranged like a
+                                 pavement on the surface of the sponge.
+
+  _Exhalent_ (or _efferent_)     A tubular canal through which water
+  _canal_                        passes from a ciliated chamber towards
+                                 the osculum.
+
+  _Fibres_ (skeleton)            Thread-like structures that compose the
+                                 skeleton of the sponge and are formed
+                                 (in the Spongillid�) mainly of
+                                 overlapping spicules.
+
+  _Flesh-spicules_               Microscleres (_q. v._) that lie free in
+                                 the parenchyma and the derma.
+
+  _Foramen_                      An orifice of the gemmule.
+
+  _Foraminal tubule_             A horny tube that surrounds the foramina
+                                 of some gemmules.
+
+  _Gemmule_                      A mass of cells packed with food-material,
+                                 surrounded by at least one horny coat,
+                                 capable of retaining vitality in
+                                 unfavourable conditions and finally of
+                                 giving origin to a new sponge.
+
+  _Green corpuscles_             Minute green bodies found inside cells
+                                 of sponges and other animals and
+                                 representing a stage in the life-history
+                                 of an alga (_Chlorella_).
+
+  _Inhalent_ (or _afferent_)     A tubular canal through which water
+  canal                          passes from the exterior towards a
+                                 ciliated chamber.
+
+  _Megascleres_                  The larger spicules that (in the
+                                 Spongillid�) form the basis of the
+                                 skeleton of the sponge.
+
+  _Microscleres_                 Smaller spicules that lie free in the
+                                 substance or the derma of the sponge, or
+                                 are associated with the gemmule.
+
+  _Monaxon_                      (Of spicules) having a single main axis;
+                                 (of sponges) possessing skeleton spicules
+                                 of this type.
+
+  _Osculum_                      An aperture through which water is
+                                 ejected from the sponge.
+
+  _Oscular collar_               A ring-shaped membrane formed by an
+                                 extension of the derma round an osculum.
+
+  _Parenchyma_                   The gelatinous part of the sponge.
+
+  _Pavement layer_               Adherent gemmules arranged close together
+                                 in a single layer at the base of a sponge.
+
+  _Pneumatic coat_               A horny or chitinous layer on the surface
+                                 of the gemmule containing air-spaces.
+                                 If these spaces are of regular form and
+                                 arrangement it is said to be _cellular_;
+                                 if they are minute and irregular it is
+                                 called _granular_.
+
+  _Pore_                         A minute hole through which water is
+                                 taken into the sponge.
+
+  _Pore-cell_ (_porocyte_)       A cell pierced by a pore.
+
+  _Radiating fibres_             Fibres in the skeleton of a sponge that
+                                 are vertical or radiate from its centre.
+
+  _Rotula_                       A transverse disk borne by a microsclere.
+
+  _Rotulate_ (subst. or adj.)    Spicule bearing one or two transverse
+                                 disks.
+
+  _Spicule_                      A minute mineral body of regular and
+                                 definite shape due not to the forces of
+                                 crystallization but to the activity of
+                                 the living cell or cells in which it is
+                                 formed.
+
+  _Spongin_                      The horny substance found in the skeletal
+                                 framework and the coverings of gemmules
+                                 of sponges. Structures formed of
+                                 this substance are often referred to as
+                                 _chitinous_.
+
+  _Subdermal cavity_             A cavity immediately below the derma
+                                 (_q. v._).
+
+  _Transverse fibres_            Fibres in the skeleton of a sponge that
+                                 run across between the radiating fibres.
+
+  _Tubelliform_ (of spicule)     Having a straight shaft with a transverse
+                                 disk at one end and a comparatively
+                                 small knob-like projection at the other.
+
+
+
+
+SYSTEMATIC LIST OF THE INDIAN SPONGILLID�.
+
+
+[Types, schizotypes, or cotypes have been examined in the case of all
+species, &c., whose names are marked thus, *.]
+
+  Genus 1. SPONGILLA, Lamarck (1816).
+    Subgenus A. EUSPONGILLA, Vejdovsky (1883).
+       1.     ? _S. lacustris_, auct. (perhaps in N.W. India).
+       1_a_. _S. lacustris_ subsp. _reticulata_*, Annandale (1907).
+       2.    _S. proliferens_*, Annandale (1907).
+       3.    _S. alba_*, Carter (1849).
+       3_a_. _S. alba_ var. _cerebellata_, Bowerbank (1863).
+       3_b_. _S. alba_ var. _bengalensis_*, Annandale (1906).
+       4.    _S. cinerea_*, Carter (1849).
+       5.    _S. travancorica_*, Annandale (1909).
+       6.    _S. hemephydatia_*, Annandale (1909).
+       7.    _S. crateriformis_* (Potts) (1882).
+    Subgenus B. EUNAPIUS, J. E. Gray (1867).
+       8_a_. _S. carteri_ var. _mollis_*, nov.
+       8_b_. _S. carteri_ var. _cava_*, nov.
+       8_c_. _S. carteri_ var. _lobosa_*, nov.
+       9_a_. _S. fragilis_ subsp. _calcuttana_*, nov.
+       9_b_. _S. fragilis_ var. _decipiens_, Weber (probably Malaysian,
+              not Indian).
+      10.    _S. gemina_*, sp. nov.
+      11.    _S. crassissima_*, Annandale (1907).
+      11_a_. _S. crassissima_ var. _crassior_*, Annandale (1907).
+    Subgenus C. STRATOSPONGILLA, Annandale (1909).
+      12.    _S. indica_*, Annandale (1908).
+      13.    _S. bombayensis_*, Carter (1882).
+      14.    _S. ultima_*, Annandale (1910).
+
+  Genus 2. PECTISPONGILLA, Annandale (1909).
+      15.    _P. aurea_*, Annandale (1909).
+      15_a_. _P. aurea_ var. _subspinosa_*, nov.
+
+  Genus 3. EPHYDATIA, Lamouroux (1816).
+      16.    _E. meyeni_* (Carter) (1849).
+
+  Genus 4. DOSILIA, J. E. Gray (1867).
+      17.    _D. plumosa_* (Carter) (1849).
+
+  Genus 5. TROCHOSPONGILLA, Vejdovsky (1883).
+      18.    _T. latouchiana_*, Annandale (1907).
+      19.    _T. phillottiana_*, Annandale (1907).
+      20.    _T. pennsylvanica_* (Potts) (1882).
+
+  Genus 6. TUBELLA, Carter (1881).
+      21.    _T. vesparioides_*, Annandale (1908).
+
+  Genus 7. CORVOSPONGILLA, nov.
+      22.    _C. burmanica_* (Kirkpatrick) (1908).
+      23.    _C. lapidosa_* (Annandale) (1908).
+
+
+Order HALICHONDRINA.
+
+
+Siliceous monaxon sponges in which the horny skeleton is much reduced or
+absent and the spicular skeleton is more or less definitely reticulate.
+The microscleres are usually rod-like and rarely have more than one main
+axis.
+
+
+Family SPONGILLID�.
+
+SPONGILLAD�, J. E. Gray, P. Zool. Soc. London, 1867, p. 550.
+
+Freshwater Halichondrina which at certain seasons produce gemmules armed
+with peculiar microscleres. Two distinct kinds of microsclere are often
+present, that associated with the gemmule sometimes consisting of a
+vertical shaft at the ends of which transverse disks or rotul� are
+borne. There is always at least a trace of a subdermal cavity.
+
+Many authors divide the Spongillid� into two subfamilies:--Spongillin�
+(or Euspongillin�), in which the gemmule-spicules have no transverse
+rotul�, and Meyenin� (or Ephydatiin�), in which they have rotules at one
+or both ends. So gradual, however, is the transition that I find it
+difficult to decide in one instance to which of two genera, typical
+respectively of the two "subfamilies," a species should be assigned.
+Minchin in his account of the Porifera in Lankester's "Treatise on
+Zoology" (1900) regards the Spongillid� merely as a subfamily of the
+Heterorrhaphid�, and there certainly are few differences of a definite
+nature between them and the marine family (or subfamily) Remerid�.
+
+
+  _Key to the Indian Genera of_ Spongillid�.
+
+    I. Microscleres without transverse disks.
+       A. Microscleres of the parenchyma similar
+          in general structure to those or the
+          gemmule; the latter without comb-like
+          vertical rows of spines at the ends           SPONGILLA, p. 67.
+       B. Microscleres of the gemmule with comb-like
+          vertical rows of spines at both ends    PECTISPONGILLA, p. 106.
+
+   II. Some or all of the microscleres birotulate.
+       (Birotulate microscleres of one kind only.)
+       A. Microscleres of the gemmule birotulate, the
+          rotules with serrated or strongly sinuous
+          edges; parenchyma spicules usually absent,
+          never of complicated structure               EPHYDATIA, p. 108.
+       B. Microscleres of the gemmule as in
+          _Ephydatia_; microscleres of the parenchyma
+          consisting of numerous shafts
+          meeting in different planes in a central
+          nodule                                         DOSILIA, p. 110.
+       C. Microscleres as in _Ephydatia_ except
+          that the rotul� of the gemmule-spicules
+          have smooth edges                      TROCHOSPONGILLA, p. 113.
+       D. Microscleres of the gemmule without a
+          trace of rotules, those of the parenchyma
+          birotulate                        CORVOSPONGILLA, nov., p. 122.
+
+  III. Microscleres of the gemmule with a well-developed
+       basal rotule and a vertical shaft
+       ending above in a mere knob.                      TUBELLA, p. 120.
+
+The most distinct genus of Spongillid� not yet found in India is
+_Heteromeyenia_, Potts. It is easily distinguished from all others by
+the fact that the birotulate spicules of the gemmule are of two quite
+distinct kinds, which occur together on every mature gemmule.
+_Heteromeyenia_ is represented by several American species, one of which
+has been found in Europe. _Acalle_, J. E. Gray, which is represented by
+a single South American species (_Spongilla recurvata_, Bowerbank), is
+related to _Heteromeyenia_ but has one kind of gemmule-spicule
+tubelliform, the other birotulate. Probably _Uraguaya_, Carter, should
+be regarded as a subgenus of _Trochospongilla_ with an unusually solid
+skeleton; it is peculiar to S. America. _Parmula_, Carter (=_Drulia_,
+Gray) includes South American forms allied to _Tubella_, but with the
+shaft of the gemmule-spicule degenerate and consisting of a mere
+projection in the centre of a shield-like body, which represents the
+lower rotule. The status of _Potamolepis_, Marshall, originally
+described from the Lake of Galilee, is very doubtful; possibly some or
+all of its species belong to the subgenus of _Spongilla_ here called
+_Stratospongilla_ (p. 100); but they are stated never to produce
+gemmules. The same is the case as regards _Pachydictyum_, Weltner, which
+consists of a single species from Celebes.
+
+The sponges from Lake Baikal assigned by Weltner (Arch. Naturg. lxi (i)
+p. 131) to the subfamily Lubomirskin� are of doubtful position and need
+not be considered here; while _Lessepsia_, Keller, from one of the salt
+lakes on the Suez Canal, certainly does not belong to the family,
+although it is assigned to it by von Lendenfeld (Mon. Horny Sponges, p.
+904 (1889)) and subsequently by Minchin (Porifera, p. 152, in
+Lankester's Treatise on Zoology, part ii (1900)).
+
+
+Genus 1. SPONGILLA, _Lamarck_ (Carter _emend._).
+
+    _Spongilla_, Lamarck, Histoire des Animaux sans Vert�bres, ii, p. 111
+      (1836).
+    _Spongilla_, Carter, Ann. Nat. Hist. (5) vii, p. 86 (1881).
+    _Euspongilla_, Vejdovsky, Abh. B�hm. Ges. xii, p. 15 (1883).
+    _Spongilla_, Potts, P. Ac. Philad. 1887, p. 182.
+
+TYPE, _Spongilla lacustris_, auctorum.
+
+Spongillid� in which the gemmules have (normally) cylindrical or
+subcylindrical spicules that are sharp or blunt at the ends, without a
+distinct transverse disk or disks and without comb-like vertical rows of
+spines.
+
+The skeleton is variable in structure, sometimes being almost amorphous,
+sometimes having well-defined radiating and transverse fibres firmly
+compacted with spongin. The skeleton-spicules are either sharp or blunt
+at the ends. Flesh-spicules are often absent; when present they are
+needle-like and resemble the gemmule-spicules in general structure; they
+have not even rudimentary rotules at their ends. The gemmules either lie
+free in the substance of the sponge or are attached to its support;
+sometimes they adhere together in free or attached groups.
+
+_Spongilla_ is undoubtedly the most primitive genus of the Spongillid�,
+its spicules showing less sign of specialization than those of any other
+genus included in the family. As a fossil it goes back at any rate to
+the Upper Jurassic (p. 52).
+
+GEOGRAPHICAL DISTRIBUTION.--Cosmopolitan. In most countries the majority
+of the freshwater sponges belong to this genus, but in Japan _Ephydatia_
+seems to predominate.
+
+
+_Key to the Indian Species of_ Spongilla.
+
+  I. Gemmule provided with a thick, apparently
+      granular pneumatic coat in
+      which the gemmule-spicules are arranged
+      tangentially or vertically. (Subgenus
+      _Euspongilla_, p. 69.)
+    A. No foraminal tubule.
+      _a._  Sponge bright green, soft and
+            compressiblewhen fresh, very fragile
+            dry                                    _lacustris_, p. 69.
+      _a'._ Sponge white or grey, hard both
+            fresh and dry                          _alba_, p. 76.
+    B. A foraminal tubule present.
+      _b._  Skeleton-spicules smooth.
+        beta.   Gemmules free; gemmule-spicules
+                arranged tangentially and
+                horizontally                       _proliferens_, p. 72.
+        beta'.  Gemmules free; gemmule-spicules
+                arranged vertically or nearly
+                so in a single series              _hemephydatia_, p. 82.
+        beta''. Gemmules firmly fixed
+                to the support of the sponge;
+                gemmule-spicules almost vertical,
+                irregularly arranged, as a rule in
+                more than one series               _travancorica_, p. 81.
+      _b'._ Skeleton-spicules spiny or
+            irregular in outline.
+        beta'''. Gemmule-spicules tangential
+                 and horizontal, without
+                 rudimentary rotules               _cinerea_, p. 79.
+        beta''''. Gemmule-spicules vertical or
+                 nearly so, often with
+                 rudimentary rotules at the tips   _crateriformis_, p. 83.
+
+  II. Gemmules surrounded in several layers
+      by distinct polygonal air-spaces with
+      chitinous walls. (Subgenus _Eunapius_,
+      p. 86.)
+    A. Gemmules single. Skeleton- and
+       gemmule-spicules smooth, pointed,
+       not very stout                              _carteri_, p. 87.
+    B. Gemmules bound together in pairs.
+       Skeleton friable; skeleton-spicules
+       slender                                     _gemina_, nov., p. 97.
+    C. Gemmules bound together in free
+       groups of more than two or forming
+       a "pavement-layer" at the base of
+       the sponge.
+      _c._  Skeleton friable;
+            skeleton-spicules slender              _fragilis_, p. 95.
+      _c'._ Skeleton very hard and
+            resistant; skeleton-spicules stout     _crassissima_, p. 98.
+
+  III. Gemmules without or with irregular
+       pneumatic coat, covered by a chitinous
+       membrane or membranes in which the
+       gemmule-spicules lie parallel to the
+       surface. (Subgenus _Stratospongilla_,
+       p. 100.)
+
+    A. Skeleton spicules spiny or irregular in
+       outline.
+
+      _a._  Skeleton-spicules blunt; gemmules
+            covered by a single chitinous
+            membrane                               _indica_, p. 100.
+
+      _a'._ Skeleton-spicules sharp; gemmules
+            covered by two chitinous membranes     _bombayensis_, p. 102.
+
+    B. Skeleton-spicules smooth.
+       Skeleton-spicules sharp; gemmule
+       spicules very irregular in form             _ultima_, p. 104.
+
+
+Subgenus A. EUSPONGILLA, _Vejdovsky_.
+
+    _Euspongilla_, Vejdovsky, Abh. B�hm. Ges. xii, p. 15 (1883).
+    _Euspongilla_, _id._, in Potts's "Fresh-Water Sponges," P. Ac. Philad.
+      1887, p. 172.
+    _Euspongilla_, Weltner, in Zacharias's Tier- und Pflanzenwelt des
+      S�sswassers, i, p. 210 (1891).
+
+TYPE, _Spongilla lacustris_, auctorum.
+
+Spongill� in which the gemmules are covered with a thick, apparently
+granular pneumatic coat. A delicate membrane often occurs outside this
+coat, but it is never thick or horny. The gemmules usually lie free in
+the sponge but sometimes adhere to its support; rarely they are fastened
+together in groups (_e. g._ in _S. aspinosa_, Potts). The
+skeleton-spicules are never very stout and the skeleton is always
+delicate.
+
+The species in this subgenus are closely allied and must be
+distinguished rather by the sum of their peculiarities than by any one
+character. They occur in all countries in which Spongillid� are found.
+Seven Indian species may be recognized.
+
+
+1. Spongilla lacustris, _auctorum_.
+
+    _Spongilla lacustris_, Bowerbank, P. Zool. Soc. London, 1863, p. 441,
+      pl. xxxviii, fig. 14.
+    _Spongilla lacustris_, Carter, Ann. Nat. Hist. (5) vii, p. 87 (1881).
+    _Euspongilla lacustris_, Vejdovsky, in Potts's "Fresh-Water Sponges,"
+      P. Ac. Philad. 1887, p. 172.
+    _Spongilla lacustris_, Potts, _ibid._, p. 186, pl. v, fig. 1, pl. vii,
+      figs. 1-6.
+    _Euspongilla lacustris_, Weltner, in Zacharias's Tier- und Pflanzenwelt
+      des S�sswassers, i, p. 211, figs. 36-38 (1891).
+    _Spongilla lacustris_, _id._, Arch. Naturg. lxi (i), pp. 118, 133-135
+      (1895).
+    _Spongilla lacustris_, Annandale, J. Linn. Soc., Zool., xxx, p. 245
+      (1908).
+
+     [I have not attempted to give a detailed synonymy of this
+     common species. There is no means of telling whether many of
+     the earlier names given to forms or allies of _S. lacustris_
+     are actual synonyms, and it would serve no useful purpose,
+     so far as the fauna of India is concerned, to complicate
+     matters by referring to obscure descriptions or possible
+     descriptions of a species only represented in India, so far
+     as we know, by a specialized local race, to which separate
+     references are given.]
+
+_Sponge_ soft and easily compressed, very brittle when dry, usually
+consisting of a flat or rounded basal portion of no great depth and of
+long free cylindrical branches, which droop when removed from the water;
+branches occasionally absent. Colour bright green when the sponge is
+growing in a strong light, dirty flesh-colour when it is growing in the
+shade. (Even in the latter case traces of the "green corpuscles" can be
+detected in the cells of the parenchyma.) Oscula star-shaped, of
+moderate size, as a rule rendered conspicuous by the furrows that
+radiate from them over the outer surface of the parenchyma below the
+external membrane; oscular collars well developed.
+
+_Skeleton_ reticulate, loose, with definite radiating and transverse
+fibres held together by a small quantity of spongin; the fibres slender
+but not extremely so.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, long, slender.
+Flesh-spicules slender, covered with small spines, sharply pointed,
+nearly straight. Gemmule-spicules resembling the flesh-spicules but
+shorter and as a rule more strongly curved, sometimes bent so as to form
+semicircular figures, usually pointed somewhat abruptly; their spines
+relatively longer than those of the flesh-spicules, often curved
+backwards, especially near the ends of the spicules, at which points
+they are often longer than elsewhere.
+
+_Gemmules_ usually numerous in autumn, lying free in the sponge,
+spherical, variable in size but usually rather large, as a rule covered
+with a thick granular coat in which the spicules are arranged
+tangentially; a horizontal layer of spicules often present in the
+external membrane; the granular coat and its spicules occasionally
+deficient. No foraminal tubule; its place sometimes taken by an open,
+bowl-shaped chitinous structure the base of which is in continuity with
+the inner chitinous coat of the gemmule.
+
+_S. lacustris_ is an extremely variable species, varying in the size,
+proportions and shape of its spicules, in its external form and in the
+size and structure of the gemmule. A considerable number of varieties
+have been described from different parts of Europe and N. America, but
+some of these may represent distinct but closely-allied species;
+descriptions of most of them will be found in Potts's "Fresh-Water
+Sponges." The embryology and the earlier stages of the development from
+the egg have been described in great detail by Evans (Quart. J. Micr.
+Sci. (n. s.) xlii, p. 363 (1899)), while the anatomy and physiology are
+discussed by most authors who have written on these features in the
+Spongillid�.
+
+TYPE.--It is impossible to say who was the first authority to use the
+name _Spongilla lacustris_ in the sense in which it is used by recent
+authors. No type can therefore be recognized.
+
+GEOGRAPHICAL DISTRIBUTION.--_S. lacustris_ occurs all over Europe and N.
+America and is probably the commonest species in most parts of both
+continents. It has also been found in Northern Asia and may occur in the
+Himalayan lakes and in the north-west of India.
+
+
+1 _a._ Subspecies reticulata*, _Annandale_.
+
+     _Spongilla reticulata_, Annandale, Rec. Ind. Mus. i, p. 387,
+     pl. xiv, fig. 1 (1907).
+
+     _Spongilla lacustris_ subspecies _reticulata_, _id._, P.
+     U.S. Mus. xxxvii, p. 401 (1909).
+
+This race differs from the typical _S. lacustris_ in the following
+particulars:--
+
+     (1) The branches are always compressed and anastomose
+     freely when well developed (fig. 5, p. 37);
+
+     (2) the skeleton-fibres are finer;
+
+     (3) the skeleton-spicules are longer;
+
+     (4) the gemmule-spicules are longer and more slender and are
+     never strongly bent.
+
+[Illustration: Fig. 8.
+
+A=gemmule-spicules of _Spongilla lacustris_ subsp. _reticulata_ (from
+type); B=gemmule-spicules of _S. alba_ from Calcutta: both highly
+magnified.]
+
+As regards the form of the skeleton- and gemmule-spicules and also that
+of the branches the subspecies _reticulata_ resembles _S. alba_ rather
+than _S. lacustris_, but owing to the fact that it agrees with _S.
+lacustris_ in its profuse production of branches, in possessing green
+corpuscles and in its fragility, I think it should be associated with
+that species.
+
+The branches are sometimes broad (fig. 5, p. 37), sometimes very
+slender. In the latter condition they resemble blades of grass growing
+in the water.
+
+TYPE in the Indian Museum; a co-type in the British Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--All over Eastern India and Burma; also in
+the Bombay Presidency. _Localities:_--BENGAL, Port Canning, Ganges
+delta; Rajshahi (Rampur Bhulia) on the Ganges, 150 miles N. of Calcutta
+(_Annandale_); Puri district, Orissa (_Annandale_); R. Jharai, Siripur,
+Saran district, Tirhut (_M. Mackenzie_): MADRAS PRESIDENCY, Madras
+(town) (_J. R. Henderson_): BOMBAY PRESIDENCY, Igatpuri, W. Ghats
+(_Annandale_).
+
+BIOLOGY.--This subspecies is usually found in small masses of water,
+especially in pools of rain-water, but Mr. Mackenzie found it growing
+luxuriantly in the Jharai at a time of flood in September. It is very
+abundant in small pools among the sand-dunes that skirt the greater part
+of the east coast of India. Here it grows with great rapidity during the
+"rains," and often becomes desiccated even more rapidly as soon as the
+rain ceases. As early in the autumn as October I have seen masses of the
+sponge attached, perfectly dry, to grass growing in the sand near the
+Sur Lake in Orissa. They were, of course, dead but preserved a life-like
+appearance. Some of them measured about six inches in diameter. At Port
+Canning the sponge grows during the rains on the brickwork of bridges
+over ditches of brackish water that dry up at the beginning of winter,
+while at Rajshahi and at Igatpuri I found it at the edges of small
+ponds, at the latter place in November, at the former in February.
+Specimens taken at Madras by Dr. Henderson during the rains in small
+ponds in the sand contained no gemmules, but these structures are very
+numerous in sponges examined in autumn or winter.
+
+Numerous larv� of _Sisyra indica_ (p. 92) were found in this sponge at
+Rajshahi. Unlike those obtained from _S. alba_, they had a green colour
+owing to the green matter sucked from the sponge in their stomachs. The
+_coralloides_ phase of _Plumatella fruticosa_ (p. 219) was also found in
+_S. lacustris_ subsp. _reticulata_ at Rajshahi.
+
+So far as my experience goes, this subspecies has always a bright green
+colour due to the presence of "green corpuscles," even when it is
+growing in a pond heavily shaded by trees or under the arch of a small
+bridge. Probably the more intense light of India enables the corpuscles
+to flourish in situations in which in Europe they would lose their
+chlorophyll.
+
+
+2. Spongilla proliferens*, _Annandale_.
+
+     _Spongilla cinerea_, Weber (_nec_ Carter), Zool. Ergeb.
+     Niederl. Ost-Ind. vol. i, pp. 35, 46 (1890).
+
+     _Spongilla proliferens_, Annandale, J. Asiat. Soc. Bengal,
+     1907, p. 15, fig. 1.
+
+     _Spongilla proliferens_, _id._, Rec. Ind. Mus. i, pp. 267,
+     271 (1907).
+
+_Sponge_ forming soft, shallow cushions rarely more than 10 cm. in
+diameter on the leaves of water-plants, or small irregular masses on
+their roots and stems. Colour bright green. Oscula moderate, flat,
+surrounded by deep, cone-shaped collars; radiating furrows and canals in
+the parenchyma surrounding them often deep. External pores contained
+normally in single cells. The surface frequently covered by small
+rounded buds; true branches if present more or less flattened or
+conical, always short, as a rule absent.
+
+_Skeleton_ loose, feebly reticulate at the base of the sponge;
+transverse fibres slender in the upper part of the sponge, often
+scarcely recognizable at its base. Very little spongin present.
+
+_Spicules._ Skeleton-spicules long, smooth, sharply pointed; the length
+on an average at least 20 times the greatest breadth, often more.
+Flesh-spicules slender, gradually pointed, nearly straight, covered with
+minute straight or nearly straight spines. Gemmule-spicules very
+similar, but usually a little stouter and often blunt at the ends; their
+spines rather longer than those on the flesh-spicules, usually more
+numerous near the ends than in the middle of the spicule, slightly
+retroverted, those at the extreme tips often so arranged as to suggest a
+rudimentary rotule.
+
+[Illustration: Fig. 9.--Gemmule of _Spongilla proliferens_ as seen in
+optical section (from Calcutta), � 140.]
+
+_Gemmules_ usually numerous, lying free near the base of the sponge,
+very variable in size, spherical, surrounded by a thick granular layer
+in which the spicules, which are always very numerous, are arranged
+tangentially, their position being more near the vertical than the
+horizontal; a few horizontal spicules usually present on the external
+surface of the gemmule, which frequently has a ragged appearance owing
+to some of the tangential spicules protruding further than others.
+Foraminal tubule stout, cylindrical, usually somewhat contorted; its
+orifice irregular in outline. Sometimes more than one foramen present.
+
+_S. proliferens_ can be distinguished from all forms of _S. lacustris_
+and _S. alba_ by the fact that its gemmules possess a foraminal tubule;
+from _S. cinerea_ it can be distinguished by its colour and its smooth
+skeleton-spicules, and from _S. travancorica_ by its free gemmules. I
+have been enabled by the kindness of Prof. Max Weber to examine
+specimens from Celebes and Java identified by him as _S. cinerea_,
+Carter, and have no doubt that they belong to my species.
+
+TYPE in the Indian Museum; a co-type in the British Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--All over Eastern India and Burma; also in
+Cochin on the west coast; Ceylon; W. China; Java, Flores and Celebes.
+_Localities_:--BENGAL, Calcutta and neighbourhood (_Annandale_);
+Berhampore, Murshidabad district (_R. E. Lloyd_): ASSAM, Mangal-dai near
+the Bhutan frontier (_S. W. Kemp_): MADRAS PRESIDENCY, Madras (town) and
+neighbourhood (_J. R. Henderson_); Rambha, Ganjam district
+(_Annandale_); Bangalore, Mysore (alt. _ca._ 3000 ft.) (_Annandale_);
+Ernakulam and Trichur, Cochin (_G. Mathai_): BURMA, Rangoon
+(_Annandale_, _J. Coggin Brown_); Prome, Upper Burma (_J. Coggin
+Brown_); Kawkareik, Amherst district, Tenasserim (_Annandale_): CEYLON,
+between Maradankawela and Galapita-Gala, North Central Province
+(_Willey_). Mr. J. Coggin Brown has recently brought back specimens from
+Yunnan.
+
+BIOLOGY.--_S. proliferens_ is usually found in ponds which never dry up;
+Prof. Max Weber found it in small streams in Malaysia. It is common in
+India on the leaves of _Vallisneria_ and _Limnanthemum_, on the roots of
+_Pistia stratiotes_ and on the stems of rushes and grass. So far as I
+have been able to discover, the life of the individual sponge is short,
+only lasting a few weeks.
+
+Sexual reproduction occurs seldom or never, but reproduction by means of
+buds and gemmules continues throughout the year. The former is a rare
+method of reproduction in most Spongillid� but in this species occurs
+normally and constantly, the buds being often very numerous on the
+external surface. They arise a short distance below the surface as
+thickenings in the strands of cells that accompany the radiating fibres
+of the skeleton. As they grow they push their way up the fibres, forcing
+the external membrane outwards. The membrane contracts gradually round
+their bases, cuts off communication between them and the parent sponge
+and finally sets them adrift. No hole remains when this takes place, for
+the membrane closes up both round the base of the bud and over the
+aperture whence it has emerged.
+
+The newly liberated bud already possesses numerous minute pores, but as
+yet no osculum; its shape exhibits considerable variation, but the end
+that was farthest from the parent-sponge before liberation is always
+more or less rounded, while the other end is flat. The size also varies
+considerably. Some of the buds float, others sink. Those that float do
+so either owing to their shape, which depends on the degree of
+development they have reached before liberation, or to the fact that a
+bubble of gas is produced in their interior. The latter phenomenon only
+occurs when the sun is shining on the sponge at the moment they are set
+free, and is due to the action of the chlorophyll of the green bodies so
+abundant in certain of the parenchyma cells of this species. If the
+liberation of the bud is delayed rather longer than usual, numbers of
+flesh-spicules are produced towards the ends of the primary
+skeleton-fibres and spread out in one plane so as to have a fan-like
+outline; in such buds the form is more flattened and the distal end less
+rounded than in others, and the superficial area is relatively great, so
+that they float more readily. Those buds that sink usually fall in such
+a way that their proximal, flattened end comes in contact with the
+bottom or some suspended object, to which it adheres. Sometimes,
+however, owing to irregularity of outline in the distal end, the
+proximal end is uppermost. In this case it is the distal end that
+adheres. Whichever end is uppermost, it is in the uppermost end, or as
+it may now be called, the upper surface, that the osculum is formed.
+Water is drawn into the young sponge through the pores and, finding no
+outlet, accumulates under the external membrane, the subdermal cavity
+being at this stage even larger than it is in the adult sponge.
+Immediately after adhesion the young sponge flattens itself out. This
+process apparently presses together the water in the subdermal cavity
+and causes a large part of it to accumulate at one point, which is
+usually situated near the centre of the upper surface. A transparent
+conical projection formed of the external membrane arises at this point,
+and at the tip of the cone a white spot appears. What is the exact cause
+of this spot I have not yet been able to ascertain, but it marks the
+point at which the imprisoned water breaks through the expanded
+membrane, thus forming the first osculum. Before the aperture is formed,
+it is already possible to distinguish on the surface of the parenchyma
+numerous channels radiating from the point at which the osculum will be
+formed to the periphery of the young sponge. These channels as a rule
+persist in the adult organism and result from the fact that the inhalent
+apertures are situated at the periphery, being absent from both the
+proximal and the distal ends of the bud. In the case of floating buds
+the course of development is the same, except that the osculum, as in
+the case of development from the gemmule in other species (see Zykoff,
+Biol. Centrbl. xii, p. 713, 1892), is usually formed before adhesion
+takes place.
+
+The sponge of _S. proliferens_ is usually too small to afford shelter to
+other animals, and I have not found in it any of those commonly
+associated with _S. carteri_ and _S. alba_.
+
+Owing to its small size _S. proliferens_ is more easily kept alive in an
+aquarium than most species, and its production of buds can be studied in
+captivity. In captivity a curious phenomenon is manifested, viz. the
+production of extra oscula, often in large numbers. This is due either
+to a feebleness in the currents of the sponge which makes it difficult
+to get rid of waste substances or to the fact that the canals get
+blocked. The effluent water collects in patches under the external
+membrane instead of making its way out of the existing oscula, and new
+oscula are formed over these patches in much the same way as the first
+osculum is formed in the bud.
+
+
+3. Spongilla alba*, _Carter_.
+
+     _Spongilla alba_, Carter, J. Bombay Asiat. Soc. iii, p. 32,
+     pl. i, fig. 4 & Ann. Nat. Hist. (2) iv, p. 83, pl. iii, fig.
+     4 (1849)
+
+     _Spongilla alba_, Bowerbank, P. Zool. Soc. London, 1863, p.
+     463 pl. xxxviii, fig. 15.
+
+     _Spongilla alba_, Carter, Ann. Nat. Hist. (5) vii, p. 88
+     (1881).
+
+     _Spongilla alba_, Petr, Rozp. Ceske Ak. Praze, Tr�da, ii,
+     pl. i, figs. 3-6 (1899) (text in Czech).
+
+     _Spongilla alba_, Annandale, Rec. Ind. Mus. i, p. 388, pl.
+     xiv, fig. 2 (1907).
+
+_Sponge_ forming masses of considerable area, but never of more than
+moderate depth or thickness. Surface smooth and undulating or with
+irregular or conical projections; sponge hard but brittle; colour white
+or whitish; oscula of moderate or large size, never very conspicuous;
+radiating furrows absent or very short; external membrane adhering to
+the substance of the sponge.
+
+_Skeleton_ forming a moderately dense network of slender radiating and
+transverse fibres feebly held together; little spongin present; the
+meshes much smaller than in _S. lacustris_ or _S. proliferens_.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, slender, feebly
+curved. Gemmule-spicules (fig. 8, p. 71) slender, cylindrical, blunt or
+abruptly pointed at the ends, feebly curved, bearing relatively long
+backwardly directed spines, which are usually more numerous at the ends
+than near the middle of the shaft. Flesh-spicules very numerous in the
+parenchyma and especially the external membrane, as a rule considerably
+more slender and more sharply pointed than the gemmule-spicules, covered
+with straight spines which are often longer at the middle of the shaft
+than at the ends.
+
+_Gemmules_ usually of large size, with a moderately thick granular
+layer; spicules never very numerous, often lying horizontally on the
+external surface of the gemmule as well as tangentially in the granular
+layer; no foraminal tubule; a foraminal cup sometimes present.
+
+
+3_a_. Var. cerebellata, _Bowerbank_.
+
+     _Spongilla cerebellata_, Bowerbank, P. Zool. Soc. London,
+     1863, p. 465, pl. xxxviii, fig. 16.
+
+     _Spongilla alba_ var. _cerebellata_, Carter, Ann. Nat. Hist.
+     (5) vii, p. 88 (1881).
+
+     _Spongilla cerebellata_, Weltner, Arch. Naturg. lxi (i), p.
+     117 (1895).
+
+     _Spongilla cerebellata_, Kirkpatrick, Ann. Nat. Hist. (7)
+     xx, p. 523 (1907).
+
+This variety is distinguished from the typical form by the total absence
+of flesh-spicules. The gemmule-spicules are also more numerous and cross
+one another more regularly.
+
+
+3_b_. Var. bengalensis*, _Annandale_. (Plate I, figs. 1-3.)
+
+     _Spongilla lacustris_ var. _bengalensis_, Annandale, J.
+     Asiat. Soc. Bengal, 1906, p. 56.
+
+     _Spongilla alba_ var. _marina_, _id._, Rec. Ind. Mus. i, p.
+     389 (1907).
+
+The sponge is either devoid of branches or produces irregular,
+compressed, and often digitate processes, sometimes of considerable
+length and delicacy. Flesh-spicules are usually present throughout the
+sponge, but are sometimes absent from one part of a specimen and present
+in others. Some of the gemmules are often much smaller than the others.
+Perhaps this form should be regarded as a phase rather than a true
+variety (see p. 18).
+
+All forms of _S. alba_ can be distinguished from all forms of _S.
+lacustris_ by the much closer network of the skeleton and by the
+consequent hardness of the sponge; also by the complete absence of green
+corpuscles.
+
+TYPES. The types of the species and of the var. _cerebellata_ are in the
+British Museum, with fragments of the former in the Indian Museum; that
+of var. _bengalensis_ is in the Indian Museum, with a co-type in London.
+
+GEOGRAPHICAL DISTRIBUTION.--India And Egypt. _Localities_:--BOMBAY
+PRESIDENCY, island of Bombay (_Carter_); Igatpuri, W. Ghats
+(_Annandale_): BENGAL, Calcutta; Port Canning, Ganges delta (var.
+_bengalensis_) (_Annandale_); Garia, Salt Lakes, nr. Calcutta (var.
+_bengalensis_) (_B. L. Chaudhuri_); Chilka Lake, Orissa (var.
+_bengalensis_) (_Gopal Chunder Chatterjee_): MADRAS PRESIDENCY, Rambha,
+Ganjam district (_Annandale_): NIZAM'S TERRITORY, Aurangabad
+(_Bowerbank_, var. _cerebellata_). The var. _cerebellata_ has also been
+taken near Cairo.
+
+BIOLOGY.--The typical form of the species is usually found growing on
+rocks or bricks at the edges of ponds, while the variety _bengalensis_
+abounds on grass-roots in pools and swamps of brackish water in the
+Ganges delta and has been found on mussel-shells (_Modiola jenkinsi_,
+Preston) in practically salt water in the Chilka Lake. Carter procured
+the typical form at Bombay on stones which were only covered for six
+months in the year, and "temporarily on floating objects." In Calcutta
+this form flourishes in the cold weather on artificial stonework in the
+"tanks" together with _S. carteri_, _S. fragilis_, _Ephydatia meyeni_,
+and _Trochospongilla latouchiana_.
+
+The variety _bengalensis_ is best known to me as it occurs in certain
+ponds of brackish water at Port Canning on the Mutlah River, which
+connects the Salt Lakes near Calcutta with the sea. It appears in these
+ponds in great luxuriance every year at the beginning of the cold
+weather and often coats the whole edge for a space of several hundred
+feet, growing in irregular masses which are more or less fused together
+on the roots and stems of a species of grass that flourishes in such
+situations. Apparently the tendency for the sponges to form branches is
+much more marked in some years than in others (see Pl. I, figs. 1-3).
+The gemmules germinate towards the end of the "rains," and large masses
+of sponge are not formed much before December. At this season, however,
+the level of the water in the ponds sinks considerably and many of the
+sponges become dry. If high winds occur, the dry sponges are broken up
+and often carried for considerable distances over the flat surrounding
+country. In January the gemmules floating on the surface of the ponds
+form a regular scum. _S. alba_ var. _bengalensis_ is the only sponge
+that occurs in these ponds at Port Canning, but _S. lacustris_, subsp.
+_reticulata_, is occasionally found with it on brickwork in the ditches
+that drain off the water from the neighbouring fields into the Mutlah
+estuary. The latter sponge, however, perishes as these ditches dry up,
+at an earlier period than that at which _S. alba_ reaches its maximum
+development.
+
+The larv� of _Sisyra indica_ are commonly found in the oscula of the
+typical form of _S. alba_ as well as in those of _S. lacustris_ subsp.
+_reticulata_, and _S. carteri_; but the compact structure of the sponge
+renders it a less suitable residence for other _incol�_ than _S.
+carteri_.
+
+In the variety _bengalensis_, as it grows in the ponds at Port Canning,
+a large number of arthropods, molluscs and other small animals take
+shelter. Apart from protozoa and rotifers, which have as yet been little
+studied, the following are some of the more abundant inhabitants of the
+sponge:--The sea-anemone, _Sagartia schilleriana_ subsp. _exul_ (see p.
+140), which frequently occurs in very large numbers in the broader
+canals; the free-living nematode, _Oncholaimus indicus_[W], which makes
+its way in and out of the oscula; molluscs belonging to several species
+of the genus _Corbula_, which conceal themselves in the canals but are
+sometimes engulfed in the growing sponge and so perish; young
+individuals of the crab _Varuna litterata_, which hide among the
+branches and ramifications of the larger sponges together with several
+small species of prawns and the schizopod _Macropsis orientalis_[X]; the
+peculiar amphipod _Quadrivisio bengalensis_[Y], only known from the
+ponds at Port Canning, which breeds in little communities inside the
+sponge; a small isopod[Z], allied to _Sph�roma walkeri_, Stebbing; the
+larva of a may-fly, and those of at least two midges (Chironomid�).
+
+     [Footnote W: O. von Linstow, Rec. Ind. Mus. i, p. 45
+     (1907).]
+
+     [Footnote X: W. M. Tattersall, _ibid._, ii, p. 236 (1908).]
+
+     [Footnote Y: T. R. R. Stebbing, _ibid._, i, p. 160 (1907);
+     and N. Annandale, _ibid._, ii, p. 107 (1908).]
+
+     [Footnote Z: Mr. Stebbing has been kind enough to examine
+     specimens of this isopod, which he will shortly describe in
+     the Records of the Indian Museum. _S. walkeri_, its nearest
+     ally, was originally described from the Gulf of Manaar,
+     where it was taken in a tow-net gathering (see Stebbing in
+     Herdman's Report on the Ceylon Pearl Fisheries, pt. iv, p.
+     31 (1905)).]
+
+The peculiarly mixed nature (marine and lacustrine) of the fauna
+associated with _S. alba_ in the ponds at Port Canning is well
+illustrated by this list, and it only remains to be stated that little
+fish (_Gobius alcockii_, _Barbus stigma_, _Haplochilus melanostigma_,
+_H. panchax_, etc.) are very common and feed readily on injured sponges.
+They are apparently unable to attack a sponge so long as its external
+membrane is intact, but if this membrane is broken, they swarm round the
+sponge and devour the parenchyma greedily. In fresh water one of these
+fishes (_Gobius alcockii_, see p. 94) lays its eggs in sponges.
+
+The chief enemy of the sponges at Port Canning is, however, not an
+animal but a plant, viz., a green filamentous alga which grows inside
+the sponge, penetrating its substance, blocking up its canals and so
+causing it to die. Similar alg� have been described as being beneficial
+to the sponges in which they grow[AA], but my experience is that they
+are deadly enemies, for the growth of such alg� is one of the
+difficulties which must be fought in keeping sponges alive in an
+aquarium. The alga that grows in _S. alba_ often gives it a dark green
+colour, which is, however, quite different from the bright green caused
+by the presence of green corpuscles. The colour of healthy specimens of
+the variety _bengalensis_ is a rather dark grey, which appears to be due
+to minute inorganic particles taken into the cells of the parenchyma
+from the exceedingly muddy water in which this sponge usually grows. If
+the sponge is found in clean water, to whichever variety of the species
+it belongs, it is nearly white with a slight yellowish tinge. Even when
+the typical form is growing in close proximity to _S. proliferens_, as
+is often the case, no trace of green corpuscles is found in its cells.
+
+     [Footnote AA: See M. and A. Weber in M. Weber's Zool. Ergeb.
+     Niederl. Ost-Ind. vol. i, p. 48, pl. v (1890).]
+
+
+4. Spongilla cinerea*, _Carter_.
+
+     _Spongilla cinerea_, Carter, J. Bombay Soc. iii, p. 30, pl.
+     i, fig. 5, & Ann. Nat. Hist. (2) iv, p. 82, pl. iii, fig. 5
+     (1849).
+
+     _Spongilla cinerea_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 468, pl. xxxviii, fig. 19.
+
+     _Spongilla cinerea_, Carter, Ann. Nat. Hist. (5) vii, p. 263
+     (1881).
+
+_Sponge_ forming large, flat sheets, never more than a few millimetres
+in thickness, without a trace of branches, compact but very friable, of
+a dark greyish colour; oscula small and inconspicuous or moderately
+large, never prominent; membrane adhering closely to the sponge.
+
+_Skeleton_ with well-defined but slender radiating fibres, which contain
+very little spongin; transverse fibres close together but consisting for
+the most part of one or two spicules only.
+
+_Spicules._ Skeleton-spicules short, slender, sharply pointed, minutely
+serrated or irregular in outline, almost straight. Gemmule-spicules very
+small, rather stout, cylindrical, pointed, covered with relatively long
+and stout spines which are either straight or directed towards the ends
+of the spicule. Flesh-spicules fairly numerous in the external membrane
+but by no means abundant in the parenchyma, very slender, gradually
+pointed, covered uniformly with minute but distinct spines.
+
+_Gemmules_ very small, only visible to the naked eye as minute specks,
+as a rule numerous, free in the substance of the sponge, each provided
+with a slender foraminal tubule and covered with a thick granular coat
+in which the gemmule-spicules are arranged almost horizontally; a
+horizontal layer of spicules also present on the external surface of the
+gemmule; gemmule-spicules very numerous.
+
+[Illustration: Fig. 10.--Gemmules and fragment of the skeleton of
+_Spongilla cinerea_ (from type specimen), � 35.]
+
+This sponge is easily distinguished from its Indian allies by the form
+of its skeleton-spicules, which are, as Bowerbank expresses it,
+"subspined"; that it to say, under a high power of the microscope their
+outline appears to be very minutely serrated, although under a low power
+they seem to be quite smooth. The spicules also are smaller than those
+of _S. alba_, the only species with which _S. cinerea_ is likely to be
+confused, and the gemmule has a well-developed foraminal tubule; the
+skeleton is much closer than in _S. proliferens_.
+
+TYPE in the British Museum; a piece in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--_S. cinerea_ is only known from the Bombay
+Presidency. Carter obtained the original specimens at Bombay and the
+only ones I have found were collected at Nasik, which is situated on the
+eastern slopes of the Western Ghats, about 90 miles to the north-east.
+
+BIOLOGY.--Carter's specimens were growing on gravel, rocks and stones at
+the edge of "tanks," and were seldom covered for more than six months in
+the year. Mine were on the sides of a stone conduit built to facilitate
+bathing by conveying a part of the water of the Godaveri River under a
+bridge. They were accompanied by _Spongilla indica_ and _Corvospongilla
+lapidosa_ (the only other sponges I have found in running water in
+India) and in the month of November appeared to be in active growth.
+
+
+5. Spongilla travancorica*, _Annandale_.
+
+     _Spongilla travancorica_, Annandale, Rec. Ind. Mus. iii, p.
+     101, pl. xii, fig. 1 (1909).
+
+_Sponge_ small, encrusting, without branches, hard but brittle; its
+structure somewhat loose; colour dirty white. Dermal membrane in close
+contact with the skeleton; pores and oscula inconspicuous. Surface
+minutely hispid, smooth and rounded as a whole.
+
+_Skeleton_ consisting of moderately stout and coherent radiating fibres
+and well-defined transverse ones; a number of horizontal megascleres
+present at the base and surface, but not arranged in any definite order.
+No basal membrane.
+
+[Illustration: Fig. 11.--Microscleres of _Spongilla travancorica_.
+
+A=Gemmule-spicules; B=flesh-spicules (from type specimen), � 240.]
+
+_Spicules._ Skeleton-spicules smooth, pointed at either end, moderately
+stout, straight or curved, sometimes angularly bent; curvature usually
+slight. Free microscleres abundant in the dermal membrane, slender,
+nearly straight, gradually and sharply pointed, profusely ornamented
+with short straight spines, which are much more numerous and longer at
+the middle than near the ends. Gemmule-spicules stouter and rather
+longer, cylindrical, terminating at each end in a sharp spine,
+ornamented with shorter spines, which are more numerous and longer at
+the ends than at the middle; at the ends they are sometimes directed
+backwards, without, however, being curved.
+
+_Gemmules_ firmly adherent to the support of the sponge, at the base of
+which they form a layer one gemmule thick; each provided with at least
+one foraminal tubule, which is straight and conical: two tubules, one at
+the top and one at one side, usually present. Granular layer well
+developed. Spicules arranged irregularly in this layer, as a rule being
+more nearly vertical than horizontal but pointing in all directions, not
+confined externally by a membrane; no external layer of horizontal
+spicules.
+
+  _Measurements of Spicules and Gemmules._
+
+  Length of skeleton-spicules                 0.289-0.374 mm.
+  Greatest diameter of skeleton-spicules      0.012-0.016  "
+  Length of free microscleres                 0.08-0.096   "
+  Greatest diameter of free microscleres      0.002 mm.
+  Length of gemmule-spicules                  0.1-0.116    "
+  Diameter of gemmule-spicule                 0.008 mm.
+    "       " gemmule                         0.272-0.374  "
+
+This species is easily distinguished from its allies of the subgenus
+_Euspongilla_ by its adherent gemmules with their (usually) multiple
+apertures and rough external surface.
+
+TYPE in the collection of the Indian Museum.
+
+HABITAT. Backwater near Shasthancottah, Travancore, in slightly brackish
+water; on the roots of shrubs growing at the edge; November, 1908
+(_Annandale_).
+
+The specimens were dead when found.
+
+
+6. Spongilla hemephydatia*, _Annandale_.
+
+     _Spongilla hemephydatia_, Annandale, Rec. Ind. Mus. iii, p.
+     275 (1909).
+
+[Illustration: Fig. 12.--Gemmule and spicules of _Spongilla
+hemephydatia_ (from type specimen).]
+
+_Sponge_ soft, fragile, amorphous, of a dirty yellow colour, with large
+oscula, which are not conspicuously raised above the surface but open
+into very wide horizontal channels in the substance of the sponge. The
+oscular collars are fairly well developed, but the subepidermal space is
+not extensive.
+
+_Skeleton_ diffuse, consisting of very fine radiating fibres, which are
+crossed at wide and irregular intervals by still finer transverse ones;
+very little chitinoid substance present.
+
+_Spicules._ Skeleton-spicules smooth, slender, sharply pointed at both
+ends, nearly straight. No true flesh-spicules. Gemmule-spicules straight
+or nearly so, cylindrical, or constricted in the middle, obscurely
+pointed or blunt, clothed with short, sharp, straight spines, which are
+very numerous but not markedly longer at the two ends; these spicules
+frequently found free in the parenchyma.
+
+_Gemmules_ numerous, small, free, spherical, yellow, with a
+well-developed granular coat (in which the spicules are arranged almost
+horizontally) and external to it a fine membrane which in preserved
+specimens becomes puckered owing to unequal contraction; each gemmule
+with a single aperture provided with a straight, rather wide, but very
+delicate foraminal tubule.
+
+  _Measurements of Spicules and Gemmules._
+
+  Length of skeleton-spicule       0.313 mm.
+  Breadth of skeleton-spicule      0.012 "
+  Length of gemmule-spicule        0.062 "
+  Breadth of gemmule-spicule       0.004 "
+  Diameter of gemmule              0.313-0.365 mm.
+
+This sponge in its general structure bears a very close resemblance to
+_Spongilla crateriformis_.
+
+TYPE in the collection of the Indian Museum.
+
+HABITAT. Growing on weeds at the edge of the Sur Lake, Orissa, October
+1908. Only one specimen was taken, together with many examples of _S.
+lacustris_ subsp. _reticulata_, _S. carteri_ and _S. crassissima_.
+
+
+7. Spongilla crateriformis* (_Potts_).
+
+     _Meyenia crateriforma_, Potts, P. Ac. Philad. 1882, p. 12.
+
+     _Meyenia crateriformis, id., ibid._ 1887, p. 228, pl. v,
+     fig. 6, pl. x, fig. 5.
+
+     ? _Ephydatia crateriformis_, Hanitsch, Nature, ii, p. 511
+     (1895).
+
+     _Ephydatia crateriformis_, Weltner, Arch. Naturg. lxi (i),
+     pp. 122, 134 (1895).
+
+     ? _Ephydatia crateriformis_, Hanitsch, Irish Natural. iv, p.
+     125, pl. iv, fig. 5 (1895).
+
+     _Ephydatia indica_, Annandale, J. Asiat. Soc. Bengal, 1907,
+     p. 20 (figures poor).
+
+     _Ephydatia indica, id._, Rec. Ind. Mus. i, pp. 272, 279,
+     388, 391 (1907).
+
+     _Ephydatia crateriformis_, Scharff, European Animals, p. 34
+     (1907).
+
+     _Ephydatia crateriformis_, Annandale, P. U.S. Mus. xxxvii,
+     p. 402, fig. 1 (1909).
+
+_Sponge_ very fragile, forming soft irregular masses on the roots and
+stems of water-plants, between which it is sometimes stretched as a
+delicate film, or thin layers or cushions on flat surfaces. Oscula
+large, flat, circular, or of irregular shape, opening into broad
+horizontal canals, which at their distal end are superficial and often
+covered by the external membrane only. Colour white, yellowish, greyish,
+or blackish.
+
+_Skeleton_ very delicate; radiating fibres rarely consisting of more
+than two parallel spicules; transverse fibres far apart, frequently
+consisting of single spicules; very little spongin present.
+
+[Illustration: Fig 13.--Spicules of _Spongilla crateriformis_.
+
+A. From specimen taken in July in a tank on the Calcutta maidan. B. From
+type specimen of _Ephydatia indica_ taken in the Indian Museum tank in
+winter. Both figures � 240.]
+
+_Spicules._ Skeleton-spicules feebly curved, slender, as a rule
+irregular in outline, sometimes almost smooth; the ends as a rule
+sharply pointed, often constricted off and expanded so as to resemble
+spear-heads, occasionally blunt. No true flesh-spicules.
+Gemmule-spicules often free in the parenchyma, cylindrical, slender,
+very variable in length in different sponges, straight or nearly so, as
+a rule with an irregular circle of strong straight or recurved spines at
+either end resembling a rudimentary rotule, and with shorter straight
+spines scattered on the shaft, sometimes without the rudimentary rotule,
+either truncate at the ends or terminating in a sharp spine.
+
+_Gemmules_ small, free, each surrounded by a thick granular layer in
+which the spicules stand upright or nearly so, and covered externally by
+a delicate but very distinct chitinous membrane; no horizontal spicules;
+foramen situated at the base of a crater-like depression in the granular
+coat, which is sometimes raised round it so as to form a conspicuous
+rampart; a short, straight foraminal tubule.
+
+The shape of the spicules is extremely variable, and sponges in which
+they are very different occur in the same localities and even in the
+same ponds. It is possible that the differences are directly due to
+slight changes in the environment, for in one pond in Calcutta a form
+with _Spongilla_-like gemmule-spicules appears to replace the typical
+form, which is common in winter, during the hot weather and "rains." I
+have not, however, found this to be the case in other ponds. Perhaps _S.
+hemephydatia_ will ultimately prove to be a variety of this very
+variable species, but its smooth and regular skeleton-spicules and
+short-spined gemmule-spicules afford a ready method of distinguishing it
+from _S. crateriformis_. The two sponges are easily distinguished from
+all others in the subgenus _Euspongilla_ by the upright and regular
+arrangement of their gemmule-spicules, for although in _S. proliferens_
+and _S. travancorica_ some of the gemmule-spicules are nearly vertical,
+their arrangement is always irregular, a large proportion of the
+spicules make an acute angle with the inner coat of the gemmule and a
+few as a rule lie parallel to it. The systematic position of _S.
+crateriformis_ is almost exactly intermediate between _Euspongilla_ and
+_Ephydatia_, to which genus it has hitherto been assigned. I think,
+however, that taking into consideration its close relationship to _S.
+hemephydatia_, it is best to assign it to _Spongilla_, as its
+rudimentary rotules never form distinct disks. I have examined some of
+Potts's original specimens from different American localities and can
+detect no constant difference between them and Indian specimens.
+
+TYPES in the United States National Museum; co-types in Calcutta.
+
+GEOGRAPHICAL DISTRIBUTION.--This sponge was originally described from
+North America (in which continent it is widely distributed) and has been
+recorded from the west of Ireland with some doubt. In India and Burma it
+is widely distributed. BENGAL, Calcutta and neighbourhood (_Annandale_);
+Sonarpur, Gangetic delta (_Annandale_); BOMBAY PRESIDENCY, Igatpuri
+Lake, W. Ghats (altitude _ca._ 2,000 feet) (_Annandale_); MADRAS
+PRESIDENCY, neighbourhood of Madras town (_J. R. Henderson_); Museum
+compound, Egmore (Madras town) (_Annandale_); near Bangalore (alt. _ca._
+3,000 ft.), Mysore State (Annandale); Ernakulam, Cochin (_G. Mathai_):
+BURMA, Kawkareik, interior of Amherst district, Tenasserim, and the
+Moulmein waterworks in the same district (_Annandale_).[AB]
+
+     [Footnote AB: Mr. C. A. Paiva, Assistant in the Indian
+     Museum, has lately (March 31st, 1911) obtained specimens of
+     _S. crateriformis_ in a small pond of fresh water on Ross
+     Island in the Andaman group. The existence of this widely
+     distributed species on an oceanic island is noteworthy.]
+
+BIOLOGY.--_S. crateriformis_ flourishes in Calcutta throughout the year.
+Here it is usually found adhering to the roots of water-plants,
+especially _Pistia_ and _Limnanthemum_. In the case of the former it
+occurs at the surface, in that of the latter at the bottom. When growing
+near the surface or even if attached to a stone at the bottom in clear
+water, it is invariably of a pale yellowish or greyish colour. When
+growing on the roots of _Limnanthemum_ in the mud of the Gangetic
+alluvium, however, it is almost black, and when growing in the reddish
+muddy waters of the tanks round Bangalore of a reddish-brown colour.
+This appears to be due entirely to the absorption of minute particles of
+inorganic matter by the cells of the parenchyma. If black sponges of the
+species are kept alive in clean water, they turn pure white in less than
+a week, apparently because these particles are eliminated. When growing
+on stones the sponge, as found in India, often conforms exactly with
+Potts's description: "a filmy grey sponge, branching off here and there
+... yet with a curious lack of continuity...."
+
+The wide efferent canals of this sponge afford a convenient shelter to
+small crustacea, and the isopod _Tach�a spongillicola_, Stebbing (see p.
+94), is found in them more abundantly than in those of any other sponge.
+This is especially the case when the sponge is growing at the bottom. On
+the surface of the sponge I have found a peculiar protozoon which
+resembles the European _Trichodina spongill�_ in general structure but
+belongs, I think, to a distinct species, if not to a distinct genus.
+
+
+Subgenus B. EUNAPIUS, _J. E. Gray_.
+
+     _Eunapius_, J. E. Gray (_partim_), P. Zool. Soc. London,
+     1867, p. 552.
+
+     _Spongilla_ (_s. str._), Vejdovsky, in Potts's "Fresh-Water
+     Sponges," P. Ac. Philad. 1887, p. 172.
+
+     _Spongilla_ (_s. str._), Weltner, in Zacharias's Tier- und
+     Pflanzenwelt des S�sswassers, i, p. 214 (1891).
+
+     _Spongilla_ (_s. str._), Annandale, Zool. Jahrb., Syst.
+     xxvii, p. 559 (1909).
+
+TYPE, _Spongilla carteri_, Carter.
+
+Spongill� in which the gemmules are covered with layers of distinct
+polygonal air-spaces with chitinous walls.
+
+The gemmules are usually fastened together in groups, which may either
+be free in the sponge or adhere to its support as a "pavement layer";
+sometimes, however, they are not arranged in this manner, but are quite
+independent of one another. The skeleton is usually delicate, sometimes
+very stout (_e. g._, in _S. nitens_, Carter).
+
+The term _Eunapius_ here used is not quite in the original sense, for
+Gray included under it Bowerbank's _Spongilla paupercula_ which is now
+regarded as a form of _S. lacustris_. His description, nevertheless,
+fits the group of species here associated except in one particular,
+viz., the smoothness of the gemmule-spicules to which he refers, for
+this character, though a feature of _S. carteri_, is not  found in
+certain closely allied forms. The use of "_Spongilla_" in a double sense
+may be avoided by the adoption of Gray's name.
+
+The subgenus _Eunapius_ is, like _Euspongilla_, cosmopolitan. It is not,
+however, nearly so prolific in species. Four can be recognized in India,
+two of which range, in slightly different forms, as far north as Europe,
+one of them also being found in North America, Northern Asia, and
+Australia.
+
+
+8. Spongilla carteri* _Carter_ (_Bowerbank_, in litt.). (Plate II. fig.
+1.)
+
+     _Spongilla friabilis_?, Carter (_nec_ Lamarck), J. Bombay
+     Asiat. Soc. iii, p. 31, pl. i, fig. 3 (1849), & Ann. Nat.
+     Hist. (2) iv, p. 83, pl. ii. fig. 3 (1849).
+
+     _Spongilla carteri_, Carter, Ann. Nat. Hist. (3) iii, p.
+     334, pl. viii, figs. 1-7 (1859).
+
+     _Spongilla carteri_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 469, pl. xxxviii, fig. 20.
+
+     _Eunapius carteri_, J. E. Gray, _ibid._ 1867, p. 552.
+
+     _Spongilla carteri_, Carter, Ann. Nat. Hist. (5) vii, p. 86
+     (1881).
+
+     _Spongilla carteri_, _id._, _ibid._ x, p. 369 (1882).
+
+     _Spongilla carteri_, Potts, P. Ac. Philad. 1887, p. 194.
+
+     _Spongilla carteri_, Weltner, Arch. Naturg. lxi (i), pp.
+     117, 134 (1895).
+
+     _Spongilla carteri_, Kirkpatrick, P. Zool. Soc. London, 1906
+     (i), p. 219, pl. xv, figs. 3, 4 (? figs. 1, 2).
+
+     _Spongilla carteri_, Annandale, J. Asiat. Soc. Bengal, 1906,
+     p. 188, pl. i, fig. 1.
+
+     _Spongilla carteri_, Willey, Spolia Zeyl. iv, p. 184 (1907).
+
+     _Spongilla carteri_, Annandale, _ibid._ vii, p. 63, pl. 1,
+     fig. 1 (1910).
+
+[Illustration: Fig. 14.--Gemmule of _Spongilla carteri_ (from Calcutta),
+as seen in optical section, � 140.]
+
+_Sponge_ massive, as a rule with the surface smooth and rounded,
+occasionally bearing irregular ridges, which may even take the form of
+cockscombs; the oscula large, rounded, conspicuous but not raised above
+the surface of the sponge, leading into broad vertical canals; the
+lateral canals, except in the immediate vicinity of the central vertical
+ones, not very broad; the oscular collars extending for a considerable
+distance over the oscula in living or well-preserved specimens, never
+standing out from the surface; the oscula never surrounded by radiating
+furrows. The inhalent pores surrounded externally by unmodified cells of
+the external membrane. Colour greyish, sometimes with a flush of green
+on the external surface.
+
+The sponge has a peculiarly strong and offensive smell.
+
+_Skeleton_ fairly compact, with well-developed radiating fibres; the
+transverse fibres splayed out at either end so that they sometimes
+resemble a pair of fans joined together by the handles (fig. 3, p. 33).
+A moderate amount of spongin present.
+
+_Spicules._ Skeleton-spicules smooth, pointed, nearly straight, never
+very stout but somewhat variable in exact proportions. Gemmule-spicules
+similar but much smaller. (There are no true flesh-spicules, but
+immature skeleton-spicules may easily be mistaken for them.)
+
+_Gemmules_ as a rule numerous, spherical or flattened at the base,
+variable in size, each covered by a thick coat consisting of several
+layers of relatively large polygonal air-spaces. A single aperture
+surrounded by a crater-like depression in the cellular coat and provided
+with a foraminal tubule resembling an inverted bottle in shape. (This
+tubule, which does not extend beyond the surface of the cellular coat,
+is liable to be broken off in dried specimens.) The spicules variable in
+quantity, arranged irregularly among the spaces of the cellular coat and
+usually forming a sparse horizontal layer on its external surface. Each
+gemmule contained in a cage of skeleton-spicules, by the pressure of
+which it is frequently distorted.
+
+
+8_a._ Var. mollis*, nov.
+
+This variety is characterized by a paucity of skeleton-spicules. The
+sponge is therefore soft and so fragile that it usually breaks in pieces
+if lifted from the water by means of its support. Owing to the paucity
+of skeleton-spicules, which resemble those of the typical form
+individually, the radiating and transverse fibres are extremely
+delicate.
+
+Common in Calcutta.
+
+
+8_b._ Var. cava*, nov.
+
+This variety is characterized by the fact that the oscula open into
+broad horizontal canals, the roof of which is formed by a thin layer of
+parenchyma and skeleton or, in places, of the external membrane only.
+The skeleton is loose and fragile, and the living sponge has a peculiar
+glassy appearance. In spirit the colour is yellowish, during life it is
+greenish or white.
+
+Taken at Bombay; November, 1907.
+
+
+8_c._ Var. lobosa*, nov.
+
+The greater part of the sponge in this variety consists of a number of
+compressed but pointed vertical lobes, which arise from a relatively
+shallow, rounded base, in which the oscula occur. The dried sponge has a
+yellowish colour.
+
+Apparently common in Travancore.
+
+       *     *     *     *     *
+
+I cannot distinguish these three "varieties"[AC] from the typical form
+as distinct species; indeed, their status as varieties is a little
+doubtful in two cases out of the three. Var. _cava_ appears to be a
+variety in the strict sense of the word (see p. 18), for it was found on
+the island of Bombay, the original locality of the species, growing side
+by side with the typical form. Var. _lobosa_, however, should perhaps be
+regarded as a subspecies rather than a variety, for I have received
+specimens from two localities in the extreme south-west of India and
+have no evidence that the typical form occurs in that part of the
+country. Evidence, however, is rather scanty as regards the occurrence
+of freshwater sponges in S. India. Var. _mollis_, again, may be a phase
+directly due to environment. It is the common form in the ponds of
+certain parts (_e. g._ in the neighbourhood of the Maidan and at
+Alipore) of the Calcutta municipal area, but in ponds in other parts
+(_e. g._ about Belgatchia) of the same area, only the typical form is
+found. It is possible that the water in the former ponds may be
+deficient in silica or may possess some other peculiarity that renders
+the production of spicules difficult for _S. carteri_; but this seems
+hardly probable, for _S. crassissima_, a species with a rather dense
+siliceous skeleton, flourishes in the same ponds. I have noticed that in
+ponds in which the aquatic vegetation is luxuriant and such genera of
+plants as _Pistia_ and _Limnanthemum_ flourish, there is always a
+tendency for _S. carteri_ to be softer than in ponds in which the
+vegetation is mostly cryptogamic, and in Calcutta those parts of the
+town in which sponges of this species produce most spicules are those in
+which a slight infiltration of brackish water into the ponds may be
+suspected; but in the interior of India, in places where the water is
+absolutely fresh, hard specimens seem to be the rule rather than the
+exception.
+
+     [Footnote AC: The only complete European specimen of the
+     species I have seen differs considerably in outward form
+     from any Indian variety, consisting of a flat basal area
+     from which short, cylindrical turret-like branches arise.
+     This specimen is from Lake Balaton in Hungary and was sent
+     me by Prof. von Daday de Dees of Buda-Pesth.]
+
+_S. carteri_ is closely related to _S. nitens_, Carter (Africa, and
+possibly S. America), but differs from that species in its comparatively
+slender, sharp skeleton-spicules and smooth gemmule-spicules. It may
+readily be distinguished from all other Indian freshwater sponges by its
+large, deep, round oscula, but this feature is not so marked in var.
+_lobosa_ as in the other forms. The typical form and var. _mollis_ grow
+to a larger size than is recorded for any other species of the family. I
+possess a specimen of the typical form from the neighbourhood of
+Calcutta which measures 30 � 27 cm. in diameter and 19.5 cm. in depth,
+and weighs (dry) 24-3/4 oz. The base of this specimen, which is solid
+throughout, is nearly circular, and the general form is mound-shaped.
+Another large specimen from Calcutta is in the form of an irregular
+wreath, the greatest diameter of which is 34 cm. This specimen weighs
+(dry) 16-1/4 oz. Both these specimens probably represent the growth of
+several years.
+
+TYPES.--The types of the varieties _mollis_, _cava_ and _lobosa_ are in
+the collection of the Indian Museum. I regard as the type of the species
+the specimen sent by Carter to Bowerbank and by him named _S. carteri_,
+although, owing to some confusion, Carter's description under this name
+appeared some years before Bowerbank's. This specimen is in the British
+Museum, with a fragment in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--The range of the species extends westwards
+to Hungary, southwards to Mauritius and eastwards to the island of
+Madura in the Malay Archipelago; a specimen from Lake Victoria Nyanza in
+Central Africa has been referred to it by Kirkpatrick (P. Zool. Soc.
+London, 1906 (i), p. 219), but I doubt whether the identification is
+correct. In India _S. carteri_ is by far the most universally
+distributed and usually much the commonest freshwater sponge; it is one
+of the only two species as yet found in Ceylon. Specimens are known from
+the following localities:--PUNJAB, Lahore (_J. Stephenson_): BOMBAY
+PRESIDENCY, island of Bombay (_Carter_, _Kirkpatrick_, _Annandale_);
+Igatpuri, W. Ghats (alt. _ca._ 2,000 ft.) (_Annandale_): UNITED
+PROVINCES (plains), Agra (_Kirkpatrick_); Lucknow: HIMALAYAS, Bhim Tal,
+Kumaon (alt. 4,500 ft.) (_Annandale_); Tribeni, Nepal (_Hodgart_):
+BENGAL, Calcutta and neighbourhood; Rajshahi (Rampur Bhulia) on the R.
+Ganges about 150 miles N. of Calcutta (_Annandale_); Berhampur,
+Murshidabad district (_R. E. Lloyd_); Pusa, Darbbhanga district
+(_Bainbrigge Fletcher_); Siripur, Saran district, Tirhut (_M.
+Mackenzie_); Puri and the Sur Lake, Orissa (_Annandale_): MADRAS
+PRESIDENCY, near Madras town (_J. R. Henderson_); Madura district (_R.
+Bruce Foote_); Bangalore (_Annandale_) and Worgaum, Mysore State
+(2,500-3,000 ft.); Ernakulam and Trichur, Cochin (_G. Mathai_);
+Trivandrum and the neighbourhood of C. Comorin, Travancore (var.
+_lobosa_) (_R. S. N. Pillay_): BURMA, Kawkareik, interior of Amherst
+district, Tenasserim (_Annandale_); Rangoon (_Annandale_); Bhamo, Upper
+Burma (_J. Coggin Brown_): CEYLON, Peradeniya (_E. E. Green_); outlet of
+the Maha Rambaikulam between Vavuniya and Mamadu, Northern Province
+(_Willey_); Horowapotanana, between Trincomalee and Anuradihapura,
+North-Central Province (_Willey_).
+
+BIOLOGY.--_S. carteri_ usually grows in ponds and lakes; I have never
+seen it in running water. Mr. Mackenzie found it on the walls of old
+indigo wells in Tirhut.
+
+The exact form of the sponge depends to some extent on the forces acting
+on it during life. At Igatpuri, for instance, I found that specimens
+attached to the stems of shrubs growing in the lake and constantly
+swayed by the wind had their surface irregularly reticulated with high
+undulating ridges, while those growing on stones at the bottom of a
+neighbouring pond were smooth and rounded.
+
+Sponges of this species do not shun the light.
+
+In Calcutta _S. carteri_ flourishes during the cold weather (November to
+March). By the end of March many specimens that have attached themselves
+to delicate stems such as those of the leaves of _Limnanthemum_, or to
+the roots of _Pistia stratiotes_, have grown too heavy for their support
+and have sunk down into the mud at the bottom of the ponds, in which
+they are quickly smothered. Others fixed to the end of branches
+overhanging the water or to bricks at the edge have completely dried up.
+A large proportion, however, still remain under water; but even these
+begin to show signs of decay at this period. Their cells migrate to the
+extremities of the sponge, leaving a mass of gemmules in the centre, and
+finally perish.
+
+Few sponges exist in an active condition throughout the hot weather. The
+majority of those that do so exhibit a curious phenomenon. Their surface
+becomes smoothly rounded and they have a slightly pinkish colour; the
+majority of the cells of their parenchyma, if viewed under a high power
+of the microscope, can be seen to be gorged with very minute drops of
+liquid. This liquid is colourless in its natural condition, but if the
+sponge is plunged into alcohol the liquid turns of a dark brown colour
+which stains both the alcohol and the sponge almost instantaneously.
+Probably the liquid represents some kind of reserve food-material. Even
+in the hot weather a few living sponges of the species may be found that
+have not this peculiarity, but, in some ponds at any rate, the majority
+that survive assume the peculiar summer form, which I have also found at
+Lucknow.
+
+Reproduction takes place in _S. carteri_ in three distinct ways, two of
+which may be regarded as normal, while the third is apparently the
+result of accident. If a healthy sponge is torn into small pieces and
+these pieces are kept in a bowl of water, little masses of cells
+congregate at the tips of the radiating fibres of the skeleton and
+assume a globular form. At first these cells are homogeneous, having
+clear protoplasm full of minute globules of liquid. The masses differ
+considerably in size but never exceed a few millimetres in diameter. In
+about two days differentiation commences among the cells; then spicules
+are secreted, a central cavity and an external membrane formed, and an
+aperture, the first osculum, appears in the membrane. In about ten days
+a complete young sponge is produced, but the details of development have
+not been worked out.
+
+The most common normal form of reproduction is by means of gemmules,
+which are produced in great numbers towards the end of the cold weather.
+If small sponges are kept alive in an aquarium even at the beginning of
+the cold weather, they begin to produce gemmules almost immediately, but
+these gemmules although otherwise perfect, possess few or no
+gemmule-spicules. If the sponge becomes desiccated at the end of the
+cold weather and is protected in a sheltered place, some or all of the
+gemmules contained in the meshes of its skeleton germinate _in situ_ as
+soon as the water reaches it again during the "rains." It is by a
+continuous or rather periodical growth of this kind, reassumed season
+after season, that large masses of sponge are formed. In such masses it
+is often possible to distinguish the growth of the several years, but as
+a rule the layers become more or less intimately fused together, for no
+limiting membrane separates them. A large proportion of the gemmules
+are, however, set free and either float on the surface of the water that
+remains in the ponds or are dried up and carried about by the wind. In
+these circumstances they do not germinate until the succeeding cold
+weather, even if circumstances other than temperature are favourable;
+but as soon as the cold weather commences they begin to produce new
+sponges with great energy.
+
+Sexual reproduction, the second normal form, takes place in _S. carteri_
+mainly if not only at the approach of a change of season, that is to say
+about March, just before the hot weather commences, and about November,
+just as the average temperature begins to sink to a temperate level. At
+these seasons healthy sponges may often be found full of eggs and
+embryos, which lie in the natural cavities of the sponge without
+protecting membrane.
+
+In the ponds of Calcutta a large number of animals are found associated
+in a more or less definite manner with _Spongilla carteri_. Only one,
+however, can be described with any degree of certainty as being in
+normal circumstances an enemy, namely the larva of _Sisyra indica_,[AD]
+and even in the case of this little insect it is doubtful how far its
+attacks are actually injurious to the sponge. The larva is often found
+in considerable numbers clinging to the oscula and wide efferent canals
+of _S. carteri_, its proboscis inserted into the substance of the
+sponge. If the sponge dies and the water becomes foul the larv� swim or
+crawl away. If the sponge dries up, they leave its interior (in which,
+however, they sometimes remain for some days after it has become dry)
+and pupate in a silken cocoon on its surface. Hence they emerge as
+perfect insects after about a week.
+
+     [Footnote AD: Needham. Rec. Ind. Mus. iii, p. 206 (1909).]
+
+An animal that may be an enemy of _S. carteri_ is a flat-worm (an
+undescribed species of _Planaria_) common in its larger canals and
+remarkable for the small size of its pharynx. The same worm, however, is
+also found at the base of the leaves of bulrushes and in other like
+situations, and there is no evidence that it actually feeds on the
+sponge. Injured sponges are eaten by the prawn _Pal�mon lamarrei_,
+which, however, only attacks them when the dermal membrane is broken. A
+_Tanypus_ larva (Chironomid Diptera) that makes its way though the
+substance of the sponge may also be an enemy; it is commoner in decaying
+than in vigorous sponges.
+
+The presence of another Chironomid larva (_Chironomus_, sp.) appears to
+be actually beneficial. In many cases it is clear that this larva and
+the sponge grow up together, and the larva is commoner in vigorous than
+in decayed sponges. Unlike the _Tanypus_ larva, it builds parchment-like
+tubes, in which it lives, on the surface of the sponge. The sponge,
+however, often grows very rapidly and the larva is soon in danger of
+being engulfed in its substance. The tube is therefore lengthened in a
+vertical direction to prevent this catastrophe and to maintain
+communication with the exterior. The process may continue until it is
+over an inch in length, the older part becoming closed up owing to the
+pressure of the growing sponge that surrounds it. Should the sponge die,
+the larva lives on in its tubes without suffering, and the ends of tubes
+containing larv� may sometimes be found projecting from the worn surface
+of dead sponges. The larva does not eat the sponge but captures small
+insects by means of a pair of legs on the first segment of its thorax.
+In so doing it thrusts the anterior part of its body out of the tube, to
+the inner surface of which it adheres by means of the pair of false legs
+at the tip of the abdomen. This insect, which is usually found in the
+variety _mollis_, appears to do good to the sponge in two ways--by
+capturing other insects that might injure it and by giving support to
+its very feeble skeleton.
+
+A precisely similar function, so far as the support of the sponge is
+concerned, is fulfilled by the tubular zooecia of a phase of the
+polyzoon _Plumatella fruticosa_ (see p. 218) which in India is more
+commonly found embedded in the substance of _S. carteri_ than in that of
+any other species, although in Great Britain it is generally found in
+that of _S. lacustris_, which is there the commonest species of
+freshwater sponge.
+
+Another animal that appears to play an active part in the oeconomy of
+the sponge is a peculiar little worm (_Ch�togaster spongill�_) also
+found among the zooecia of _Plumatella_ and belonging to a widely
+distributed genus of which several species are found in association with
+pond-snails. _Ch�togaster spongill�_ often occurs in enormous numbers in
+dead or dying sponges of _S. carteri_, apparently feeding on the
+decaying organic matter of the sponge and assisting by its movements in
+releasing numerous gemmules. In so doing it undoubtedly assists in the
+dissemination of the species.
+
+Major J. Stephenson (Rec. Ind. Mus. v, p. 233) has recently found two
+other species of oligoch�tes inhabiting _S. carteri_ var. _lobosa_ from
+Travancore. Both these species, unlike _Ch�togaster spongill�_, belong
+to a genus that is vegetarian in habits. One of them, _Nais pectinata_,
+has not yet been found elsewhere, while the other, _Nais communis_, has
+a very wide distribution. The latter, however, occurs in the sponge in
+two forms--one with eyes, the other totally blind. The blind form (_N.
+communis_ var. _c�ca_) has only been found in this situation, but the
+other (var. _punjabensis_) lives free as well as in association with the
+sponge, in which the blind form was the commoner of the two.
+
+The majority of the animals found in association with _S. carteri_ gain
+shelter without evident assistance to the sponge. This is the case as
+regards the little fish (_Gobius alcockii_), one of the smallest of the
+vertebrates (length about 1/2 inch), which lays its eggs in the patent
+oscula, thus securing for them a situation peculiarly favourable to
+their development owing to the constant current of water that passes
+over them. In the absence of sponges, however, this fish attaches its
+eggs to the floating roots of the water-plant _Pistia stratiotes_.
+Numerous small crustacea[AE] also take temporary or permanent refuge in
+the cavities of _S. carteri_, the most noteworthy among them being the
+Isopod _Tach�a spongillicola_[AF], the adults of which are found in the
+canal of this and other sponges, while the young cling to the external
+surface of the carapace of _Pal�mon lamarrei_ and other small prawns.
+Many worms and insects of different kinds also enter the canals of _S.
+carteri_, especially when the sponge is becoming desiccated; from
+half-dry sponges numerous beetles and flies may be bred, notably the
+moth-fly _Psychoda nigripennis_[AG] of which enormous numbers sometimes
+hatch out from such sponges.
+
+     [Footnote AE: According to the late Rai Bahadur R. B.
+     Sanyal, freshwater sponges are called in Bengali "shrimps'
+     nests." From his description it is evident that he refers
+     mainly to _S. carteri_ (see Hours with Nature, p. 46;
+     Calcutta 1896).]
+
+     [Footnote AF: Stebbing, J. Linn. Soc. xxx, p. 40; Annandale,
+     Rec. Ind. Mus. i, p. 279.]
+
+     [Footnote AG: Brunetti, Rec. Ind. Mus. ii, p. 376 (1908).]
+
+As the sponge grows it frequently attaches itself to small molluscs such
+as the young of _Vivipara bengalensis_, which finally become buried in
+its substance and thus perish. Possibly their decaying bodies may afford
+it nourishment, but of the natural food of sponges we know little. _S.
+carteri_ flourishes best and reaches its largest size in ponds used for
+domestic purposes by natives of India, and thrives in water thick with
+soap-suds. It is possible, though direct proof is lacking, that the
+sponge does good in purifying water used for washing the clothes,
+utensils, and persons of those who drink the same water, by absorbing
+decaying animal and vegetable matter from it.
+
+Various minute alg� are found associated with _S. carteri_, but of these
+little is yet known. The green flush sometimes seen on the surface of
+the typical form is due to the fact that the superficial cells of the
+parenchyma contain green corpuscles. These, however, are never very
+numerous and are not found in the inner parts of the sponge, perhaps
+owing to its massive form. It is noteworthy that these green bodies
+flourish in large numbers throughout the substance of sponges of _S.
+proliferens_, a species always far from massive, growing in the same
+ponds as _S. carteri_.
+
+
+9. Spongilla fragilis, _Leidy_.
+
+     _Spongilla fragilis_, Leidy, P. Ac. Philad. 1851, p. 278.
+
+     _Spongilla lordii_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 466, pl. xxxviii, fig. 17.
+
+     _Spongilla contecta_, Noll, Zool. Garten*, 1870, p. 173.
+
+     _Spongilla ottav�nsis_, Dawson, Canad. Nat.* (new series)
+     viii, p. 5 (1878).
+
+     _Spongilla sibirica_, Dybowski, Zool. Anz., Jahr. i, p. 53
+     (1878).
+
+     _Spongilla morgiana_, Potts, P. Ac. Philad. 1880, p. 330.
+
+     _Spongilla lordii_, Carter, Ann. Nat. Hist. (5) vii, p. 89,
+     pl. vi, fig. 13 (1881).
+
+     _Spongilla sibirica_, Dybowski, M�m. Ac. St. P�tersb. (7)
+     xxx, no. x, p. 10, fig. 12.
+
+     _Spongilla glomerata_, Noll, Zool. Anz., Jahr. ix, p. 682
+     (1886).
+
+     _Spongilla fragilis_, Vejdovsky, P. Ac. Philad. 1887, p.
+     176.
+
+     _Spongilla fragilis_, Potts, _ibid._ p. 197, pl. v, fig. 2;
+     pl. viii, figs. 1-4.
+
+     _Spongilla fragilis_, Weltner, Arch. Naturg. lix (1), p.
+     266, pl. ix, figs. 18-20 (1893).
+
+     _Spongilla fragilis_, _id._, Arch. Naturg. lxi (i), p. 117
+     (1895).
+
+     _Spongilla fragilis_, _id._, in Semon's Zool. Forsch. in
+     Austral. u. d. Malay. Arch. v, part v, p. 523.
+
+     _Spongilla fragilis_, Annandale, P. U.S. Mus. xxxvii, p. 402
+     (1909).
+
+     _Spongilla fragilis_, _id._, Annot. Zool. Japon. vii, part
+     ii, p. 106, pl. ii, fig. 1 (1909).
+
+_Sponge_ flat, lichenoid, never of great thickness, devoid of branches,
+dense in texture but very friable; colour brown, green, or whitish;
+oscula numerous, small, flat, distinctly star-shaped.
+
+_Skeleton_ with well defined radiating and transverse fibres, which are
+never strong but form a fairly dense network with a small amount of
+spongin.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, moderately stout,
+as a rule nearly straight. No flesh-spicules. Gemmule-spicules
+cylindrical, blunt or abruptly pointed, nearly straight, covered with
+relatively stout, straight, irregular spines, which are equally
+distributed all over the spicule.
+
+_Gemmules_ bound together in free groups of varying numbers and forming
+a flat layer at the base of the sponge; each gemmule small in size,
+surrounded by a thick cellular coat of several layers; with a relatively
+long and stout foraminal tubule, which projects outwards through the
+cellular coat at the sides of the group or at the top of the basal layer
+of gemmules, is usually curved, and is not thickened at the tip; more
+than one foraminal tubule sometimes present on a single gemmule;
+gemmule-spicules arranged horizontally or at the base of the cellular
+coat.
+
+The species as a species is easily distinguished from all others, its
+nearest ally being the N. American _S. ingloriformis_ with sparsely
+spined skeleton-spicules which are very few in number, and gemmule
+groups in which the foraminal tubules all open downwards.
+
+Several varieties of _S. fragilis_ have been described in Europe and
+America.
+
+TYPE.--Potts refers to the type as being in the Academy of Natural
+Sciences at Philadelphia.
+
+GEOGRAPHICAL DISTRIBUTION.--All over Europe and N. America; also in
+Siberia, Australia, and S. America. The species is included in this work
+in order that its Asiatic local races may be fitly described.
+
+
+9 _a._ Subsp. calcuttana*, nov.
+
+     ? _Spongilla decipiens_, Weltner (_partim_), Arch. Naturg.
+     lxi (i), pp. 117, 134 (1895).
+
+     _Spongilla decipiens_, Annandale, Journ. As. Soc. Beng.
+     1906, p. 57.
+
+     _Spongilla fragilis_, _id._, Rec. Ind. Mus. i, p. 390
+     (1907).
+
+[Illustration: Fig. 15.--_Spongilla fragilis_ subsp. _calcuttana_.
+A=group of gemmules, � 70; B=spicules, � 240. From type specimen.]
+
+This local race, which is common in Calcutta, is distinguished from the
+typical form mainly by the shape of its skeleton-spicules, most of which
+are abruptly pointed or almost rounded at the tips, sometimes bearing a
+minute conical projection at each end. The gemmule-spicules, which are
+usually numerous, are slender. The foraminal tubules are usually long
+and bent, but are sometimes very short and quite straight. The colour is
+usually greyish, occasionally brown.
+
+I have not found this race except in Calcutta, in the ponds of which it
+grows on bricks or, very commonly, on the stems of bulrushes, often
+covering a considerable area.
+
+TYPE in the Indian Museum.
+
+
+9 _b._ Subsp. decipiens*, _Weber_.
+
+     _Spongilla decipiens_, Weber, Zool. Ergeb. Niederl�nd.
+     Ost-Ind. i, p. 40, pl. iv, figs. 1-5 (1890).
+
+This (?) local race is distinguished by the fact that the foraminal
+tubules are invariably short and straight and thickened at the tips, and
+that gemmule-spicules do not occur on the external surface of the
+cellular coat of the gemmules.
+
+I include Weber's _Spongilla decipiens_ in the Indian fauna on the
+authority of Weltner, who identified specimens from the Museum "tank,"
+Calcutta, as belonging to this form. All, however, that I have examined
+from our "tank" belong to the subspecies _calcuttana_, most of the
+skeleton-spicules of which are much less sharp than those of
+_decipiens_. By the kindness of Prof. Max Weber I have been able to
+examine a co-type of his species, which is probably a local race
+peculiar to the Malay Archipelago.
+
+TYPE in the Amsterdam Museum; a co-type in Calcutta.
+
+Perhaps the Japanese form, which has spindle-shaped gemmule-spicules
+with comparatively short and regular spines, should be regarded as a
+third subspecies, and the Siberian form as a fourth.
+
+
+10. Spongilla gemina*, sp. nov.
+
+_Sponge_ forming small, shallow, slightly dome-shaped patches of a more
+or less circular or oval outline, minutely hispid on the surface,
+friable but moderately hard. Oscula numerous but minute and
+inconspicuous, never star-shaped. Dermal membrane adhering closely to
+the sponge. Colour grey or brown.
+
+_Skeleton_ forming a close and regular network at the base of the
+sponge, becoming rather more diffuse towards the external surface; the
+radiating and the transverse fibres both well developed, of almost equal
+diameter. Little spongin present.
+
+_Spicules._ Skeleton-spicules slender, smooth, sharply pointed. No
+flesh-spicules. Gemmule-spicules long, slender, cylindrical, blunt or
+bluntly pointed, somewhat irregularly covered with minute straight
+spines.
+
+_Gemmules_ small, bound together in pairs, as a rule free in the
+parenchyma but sometimes lightly attached at the base of the sponge.
+Each gemmule flattened on the surface by which it is attached to its
+twin, covered with a thin coat of polygonal air-spaces which contains
+two layers of gemmule-spicules crossing one another irregularly in a
+horizontal plane. One or two foraminal tubules present on the surface
+opposite the flat one, bending towards the latter, often of considerable
+length, cylindrical and moderately stout.
+
+TYPE in the Indian Museum.
+
+This species is closely allied to _S. fragilis_, from which it may be
+distinguished by the curious twinned arrangement of its gemmules. It
+also differs from _S. fragilis_ in having extremely small and
+inconspicuous oscula.
+
+_Locality._ I only know this sponge from the neighbourhood of Bangalore,
+where Dr. Morris Travers and I found it in October, 1910 growing on
+stones and on the leaves of branches that dipped into the water at the
+edge of a large tank.
+
+
+11. Spongilla crassissima*, _Annandale_.
+
+     _Spongilla crassissima_, Annandale, J. Asiat. Soc. Bengal,
+     1907, p. 17, figs. 2, 3.
+
+     _Spongilla crassissima_, _id._, _ibid._ p. 88.
+
+     _Spongilla crassissima_, _id._, Rec. Ind. Mus. i. p. 390,
+     pl. xiv, fig. 4 (1907).
+
+_Sponge_ very hard and strong, nearly black in colour, sometimes with a
+greenish tinge, forming spherical, spindle-shaped or irregular masses
+without branches but often several inches in diameter. Oscula circular
+or star-shaped, usually surrounded by radiating furrows; pores normally
+contained in single cells. External membrane closely adherent to the
+sponge except immediately round the oscula.
+
+_Skeleton_ dense, compact and only to be broken by the exercise of
+considerable force; radiating and transverse fibres not very stout but
+firmly bound together by spongin (fig. 6, p. 38), which occasionally
+extends between them as a delicate film; their network close and almost
+regular.
+
+_Spicules._ Skeleton-spicules smooth, feebly curved, sausage-shaped but
+by no means short, as a rule bearing at each end a minute conical
+projection which contains the extremity of the axial filament. No
+flesh-spicules. Gemmule-spicules closely resembling those of _S.
+fragilis_ subsp. _calcuttana_, but as a rule even more obtuse at the
+ends.
+
+_Gemmules_ as in _S. fragilis_ subsp. _calcuttana_; a basal layer of
+gemmules rarely formed.
+
+
+11 _a._ Var. crassior*, _Annandale_.
+
+     _Spongilla crassior_, Annandale, Rec. Ind. Mus. i, p. 389,
+     pl. xiv, fig. 3 (1907).
+
+This variety differs from the typical form chiefly in its even stronger
+skeleton (fig. 3, p. 33) and its stouter skeleton-spicules, which do not
+so often possess a terminal projection. The sponge is of a brownish
+colour and forms flat masses of little thickness but of considerable
+area on sticks and on the stems of water-plants.
+
+TYPES.--The types of both forms are in the Indian Museum. Co-types have
+been sent to London.
+
+GEOGRAPHICAL DISTRIBUTION.--This sponge is only known from Bengal. The
+variety _crassior_ was found at Rajshahi (Rampur Bhulia) on the Ganges,
+about 150 miles N. of Calcutta, while the typical form is fairly common
+in the "tanks" of Calcutta and very abundant in the Sur Lake near Puri
+in Orissa.
+
+[Illustration: Fig. 16.--Spicules of _Spongilla crassissima_ var.
+_crassior_ (from type specimen), � 240.]
+
+BIOLOGY.--_S. crassissima_ is usually found near the surface in shallow
+water. Attached to the roots of the floating water-plant _Pistia
+stratiotes_ it assumes a spherical form, while on sticks or like objects
+it is spindle-shaped. Sometimes it is found growing on the same stick or
+reed-stem as _S. carteri_, the two species being in close contact and
+_S. carteri_ always overlapping _S. crassissima_. The dark colour is due
+to minute masses of blackish pigment in the cells of the parenchyma. The
+dense structure of the sponge is not favourable to the presence of
+_incol�_, but young colonies of the polyzoon _Plumatella fruticosa_ are
+sometimes overgrown by it. Although they may persist for a time by
+elongating their tubular zooecia through the substance of the sponge,
+they do not in these circumstances reach the same development as when
+they are overgrown by the much softer _S. carteri_.
+
+_S. crassissima_ is found during the "rains" and the cold weather. In
+Calcutta it attains its maximum size towards the end of the latter
+season. In spite of its hard and compact skeleton, the sponge does not
+persist from one cold weather to another.
+
+A curious phenomenon has been noticed in this species, but only in the
+case of sponges living in an aquarium, viz. the cessation during the
+heat of the day of the currents produced by its flagella.
+
+
+Subgenus C. STRATOSPONGILLA, _Annandale_.
+
+     _Stratospongilla_, Annandale, Zool. Jahrb., Syst. xxvii, p.
+     561 (1909).
+
+TYPE, _Spongilla bombayensis_, Carter.
+
+Spongill� in the gemmules of which the pneumatic layer is absent or
+irregularly developed, its place being sometimes taken by air-spaces
+between the stout chitinous membranes that cover the gemmule. At least
+one of these membranes is always present.
+
+The gemmule-spicules lie in the membrane or membranes parallel to the
+surface of the gemmule, and are often so arranged as to resemble a
+mosaic. The gemmules themselves are usually adherent to the support of
+the sponge. The chitinous membrane or membranes are often in continuity
+with a membrane that underlies the base of the sponge. The skeleton is
+usually stout, though often almost amorphous, and the skeleton-spicules
+are sometimes sausage-shaped.
+
+Sponges of this subgenus form crusts or sheets on solid submerged
+objects.
+
+_Stratospongilla_ is essentially a tropical subgenus, having its
+head-quarters in Central Africa and Western India. One of its species,
+however, (_S. sumatrana_*, Weber) occurs both in Africa and the Malay
+Archipelago, while another has only been found in S. America (_S.
+navicella_, Carter).
+
+Aberrant species occur in China (_S. sinensis_*, _S. coggini_*) and the
+Philippines (_S. clementis_*). Three species have been found in the
+Bombay Presidency and Travancore, one of which (_S. bombayensis_*)
+extends its range eastwards to Mysore and westwards across the Indian
+Ocean to Natal.
+
+
+12. Spongilla indica*, _Annandale_.
+
+     _Spongilla indica_, Annandale, Rec. Ind. Mus. ii, p. 25,
+     figs. 1, 2 (1908).
+
+_Sponge_ forming a very thin layer, of a bright green or pale grey
+colour; surface smooth, minutely hispid; pores and oscula inconspicuous,
+the latter approached in some instances by radiating furrows; subdermal
+cavity small; texture compact, rather hard.
+
+_Skeleton_ incoherent, somewhat massive owing to the large number of
+spicules present. Spicules forming triangular meshes and occasionally
+arranged in vertical lines several spicules broad but without spongin.
+
+_Spicules._ Skeleton-spicules straight or nearly straight, slender,
+cylindrical, amphistrongylous, uniformly covered with minute, sharp
+spines; flesh-spicules slender, sharply pointed, straight or curved,
+irregularly covered with relatively long, straight sharp spines,
+abundant in the dermal membrane, scarce in the substance of the sponge.
+Gemmule-spicules short, stout, sausage-shaped, covered with minute
+spines, which are sometimes absent from the extremities.
+
+_Gemmules_ spherical, somewhat variable in size, with a single aperture,
+which is provided with a trumpet-shaped foraminal tubule and is situated
+at one side of the gemmule in its natural position; the inner chitinous
+coat devoid of spicules, closely covered by an outer coat composed of a
+darkly coloured chitinoid substance in which the gemmule-spicules are
+embedded, lying parallel or almost parallel to the inner coat. The outer
+coat forms a kind of mantle by means of the skirts of which the gemmule
+is fastened to the support of the sponge. This coat is pierced by the
+foraminal tubule.  The gemmules are distinct from one another.
+
+[Illustration: Fig. 17.--Gemmule of _Spongilla indica_ seen from the
+side (from type specimen), magnified.]
+
+  Average length of skeleton-spicules       0.2046 mm.
+     "   breadth of skeleton-spicules       0.0172  "
+     "   length of flesh-spicules           0.053   "
+     "   breadth of flesh-spicules          0.0053  "
+     "   length of gemmule-spicules         0.044   "
+     "   breadth of gemmule-spicules        0.0079  "
+
+_S. indica_ is closely allied to _S. sumatrana_*, Weber, which has been
+found both in the Malay Archipelago and in East Africa. It may be
+distinguished by its blunt, almost truncated megascleres and
+comparatively slender gemmule-spicules.
+
+TYPE in the Indian Museum.
+
+HABITAT, etc.--Growing, together with _S. cinerea_ and _Corvospongilla
+lapidosa_, on the stone sides of an artificial conduit in the R.
+Godaveri at Nasik on the eastern side of the Western Ghats in the Bombay
+Presidency. The water was extremely dirty and was used for bathing
+purposes. The sponge was green where the light fell upon it, grey where
+it was in the shadow of the bridge under which the conduit ran. The only
+specimens I have seen were taken in November, 1907.
+
+
+13. Spongilla bombayensis*, _Carter_. (Plate II, fig. 2.)
+
+     _Spongilla bombayensis_, Carter, Ann. Nat. Hist. (5) x, p.
+     369, pl. xvi, figs. 1-6 (1882).
+
+     _Spongilla bombayensis_, Annandale, Zool. Jahrb., Syst.
+     xxvii, p. 562, figs. B, C (1909).
+
+_Sponge_ hard but friable, forming thin layers or cushions; its surface
+often irregular but without a trace of branches; its area never very
+great; oscula inconspicuous; external membrane adhering closely to the
+sponge; colour brownish or greyish.
+
+[Illustration: Fig. 18.--Gemmule of _Spongilla bombayensis_ as seen from
+above (from type specimen), magnified.]
+
+_Skeleton_ almost amorphous, very dense, consisting of large numbers of
+spicules arranged irregularly; radiating fibres occasionally visible in
+sections, but almost devoid of spongin; a more or less definite
+reticulation of horizontal spicules lying immediately under the external
+membrane.
+
+_Spicules._ Skeleton-spicules slender, pointed, feebly curved,
+irregularly roughened or minutely spined all over the surface.
+Flesh-spicules straight, narrowly rhomboidal in outline, sharply
+pointed, slender, covered with minute, irregular, straight spines,
+scanty in the parenchyma, abundant in the external membrane.
+Gemmule-spicules sausage-shaped or bluntly pointed, variable in length
+but usually rather stout, covered with minute spines, as a rule
+distinctly curved.
+
+_Gemmules_ round or oval, firmly adherent[AH] to the base of the sponge,
+as a rule rather shallowly dome-shaped, covered by two thick chitinous
+membranes, in each of which there is a dense horizontal layer of
+spicules; no granular or cellular covering; the two chitinous coats
+separated by an empty space; the aperture or apertures on the side of
+the gemmule in its natural position, provided with foraminal tubules,
+which may be either straight or curved, project through the outer
+chitinous membrane and often bend down towards the base of the gemmule.
+The spicules of the outer layer often more irregular in outline and less
+blunt than those of the inner layer.
+
+     [Footnote AH: The outer covering by means of which the
+     gemmule is fixed is not formed until the other structures
+     are complete. In young sponges, therefore, free gemmules may
+     often be found.]
+
+This sponge is allied to _S. indica_, but is distinguished among other
+characters by its sharp skeleton-spicules and by the fact that the
+gemmule is covered by two chitinous membranes instead of one.
+
+TYPE in the British Museum; a fragment in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--S. and W. India and S. Africa. Carter's type
+was found in the island of Bombay, my own specimens in Igatpuri Lake in
+the Western Ghats. I have recently (October 1910) found sponges and bare
+gemmules attached to stones at the end of a tank about 10 miles from
+Bangalore (Mysore State) in the centre of the Madras Presidency. Prof.
+Max Weber obtained specimens in Natal.
+
+BIOLOGY.--The specimens collected by Prof. Weber in Natal and those
+collected by myself in the Bombay Presidency were both obtained in the
+month of November. It is therefore very interesting to compare them from
+a biological point of view. In so doing, it must be remembered that
+while in S. Africa November is near the beginning of summer, in India it
+is at the beginning of the "cold weather," that is to say, both the
+coolest and the driest season of the year. The lake in which my
+specimens were obtained had, at the time when they were collected,
+already sunk some inches below its highest level, leaving bare a gently
+sloping bank of small stones. Adhering to the lower surface of these
+stones I found many small patches of _Spongilla bombayensis_, quite dry
+but complete so far as their harder parts were concerned and with the
+gemmules fully formed at their base. From the shallow water at the edge
+of the lake I took many similar stones which still remained submerged.
+It was evident that the sponge had been just as abundant on their lower
+surface as on that of the stones which were now dry; but only the
+gemmules remained, sometimes with a few skeleton-spicules adhering to
+them (Pl. II, fig. 2). The bulk of the skeleton had fallen away and the
+parenchyma had wholly perished. In a few instances a small sponge, one
+or two millimetres in diameter, had already been formed among the
+gemmules; but these young sponges appeared to belong to some other
+species, possibly _Spongilla indica_, which was also common in the lake.
+
+Carter's specimen of _S. bombayensis_, which was evidently in much the
+same condition as those I found still submerged a month later, was taken
+in October in a disused quarry. It was surrounded by a mass of _S.
+carteri_ three inches in diameter, and was attached to a herbaceous
+annual. The point on the edge of the quarry at which this plant grew was
+not reached by the water until July. It is therefore necessary to assume
+that the gemmules of _S. bombayensis_ had been formed between July and
+October. Probably the larva of the sponge had settled down on the plant
+during the "rains"--which commence in Bombay about the beginning of
+June--and had grown rapidly. The production of gemmules may have been
+brought about owing to the sponge being choked by the more vigorous
+growth of _S. carteri_, a species which grows to a considerable size in
+a comparatively short time, while _S. bombayensis_ apparently never
+reaches a thickness of more than a few millimetres.
+
+The manner in which the gemmules of _S. bombayensis_ are fastened to the
+solid support of the sponge must be particularly useful in enabling them
+to sprout in a convenient environment as soon as the water reaches them.
+The fact that the gemmules remained fixed without support renders it
+unnecessary for the skeleton to persist as a cage containing them (or at
+any rate a proportion of them) during the period of rest.
+
+Prof. Weber's specimens of _S. bombayensis_ were collected in a river,
+apparently on stones or rocks, towards the beginning of the S. African
+summer. They contain comparatively few gemmules and were evidently in a
+vigorous condition as regards vegetative growth. Unfortunately we know
+nothing of the seasonal changes which take place in freshwater sponges
+in S. Africa, but the difference between these changes in Europe and in
+India shows that they are dependent on environment as well as the
+idiosyncrasy of the species. It is very interesting, therefore, to see
+that the condition of sponges taken in S. Africa differs so widely from
+that of other individuals of the same species taken in India at the same
+season.
+
+In Prof. Weber's specimens I have found numerous small tubules of
+inorganic d�bris. These appear to be the work of Chironomid larv�, of
+which there are several specimens loose in the bottle containing the
+sponges. Other tubules of a very similar appearance but with a delicate
+chitinoid foundation appear to be the remains of a species of
+_Plumatella_ of which they occasionally contain a statoblast.
+
+
+14. Spongilla ultima*, _Annandale_. (Plate II, fig. 3.)
+
+     _Spongilla ultima_, Annandale, Rec. Ind. Mus. v, p. 31 (1910).
+
+_Sponge_ hard and strong, forming a thin layer on solid objects, of a
+pale green colour (dry); the oscula small but rendered conspicuous by
+the deep radiating furrows that surround them; external surface of the
+sponge rough but not spiny.
+
+_Skeleton_ forming a compact but somewhat irregular reticulation in
+which the radiating fibres are not very much more distinct than the
+transverse ones; a considerable amount of almost colourless spongin
+present.
+
+_Spicules._ Skeleton-spicules smooth, stout, amphioxous, as a rule
+straight or nearly straight, not infrequently inflated in the middle or
+otherwise irregular. No flesh-spicules. Gemmule-spicules variable in
+size, belonging to practically every type and exhibiting practically
+every abnormality possible in the genus, the majority being more or less
+sausage-shaped and having a roughened surface, but others being
+cruciform, spherical, subspherical, rosette-like, needle-like, bifid or
+even trifid at one extremity.
+
+[Illustration: Fig. 19.--Spicules of _Spongilla ultima_ (from type
+specimen), � 120.]
+
+_Gemmules_ adherent, spherical, large, each covered by two distinct
+layers of horizontal spicules; the outer layer intermixed with
+skeleton-spicules and often containing relatively large siliceous
+spheres, a large proportion of the spicules being irregular in shape;
+the spicules of the inner layer much more regular and as a rule
+sausage-shaped. The outer layer is contained in a chitinous membrane
+which spreads out over the base of the sponge. The foraminal tubules are
+short and straight.
+
+This sponge is allied to _S. bombayensis_, from which it is
+distinguished not only by the abnormal characters of its
+gemmule-spicules and the absence of flesh-spicules, but also by the form
+of its skeleton-spicules and the structure of its skeleton. I have
+examined several specimens dry and in spirit; but _S. ultima_ is the
+only Indian freshwater sponge, except _Corvospongilla burmanica_, I have
+not seen in a fresh condition.
+
+TYPES in the Indian Museum; co-types at Trivandrum.
+
+HABITAT. Discovered by Mr. R. Shunkara Narayana Pillay, of the
+Trivandrum Museum, in a tank near Cape Comorin, the southernmost point
+of the Indian Peninsula.
+
+
+Genus 2. PECTISPONGILLA, _Annandale_.
+
+     _Pectispongilla_, Annandale, Rec. Ind. Mus. iii, p. 103 (1909).
+
+TYPE, _Pectispongilla aurea_, Annandale.
+
+The structure of the sponge resembling that of _Euspongilla_ or
+_Ephydatia_; but the gemmule-spicules bear at either end, at one side
+only, a double vertical row of spines, so that they appear when viewed
+in profile like a couple of combs joined together by a smooth bar.
+
+[Illustration: Fig. 20.--Gemmule and spicules of _Pectispongilla aurea_
+(type specimen). _a_, Skeleton-spicules; _b_, gemmule-spicules; _b'_, a
+single gemmule-spicule more highly magnified.]
+
+GEOGRAPHICAL DISTRIBUTION.--The genus is monotypic and is only known
+from Travancore and Cochin in the south-west of the Indian Peninsula.
+
+
+15. Pectispongilla aurea*, _Annandale_.
+
+     _Pectispongilla aurea_, Annandale, _op. cit._, p. 103, pl.
+     xii, fig. 2.
+
+_Sponge_ forming minute, soft, cushion-like masses of a deep golden
+colour (dull yellow in spirit); the surface smooth, minutely hispid. One
+relatively large depressed osculum usually present in each sponge; pores
+inconspicuous; dermal membrane in close contact with the parenchyma.
+
+_Skeleton_ consisting of slender and feebly coherent radiating fibres as
+a rule two or three spicules thick, with single spicules or ill-defined
+transverse fibres running horizontally. Towards the  external surface
+transverse spicules are numerous, but they do not form any very regular
+structure.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, straight or
+nearly so. Gemmule-spicules minute, with the stem smooth and
+cylindrical, relatively stout and much longer than the comb at either
+end; the two combs equal, with a number of minute, irregularly scattered
+spines between the two outer rows of stouter ones. No free microscleres.
+
+_Gemmules_ minute, spherical, with a single aperture, which is provided
+with a very short foraminal tubule; the granular coat well developed;
+the spicules arranged in a slanting position, but more nearly vertically
+than horizontally, with the combs pointing in all directions; no
+external chitinous membrane.
+
+  Length of skeleton-spicule                     0.2859 mm.
+  Greatest diameter of skeleton-spicule          0.014  "
+  Length of gemmule-spicule                      0.032-0.036 mm.
+  Length of comb of gemmule-spicule              0.008 mm.
+  Greatest diameter of shaft of gemmule-spicule  0.004  "
+  Diameter of gemmule                            0.204-0.221 mm.
+
+The gemmule-spicules first appear as minute, smooth, needle-like bodies,
+which later become roughened on one side at either end and so finally
+assume the mature form. There are no bubble-cells in the parenchyma.
+
+
+15_a._ Var. subspinosa*, nov.
+
+This variety differs from the typical form in having its skeleton
+spicules covered with minute irregular spines or conical projections.
+
+TYPES of both the typical form and the variety in the Indian Museum;
+co-types of the typical form in the Trivandrum Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--The same as that of the genus.
+_Localities_:--Tenmalai, at the base of the western slopes of the W.
+Ghats in Travancore (typical form) (_Annandale_); Ernakulam and Trichur
+in Cochin (var. _subspinosa_) (_G. Mathai_).
+
+BIOLOGY.--My specimens, which were taken in November, were growing on
+the roots of trees at the edge of an artificial pool by the roadside.
+They were in rather dense shade, but their brilliant golden colour made
+them conspicuous objects in spite of their small size. Mr. Mathai's
+specimens from Cochin were attached to water-weeds and to the husk of a
+cocoanut that had fallen or been thrown into the water.
+
+
+Genus 3. EPHYDATIA, _Lamouroux_.
+
+     _Ephydatia_, Lamouroux, Hist. des Polyp. corall. flex.* p. 6
+     (_fide_ Weltner) (1816).
+
+     _Ephydatia_, J. E. Gray, P. Zool. Soc. London. 1867, p. 550.
+
+     _Trachyspongilla_, Dybowsky (_partim_), Zool. Anz. i, p. 53
+     (1874).
+
+     _Meyenia_, Carter (_partim_), Ann. Nat. Hist. (5) vii, p. 90
+     (1881).
+
+     _Carterella_, Potts & Mills (_partim_), P. Ac. Philad. 1881,
+     p. 150.
+
+     _Ephydatia_, Vejdovsky, Abh. B�hm. Ges. xii, p. 23 (1883).
+
+     _Meyenia_, Potts (_partim_), _ibid._ 1887, p. 210.
+
+     _Carterella_, _id._ (_partim_), _ibid._ 1887, p. 260.
+
+     _Ephydatia_, Weltner (_partim_), Arch. Naturg. lxi (i), p.
+     121 (1895).
+
+     _Ephydatia_, Annandale, P. U.S. Mus. xxxvii, p. 404 (1909).
+
+TYPE, (?) _Spongilla fluviatilis_, auctorum.
+
+This genus is separated from _Spongilla_ by the structure of the
+gemmule-spicules, which bear at either end a transverse disk with
+serrated or deeply notched edges, or at any rate with edges that are
+distinctly undulated. The disks are equal and similar. True
+flesh-spicules are usually absent, but more or less perfect birotulates
+exactly similar to those associated with the gemmules are often found
+free in the parenchyma. The skeleton is never very stout and the
+skeleton-spicules are usually slender.
+
+As has been already stated, some authors consider _Ephydatia_ as the
+type-genus of a subfamily distinguished from the subfamily of which
+_Spongilla_ is the type-genus by having rotulate gemmule-spicules. The
+transition between the two genera, however, is a very easy one. Many
+species of the subgenus _Euspongilla_, the typical subgenus of
+_Spongilla_ (including _S. lacustris_, the type-species of the genus),
+have the spines at the ends of the gemmule-spicules arranged in such a
+way as to suggest rudimentary rotules, while in the typical form of _S.
+crateriformis_ this formation is so distinct that the species has
+hitherto been placed in the genus _Ephydatia_ (_Meyenia_), although in
+some sponges that agree otherwise with the typical form of the species
+the gemmule-spicules are certainly not rotulate and in none do these
+spicules bear definite disks.
+
+GEOGRAPHICAL DISTRIBUTION.--_Ephydatia_, except _Spongilla_, is the most
+generally distributed genus of the Spongillid�, but in most countries it
+is not prolific in species. In Japan, however, it appears to predominate
+over _Spongilla_. Only one species is known from India, but another (_E.
+blembingia_*, Evans) has been described from the Malay Peninsula, while
+Weber found both the Indian species and a third (_E. bogorensis_*) in
+the Malay Archipelago.
+
+
+16. Ephydatia meyeni* (_Carter_).
+
+     _Spongilla meyeni_, Carter, J. Bomb. Asiat. Soc. iii, p. 33,
+     pl. i, fig. 1, & Ann. Nat. Hist. (2) iv, p. 84, pl. iii,
+     fig. 1 (1849).
+
+     _Spongilla meyeni_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 448, pl. xxxviii, fig. 4.
+
+     _Spongilla meyeni_, Carter, Ann. Nat. Hist. (5) vii, p. 93
+     (1881).
+
+     _Ephydatia fluviatilis_, Weber, Zool. Ergeb. Niederl�nd.
+     Ost-Ind. i. pp. 32, 46 (1890).
+
+     _Ephydatia m�lleri_, Weltner (_partim_), Arch. Naturg. lxi
+     (i), p. 125 (1895).
+
+     _Ephydatia robusta_, Annandale, J. Asiat. Soc. Bengal, 1907,
+     p. 24, fig. 7.
+
+     _Ephydatia m�lleri_ subsp. _meyeni_, _id._, Rec. Ind. Mus.
+     ii, p. 306 (1908).
+
+_Sponge_ hard and firm but easily torn, usually of a clear white,
+sometimes tinged with green, forming irregular sheets or masses never of
+great thickness, without branches but often with stout subquadrate
+projections, the summits of which are marked with radiating grooves; the
+whole surface often irregularly nodulose and deeply pitted; the oscula
+inconspicuous; the membrane adhering closely to the parenchyma. _The
+parenchyma contains numerous bubble-cells_ (see p. 31, fig. 2).
+
+_Skeleton_ dense but by no means regular; the radiating fibres distinct
+and containing a considerable amount of spongin, at any rate in the
+outer part of the sponge; transverse fibres hardly distinguishable,
+single spicules and irregular bundles of spicules taking their place.
+
+[Illustration: Fig. 21.--Gemmule and spicules of _Ephydatia meyeni_
+(from Calcutta). _a_, Skeleton-spicules; _b_, gemmule-spicules.]
+
+_Spicules._ Skeleton-spicules entirely smooth, moderately stout, feebly
+curved, sharply pointed. No flesh-spicules. Gemmule-spicules with the
+shaft as a rule moderately stout, much longer than the diameter of one
+disk, smooth or with a few stout, straight horizontal spines, which are
+frequently bifid or trifid; the disks flat, of considerable size, with
+their margins cleanly and deeply divided into a comparatively small
+number of deep, slender, triangular processes of different sizes; the
+shaft extending not at all or very little beyond the disks.
+
+_Gemmules_ spherical, usually numerous and of rather large size; each
+covered by a thick layer of minute air-spaces, among which the
+gemmule-spicules are arranged vertically, often in two or even three
+concentric series; a single short foraminal tubule; the pneumatic coat
+confined externally by a delicate membrane, with small funnel-shaped
+pits over the spicules of the outer series.
+
+I think that the gemmules found by me in Bhim Tal and assigned to
+Potts's _Meyenia robusta_ belong to this species, but some of the
+spicules are barely as long as the diameter of the disks. In any case
+Potts's description is so short that the status of his species is
+doubtful. His specimens were from N. America.
+
+_E. meyeni_ is closely related to the two commonest Holarctic species of
+the genus, _E. fluviatilis_ and _E. m�lleri_, which have been confused
+by several authors including Potts. From _E. fluviatilis_ it is
+distinguished by the possession of bubble-cells in the parenchyma, and
+from _E. m�lleri_ by its invariably smooth skeleton-spicules and the
+relatively long shafts of its gemmule-spicules. The latter character is
+a marked feature of the specimens from the Malay Archipelago assigned by
+Prof. Max Weber to _E. fluviatilis_; I am indebted to his kindness for
+an opportunity of examining some of them.
+
+TYPE in the British Museum; a fragment in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--India and Sumatra. _Localities_:--BENGAL,
+Calcutta and neighbourhood (_Annandale_); MADRAS PRESIDENCY, Cape
+Comorin, Travancore (_Trivandrum Mus._): BOMBAY PRESIDENCY, Island of
+Bombay (_Carter_): HIMALAYAS, Bhim Tal, Kumaon (alt. 4,500 feet)
+(_Annandale_).
+
+BIOLOGY.--My experience agrees with Carter's, that this species is never
+found on floating objects but always on stones or brickwork. It grows in
+the Calcutta "tanks" on artificial stonework at the edge of the water,
+together with _Spongilla carteri_, _S. alba_, _S. fragilis_ subsp.
+_calcuttana_, and _Trochospongilla latouchiana_. It flourishes during
+the cold weather and often occupies the same position in succeeding
+years. In this event the sponge usually consists of a dead base, which
+is of a dark brownish colour and contains no cells, and a living upper
+layer of a whitish colour.
+
+The larva of _Sisyra indica_ is sometimes found in the canals, but the
+close texture of the sponge does not encourage the visits of other
+_incol�_.
+
+
+Genus 4. DOSILIA, _Gray_.
+
+     _Dosilia_, J. E. Gray, P. Zool. Soc. London, 1867, p. 550.
+
+TYPE, _Spongilla plumosa_, Carter.
+
+This genus is distinguished from _Ephydatia_ by the nature of the free
+microscleres, the microscleres of the gemmule being similar in the two
+genera. The free microscleres consist as a rule of several or many
+shafts meeting together in several or many planes at a common centre,
+which is usually nodular. The free ends of these shafts often possess
+rudimentary rotul�. Occasionally a free microsclere may be found that is
+a true monaxon and sometimes such spicules are more or less distinctly
+birotulate. The skeleton is also characteristic. It consists mainly of
+radiating fibres which bifurcate frequently in such a way that a
+bush-like structure is produced. Transverse fibres are very feebly
+developed and are invisible to the naked eye. Owing to the structure of
+the skeleton the sponge has a feathery appearance.
+
+Gray originally applied the name _Dosilia_ to this species and to
+_"Spongilla" baileyi_, Bowerbank. It is doubtful how far his generic
+description applies to the latter, which I have not seen; but although
+the position of _"Spongilla" baileyi_ need not be discussed here, I may
+say that I do not regard it as a congener of _Dosilia plumosa_, the free
+microscleres of which are of a nature rare but not unique in the family.
+With _Dosilia plumosa_ we must, in any case, associate in one genus the
+two forms that have been described as varieties, viz., _palmeri_*, Potts
+from Texas and Mexico, and _brouini_*, Kirkpatrick from the White Nile.
+By the kindness of the authorities of the Smithsonian Institution and
+the British Museum I have been able to examine specimens of all three
+forms, in each case identified by the author of the name, and I am
+inclined to regard them as three very closely allied but distinct
+species. Species with free microscleres similar to those of these three
+forms but with heterogeneous or tubelliform gemmule-spicules will
+probably need the creation of a new genus or new genera for their
+reception.
+
+GEOGRAPHICAL DISTRIBUTION.--The typical species occurs in Bombay and
+Madras; _D. palmeri_ has probably an extensive range in the drier parts
+of Mexico and the neighbouring States, while _D. brouini_ has only been
+found on the banks of the White Nile above Khartoum, in Tropical Africa.
+
+
+17. Dosilia plumosa* (_Carter_).
+
+     _Spongilla plumosa_, Carter, J. Bomb. Asiat. Soc. iii, p.
+     34, pl. i, fig. 2, & Ann. Nat. Hist. (2) iv, p. 85, pl. iii,
+     fig. 2 (1849).
+
+     _Spongilla plumosa_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 449, pl. xxxviii, fig. 5.
+
+     _Dosilia plumosa_, J. E. Gray, _ibid._ 1867, p. 551.
+
+     _Meyenia plumosa_, Carter, Ann. Nat. Hist. (5) vii, p. 94,
+     pl. v, fig. 6 (1881).
+
+     _Meyenia plumosa_, Potts, P. Ac. Philad. 1887, p. 233.
+
+     _Ephydatia plumosa_, Weltner, Arch. Naturg. lxi (i), p. 126
+     (1895).
+
+     _Ephydatia plumosa_, Petr, Rozp. Ceske Ak. Praze, Tr�da ii,
+     pl. ii, figs. 29, 30 (text in Czech) (1899).
+
+_Sponge_ forming soft irregular masses which are sometimes as much as 14
+cm. in diameter, of a pale brown or brilliant green colour; no branches
+developed but the surface covered with irregular projections usually of
+a lobe-like nature.
+
+_Skeleton_ delicate, with the branches diverging widely, exhibiting the
+characteristic structure of the genus in a marked degree, containing a
+considerable amount of chitin, which renders it resistant in spite of
+its delicacy.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, nearly straight,
+moderately slender, about twenty times as long as their greatest
+transverse diameter. Flesh-spicules occasionally amphioxous or
+birotulate and with a single shaft, more frequently consisting of many
+shafts meeting in a distinct central nodule, which is itself smooth; the
+shafts irregularly spiny, usually more or less nodular at the tip, which
+often bears a distinct circle of recurved spines that give it a rotulate
+appearance. Gemmule-spicules with long, slender, straight shafts, which
+bear short, slender, straight, horizontal spines sparsely and
+irregularly scattered over their surface; the rotul� distinctly convex
+when seen in profile; their edge irregularly and by no means deeply
+notched; the shafts not extending beyond their surface but clearly seen
+from above as circular umbones.
+
+[Illustration: Fig. 22.--_Dosilia plumosa._
+
+A=microscleres, � 240; B=gemmule as seen in optical section from
+below, � 75. (From Rambha.)]
+
+_Gemmules._ Somewhat depressed, covered with a thick granular pneumatic
+coat, in which the spicules stand erect; the single aperture depressed.
+Each gemmule surrounded more or less distinctly by a circle or several
+circles of flesh-spicules.
+
+TYPE in the British Museum; some fragments in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--Bombay and Madras. Carter's specimens were
+taken in the island of Bombay, mine at Rambha in the north-east of the
+Madras Presidency. I have been unable to discover this species in the
+neighbourhood of Calcutta, but it is apparently rare wherever it occurs.
+
+BIOLOGY.--Carter writes as regards this species:--"This is the coarsest
+and most resistant of all the species. As yet I have only found three or
+four specimens of it, and these only in two tanks. I have never seen it
+fixed on any solid body, but always floating on the surface of the
+water, about a month after the first heavy rains of the S.W. monsoon
+have fallen. Having made its appearance in that position, and having
+remained there for upwards of a month, it then sinks to the bottom. That
+it grows like the rest, adherent to the sides of the tank, must be
+inferred from the first specimen which I found (which exceeds two feet
+in circumference) having had a free and a fixed surface, the latter
+coloured by the red gravel on which it had grown. I have noticed it
+growing, for two successive years in the month of July, on the surface
+of the water of one of the two tanks in which I have found it, and would
+account for its temporary appearance in that position, in the following
+way, viz., that soon after the first rains have fallen, and the tanks
+have become filled, all the sponges in them appear to undergo a partial
+state of putrescency, during which gas is generated in them, and
+accumulates in globules in their structure, through which it must burst,
+or tear them from their attachments and force them to the surface of the
+water. Since then the coarse structure of _plumosa_ would appear to
+offer greater resistance to the escape of this air, than that of any of
+the other species, it is probable that this is the reason of my having
+hitherto only found it in the position mentioned."
+
+It seems to me more probable that the sponges are actually broken away
+from their supports by the violence of the rain and retain air
+mechanically in their cavities. The only specimens of _D. plumosa_ that
+I have seen alive were attached very loosely to their support. In
+writing of the "coarse structure" of this species, Carter evidently
+alludes to the wide interspaces between the component branches of the
+skeleton.
+
+My specimens were attached to the stem of a water-lily growing in a pool
+of slightly brackish water and were of a brilliant green colour. I
+mistook them at first for specimens of _S. lacustris_ subsp.
+_reticulata_ in which the branches had not developed normally. They were
+taken in March and were full of gemmules. The pool in which they were
+growing had already begun to dry up.
+
+
+Genus 5. TROCHOSPONGILLA, _Vejdovsky_.
+
+     _Trochospongilla_, Vejdovsky, Abh. K. B�hm. Ges. Wiss. xii,
+     p. 31 (1883).
+
+     _Trochospongilla_, Wierzejski, Arch. Slaves de Biologie, i,
+     p. 44 (1886).
+
+     _Trochospongilla_, Vejdovsky, P. Ac. Philad. 1887, p. 176.
+
+     _Meyenia_, Potts (_partim_), _ibid._ p. 210.
+
+     _Tubella_, _id._ (_partim_), _ibid._, p. 248.
+
+     _Meyenia_, Carter (_partim_), Ann. Nat. Hist. (5) vii, p. 90
+     (1881).
+
+     _Trochospongilla_, Weltner, in Zacharias's Tier- und
+     Pflanzenwelt, i, p. 215 (1891).
+
+     _Trochospongilla_, _id._, Arch. Naturg. lxi (i), p. 120
+     (1895).
+
+     _Tubella_, _id._ (_partim_), _ibid._ p. 128.
+
+TYPE, _Spongilla erinaceus_, Ehrenberg.
+
+The characteristic feature of this genus is that the rotul� of the
+gemmule-spicules, which are homogeneous, have smooth instead of serrated
+edges. Their stem is always short and they are usually embedded in a
+granular pneumatic coat. The sponge is small in most of the species as
+yet known; in some species microscleres without rotul� are associated
+with the gemmules.
+
+[Illustration: Fig. 23.--A=skeleton-spicule of _Trochospongilla
+latouchiana_; A'=gemmule-spicule of the same species; B=gemmule of _T.
+phillottiana_ as seen in optical section from above; B'=skeleton-spicule
+of same species: A, A', B' � 240; B � 75. All specimens from Calcutta.]
+
+I think it best to include in this genus, as the original diagnosis
+would suggest, all those species in which all the gemmule-spicules are
+definitely birotulate and have smooth edges to their disks, confining
+the name _Tubella_ to those in which the upper rotula is reduced to a
+mere knob. Even in those species in which the two disks are normally
+equal, individual spicules may be found in which the equality is only
+approximate, while, on the other hand, it is by no means uncommon for
+individual spicules in such species as _"Tubella" pennsylvanica_, which
+is here included in _Trochospongilla_, to have the two disks nearly
+equal, although normally the upper one is much smaller than the lower.
+There is very rarely any difficulty, however, in seeing at a glance
+whether the edge of the disk is smooth or serrated, the only species in
+which this difficulty would arise being, so far as I am aware, the
+Australian _Ephydatia capewelli_* (Haswell), the disks of which are
+undulated and nodulose rather than serrated.
+
+GEOGRAPHICAL DISTRIBUTION.--The genus includes so large a proportion of
+small, inconspicuous species that its distribution is probably known but
+imperfectly. It would seem to have its headquarters in N. America but
+also occurs in Europe and Asia. In India three species have been found,
+one of which (_T. pennsylvanica_) has an extraordinarily wide and
+apparently discontinuous range, being common in N. America, and having
+been found in the west of Ireland, the Inner Hebrides, and near the west
+coast of S. India. The other two Indian species are apparently of not
+uncommon occurrence in eastern India and Burma.
+
+
+  _Key to the Indian Species of_ Trochospongilla.
+
+   I. Rotules of the gemmule-spicules equal
+      or nearly so.
+      A. Skeleton-spicules smooth, usually
+         pointed                             _latouchiana_, p. 115.
+      B. Skeleton-spicules spiny, blunt      _phillottiana_, p. 117.
+  II. Upper rotule of the gemmule-spicules
+      distinctly smaller than the lower.
+      Skeleton-spicules spiny, pointed       _pennsylvanica_, p. 118.
+
+
+18. Trochospongilla latouchiana*, _Annandale_.
+
+     _Trochospongilla latouchiana_, Annandale, J. Asiat. Soc.
+     Bengal, 1907, p. 21, fig. 5.
+
+     _Trochospongilla latouchiana_, _id._, Rec. Ind. Mus. ii, p.
+     157 (1908).
+
+     _Trochospongilla leidyi_, _id._ (_nec_ Bowerbank), _ibid._
+     iii, p. 103 (1909).
+
+[Illustration: Fig. 24.--_Trochospongilla latouchiana._
+
+Vertical section of part of skeleton with gemmules _in situ_, � 30; also
+a single gemmule, � 70. (From Calcutta).]
+
+_Sponge_ forming cushion-shaped masses rarely more than a few
+centimetres in diameter or thickness and of a brown or yellow colour,
+hard but rather brittle; surface evenly rounded, minutely hispid; oscula
+inconspicuous, small, circular, depressed, very few in number; external
+membrane adhering closely to the parenchyma; a chitinous membrane at the
+base of the sponge. Larger sponges divided into several layers by
+similar membranes.
+
+_Skeleton_ dense, forming a close reticulation; radiating fibres slender
+but quite distinct, running up right through the sponge, crossed at
+frequent intervals by single spicules or groups of spicules.
+
+_Spicules._ Skeleton-spicules smooth, about twenty times as long as the
+greatest transverse diameter, as a rule sharply pointed; smooth
+amphistrongyli, which are often inflated in the middle, sometimes mixed
+with them but never in large numbers. No flesh-spicules.
+Gemmule-spicules with the rotul� circular or slightly asymmetrical, flat
+or nearly flat, marked with a distinct double circle as seen from above,
+sometimes not quite equal; the shaft not projecting beyond them; the
+diameter of the rotule 4-1/2 to 5 times that of the shaft, which is
+about 2-2/3 times as long as broad.
+
+_Gemmules_ small (0.2 � 0.18 mm.), as a rule very numerous and scattered
+throughout the sponge, flask-shaped, clothed when mature with a thin
+microcell coat in which the birotulates are arranged with overlapping
+rotul�, their outer rotul� level with the surface; foraminal aperture
+circular, situated on an eminence.
+
+
+  _Average Measurements._
+
+  Diameter of gemmule                0.2 � 0.18 mm.
+  Length of skeleton-spicule               0.28  "
+  Length of birotulate-spicule             0.175 "
+  Diameter of rotula                       0.02  "
+
+_T. latouchiana_ is closely related to _T. leidyi_ (Bowerbank) from N.
+America, but is distinguished by its much more slender
+skeleton-spicules, by the fact that the gemmules are not enclosed in
+cages of megascleres or confined to the base of the sponge, and by
+differences in the structure of the skeleton.
+
+TYPE in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--Lower Bengal and Lower Burma.
+_Localities_:--BENGAL, Calcutta and neighbourhood (_Annandale_): BURMA,
+Kawkareik, Amherst district, Tenasserim (_Annandale_).
+
+BIOLOGY.--This species, which is common in the Museum tank, Calcutta, is
+apparently one of those that can grow at any time of year, provided that
+it is well covered with water. Like _T. leidyi_ it is capable of
+producing fresh layers of living sponge on the top of old ones, from
+which they are separated by a chitinous membrane. These layers are not,
+however, necessarily produced in different seasons, for it is often
+clear from the nature of the object to which the sponge is attached that
+they must all have been produced in a short space of time. What appears
+to happen in most cases is this:--A young sponge grows on a brick, the
+stem of a reed or some other object at or near the edge of a pond, the
+water in which commences to dry up. As the sponge becomes desiccated its
+cells perish. Its gemmules are, however, retained in the close-meshed
+skeleton, which persists without change of form. A heavy shower of rain
+then falls, and the water rises again over the dried sponge. The
+gemmules germinate immediately and their contents spread out over the
+old skeleton, secrete a chitinous membrane and begin to build up a new
+sponge. The process may be repeated several times at the change of the
+seasons or even during the hot weather, or after a "break in the rains."
+If, however, the dried sponge remains exposed to wind and rain for more
+than a few months, it begins to disintegrate and its gemmules are
+carried away to other places. Owing to their thin pneumatic coat and
+relatively heavy spicules they are not very buoyant. Even in the most
+favourable circumstances the sponge of _T. latouchiana_ never forms
+sheets of great area. In spite of its rapid growth it is frequently
+overgrown by _Spongilla carteri_.
+
+
+19. Trochospongilla phillottiana*, _Annandale_.
+
+     _Trochospongilla phillottiana_, Annandale, J. Asiat. Soc.
+     Bengal, 1907, p. 22, fig. 6.
+
+     _Trochospongilla phillottiana_, _id._, Rec. Ind. Mus. i, p.
+     269 (1907).
+
+     _Trochospongilla phillottiana_, _id._, _ibid._ ii, p. 157
+     (1908).
+
+_Sponge_ hard but friable, forming sheets or patches often of great
+extent but never more than about 5 mm. thick; the surface minutely
+hispid, flat; colour pale yellow, the golden-yellow gemmules shining
+through the sponge in a very conspicuous manner; oscula inconspicuous;
+external membrane adherent; no basal chitinous membrane.
+
+_Skeleton_ dense but by no means strong; the reticulation close but
+produced mainly by single spicules, which form triangular meshes;
+radiating fibres never very distinct, only persisting for a short
+distance in a vertical direction; each gemmule enclosed in an open,
+irregular cage of skeleton-spicules.
+
+_Spicules._ Skeleton-spicules short, slender, blunt, more or less
+regularly and strongly spiny, straight or feebly curved. No
+flesh-spicules. Gemmule-spicules with the rotul� circular, very wide as
+compared with the shaft, concave on the surface, with the shaft
+projecting as an umbo on the surface; the lower rotula often a little
+larger than the upper.
+
+_Gemmules_ numerous, situated at the base of the sponge in irregular,
+one-layered patches, small (0.32 � 0.264 mm.), of a brilliant golden
+colour, distinctly wider than high, with a single aperture situated on
+an eminence on the apex, each clothed (when mature) with a pneumatic
+coat that contains relatively large but irregular air-spaces among which
+the spicules stand with the rotul� overlapping alternately, a
+funnel-shaped pit in the coat descending from the surface to the upper
+rotula of each of them; the surface of the gemmule covered with
+irregular projections.
+
+  Diameter of gemmule          0.32 � 0.264 mm.
+  Length of skeleton-spicule          0.177  "
+  Length of gemmule-spicule           0.015  "
+  Diameter of rotule                  0.022  "
+
+This species appears to be related to _T. pennsylvanica_, from which it
+differs mainly in the form of its gemmule-spicules and the structure of
+its gemmule. My original description was based on specimens in which the
+gemmule-spicules were not quite mature.
+
+TYPE in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--Lower Bengal and Lower Burma.
+_Localities_:--BENGAL, Calcutta (_Annandale_): BURMA, jungle pool near
+Kawkareik, Amherst district, Tenasserim (_Annandale_).
+
+BIOLOGY.--This species covers a brick wall at the edge of the Museum
+tank in Calcutta every year during the "rains." In the cold weather the
+wall is left dry, but it is usually submerged to a depth of several feet
+before the middle of July. It is then rapidly covered by a thin layer of
+the sponge, which dies down as soon as the water begins to sink when the
+"rains" are over. For some months the gemmules adhere to the wall on
+account of the cage of spicules in which each of them is enclosed, but
+long before the water rises again the cages disintegrate and the
+gemmules are set free. Many of them fall or are carried by the wind into
+the water, on the surface of which, owing to their thick pneumatic coat,
+they float buoyantly. Others are lodged in cavities in the wall. On the
+water the force of gravity attracts them to one another and to the edge
+of the pond, and as the water rises they are carried against the wall
+and germinate. In thick jungle at the base of the Dawna Hills near
+Kawkareik[AI] in the interior of Tenasserim, I found the leaves of
+shrubs which grew round a small pool, covered with little dry patches of
+the sponge, which had evidently grown upon them when the bushes were
+submerged. This was in March, during an unusually severe drought.
+
+     [Footnote AI: This locality is often referred to in
+     zoological literature as Kawkare_et_ or Kawkari_t_, or even
+     K_o_kari_t_.]
+
+
+20. Trochospongilla pennsylvanica* (_Potts_).
+
+     _Tubella pennsylvanica_, Potts, P. Ac. Philad. 1882, p. 14.
+
+     _Tubella pennsylvanica_, _id._, _ibid._ 1887, p. 251, pl.
+     vi, fig. 2, pl. xii, figs. 1-3.
+
+     _Tubella pennsylvanica_, Mackay, Trans. Roy. Soc. Canada,
+     1889, Sec. iv, p. 95.
+
+     _Tubella pennsylvanica_, Hanitsch, Nature, li, p. 511
+     (1895).
+
+     _Tubella pennsylvanica_, Weltner, Arch. Naturg. lxi (i), p.
+     128 (1895).
+
+     _Tubella pennsylvanica_, Hanitsch, Irish Natural. iv, p. 129
+     (1895).
+
+     _Tubella pennsylvanica_, Annandale, J. Linn. Soc., Zool.,
+     xxx, p. 248 (1908).
+
+     _Tubella pennsylvanica_, _id._, Rec. Ind. Mus. iii, p. 102
+     (1909).
+
+     _Tubella_ _pennsylvanica_, _id._, P. U.S. Mus. xxxvii, p.
+     403, fig. 2 (1909).
+
+_Sponge_ soft, fragile, forming small cushion-shaped masses, grey or
+green; oscula few in number, often raised on sloping eminences
+surrounded by radiating furrows below the external membrane; external
+membrane adhering to the parenchyma.
+
+_Skeleton_ close, almost structureless. "Surface of mature specimens
+often found covered with parallel skeleton spicules, not yet arranged to
+form cell-like interspaces" (_Potts_).
+
+_Spicules._ Skeleton-spicules slender, cylindrical, almost straight,
+sharp or blunt, minutely, uniformly or almost uniformly spined; spines
+sometimes absent at the tips. No flesh-spicules. Gemmule-spicules with
+the lower rotula invariably larger than the upper; both rotul� flat or
+somewhat sinuous in profile, usually circular but sometimes asymmetrical
+or subquadrate in outline, varying considerably in size.
+
+_Gemmules_ small, numerous or altogether absent, covered with a granular
+pneumatic coat of variable thickness; the rotul� of the gemmule-spicules
+overlapping and sometimes projecting out of the granular coat.
+
+The measurements of the spicules and gemmules of an Indian specimen and
+of one from Lehigh Gap, Pennsylvania, are given for comparison:--
+
+                                   Travancore.          Pennsylvania.
+  Length of skeleton-spicules    0.189-0.242 mm.        0.16-0.21 mm.
+                              (average 0.205 mm.)   (average 0.195 mm.)
+  Breadth      "        "       0.0084-0.0155 mm.        0.0084 mm.
+  Length of birotulate                 0.0126  "         0.0099  "
+  Diameter of upper rotula             0.0084  "         0.0084  "
+       "      lower   "                0.0169  "         0.0168  "
+       "      gemmule                  0.243-0.348 mm.   0.174-0.435 mm.
+
+The spicules of the Travancore specimen are, therefore, a trifle larger
+than those of the American one, but the proportions are closely similar.
+
+The difference between the gemmule-spicules of this species and those of
+such a form as _T. phillottiana_ is merely one of degree and can hardly
+be regarded as a sufficient justification for placing the two species in
+different genera. If, as I have proposed, we confine the generic name
+_Tubella_ to those species in which the gemmule-spicules are really like
+"little trumpets," the arrangement is a much more natural one, for these
+species have much in common apart from the gemmule-spicules. _T.
+pennsylvanica_ does not appear to be very closely related to any other
+known species except _T. phillottiana_.
+
+TYPE in the U.S. National Museum, from which specimens that appear to be
+co-types have been sent to the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--Very wide and apparently discontinuous:--N.
+America (widely distributed), Ireland (_Hanitsch_), Hebrides of Scotland
+(_Annandale_), Travancore, S. India (_Annandale_). The only Indian
+locality whence I have obtained specimens is Shasthancottah Lake near
+Quilon in Travancore.
+
+BIOLOGY.--In Shasthancottah Lake _T. pennsylvanica_ is found on the
+roots of water-plants that are matted together to form floating islands.
+It appears to avoid light and can only be obtained from roots that have
+been pulled out from under the islands. In Scotland I found it on the
+lower surface of stones near the edge of Loch Baa, Isle of Mull. In such
+circumstances the sponge is of a greyish colour, but specimens of the
+variety _minima_ taken by Potts on rocks and boulders in Bear Lake,
+Pennsylvania, were of a bright green.
+
+Sponges taken in Travancore in November were full of gemmules; in my
+Scottish specimens (taken in October) I can find no traces of these
+bodies, but embryos are numerous.
+
+
+Genus 6. TUBELLA, _Carter_.
+
+     _Tubella_, Carter, Ann. Nat. Hist. (5) vii, p. 96 (1881).
+
+     _Tubella_, Potts (_partim_), P. Ac. Philad. 1887, p. 248.
+
+     _Tubella_, Weltner (_partim_), Arch. Naturg. lxi (i), p. 128
+     (1895).
+
+TYPE, _Spongilla paulula_, Bowerbank.
+
+This genus is distinguished from _Ephydatia_ and _Trochospongilla_ by
+the fact that the two ends of the gemmule-spicules are unlike not only
+in size but also in form. It sometimes happens that this unlikeness is
+not so marked in some spicules as in others, but in some if not in all
+the upper end of the shaft (that is to say the end furthest removed from
+the inner coat of the gemmule in the natural position) is reduced to a
+rounded knob, while the lower end expands into a flat transverse disk
+with a smooth or denticulated edge. The spicule thus resembles a little
+trumpet resting on its mouth. The shaft of the spicule is generally
+slender and of considerable length. The skeleton of the sponge is as a
+rule distinctly reticulate and often hard; the skeleton-spicules are
+either slender or stout and sometimes change considerably in proportions
+and outline as they approach the gemmules.
+
+GEOGRAPHICAL DISTRIBUTION.--The genus is widely distributed in the
+tropics of both Hemispheres, its headquarters apparently being in S.
+America; but it is nowhere rich in species. Only two are known from the
+Oriental Region, namely _T. vesparium_* from Borneo, and _T.
+vesparioides_* from Burma.
+
+
+21. Tubella vesparioides*, _Annandale_. (Plate II, fig. 4.)
+
+     _Tubella vesparioides_, Annandale, Rec. Ind. Mus. ii, p. 157
+     (1908).
+
+_Sponge_ forming rather thick sheets of considerable size, hard but
+brittle, almost black in colour; oscula inconspicuous; external membrane
+supported on a reticulate horizontal skeleton.
+
+_Skeleton._ The surface covered with a network of stout spicule-fibres,
+the interstices of which are more or less deeply sunk, with sharp fibres
+projecting vertically upwards at the nodes; the whole mass pervaded by a
+similar network, which is composed of a considerable number of spicules
+lying parallel to one another, overlapping at the ends and bound
+together by a profuse secretion of spongin.
+
+[Illustration: Fig. 25.--Spicules of _Tubella vesparioides_ (from type
+specimen). � 240.]
+
+_Spicules._ Skeleton-spicules slender, smooth, amphioxous, bent in a
+wide arc or, not infrequently, at an angle. No true flesh-spicules.
+Gemmule-spicules terminating above in a rounded, knob-like structure and
+below in a relatively broad, flat rotula, which is very deeply and
+irregularly indented round the edge when mature, the spicules at an
+earlier stage of development having the form of a sharp pin with a round
+head; shaft of adult spicules projecting slightly below the rotula,
+long, slender, generally armed with a few stout conical spines, which
+stand out at right angles to it.
+
+_Gemmules_ numerous throughout the sponge, spherical, provided with a
+short, straight foraminal tubule, surrounded by one row of spicules,
+which are embedded in a rather thin granular coat.
+
+  Average length of skeleton-spicule          0.316 mm.
+    "     breadth of skeleton-spicule         0.0135 "
+    "     length of gemmule-spicule           0.046  "
+    "     diameter of rotula                  0.0162 "
+    "         "       gemmule                 0.446  "
+
+This sponge is closely related to _Tubella vesparium_ (v. Martens) from
+Borneo, from which it may be distinguished by its smooth
+skeleton-spicules and the deeply indented disk of its gemmule-spicules.
+The skeleton-fibres are also rather less stout. By the kindness of Dr.
+Weltner, I have been able to compare types of the two species.
+
+TYPE in the Indian Museum.
+
+HABITAT.--Taken at the edge of the Kanghyi ("great pond") at Mudon near
+Moulmein in the Amherst district of Tenasserim. The specimens were
+obtained in March in a dry state and had grown on logs and branches
+which had evidently been submerged earlier in the year. The name
+_vesparium_ given to the allied species on account of its resemblance to
+a wasps' nest applies with almost equal force to this Burmese form.
+
+
+Genus 7. CORVOSPONGILLA, nov.
+
+TYPE[AJ], _Spongilla loricata_, Weltner.
+
+     [Footnote AJ: Potts's _Spongilla nov�-terr�_ from
+     Newfoundland and N. America cannot belong to this genus
+     although it has similar flesh-spicules, for, as Weltner has
+     pointed out (_op. cit. supra_ p. 126), the gemmule-spicules
+     are abortive rotul�. This is shown very clearly in the
+     figure published by Petr (Rozp. Ceske Ak. Praze, Tr�da, ii,
+     pl. ii, figs. 27, 28, 1899), who assigns the species to
+     _Heteromeyenia_. Weltner places it in _Ephydatia_, and it
+     seems to be a connecting link between the two genera. It has
+     been suggested that it is a hybrid (Traxler, Termes.
+     Fuzetek, xxi, p. 314, 1898).]
+
+Spongillid� in which the gemmule-spicules are without a trace of rotul�
+and the flesh-spicules have slender cylindrical shafts that bear at or
+near either end a circle of strong recurved spines. The gemmule-spicules
+are usually stout and sausage-shaped, and the gemmules resemble those of
+_Stratospongilla_ in structure. The skeleton is strong and the
+skeleton-spicules stout, both resembling those of the "genus"
+_Potamolepis_, Marshall.
+
+As in all other genera of Spongillid� the structure of the skeleton is
+somewhat variable, the spicule-fibres of which it is composed being much
+more distinct in some species than in others. The skeleton-spicules are
+often very numerous and in some cases the skeleton is so compact and
+rigid that the sponge may be described as stony. The flesh-spicules
+closely resemble the gemmule-spicules of some species of _Ephydatia_ and
+_Heteromeyenia_.
+
+GEOGRAPHICAL DISTRIBUTION.--The species of this genus are probably
+confined to Africa (whence at least four are known) and the Oriental
+Region. One has been recorded from Burma and another from the Bombay
+Presidency.
+
+
+  _Key to the Indian Species of_ Corvospongilla.
+
+  I. Gemmule with two layers of gemmule-spicules;
+  those of the inner layer not
+  markedly smaller than those of the outer.       _burmanica_, p. 123.
+
+  II. Gemmule with two layers of gemmule-spicules,
+  the outer of which contains
+  spicules of much greater size than the
+  inner.                                          _lapidosa_, p. 124.
+
+
+22. Corvospongilla burmanica* (_Kirkpatrick_). (Plate II, fig. 5.)
+
+     _Spongilla loricata_ var. _burmanica_, Kirkpatrick, Rec.
+     Ind. Mus. ii, p. 97, pl. ix (1908).
+
+_Sponge_ forming a shallow sheet, hard, not very strong, of a pale
+brownish colour; the surface irregularly spiny; the oscula small but
+conspicuous, circular, raised on little turret-like eminences; the
+external membrane adhering closely to the sponge.
+
+_Skeleton_ dense but by no means regular; the network composed largely
+of single spines; thick radiating fibres distinguishable in the upper
+part of the sponge.
+
+_Spicules._ Skeleton-spicules smooth, not very stout, amphistrongylous,
+occasionally a little swollen at the ends, often with one or more
+fusiform swellings, measuring on an average about 0.27 � 0.0195 mm.
+Flesh-spicules with distinct rotules, the recurved spines numbering 4 to
+6, measuring about 1/7 the length of the spicules; the shaft by no means
+strongly curved; their length from 0.03-0.045 mm. Gemmule-spicules
+amphioxous, as a rule distinctly curved, sometimes swollen at the ends,
+covered regularly but somewhat sparsely with fine spines, not measuring
+more than 0.49 � 0.078 mm.
+
+_Gemmules_ strongly adherent, arranged in small groups, either single or
+double; when single spherical, when double oval; each gemmule or pair of
+gemmules covered by two layers of gemmule-spicules bound together in
+chitinous substance; the inner layer on the inner coat of the gemmule,
+the outer one separated from it by a space and in contact with the outer
+cage of skeleton-spicules; the size of the gemmule-spicules variable in
+both layers; external to the outer layer a dense cage of
+skeleton-spicules; foraminal tubule short, cylindrical.
+
+This sponge is closely related to _S. loricata_, Weltner, of which
+Kirkpatrick regards it as a variety. "The main difference," he writes,
+"between the typical African form and the Burmese variety consists in
+the former having much larger microstrongyles (83 � 15.7 � [0.83 � 0.157
+mm.]) with larger and coarser spines;... Judging from Prof. Weltner's
+sections of gemmules, these bodies lack the definite outer shell of
+smooth macrostrongyles [blunt skeleton-spicules], though this may not
+improbably be due to the breaking down and removal of this layer. A
+further difference consists in the presence, in the African specimen, of
+slender, finely spined strongyles [amphistrongyli], these being absent
+in the Burmese form, though perhaps this fact is not of much
+importance."
+
+TYPE in the British Museum; a piece in the Indian Museum.
+
+HABITAT.--Myitkyo, head of the Pegu-Sittang canal, Lower Burma (_E. W.
+Oates_).
+
+BIOLOGY.--The sponge had grown over a sheet of the polyzoon _Hislopia
+lacustris_, Carter (see p. 204), remains of which can be detected on its
+lower surface.
+
+"Mr. E. W. Oates, who collected and presented the sponge, writes that
+the specimen was found encrusting the vertical and horizontal surfaces
+of the bottom beam of a lock gate, where it covered an area of six
+square feet. The beam had been tarred several times before the sponge
+was discovered. The portion of the gate on which the sponge was growing
+was submerged from November to May for eight hours a day at spring
+tides, but was entirely dry during the six days of neap tides. From May
+to October it was constantly submerged. The sponge was found in April.
+Although the canal is subject to the tides, the water at the lock is
+always fresh. The colour of the sponge during life was the same as in
+its present condition."
+
+
+23. Corvospongilla lapidosa* (_Annandale_).
+
+     _Spongilla lapidosa_ Annandale, Rec. Ind. Mus. ii, pp. 25,
+     26, figs. 3, 4, 5 (1908).
+
+The _sponge_ forms a thin but extremely hard and resistant crust the
+surface of which is either level, slightly concave, or distinctly
+corrugated; occasional groups of spicules project from it, but their
+arrangement is neither so regular nor so close as is the case in _C.
+burmanica_. The dermal membrane adheres closely to the sponge. The
+oscula are small; some of them are raised above the general surface but
+not on regular turret-shaped eminences. The colour is grey or black.
+There is a thick chitinous membrane at the base of the sponge.
+
+[Illustration: Fig. 26.--Spicules of _Corvospongilla lapidosa_ (from
+type specimen), � 240.]
+
+The _skeleton_ is extremely dense owing to the large number of spicules
+it contains, but almost structureless; broad vertical groups of spicules
+occur but lack spongin and only traverse a small part of the thickness
+of the sponge; their position is irregular. The firmness of the skeleton
+is due almost entirely to the interlocking of individual spicules. At
+the base of the sponge the direction of a large proportion of the
+spicules is horizontal or nearly horizontal, the number arranged
+vertically being much greater in the upper part.
+
+_Spicules._ The skeleton-spicules are sausage-shaped and often a little
+swollen at the ends or constricted in the middle. A large proportion are
+twisted or bent in various ways, and a few bear irregular projections or
+swellings. The majority, however, are quite smooth. Among them a few
+more or less slender, smooth amphioxi occur, but these are probably
+immature spicules. The length and curvature of the amphistrongyli varies
+considerably, but the average measurements are about 0.28 � 0.024 mm.
+The flesh-spicules also vary greatly in length and in the degree to
+which their shafts are curved. At first sight it seems to be possible to
+separate them into two categories, one in which the shaft is about 0.159
+mm. long, and another in which it is only 0.05 mm. or even less; and
+groups of birotulates of approximately the same length often occur in
+the interstices of the skeleton. Spicules of all intermediate lengths
+can, however, be found. The average diameter of the shaft is 0.0026 mm.
+and of the rotula 0.0106 mm., and the rotula consists of from 6 to 8
+spines. The gemmule-spicules vary greatly in size, the longest measuring
+about 0.08 � 0.014 and the smallest about 0.034 � 0.007 or even less.
+There appears to be in their case an even more distinct separation as
+regards size than there is in that of the flesh-spicules; but here again
+intermediate forms occur. They are all stout, more or less blunt, and
+more or less regularly covered with very short spines; most of them are
+distinctly curved, but some are quite straight.
+
+_Gemmules._ The gemmules are firmly adherent to the support of the
+sponge, at the base of which they are congregated in groups of four or
+more. They vary considerably in size and shape, many of them being
+asymmetrical and some elongate and sausage-shaped. The latter consist of
+single gemmules and not of a pair in one case. Extreme forms measure
+0.38 � 0.29 and 0.55 � 0.25. Each gemmule is covered with a thick
+chitinous membrane in close contact with its wall and surrounding it
+completely. This membrane is full of spicules arranged as in a mosaic;
+most or all of them belong to the smaller type, and as a rule they are
+fairly uniform in size. Separated from this layer by a considerable
+interval is another layer of spicules embedded in a chitinous membrane
+which is in continuity with the basal membrane of the sponge. The
+spicules in this membrane mostly belong to the larger type and are very
+variable in size; mingled with them are often a certain number of
+birotulate flesh-spicules. The membrane is in close contact with a dense
+cage of skeleton-spicules arranged parallel to it and bound together by
+chitinous substance. The walls of this cage, when they are in contact
+with those of the cages of other gemmules, are coterminous with them.
+There is a single depressed aperture in the gemmules, as a rule situated
+on one of the longer sides.
+
+This sponge is distinguished from _C. burmanica_ not only by differences
+in external form, in the proportions of the spicules and the structure
+of the skeleton, but also by the peculiar nature of the armature of the
+gemmule. The fact that birotulate spicules are often found in close
+association with them, is particularly noteworthy.
+
+TYPE in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--This sponge has only been found in the
+Western Ghats of the Bombay Presidency. _Localities_:--Igatpuri Lake and
+the R. Godaveri at Nasik.
+
+BIOLOGY.--There is a remarkable difference in external form between the
+specimens taken in Igatpuri and those from Nasik, and this difference is
+apparently due directly to environment. In the lake, the waters of which
+are free from mud, the sponges were growing on the lower surface of
+stones near the edge. They formed small crusts not more than about 5 cm.
+(2 inches) in diameter and of a pale greyish colour. Their surface was
+flat or undulated gently, except round the oscula where it was raised
+into sharply conical eminences with furrowed sides. The specimens from
+Nasik, which is about 30 miles from Igatpuri, were attached, together
+with specimens of _Spongilla cinerea_ and _S. indica_, to the sides of a
+stone conduit full of very muddy running water. They were black in
+colour, formed broad sheets and were markedly corrugated on the surface.
+Their oscula were not raised on conical eminences and were altogether
+most inconspicuous. The skeleton was also harder than that of sponges
+from the lake.
+
+In the lake _C. lapidosa_ was accompanied by the gemmules of _Spongilla
+bombayensis_, but it is interesting that whereas the latter sponge was
+entirely in a resting condition, the former was in full vegetative
+vigour, a fact which proves, if proof were necessary, that the similar
+conditions of environment do not invariably have the same effect on
+different species of Spongillid�.
+
+
+  APPENDIX TO PART I.
+
+  FORM OF UNCERTAIN POSITION.
+
+  (Plate I, fig. 4.)
+
+On more than one occasion I have found in my aquarium in Calcutta small
+sponges of a peculiar type which I am unable to refer with certainty to
+any of the species described above. Fig. 4, pl. I, represents one of
+these sponges. They are never more than about a quarter of an inch in
+diameter and never possess more than one osculum. They are
+cushion-shaped, colourless and soft. The skeleton-spicules are smooth,
+sharply pointed, moderately slender and relatively large. They are
+arranged in definite vertical groups, which project through the dermal
+membrane, and in irregular transverse formation. Small spherical
+gemmules are present but have only a thin chitinous covering without
+spicules or foramen.
+
+These sponges probably represent an abnormal form of some well-known
+species, possibly of _Spongilla carteri_. I have seen nothing like them
+in natural conditions.
+
+
+
+
+  PART II.
+
+  FRESHWATER POLYPS
+
+  (HYDRIDA).
+
+
+
+
+INTRODUCTION TO PART II.
+
+
+I.
+
+THE PHYLUM COELENTERATA AND THE CLASS HYDROZOA.
+
+
+The second of the great groups or phyla into which the metazoa are
+divided is the Coelenterata, in which are included most of the animals
+commonly known as zoophytes, and also the corals, sea-anemones and
+jelly-fish. These animals are distinguished from the sponges on the one
+hand and from the worms, molluscs, arthropods, vertebrates, etc., on the
+other by possessing a central cavity (the coelenteron or "hollow
+inside") the walls of which are the walls of the body and consist of
+_two_ layers of cells separated by a structureless, or apparently
+structureless, jelly. This cavity has as a main function that of a
+digestive cavity.
+
+An ideally simple coelenterate would not differ much in general
+appearance from an olynthus (p. 27), but it would have no pores in the
+body-wall and its upper orifice would probably be surrounded by
+prolongations of the body-wall in the form of tentacles. There would be
+no collar-cells, and the cells of the body generally would have a much
+more fixed and definite position and more regular functions than those
+of any sponge. The most characteristic of them would be the so-called
+cnidoblasts. Each of these cells contains a capsule[AK] from which a
+long thread-like body can be suddenly uncoiled and shot out.
+
+     [Footnote AK: Similar capsules are found in the tissues of
+     certain worms and molluscs, but there is the strongest
+     evidence that these animals, which habitually devour
+     coelenterates, are able to swallow the capsules uninjured
+     and to use them as weapons of defence (see Martin, Q. J.
+     Micro. Sci. London, lii, p. 261, 1908, and Grosvenor, Proc.
+     Roy. Soc. London, lxxii, p. 462, 1903). The "trichocysts" of
+     certain protozoa bear a certain resemblance to the
+     nettle-cells of coelenterates and probably have similar
+     functions.]
+
+The simplest in structure of the coelenterates are those that constitute
+the class Hydrozoa. In this class the primitive central cavity is not
+divided up by muscular partitions and there is no folding in of the
+anterior part of the body to form an oesophagus or stomatod�um such as
+is found in the sea-anemones and coral polyps. In many species and
+genera the life-history is complex, illustrating what is called the
+alternation of generations. That is to say, only alternate generations
+attain sexual maturity, those that do so being produced as buds from a
+sexless generation, which itself arises from the fertilized eggs of a
+previous sexual generation. The sexual forms as a rule differ
+considerably in structure from the sexless ones; many medus� are the
+sexual individuals in a life-cycle in which those of the sexless
+generation are sedentary.
+
+An excellent general account of the coelenterates will be found in the
+Cambridge Natural History, vol. i (by Prof. Hickson).
+
+
+STRUCTURE OF HYDRA.
+
+_Hydra_, the freshwater polyp, is one of the simplest of the Hydrozoa
+both as regards structure and as regards life-history. Indeed, it
+differs little as regards structure from the ideally simple coelenterate
+sketched in a former paragraph, while its descent is direct from one
+polyp to another, every generation laying its own eggs[AL]. The animal
+may be described as consisting of the following parts:--(1) an upright
+(or potentially upright) column or body, (2) a circle of contractile
+tentacles at the upper extremity of the column, (3) an oral disk or
+peristome surrounding the mouth and surrounded by the tentacles, and (4)
+a basal or aboral disk at the opposite extremity. The whole animal is
+soft and naked. The column, when the animal is at rest, is almost
+cylindrical in some forms but in others has the basal part distinctly
+narrower than the upper part. It is highly contractile and when
+contracted sometimes assumes an annulate appearance; but as a rule the
+external surface is smooth.
+
+     [Footnote AL: The statement is not strictly accurate as
+     regards the Calcutta phase of _H. vulgaris_, for the summer
+     brood apparently does not lay eggs but reproduces its
+     species by means of buds only. This state of affairs,
+     however, is probably an abnormality directly due to
+     environment.]
+
+The tentacles vary in number, but are never very numerous. They are
+disposed in a single circle round the oral disk and are hollow, each
+containing a prolongation of the central cavity of the column. Like the
+column but to an even greater degree they are contractile, and in some
+forms they are capable of great elongation. They cannot seize any object
+between them, but are able to move in all directions.
+
+The disk that surrounds the mouth, which is a circular aperture, is
+narrow and can to some extent assume the form of a conical proboscis,
+although this feature is never so marked as it is in some hydroids. The
+basal disk is even narrower and is not splayed out round the edges.
+
+[Illustration: Fig. 27.--Nettle-cells of _Hydra_.
+
+A=capsules from nettle-cells of a single specimen of the summer phase of
+_H. vulgaris_ from Calcutta, � 480: figures marked with a dash represent
+capsules with barbed threads. B=a capsule with the thread discharged,
+from the same specimen, � 480. C=capsule with barbed thread, from a
+specimen of _H. oligactis_ from Lahore. D=undischarged nettle-cell of
+_H. vulgaris_ from Europe (after Nussbaum, highly magnified).
+E=discharged capsule of the same (after the same author).
+_a_=cnidoblast; _b_=capsule; _c_=thread; _d_=cnidocil. Only the base of
+the thread is shown in E.]
+
+A section through the body-wall shows it to consist of the three typical
+layers of the coelenterates, viz., (i) an outer cellular layer of
+comparatively small cells, the ectoderm; (ii) an intermediate,
+structureless or apparently structureless layer, the mesogloea or
+"central jelly"; and (iii) an internal layer or endoderm consisting of
+relatively large cells. The cells of the ectoderm are not homogeneous.
+Some of them possess at their base narrow and highly contractile
+prolongations that exercise the functions of muscles. Others are
+gland-cells and secrete mucus; others have round their margins delicate
+ramifying prolongations and act as nerve-cells. Sense-cells, each of
+which bears on its external surface a minute projecting bristle, are
+found in connection with the nerve-cells, and also nettle-cells of more
+than one type.
+
+The mesogloea is very thin.
+
+The endoderm consists mainly of comparatively large cells with polygonal
+bases which can be seen from the external surface of the column in
+colourless individuals. Their inner surface is amoeboid and in certain
+conditions bears one or more vibratile cilia or protoplasmic lashes.
+Nettle-cells are occasionally found in the endoderm, but apparently do
+not originate in this layer.
+
+The walls of the tentacles do not differ in general structure from those
+of the column, but the cells of the endoderm are smaller and the
+nematocysts of the ectoderm more numerous, and there are other minor
+differences.
+
+A more detailed account of the anatomy of _Hydra_ will be found in any
+biological text-book, for instance in Parker's Elementary Biology; but
+it is necessary here to say something more as regards the nettle-cells,
+which are of great biological and systematic importance.
+
+A nettle-cell of the most perfect type and the structures necessary to
+it consist of the following parts:--
+
+     (1) A true cell (the cnidoblast), which contains--
+     (2) a delicate capsule full of liquid;
+     (3) a long thread coiled up in the capsule; and
+     (4) a cnidocil or sensory bristle, which projects from the
+         external surface of the cnidoblast.
+
+A nerve-cell is associated with each cnidoblast.
+
+In _Hydra_ the nettle-cells are of two distinct types, in one of which
+the thread is barbed at the base, whereas in the other it is simple.
+Both types have often two or more varieties and intermediate forms
+occur, but generally speaking the capsules with simple threads are much
+smaller than those with barbed ones. The arrangement of the nettle-cells
+is not the same in all species of _Hydra_, but as a rule they are much
+more numerous in the tentacles than elsewhere on the body, each large
+cell being surrounded by several small ones. The latter are always much
+more numerous than the former.
+
+
+CAPTURE AND INGESTION OF PREY: DIGESTION.
+
+The usual food of _Hydra_ consists of small insect larv�, worms, and
+crustacea, but the eggs of fish are also devoured. The method in which
+prey is captured and ingested has been much disputed, but the following
+facts appear to be well established.
+
+If a small animal comes in contact with the tentacles of the polyp, it
+instantly becomes paralysed. If it adheres to the tentacle, it perishes;
+but if, as is often the case, it does not do so, it soon recovers the
+power of movement. Animals which do not adhere are generally those (such
+as ostracod crustacea) which have a hard integument without weak spots.
+Nematocysts of both kinds shoot out their threads against prey with
+considerable violence, the discharge being effected, apparently in
+response to a chemical stimulus, by the sudden uncoiling of the thread
+and its eversion from the capsule. Apparently the two kinds of threads
+have different functions to perform, for whereas there is no doubt that
+the barbed threads penetrate the more tender parts of the body against
+which they are hurled, there is evidence that the simple threads do not
+do so but wrap themselves round the more slender parts. Nussbaum (Arch.
+mikr. Anat. xxix, pl. xx, fig. 108) figures the tail of a _Cyclops_
+attacked by _Hydra vulgaris_ and shows several simple threads wrapped
+round the hairs and a single barbed thread that has penetrated the
+integument. Sometimes the cyst adheres to the thread and remains
+attached to its cnidoblast and to the polyp, but sometimes the thread
+breaks loose. Owing to the large mass of threads that sometimes
+congregate at the weaker spots in the external covering of an animal
+attacked (_e. g._, at the little sensory pits in the integument of the
+dorsal surface of certain water-mites) it is often difficult to trace
+out the whole length of any one thread, and as a thread still attached
+to its capsule is frequently buried in the body of the prey, right up to
+the barbs, while another thread that has broken loose from its capsule
+appears immediately behind the fixed one, it seems as though the barbs,
+which naturally point towards the capsule, had become reversed. This
+appearance, however, is deceptive. The barbs are probably connected with
+the discharge of the thread and do not function at all in the same way
+as those on a spear- or arrow-head, never penetrating the object against
+which the projectile is hurled. Indeed, their position as regards the
+thread resembles that of the feathers on the shaft of an arrow rather
+than that of the barb of the head.
+
+Adhesion between the tentacles and the prey is effected partly by the
+gummy secretion of the glands of the ectoderm, which is perhaps
+poisonous as well as adhesive, and partly by the threads. Once the prey
+is fast and has ceased to struggle, it is brought to the mouth, which
+opens wide to receive it, by the contraction and the contortions of the
+tentacles, the column, and the peristome. At the same time a mass of
+transparent mucus from the gastral cavity envelops it and assists in
+dragging it in. There is some dispute as to the part played by the
+tentacles in conveying food into the mouth. My own observations lead me
+to think that, at any rate so far as _H. vulgaris_ is concerned, they do
+not push it in, but sometimes in their contortions they even enter the
+cavity accidentally.
+
+When the food has once been engulfed some digestive fluid is apparently
+poured out upon it. In _H. vulgaris_ it is retained in the upper part of
+the cavity and the soluble parts are here dissolved out, the insoluble
+parts such as the chitin of insect larv� or crustacea being ejected from
+the mouth. Digestion is, however, to a considerable extent
+intracellular, for the cells of the endoderm have the power of thrusting
+out from their surface lobular masses of their cell-substance in which
+minute nutritive particles are enveloped and dissolved. The movements of
+the cilia which can also be thrust out from and retracted into these
+cells, keep the food in the gastral cavity in motion and probably turn
+it round so as to expose all parts in turn to digestive action. Complete
+digestion, at any rate in the Calcutta form, takes several days to
+accomplish, and after the process is finished a flocculent mass of
+colourless excreta is emitted from the mouth.
+
+
+COLOUR.
+
+In _Hydra viridis_, a species that has not yet been found in India, the
+green colour is due to the presence in the cells of green corpuscles
+which closely resemble those of the cells of certain freshwater sponges.
+They represent a stage in the life-cycle of _Chlorella vulgaris_,
+Beyerinck[AM], an alga which has been cultivated independently.
+
+     [Footnote AM: Bot. Zeitung, xlviii (1890): see p. 49, _antea_.]
+
+In other species of the genus colour is largely dependent on food,
+although minute corpuscles of a _dark_ green shade are sometimes found
+in the cells of _H. oligactis_. In the Calcutta phase of _H. vulgaris_
+colour is due entirely to amorphous particles situated mainly in the
+cells of the endoderm. If the polyp is starved or exposed to a high
+temperature, these particles disappear and it becomes practically
+colourless. They probably form, therefore, some kind of food-reserve,
+and it is noteworthy that a polyp kept in the unnatural conditions that
+prevail in a small aquarium invariably becomes pale, and that its
+excreta are not white and flocculent but contain dark granules
+apparently identical with those found in the cells of coloured
+individuals (p. 154).
+
+Berninger[AN] has just published observations on the effect of
+long-continued starvation on _Hydra_ carried out in Germany. He finds
+that the tentacles, mouth, and central jelly disappear, and that a
+closed "bladder" consisting of two cellular layers remains; but, to
+judge from his figures, the colour does not disappear in these
+circumstances.
+
+     [Footnote AN: Zool. Anz. xxxvi, pp. 271-279, figs., Oct.
+     1910.]
+
+
+BEHAVIOUR.
+
+_Hydra viridis_ is a more sluggish animal than the other species of its
+genus and does not possess the same power of elongating its column and
+tentacles. It is, nevertheless, obliged to feed more frequently. Wagner
+(Quart. J. Micr. Sci. xlviii, p. 586, 1905) found it impossible to use
+this species in his physiological experiments because it died of
+starvation more rapidly than other forms. This fact is interesting in
+view of the theory that the green corpuscles in the cells of _H.
+viridis_ elaborate nutritive substances for its benefit. _H. vulgaris_,
+at any rate in Calcutta, does not ordinarily capture prey more often
+than about once in three days.
+
+All _Hydr�_ (except possibly the problematical _H. rubra_ of Roux, p.
+160) spend the greater part of their time attached by the basal disk to
+some solid object, but, especially in early life, _H. vulgaris_ is often
+found floating free in the water, and all the species possess powers of
+progression. They do not, however, all move in the same way. _H.
+viridis_ progresses by "looping" like a geometrid caterpillar. During
+each forward movement the column is arched downwards so that the
+peristome is in contact with the surface along which the animal is
+moving. The basal disk is then detached and the column is twisted round
+until the basal disk again comes in contact with the surface at a point
+some distance in advance of its previous point of attachment. The
+manoeuvre is then repeated. _H. vulgaris_, when about to move, bends
+down its column so that it lies almost prone, stretches out its
+tentacles, which adhere near the tips to the surface (p. 153), detaches
+its basal disk, and then contracts the tentacles. The column is dragged
+forward, still lying almost prone, the basal disk is bent downwards and
+again attached, and the whole movement is repeated. Probably _H.
+oligactis_ moves in the same way.
+
+When _H. viridis_ is at rest the tentacles and column, according to
+Wagner, exhibit rhythmical contractions in which those of the buds act
+in sympathy with those of the parent. In _H. vulgaris_ no such movements
+have been observed. This species, however, when it is waiting for prey
+(p. 154) changes the direction of its tentacles about once in half an
+hour.
+
+All species of _Hydra_ react to chemical and physical stimuli by
+contraction and by movements of the column and tentacles, but if the
+stimuli are constantly repeated, they lose the power to some extent. All
+species are attracted by light and move towards the point whence it
+reaches them. _H. vulgaris_, however, at any rate in India, is more
+strongly repelled by heat. Consequently, if it is placed in a glass
+vessel of water, on one side of which the sun is shining directly, it
+moves away from the source of the light[AO]. But if the vessel be
+protected from the direct rays of the sun and only a subdued light falls
+on one side of it, the polyp moves towards that side. No species of the
+genus is able to move in a straight line. Wilson (Amer. Natural. xxv, p.
+426, 1891) and Wagner (_op. cit. supra_) have published charts showing
+the elaborately erratic course pursued by a polyp in moving from one
+point to another and the effect of light as regards its movements.
+
+     [Footnote AO: Mr. F. H. Gravely tells me that this is also
+     the case as regards _H. viridis_ in England, at any rate if
+     freshly captured specimens are placed overnight in a bottle
+     in a window in such a position that the early morning
+     sunlight falls upon one side of the bottle.]
+
+If an individual of _H. vulgaris_ that contains half digested food in
+its gastral cavity is violently removed from its natural surroundings
+and placed in a glass of water, the column and tentacles contract
+strongly for a few minutes. The body then becomes greatly elongated and
+the tentacles moderately so; the tentacles writhe in all directions
+(their tips being sometimes thrust into the mouth), and the food is
+ejected.
+
+
+REPRODUCTION.
+
+Reproduction takes place in _Hydra_ (i) by means of buds, (ii) by means
+of eggs, and (iii) occasionally by fission.
+
+
+(a) _Sexual Reproduction._
+
+The sexual organs consist of ovaries (female) and spermaries (male).
+Sometimes the two kinds of organs are borne by the same individual
+either simultaneously or in succession, but some individuals or races
+appear to be exclusively of one sex. There is much evidence that in
+unfavourable conditions the larger proportion of individuals develop
+only male organs.
+
+In temperate climates most forms of _Hydra_ breed at the approach of
+winter, but starvation undoubtedly induces a precocious sexual activity,
+and the same is probably the case as regards other unfavourable
+conditions such as lack of oxygen in the water and either too high or
+too low a temperature.
+
+Downing states that in N. America (Chicago) _H. vulgaris_ breeds in
+spring and sometimes as late as December; in Calcutta it has only been
+found breeding in February and March. Except during the breeding-season
+sexual organs are absent; they do not appear in the same position on the
+column in all species.
+
+The spermaries take the form of small mound-shaped projections on the
+surface of the column. Each consists of a mass of sperm-mother cells, in
+which the spermatozoa originate in large numbers. The spermatozoa
+resemble those of other animals, each possessing a head, which is shaped
+like an acorn, and a long vibratile tail by means of which it moves
+through the water. In the cells of the spermary the spermatozoa are
+closely packed together, with their heads pointing outwards towards the
+summit of the mound through which they finally make their way into the
+water. The aperture is formed by their own movements. Downing (Zool.
+Jahrb. (Anat.) xxi, p. 379, 1905) and other authors have studied the
+origin of the spermatozoa in great detail.
+
+[Illustration: Fig. 28.--Eggs of _Hydra_ (magnified).
+
+A=egg of _H. vulgaris_ (after Chun). B=vertical section through egg of
+_H. oligactis_, form A (after Brauer). C=vertical section through egg of
+_H. oligactis_, form B (after Brauer).]
+
+The ovaries consist of rounded masses of cells lying at the base of the
+ectoderm. One of these cells, the future egg, grows more rapidly than
+the others, some or all of which it finally absorbs by means of lobose
+pseudopodia extruded from its margin. It then makes its way by amoeboid
+movements between the cells of the ectoderm until it reaches the
+surface. In _H. vulgaris_ (Mem. Asiat. Soc. Beng. i, p. 350, 1906) the
+egg is first visible with the aid of a lens as a minute star-shaped body
+of an intense white colour lying at the base of the ectoderm cells. It
+increases in size rapidly, gradually draws in its pseudopodia (the rays
+of the star) and makes its way through the ectoderm to the exterior. The
+process occupies not more than two hours. The issuing ovum does not
+destroy the ectoderm cells as it passes out, but squeezes them together
+round the aperture it makes. Owing to the pressure it exerts upon them,
+they become much elongated and form a cup, in which the embryo rests on
+the surface of the parent. By the time that the egg has become globular,
+organic connection has ceased to exist. The embryo is held in position
+partly by means of the cup of elongated ectoderm cells and partly by a
+delicate film of mucus secreted by the parent. The most recent account
+of the oogenesis ("ovogenesis") is by Downing (Zool. Jahrb. (Anat.)
+xxvii, p. 295, 1909).
+
+
+(b) _Budding._
+
+The buds of _Hydra_ arise as hollow outgrowths from the wall of the
+column, probably in a definite order and position in each species. The
+tentacles are formed on the buds much as the buds themselves arise on
+the column. There is much dispute as to the order in which these
+structures appear on the bud, and Haacke (Jenaische Zeitschr. Naturwiss.
+xiv, p. 133, 1880) has proposed to distinguish two species, _H.
+trembleyi_ and _H. roeselii_, in accordance with the manner in which the
+phenomenon is manifested. It seems probable, however, that the number of
+tentacles that are developed in the first instance is due, at any rate
+to some extent, to circumstances, for in the summer brood of _H.
+vulgaris_ in Calcutta five usually appear simultaneously, while in the
+winter brood of the same form four as a rule do so. Sometimes buds
+remain attached to their parents sufficiently long to develop buds
+themselves, so that temporary colonies of some complexity arise, but I
+have not known this to occur in the case of Indian individuals.
+
+
+(c) _Fission._
+
+Reproduction by fission occurs naturally but not habitually in all
+species of _Hydra_. It may take place either by a horizontal or by a
+vertical division of the column. In the latter case it may be either
+equal or unequal. If equal, it usually commences by an elongation in one
+direction of the circumoral disk, which assumes a narrowly oval form;
+the tentacles increase in number, and a notch appears at either side of
+the disk and finally separates the column into two equal halves, each of
+which is a complete polyp. The division sometimes commences at the base
+of the column, but this is very rare. Transverse fission can be induced
+artificially and is said to occur sometimes in natural conditions. It
+commences by a constriction of the column which finally separates the
+animal into two parts, the lower of which develops tentacles and a
+mouth, while the upper part develops a basal disk. Unequal vertical
+division occurs when the column is divided vertically in such a way that
+the two resulting polyps are unequal in size. It is apparently not
+accompanied by any great increase in the number of the tentacles, but
+probably starts by one of the tentacles becoming forked and finally
+splitting down the middle.
+
+The question of the regeneration of lost parts in _Hydra_ cannot well be
+separated from that of reproduction by fission. Over a hundred and fifty
+years ago Trembley found that if a polyp were cut into several pieces,
+each piece produced those structures necessary to render it a perfect
+polyp. He also believed that he had induced a polyp that had been turned
+inside out to adapt itself to circumstances and to reverse the functions
+and structure of the two cellular layers of its body. In this, however,
+he was probably mistaken, for there can be little doubt that his polyp
+turned right side out while not under his immediate observation. Many
+investigators have repeated some of his other experiments with success
+in Europe, but the Calcutta _Hydra_ is too delicate an animal to survive
+vivisection and invariably dies if lacerated. It appears that, even in
+favourable circumstances, for a fresh polyp to be formed by artificial
+fission it is necessary for the piece to contain cells of both
+cell-layers.
+
+
+DEVELOPMENT OF THE EGG.
+
+The egg of _Hydra_ is said to be fertilized as it lies at the base of
+the ectoderm, through which the fertilizing spermatozoon bores its way.
+As soon as the egg has emerged from the cells of its parent it begins to
+split up in such a manner as to form a hollow mass of comparatively
+large equal cells. Smaller cells are separated off from these and soon
+fill the central cavity. Before segmentation begins a delicate film of
+mucus is secreted over the egg, and within this film the larger cells
+secrete first a thick chitinous or horny egg-shell and within it a
+delicate membrane. Development in some cases is delayed for a
+considerable period, but sooner or later, by repeated division of the
+cells, an oval hollow embryo is formed and escapes into the water by the
+disintegration of the egg-shell and the subsequent rupture of the inner
+membrane. Tentacles soon sprout out from one end of the embryo's body
+and a mouth is formed; the column becomes more slender and attaches
+itself by the aboral pole to some solid object.
+
+
+ENEMIES.
+
+_Hydra_ seems to have few natural enemies. Martin (Q. J. Micr. Sci.
+London, lii, p. 261, 1908) has, however, described how the minute worm
+_Microstoma lineare_ attacks _Hydra "rubra"_ in Scottish lochs, while
+the larva of a midge devours _H. vulgaris_ in considerable numbers in
+Calcutta tanks (p. 156).
+
+
+COELENTERATES OF BRACKISH WATER.
+
+Marine coelenterates of different orders not infrequently make their way
+or are carried by the tide up the estuaries of rivers into brackish
+water, and several species have been found living in isolated lagoons
+and pools of which the water was distinctly salt or brackish. Among the
+most remarkable instances of such isolation is the occurrence in Lake
+Qurun in the Fay�m of Egypt of _Cordylophora lacustris_ and of the
+peculiar little hydroid recently described by Mr. C. L. Boulenger as
+_Moerisia lyonsi_ (Q. J. Micr. Sci. London, lii, p. 357, pls. xxii,
+xxiii, 1908). In the delta of the Ganges there are numerous ponds which
+have at one time been connected with estuaries or creeks of brackish
+water and have become isolated either naturally or by the hand of man
+without the marine element in their fauna by any means disappearing (p.
+14). The following species have been found in such ponds:--
+
+(_a_) _Hydrozoa._
+
+(1) _Bimeria vestita_, Wright (1859).
+
+Hincks, Hist. Brit. Hydr. Zooph. p. 103, pl. xv, fig. 2 (1868);
+Annandale, Rec. Ind. Mus. i, p. 141, fig. 3 (1907).
+
+This is a European species which has also been found off S. America. It
+occurs not uncommonly in the creeks that penetrate into the Ganges delta
+and has been found in pools of brackish water at Port Canning. The
+Indian form is perhaps sufficiently distinct to be regarded as a
+subspecies. The medusoid generation is suppressed in this genus.
+
+(2) _Syncoryne filamentata_, Annandale (1907).
+
+Annandale, Rec. Ind. Mus. i, p. 139, figs. 1, 2 (1907).
+
+Both hydroid and medus� were found in a small pool of brackish water at
+Port Canning. The specific name refers to the fact that the ends of the
+rhizomes from which the polyps arise are frequently free and elongate,
+for the young polyp at the tip apparently takes some time to assume its
+adult form.
+
+(3) _Irene ceylonensis_, Browne (1905).
+
+     Browne, in Herdman's Report on the Pearl Fisheries of
+     Ceylon, iv, p. 140, pl. iii, figs. 9-11 (1905); Annandale,
+     Rec. Ind. Mus. i, p. 142, fig. 4 (1907).
+
+The medusa was originally taken off the coast of Ceylon, while the
+hydroid was discovered in ponds of brackish water at Port Canning. It is
+almost microscopic in size.
+
+The first two of these species belong to the order Gymnoblastea
+(Anthomedus�) and the third to the Calyptoblastea (Leptomedus�).
+
+(b) _Actinozoa._
+
+(4) _Sagartia schilleriana_, Stoliczka (1869).
+
+     _S. schilleriana_, Stoliczka, Journ. As. Soc. Beng. (2)
+     xxxviii, p. 28, pls. x, xi (1869); _Metridium
+     schillerianum_, Annandale, Rec. Ind. Mus. i, p. 47, pl. iii
+     (1907).
+
+This sea-anemone, which has only been found in the delta of the Ganges,
+offers a most remarkable instance of what appears to be rapid adaptation
+of a species to its environment. The typical form, which was described
+in 1869 by Stoliczka from specimens taken in tidal creeks and estuaries
+in the Gangetic area and in the ponds at Port Canning, is found attached
+to solid objects by its basal disk. The race (subsp. _exul_), however,
+that is now found in the same ponds has become elongate in form and has
+adopted a burrowing habit, apparently owing to the fact that the bottom
+of the ponds in which it lives is soft and muddy.
+
+In addition to these four species a minute hydroid belonging to the
+order Gymnoblastea and now being described by Mr. J. Ritchie has been
+taken in the ponds at Port Canning. It is a very aberrant form.
+
+
+FRESHWATER COELENTERATES OTHER THAN HYDRA.
+
+_Hydra_ is the only genus of coelenterates as yet found in fresh water
+in India, but several others have been discovered in other countries.
+They are:--
+
+(1) _Cordylophora lacustris_, Allman (1843).
+
+     Hincks, Hist. Brit. Hydr. Zooph. p. 16, pl. iii, fig. 2
+     (1868).
+
+This is a branching hydroid that does not produce free medus�. It forms
+bushy masses somewhat resembling those formed by a luxuriant growth of
+_Plumatella fruticosa_ (pl. iii, fig. 1) in general appearance. _C.
+lacustris_ is abundant in canals, rivers, and estuaries in many parts of
+Europe and has recently been found in the isolated salt lake
+Birket-el-Qurun in the Fay�m of Egypt.
+
+(2) _Cordylophora whiteleggei_, v. Lendenfeld (1887).
+
+     Zool. Jahrb. ii, p. 97 (1887).
+
+A species or race of much feebler growth; as yet imperfectly known and
+only recorded from fresh water in Australia.
+
+_Cordylophora_ is a normal genus of the class Hydrozoa and the order
+Gymnoblastea; the next four genera are certainly Hydrozoa, but their
+affinities are very doubtful.
+
+(3) _Microhydra ryderi_, Potts (1885).
+
+     Potts, Q. J. Micr. Sci. London, l, p. 623, pls. xxxv, xxxvi;
+     Browne, _ibid._ p. 635, pl. xxxvii (1906).
+
+This animal, which has been found in N. America and in Germany,
+possesses both an asexual hydroid and a sexual medusoid generation. The
+former reproduces its species by direct budding as well as by giving
+rise, also by a form of budding, to medus� that become sexually mature.
+The hydroid has no tentacles.
+
+(4) _Limnocodium sowerbii_, Lankester (1880).
+
+     Lankester, Q. J. Micr. Sci. London, xx, p. 351, pls. xxx,
+     xxxi (1880); Fowler, _ibid._ xxx, p. 507, pl. xxxii (1890).
+
+There is some doubt as to the different stages in the life-cycle of this
+species. The medusa has been found in tanks in hot-houses in England,
+France and Germany, and a minute hydroid closely resembling that of
+_Microhydra ryderi_ has been associated with it provisionally.
+
+(5) _Limnocodium kawaii_, Oka (1907).
+
+     Oka, Annot. Zool. Japon. vi, p. 219, pl. viii (1907).
+
+Only the medusa, which was taken in the R. Yang-tze-kiang, is as yet
+known.
+
+(6) _Limnocnida tanganyik�_, Bohm (1889).
+
+     R. T. G�nther, Ann. Nat. Hist. (6) xi, p. 269, pls. xiii,
+     xiv (1893).
+
+Only the medusa, which is found in Lake Tanganyika, Lake Victoria Nyanza
+and the R. Niger, has been found and it is doubtful whether a hydroid
+generation exists.
+
+(7) _Polypodium hydriforme_, Ussow (1885).
+
+     Morph. Jahrb. xii, p. 137 (1887).
+
+Two stages in this peculiar hydroid, which is found in the R. Volga, are
+known, (_a_) a spiral ribbon-like form parasitic on the eggs of the
+sterlet (_Acipenser ruthenus_), and (_b_) a small _Hydra_-like form with
+both filamentous and club-shaped tentacles. The life-history has not yet
+been worked out[AP].
+
+     [Footnote AP: Since this was written, Lippen has described a
+     third stage in the life-history of _Polypodium_ (Zool. Anz.
+     Leipzig, xxxvii, Nr. 5, p. 97 (1911)).]
+
+
+II.
+
+HISTORY OF THE STUDY OF HYDRA.
+
+Hydra was discovered by Leeuwenhoek at the beginning of the eighteenth
+century and had attracted the attention of several skilful and accurate
+observers before that century was half accomplished. Among them the
+chief was Trembley, whose "M�moires pour servir � l'histoire d'un genre
+de Polype d'eau douce"* was published at Paris 1744, and is remarkable
+not only for the extent and accuracy of the observations it enshrines
+but also for the beauty of its plates. Baker in his work entitled "An
+attempt towards a natural history of the Polyp"* (London, 1743) and
+R�sel von Rosenhof in the third part of his "Insecten-Belustigung"
+(Nurenberg, 1755) also made important contributions to the study of the
+physiology and structure of _Hydra_ about the same period. Linn�
+invented the name _Hydra_, and in his "Fauna Sueica" and in the various
+editions of his "Systema Natur�" described several forms in a manner
+that permits some of them to be recognized; but Linn� did not
+distinguish between the true _Hydra_ and other soft sessile
+Coelenterates, and it is to Pallas ("Elenchus Zoophytorum," 1766) that
+the credit properly belongs of reducing the genus to order. It is a
+tribute to his insight that three of the four species he described are
+still accepted as "good" by practically all students of the
+Coelenterates, while the fourth was a form that he had not himself seen.
+
+In the nineteenth century the freshwater polyp became a favourite object
+of biological observation and was watched and examined by a host of
+observers, among the more noteworthy of whom were Kleinenberg, Nussbaum,
+and Brauer, who has since the beginning of the present century made an
+important contribution to the taxonomy of the genus.
+
+
+BIBLIOGRAPHY OF HYDRA.
+
+_Hydra_ has been examined by thousands of students in biological
+laboratories all over the civilized world, and the literature upon it is
+hardly surpassed in magnitude by that on any other genus but _Homo_. The
+following is a list of a few of the more important general memoirs and
+of the papers that refer directly to Asiatic material. A systematic
+bibliography is given by Bedot in his "Mat�riaux pour servir a
+l'Histoire des Hydro�des," Rev. Suisse Zool. xviii, fasc. 2 (1910).
+
+(a) _General._
+
+1743. BAKER, "An attempt towards a natural history of the Polyp"*
+(London).
+
+1744. TREMBLEY, "M�moires pour servir � l'histoire d'un genre de polypes
+d'eau douce"* (Paris).
+
+1755. R�SEL VON ROSENHOF, "Insecten-Belustigung: iii, Hist. Polyporum."
+
+1766. PALLAS, "Elenchus Zoophytorum."
+
+1844. LAURENT, "Rech. sur l'Hydre et l'Eponge d'eau douce" ("Voy. de la
+Bonite, Zoophytologie").
+
+1847. JOHNSTON, "A History of the British Zoophytes" (2nd edition).
+
+1868. HINCKS, "History of British Hydroid Zoophytes."
+
+1872. KLEINENBERG, "Hydra. Eine Anatomisch Entwicklungsgeschichtliche
+Untersuchung."
+
+1882. JICKELI, "Der Bau der Hydroidpolypen," Morph. Jahrb. viii, p. 373.
+
+1887. NUSSBAUM, "Ueber die Theilbarkeit der lebendigen Materie. II.
+Mittheilung. Beitr�ge zur Naturgeschichte des Genus Hydra," Arch. mikr.
+Anat. Bonn, xxix, p. 265.
+
+1891. BRAUER, "�ber die Entwicklung von Hydra," Zeitschr. wiss. Zool.
+Leipzig, lii, p. 169.
+
+1892. CHUN, "Coelenterata (Hohlthiere)," in Bronn's Thier-Reichs II (2).
+
+1905. DOWNING, "The spermatogenesis of Hydra," Zool. Jahrb. (Anat.) xxi,
+p. 379.
+
+1908. BRAUER, "Die Benennung und Unterscheidung der Hydra-Arten," Zool.
+Ann. xxxiii, p. 790.
+
+1909. FRISCHHOLZ, "Biologie und Systematik im Genus Hydra," Braun's
+Annal. Zool. (W�rzburg) iii, p. 105.
+
+1910. BERNINGER, "�ber Einwirkung des Hungers auf Hydra," Zool. Anz.
+xxxvi, p. 271.
+
+(b) _Asiatic References._
+
+1894. RICHARD, "Sur quelques Animaux inf�rieurs des eaux douces du
+Tonkin (Protozoaires, Rotif�res, Entomostrac�s)," M�m. Soc. zool.
+France, vii, p. 237.
+
+1904. VON DADAY, "Mikroskopische S�sswasserthiere aus Turkestan," Zool.
+Jahrb. (Syst.) xix, p. 469.
+
+1906. ANNANDALE, "Notes on the Freshwater Fauna of India. No. IV. _Hydra
+orientalis_ and its bionomical relations with other Invertebrates," J.
+Asiat. Soc. Bengal (new series), ii, p. 109.
+
+1906. ANNANDALE, "The Common _Hydra_ of Bengal: its Systematic Position
+and Life History," Mem. As. Soc. Bengal, i, p. 339.
+
+1907. ANNANDALE, "Notes on the Freshwater Fauna of India. No. X. _Hydra
+orientalis_ during the Rains," J. Asiat. Soc. Bengal (new series), iii,
+p. 27.
+
+1907. ANNANDALE, "Notes on the Freshwater Fauna of India. No. XI.
+Preliminary Note on the occurrence of a Medusa (_Irene ceylonensis_,
+Browne) in a brackish pool in the Ganges Delta and on the Hydroid Stage
+of the species," J. Asiat. Soc. Bengal (new series), iii, p. 79.
+
+1907. WILLEY, "Freshwater Sponge and Hydra in Ceylon," Spolia Zeylan.
+Colombo, iv, p. 184.
+
+1908. ANNANDALE, "Observations on specimens of _Hydra_ from Tibet, with
+notes on the distribution of the genus in Asia," Rec. Ind. Mus. ii, p.
+311.
+
+1910. POWELL, "Lessons in Practical Biology for Indian Students"
+(Bombay).
+
+1910. LLOYD, "An Introduction to Biology for Students in India"
+(London).
+
+
+
+
+GLOSSARY OF TECHNICAL TERMS USED IN PART II.
+
+
+  _Aboral_ (or _basal_)       The disk by means of which a free polyp
+  _disk_                      attaches itself to external objects.
+
+  _Cnidoblast_                The living cell of the nematocyst or
+                              nettle-cell (_q. v._).
+
+  _Cnidocil_                  A minute bristle that projects on the
+                              surface in connection with a nettle-cell
+                              (_q. v._).
+
+  _Column_                    The upright or potentially upright
+                              part of a polyp (_q. v._).
+
+  _Ectoderm_                  The external cell-layer of the body-wall.
+
+  _Endoderm_                  The internal cell-layer of the body-wall.
+
+  _Green (chlorophyll)        Minute green bodies contained in cells
+   corpuscles_                of polyps or other animals and
+                              representing a stage in the life-history
+                              of an alga (_Chlorella_).
+
+  _Mesogloea_                 The intermediate, gelatinous layer of
+                              the body-wall.
+
+  _Nettle-cell (nematocyst)_  A cell capsule full of liquid in which
+                              an eversible thread is coiled up.
+
+  _Oral disk_                 The eminence that surrounds the mouth
+                              and is surrounded by tentacles.
+
+  _Peristome_                 See "oral disk."
+
+  _Polyp_                     An individual coelenterate of simple
+                              structure that is fixed temporarily or
+                              permanently by one end of a more
+                              or less cylindrical body and possesses
+                              a mouth at the other end.
+
+  _Tentacles_                 Filamentous outgrowths (in _Hydra_
+                              hollow) of the body-wall round the
+                              mouth.
+
+
+
+
+  LIST OF THE INDIAN HYDRIDA.
+
+
+  Class HYDROZOA.
+
+  Order ELEUTHEROBLASTEA.
+
+  Family HYDRID�.
+
+  Genus HYDRA, _Linn�_ (1746).
+
+  24. _H. vulgaris_, Pallas (1766).
+
+  25. _H. oligactis_, Pallas (1766).
+
+
+Order ELEUTHEROBLASTEA.
+
+Naked hydrozoa which reproduce their kind by means of buds or eggs, or
+by fission, without exhibiting the phenomena of alternation of
+generations.
+
+
+Family HYDRID�.
+
+     HYDRAID�, Johnston, Hist. Brit. Zooph. (ed. 2) i, p. 120
+     (1847).
+     HYDRID�, Hincks, Hist. Brit. Hydroid. Zooph. p. 309 (1868).
+
+Small Eleutheroblastea in which the mouth is surrounded by hollow
+tentacles. Permanent colonies are not formed, but reproduction by
+budding commonly takes place.
+
+
+Genus HYDRA, _Linn�_.
+
+TYPE, _Hydra viridis_, Linn�.
+
+Freshwater polyps which produce eggs with hard chitinous shells.
+Although habitually anchored by the end of the body furthest from the
+mouth to extraneous objects, they possess considerable powers of
+locomotion. They are extremely contractile and change greatly from time
+to time in both form and size.
+
+Only three well-established species of the genus, which is universally
+distributed and occurs only in fresh or brackish[AQ] water, can be
+recognized, namely, _H. viridis_, Linn� (=_H. viridissima_, Pallas), _H.
+vulgaris_, Pallas (=_H. grisea_, Linn�), and _H. oligactis_, Pallas
+(=_H. fusca_, Linn�). The two latter occur in India, but _H. viridis_
+does not appear to have been found as yet anywhere in the Oriental
+Region, although it is common all over Europe and N. America and also in
+Japan. The distribution of _H. vulgaris_ is probably cosmopolitan, but
+there is some evidence that _H. oligactis_ avoids tropical districts,
+although, under the name _Hydra fusca_, it has been doubtfully recorded
+as occurring in Tonquin[AR].
+
+     [Footnote AQ: A small form of _H. viridis_ (var. _bakeri_,
+     Marshall) is found in brackish water in England.]
+
+     [Footnote AR: Richard, M�m. Soc. zool. France, vii, p. 237
+     (1894).]
+
+The three species may be distinguished from one another by the following
+key:--
+
+  [I. Colour leaf-green; the cells contain green
+       (chlorophyll) corpuscles of definite form.
+     A. Tentacles comparatively stout, habitually
+        shorter than the column, which is cylindrical.
+        Egg-shell without spines, ornamented
+        with a reticulate pattern                    _viridis_.]
+  II. Colour never leaf-green; no chlorophyll
+       corpuscles present in the cells.
+     A. Tentacles capable of great elongation but
+        when the animal is at rest never very much
+        longer than the column, which is cylindrical
+        when the gastral cavity is empty.
+        Largest nettle-cells almost as broad as
+        long. Egg-shell bearing long spines most
+        of which are divided at the tips             _vulgaris_, p. 148.
+     B. Tentacles, even when the animal is at rest,
+        much longer than the column, the basal
+        part of which, even when the gastral
+        cavity is empty, is constricted. Largest
+        nettle-cells considerably longer than
+        broad.  Egg-shell smooth or bearing
+        short, simple spines                         _oligactis_, p. 158.
+
+
+24. Hydra vulgaris, _Pallas_.
+
+     Polypes de la seconde esp�ce, Trembley, M�m. pour servir �
+     l'histoire d'un genre de polypes d'eau douce*, pl. i, figs.
+     2, 5; pl. vi, figs. 2, 8; pl. viii, figs. 1-7; pl. xi, figs.
+     11-13 (1744).
+
+     R�sel von Rosenhof, Insecten-Belustigung, iii, Hist.
+     Polyporum, pls. lxxvi, lxxvii, lxxix-lxxxiii (1755).
+
+     ? _Hydra polypus_, Linn�, Fauna Suecica, p. 542 (1761).
+
+     _Hydra vulgaris_, Pallas, Elenchus Zoophytorum, p. 30
+     (1766).
+
+     ? _Hydra attenuata_, _id_., _ibid_. p. 32.
+
+     _Hydra grisea_, Linn� (Gmelin), Systema Natur� (ed. 13), p.
+     3870 (1782).
+
+     _Hydra pallens_, _id_., _ibid_. p. 3871.
+
+     _Hydra vulgaris_, Ehrenberg, Abhandl. Akad. Wiss. Berlin,
+     1836, p. 134, taf. ii.
+
+     _Hydra brunnea_, Templeton, London's Mag. Nat. Hist. ix, p.
+     417 (1836).
+
+     _Hydra vulgaris_, Laurent, Rech. sur l'Hydre at l'�ponge
+     d'eau douce (Voy. de la Bonite, Zoophytologie), p. 11, pl.
+     i, pl. ii, figs. 2, 2'' (1844).
+
+     _Hydra vulgaris_, Johnston, Hist. British Zoophytes (ed. 2),
+     i, p. 122, pl. xxix, fig. 2 (1847).
+
+     _Hydra vulgaris_, Hincks, Hist. British Hydroid Zoophytes,
+     i, p. 314, fig. 41 (1868).
+
+     _Hydra aurantiaca_, Kleinenberg, Hydra, p. 70, pl. i, fig.
+     1, pl. iii, fig. 10 (1872).
+
+     _Hydra trembleyi_, Haacke, Zool. Anz. Leipzig, ii, p. 622
+     (1879).
+
+     _Hydra grisea_, Jickeli, Morph. Jahrb. viii, p. 391, pl.
+     xviii, fig. 2 (1883).
+
+     _Hydra grisea_, Nussbaum, Arch. mikr. Anat. Bonn, xxix, p.
+     272, pl. xiii, pl. xiv, figs. 33, 37, 47 (1887).
+
+     ? _Hydra hexactinella_, v. Lendenfeld, Zool. Jahrb. Jena,
+     ii, p. 96, pl. vi, figs. 13, 14 (1887).
+
+     ? _Hydra hexactinella_, _id_., Proc. Linn. Soc. N. S. Wales,
+     x, p. 678, p. xlviii, figs. 1-4 (1887).
+
+     _Hydra grisea_, Brauer, Zeit. wiss. Zool. Leipzig, lii, p.
+     169 (1891).
+
+     _Hydra grisea_, Chun, in Br�nn's Thier-Reichs, ii (2), pl.
+     ii, figs. 2_b_, 2_c_, 5 (1892).
+
+     _Hydra grisea_, Downing, Zool. Jahrb. (Anat.) Jena, xxi, p.
+     381 (1905).
+
+     _Hydra orientalis_, Annandale, J. Asiat. Soc. Bengal, (new
+     series) i, 1905, p. 72.
+
+     _Hydra orientalis_, _id._, _ibid._ (new series) ii, 1906, p.
+     109.
+
+     _Hydra orientalis_, _id._, Mem. Asiat. Soc. Bengal, i, p.
+     340 (1906).
+
+     ? _Hydra orientalis_, Willey, Spol. Zeylan. Colombo, iv, p.
+     185 (1907).
+
+     _Hydra grisea_, Weltner, Arch. Naturg. Berlin, lxxiii, i, p.
+     475 (1907).
+
+     _Hydra vulgaris_, Brauer, Zool. Anz. xxxiii, p. 792, fig. 1
+     (1908).
+
+     _Hydra orientalis_, Annandale, Rec. Ind. Mus. ii, p. 312
+     (1908).
+
+     _Hydra grisea_, Frischholz, Braun's Zool. Annal. (W�rzburg),
+     iii, pp. 107, 134, &c., figs. 1 and 10-17 (1909).
+
+     _Hydra grisea_, _id._, Biol. Centralbl. Berlin, xxix, p. 184
+     (1909).
+
+     _Hydra vulgaris_, Brauer, Die S�sswasserfauna Deutschlands,
+     xix, p. 192, figs. 336-338 (1909).
+
+     _Hydra pentactinella_, Powell, Lessons in Practical Biology
+     for Indian Students, p. 24 (Bombay, 1910).
+
+
+Phase _orientalis*_, Annandale.
+
+_Colour_ variable; in summer usually pale, in winter either deep orange,
+dull brown, or dark green. The cells do not contain spherical or oval
+coloured bodies.
+
+[Illustration: Fig. 29.--_Hydra vulgaris_, from Calcutta (phase
+_orientalis_).
+
+A=winter brood; B=summer brood, the same individual in an expanded and a
+contracted condition. B is more highly magnified than A.]
+
+_Column_ slender and capable of great elongation, normally almost
+cylindrical, but when containing food often shaped like a wine-glass.
+The surface is thickly set with nettle-cells the cnidocils of which give
+it an almost hirsute appearance under the microscope. When extended to
+the utmost the column is sometimes nearly 30 mm. (1-1/5 inches) long,
+but more commonly it is about half that length or even shorter.
+
+_Tentacles_ usually 4-6, occasionally 8. They are always slender except
+when they are contracted, then becoming swollen at the base and slightly
+globular at the tip. If the animal is at rest they are not very much
+longer than the body, but if it is hungry or about to move from one
+place to another they are capable of very great extension, often
+becoming like a string of minute beads (the groups of nettle-cells)
+strung on an invisible wire.
+
+_Nettle-cells._ The capsules with barbed threads (fig. 27, p. 131) are
+very variable in size, but they are invariably broad in proportion to
+their length and as a rule nearly spherical. In a _Hydra_ taken in
+Calcutta during the winter the largest capsules measured (unexploded)
+0.0189 mm. in breadth and 0.019 in length, but in summer they are
+smaller (about 0.012 mm. in breadth). Smaller capsules with barbed
+threads always occur. The barbed threads are very long and slender. At
+their base they bear a circle of stout and prominent spines, usually 4
+in number; above these there are a number of very small spines, but the
+small spines are usually obscure. Malformed corpuscles are common. The
+capsules with unbarbed threads are very nearly as broad at the distal as
+at the proximal end; they are broadly oval with rounded ends.
+
+_Reproductive organs._ The reproductive organs are confined to the upper
+part of the body. In India eggs (fig. 28, p. 137) are seldom produced.
+They sometimes appear, however, at the beginning of the hot weather. In
+form they are spherical, and their shell bears relatively long spines,
+which are expanded, flattened and more or less divided at the tip. The
+part of the egg that is in contact with the parent-polyp is bare.
+Spermaries are produced more readily than ovaries; they are mammillate
+in form and number from 4 to 24. Ovaries and spermaries have not been
+found on the same individual.
+
+_Buds_ are confined to a narrow zone nearer the base than the apex of
+the column. Rarely more than 2 are produced at a time, and I have never
+seen an attached bud budding. In winter 5 tentacles are as a rule
+produced simultaneously, and in summer 4. In the former case a fifth
+often makes its appearance before the bud is liberated.
+
+In Calcutta two broods can be distinguished, a cold-weather brood, which
+is larger, stouter, and more deeply coloured, produces buds more freely,
+has larger nematocysts, and as a rule possesses 6 tentacles; and a
+hot-weather brood, which is smaller, more slender and paler, produces
+buds very sparingly, has smaller nematocysts, and as a rule possesses
+only 4 or 5 tentacles. Only the cold-weather form is known to become
+sexually mature. There is evidence, however, that in those parts of
+India which enjoy a more uniform tropical climate than Lower Bengal,
+polyps found at all times of year resemble those found in the hot
+weather in Calcutta, and sometimes produce spermatozoa or eggs.
+
+I have recently had an opportunity of comparing specimens of the
+Calcutta hot-weather form with well-preserved examples of _H. vulgaris_,
+Pallas (=_H. grisea_, Linn.), from England. They differ from these
+polyps in very much the same way as, but to a greater degree than they
+do from the winter phase of their own race, and I have therefore no
+doubt that _H. orientalis_ is merely a tropical phase of Pallas's
+species. My description is based on Indian specimens, which seem to
+differ, so far as anatomy is concerned, from European ones in the
+following points:--
+
+     (1) The sexes are invariably distinct;
+     (2) the nematocysts are invariably smaller.
+
+I have seen in Burma an abnormal individual with no tentacles. Its buds,
+however, possessed these organs.
+
+TYPE. None of the older types of _Hydra_ are now in existence. That of
+_H. orientalis_ is, however, in the collection of the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--_H. vulgaris_ is common in Europe and N.
+America and is probably found all over tropical Asia. The following are
+Indian and Ceylon localities:--BENGAL, Calcutta and neighbourhood
+(_Annandale_, _Lloyd_); Adra, Manbhum district (_Paiva_), Rampur Bhulia
+on the R. Ganges (_Annandale_); Chakradharpur, Chota Nagpur
+(_Annandale_); Pusa, Bihar (_Annandale_); Puri, Orissa (_Annandale_):
+MADRAS, sea-beach near Madras town (_Henderson_): BOMBAY, island of
+Bombay (_Powell_): BURMA, Mandalay, Upper Burma, and Moulmein, N.
+Tenasserim (_Annandale_): CEYLON, Colombo and Peradeniya (_Willey_,
+_Green_). Dr. A. D. Imms tells me that he has obtained specimens that
+probably belong to this species in the Jumna at Allahabad.
+
+BIOLOGY.--In India _H. vulgaris_ is usually found, so far as my
+experience goes, in stagnant water. In Calcutta it is most abundant in
+ponds containing plenty of aquatic vegetation, and seems to be
+especially partial to the plant _Limnanthemum_, which has floating
+leaves attached to thin stalks that spring up from the bottom, and to
+_Lemna_ (duckweed). Dr. Henderson, however, found specimens in a pool of
+rain-water on the sea-shore near Madras.
+
+There is evidence that each of the two broods which occur in Lower
+Bengal represents at least one generation; probably it represents more
+than one, for tentacles are rarely if ever produced after the animal has
+obtained its full size, and never (or only owing to accident) decrease
+in number after they have once appeared. The winter form is found
+chiefly near the surface of the water, especially on the roots of
+duckweed and on the lower surface of the leaves of _Limnanthemum_; but
+the summer form affects deeper water in shady places, and as a rule
+attaches itself to wholly submerged plants. The latter form is to be met
+with between March and October, the cold-weather form between October
+and March, both being sometimes found together at the periods of
+transition. In the unnatural environment of an aquarium, however,
+individuals of the winter form lose their colour and become attenuated,
+in these features resembling the summer form, even in the cooler months.
+Buds produced in these conditions rarely have more than five tentacles
+or themselves produce buds freely after liberation.
+
+The buds appear in a fixed order and position, at any rate on
+individuals examined in winter; in specimens of the summer form the
+position is fixed, but the order is irregular. Each quadrant of the
+column has apparently the power of producing, in a definite zone nearer
+the aboral pole than the mouth, a single bud; but the buds of the
+different quadrants are not produced simultaneously. If we imagine that
+the quadrants face north, south, east, and west, and that the first bud
+is produced in the north quadrant, the second will be produced in the
+east quadrant, the third in the south, and the fourth in the west. It is
+doubtful whether more than four buds are produced in the lifetime of an
+individual, and apparently attached buds never bud in this race. The
+second bud usually appears before the first is liberated, and this is
+also the case occasionally as regards the third, but it is exceptional
+for four buds to be present at one time. About three weeks usually
+elapse between the date at which the bud first appears as a minute
+conical projection on the surface of the parent and that at which it
+liberates itself. This it does by bending down, fixing itself to some
+solid object by means of the tips of its tentacles, the gland-cells of
+which secrete a gummy fluid, and then tearing itself free.
+
+Although it is rare for more than two buds to be produced
+simultaneously, budding is apparently a more usual form of reproduction
+than sexual reproduction. Individuals that bear eggs have not yet been
+found in India in natural conditions, although males with functional
+spermaries are not uncommon at the approach of the hot weather. The few
+eggs that I have seen were produced in my aquarium towards the end of
+the cold weather. Starvation, lack of oxygen, and too high a temperature
+(perhaps also lack of light) appear to stimulate the growth of the male
+organs in ordinary cases, but perhaps they induce the development of
+ovaries in the case of individuals that are unusually well nourished.
+
+The spines that cover the egg retain d�bris of various kinds upon its
+surface, so that it becomes more or less completely concealed by a
+covering of fragments of dead leaves and the like even before it is
+separated from the polyp. Its separation is brought about by its falling
+off the column of the parent. Nothing is known of its subsequent fate,
+but probably it lies dormant in the mud through the hot weather. Eggs
+are sometimes produced that have no shells. This is probably due to the
+fact that they have not been fertilized.
+
+Reproduction by fission occurs rarely in the Indian _Hydra_, but both
+equal and unequal vertical fission have been observed. In the case of
+equal fission the circumoral area lengthens in a horizontal direction,
+and as many extra tentacles as those the polyp already possesses make
+their appearance. The mouth then becomes constricted in the middle and
+notches corresponding to its constriction appear at either side of the
+upper part of the column. Finally the whole animal divides into two
+equal halves in a vertical direction. I have only seen one instance of
+what appeared to be unequal vertical fission--that of a polyp consisting
+of two individuals still joined together by the basal disk, but one
+about half the size of the other. Each had three well-developed
+tentacles, and in addition a minute fourth tentacle. This was situated
+on the side opposed to that of the other individual which bore a similar
+tentacle. Transverse fission has not been observed. The Indian _Hydra_
+is a very delicate animal as compared with such a form as _H. viridis_,
+and all attempts to produce artificial fission without killing the polyp
+have as yet failed.
+
+Young individuals are often, and adults occasionally, found floating
+free in the water, either with the mouth uppermost and the tentacles
+extended so as to cover as large an area as possible or with the aboral
+pole at the surface. In the former case they float in mid-water, being
+of nearly the same specific gravity as the water, and are carried about
+by any movement set up in it. In the latter case, however, the base of
+the column is actually attached to some small object such as the cast
+skin of a water-flea or to a minute drop of mucus originally given out
+by the polyp's own mouth; the tentacles either hang downwards or are
+spread out round the mouth, and the animal is carried about by wind or
+other agencies acting on the surface.
+
+In addition to this passive method of progression the polyp can crawl
+with considerable rapidity. In doing so it bends its column down to the
+object along which it is about to move in such a way that it lies almost
+parallel to the surface, the basal disk, however, being still attached.
+The tentacles are then extended and attach themselves near the tips to
+the surface a considerable distance away. Attachment is effected by the
+secretion of minute drops of adhesive substance from gland-cells. The
+basal disk is liberated and the tentacles contract, dragging the column,
+which still lies prone, along as they do so. The basal disk again
+affixes itself, the tentacles wrench themselves free, the surface of
+their cells being often drawn out in the process into pseudopodia-like
+projections, which of course are not true pseudopodia[AS] but merely
+projections produced by the mechanical strain. The whole action is then
+repeated. The polyp can also pull itself across a space such as that
+between two stems or leaves by stretching out one of its tentacles,
+fixing the tip to the object it desires to reach, pulling itself free
+from its former point of attachment, and dragging itself across by
+contracting the fixed tentacle. The basal disk is then turned round and
+fixed to the new support.
+
+     [Footnote AS: See Zykoff, Biol. Centralbl. xviii, p. 272
+     (1898), and Annandale, Rec. Ind. Mus. i, p. 67 (1907).]
+
+The Indian polyp, like all its congeners, is attracted by light, but it
+is more strongly repelled by heat. Probably it never moves in a straight
+line, but if direct sunlight falls on one side of a glass aquarium, the
+polyps move away from that side in a much less erratic course than is
+usually the case. If conditions are favourable, they often remain in one
+spot for weeks at a time, their buds congregating round them as they are
+set free. In a natural environment it seems that regular migrations take
+place in accordance with changes in temperature, for whereas in cool
+weather many individuals are found adhering to the lower surface of the
+floating leaves of _Limnanthemum_, few are found in this position
+immediately after a rise in the thermometer. If the rise is only a small
+one, they merely crawl down the stems to the end of which the leaves are
+attached, but as soon as the hot weather begins in earnest, the few that
+survive make their way to the deepest and most shady part of the pond.
+In captivity the polyps seek the bottom of any vessel in which they are
+contained, if sunlight falls on the surface of the water.
+
+The chief function of the tentacles is that of capturing prey. The
+Indian polyp feeds as a rule in the early morning, before the day has
+become hot. In an aquarium at any rate, the tentacles are never more
+than moderately extended during the night. If the polyp is hungry, they
+are extended to their greatest length in the early morning, and if prey
+is not captured, they sometimes remain in this condition throughout the
+day. In these circumstances they hang down or stand up in the water
+closely parallel to one another, and often curved in the middle as if a
+current were directed against them. Prey that comes in contact with one
+of them has little chance of escape, for nematocysts from all the
+tentacles can be readily discharged against it. Approximately once in
+half an hour the direction of the tentacles is changed, but I have been
+unable to observe any regular rhythmical movements of the tentacles or
+any correlation between those of a parent polyp and the buds still
+attached to it.
+
+The prey consists chiefly of the young larv� of midges (Chironomid�) and
+may-flies, but small copepod and phyllopod crustacea are also captured.
+
+As soon as the prey adheres firmly to the tentacles and has become
+paralysed it is brought to the mouth by their contracting strongly and
+is involved in a mass of colourless mucus extruded from the digestive
+cavity. Partly by the contraction of muscle-fibres in the body-wall and
+partly by movements of the mouth itself assisted by the mucus, which
+apparently remains attached to the walls of the cavity, the food is
+brought into the mouth. If it is at all bulky, it remains in the upper
+part of the cavity, the gland-cells pouring out a digestive fluid upon
+it and so dissolving out soluble substances. A large share of the
+substances thus prepared falls down to the bottom of the cavity and are
+there digested by the endoderm cells. The insoluble parts of the food
+are, however, ejected from the mouth without ever reaching the base of
+the cavity.
+
+The colour of the polyp appears to be due mainly to the results of
+digestion. Brown or orange individuals recently captured in a pond and
+kept in favourable conditions take three or four days to digest their
+food, and the excreta ejected from the mouth then take the form of a
+white flocculent mass. If, however, the same individuals are kept for
+long in a glass aquarium, they lose their colour, even though they feed
+readily. Digestion is then a much more rapid process, and the excreta
+contain minute, irregular, coloured granules, which appear to be
+identical with those contained in the endoderm cells of individuals that
+have recently digested a meal fully. Starved individuals are always
+nearly colourless. It seems, therefore, that in this species colour is
+due directly to the products of digestion, and that digestion does not
+take place so fully in unfavourable conditions or at a high temperature
+as it does in more healthy circumstances. The dark green colour of some
+polyps is, however, less easily explained. I have noticed that all the
+individuals which have produced eggs in my aquarium have been of this
+colour, which they have retained in spite of captivity; whereas
+individuals that produced spermatozoa often lost their colour completely
+before doing so, sometimes becoming of a milky white owing to the
+accumulation of minute drops of liquid in their endoderm cells. Even in
+green individuals there is never any trace in the cells of coloured
+bodies of a definite form.
+
+The Indian polyp, unlike European representatives of its species, is a
+very delicate little animal. In captivity at any rate, three
+circumstances are most inimical to its life: firstly, a sudden rise in
+the temperature, which may either kill the polyp directly or cause it to
+hasten its decease by becoming sexually mature; secondly, the lack of a
+free current of air on the surface of the aquarium; and thirdly, the
+growth of a bacterium, which forms a scum on the top of the water and
+clogs up the interstices between the leaves and stems of the
+water-plants, soon killing them. If adult polyps are kept even in a
+shallow opaque vessel which is shut up in a room with closed shutters
+they generally die in a single night; indeed, they rarely survive for
+more than a few days unless the vessel is placed in such a position that
+air is moving almost continuously over its surface. The bacterium to
+which I allude often almost seals up the aquarium, especially in March
+and April, in which months its growth is very rapid. Strands of slime
+produced by it surround the polyp and even enter its mouth. In this
+event the polyp retracts its tentacles until they become mere
+prominences on its disk, and shrinks greatly in size. The colouring
+matter in its body becomes broken up into irregular patches owing to
+degeneracy of the endoderm cells, and it dies within a few hours.
+
+_Hydra_ in Calcutta is often devoured by the larva of a small midge
+(_Chironomus fasciatipennis_, Kieffer) common in the tanks from November
+to February. In the early stages of its larval life this insect wanders
+free among communities of protozoa (_Vorticella_, _Epistylis_, &c.) and
+rotifers on which it feeds, but as maturity approaches begins to build
+for itself a temporary shelter of one of two kinds, either a delicate
+silken tunnel the base of which is formed by some smooth natural
+surface, or a regular tube the base of which is fixed by a stalk
+situated near the middle of its length to some solid object, while the
+whole surface is covered with little projections. The nature of the
+covering appears to depend partly on that of the food-supply and partly
+on whether the larva is about to change its skin.
+
+I had frequently noticed that tunnels brought from the tank on the under
+surface of _Limnanthemum_ leaves had a _Hydra_ fixed to them. This
+occurred in about a third of the occupied shelters examined. The _Hydra_
+was always in a contracted condition and often more or less mutilated.
+By keeping a larva together with a free polyp in a glass of clean water,
+I have been able to observe the manner in which the polyp is captured
+and entangled. The larva settles down near the base of its column and
+commences to spin a tunnel. When this is partially completed, it passes
+a thread round the polyp's body to which it gives a sharp bite. This
+causes the polyp to bend down its tentacles, which the larva entangles
+with threads of silk, doing so by means of rapid, darting movements; for
+the nettle-cells would prove fatal should they be shot out against its
+body, which is soft. Its head is probably too thickly coated with chitin
+to excite their discharge. Indeed, small larv� of this very species form
+no inconsiderable part of the food of the polyp, and, so far as my
+observations go, a larva is always attacked in the body and swallowed in
+a doubled-up position.
+
+When the _Hydra_ has been firmly built into the wall of the shelters and
+its tentacles fastened down by their bases on the roof, the larva
+proceeds, sometimes after an interval of some hours, to eat the body,
+which it does very rapidly, leaving the tentacles attached to its
+shelter. The meal only lasts for a few minutes; after it the larva
+enjoys several hours' repose, protected by remains of its victim, which
+retain a kind of vitality for some time. During this period it remains
+still, except for certain undulatory movements of the posterior part of
+the body which probably aid in respiration. Then it leaves the shelter
+and goes in search of further prey. Its food, even when living in a
+tunnel, does not consist entirely of _Hydra_. I have watched a larva
+building its shelter near a number of rotifers, some of which it
+devoured and some of which it plastered on to its tunnel.
+
+The tubular shelters occasionally found are very much stouter structures
+than the tunnels, but are apparently made fundamentally of the same
+materials; and structures intermediate between them and the tunnels are
+sometimes produced. The larva as a rule fastens to them branches
+detached from living colonies of Vorticellid protozoa such as
+_Epistylis_[AT].
+
+     [Footnote AT: Further particulars regarding the life-history
+     of this larva will be found on pp. 114 and 115, J. Asiat.
+     Soc. Bengal, ii (n. s.) 1906.]
+
+Of animals living in more or less intimate relations with the polyp, I
+have found two very distinct species of protozoa, neither of which is
+identical with either of the two commonly found in association with
+_Hydra_ in Europe, _Trichodina pediculus_ and _Kerona polyporum_. On two
+occasions, one in January and the other at the beginning of February, I
+have seen a minute colourless flagellate on the tentacles of the
+Calcutta polyp. On the first occasion the tentacles were completely
+covered with this protozoon, so that they appeared at first sight as
+though encased in flagellated epithelium. The minute organism was
+colourless, transparent, considerably larger than the spermatozoa of
+_Hydra_, slightly constricted in the middle and rounded at each end. It
+bore a long flagellum at the end furthest from its point of attachment,
+the method of which I could not ascertain. When separated from the polyp
+little groups clung together in rosettes and gyrated in the water. On
+the other occasion only a few individuals were observed. Possibly this
+flagellate was a parasite rather than a commensal, as the individual on
+which it swarmed was unusually emaciated and colourless, and bore
+neither gonads nor buds. The larger stinging cells were completely
+covered by groups of the organism, and possibly this may have interfered
+with the discharge of stinging threads.
+
+The other protozoon was _Vorticella monilata_, Tatem, which has been
+found, not in association with _Hydra_, in Europe and S. America. In
+Calcutta I have only seen it attached to the column of the polyp, but
+probably it would also be found, if carefully looked for, attached to
+water-weeds.
+
+Especially in the four-rayed stage, the polyp not infrequently attaches
+itself to shells of _Vivipara_, and, more rarely, to those of other
+molluscs. It is doubtful whether this temporary association between
+_Hydra_ and the mollusc is of any importance to the latter. Even when
+the polyp settles on its body and not on its shell (as is sometimes the
+case) the _Vivipara_ appears to suffer no inconvenience, and makes no
+attempt to get rid of its burden. It is possible, on the other hand,
+that the _Hydra_ may protect it by devouring would-be parasites; but of
+this there is no evidence[AU].
+
+     [Footnote AU: In the Calcutta tanks operculate molluscs such
+     as _Vivipara_ are certainly more free from visible attack
+     than non-operculate species. This is the case for instance,
+     as regards the common aquatic glowworm (_Luciola_ sp.),
+     which destroys large numbers of individuals of _Limnophysa_,
+     _Limn�us_, &c. If it has been starved for several days in an
+     aquarium it will attack an operculate form, but rarely with
+     success. Similarly _Ch�togaster bengalensis_ attaches itself
+     exclusively to non-operculate forms. In the one case the
+     polyp could do very little against an adversary with so
+     stout an integument as the insect, while, in the other, it
+     is doubtful whether the worm does any harm to its host. The
+     polyp would afford very little protection against the
+     snail's vertebrate enemies or against what appears to be its
+     chief foe, namely, drought. As the water sinks in the tank
+     non-operculate species migrate to the deeper parts, but
+     _Vivipara_ and _Ampullaria_ close their shells, remain where
+     they are, and so often perish, being left high and dry,
+     exposed to the heat of the sun.]
+
+The association, however, is undoubtedly useful to _Hydra_. The mud on
+the shells of _Vivipara_ taken on floating objects shows that in cool
+weather the snail comes up from the bottom to the surface, and it
+probably goes in the opposite direction in hot weather. Moreover, the
+common Calcutta species (_V. bengalensis_) feeds very largely, if not
+exclusively, on minute green alg�. It therefore naturally moves towards
+spots where smaller forms of animal and vegetable life abound and
+conditions are favourable for the polyp. The polyp's means of
+progression are limited, and the use of a beast of burden is most
+advantageous to it, for it can detach itself when it arrives at a
+favourable habitat. If specimens are kept in water which is allowed to
+become foul, a very large proportion of them will attach themselves to
+any snails confined with them. Under natural conditions they would thus
+in all probability be rapidly conveyed to a more suitable environment.
+In the tanks it is far commoner to find young four-rayed polyps on
+_Vivipara_ than individuals with five or six rays; but the adults of the
+species are far less prone to change their position than are the young.
+
+The Calcutta _Hydra_, especially in spring, exhibits a distinct tendency
+to frequent the neighbourhood of sponges and polyzoa, such as _Spongilla
+carteri_ and the denser forms of _Plumatella_. Possibly this is owing to
+the shade these organisms provide.
+
+
+25. Hydra oligactis, _Pallas_.
+
+     Polypes de la troisi�me esp�ce, Trembley, M�m. hist.
+     Polypes,* pl. i, figs. 3, 4, 6; pl. ii, figs. 1-4; pl. iii,
+     fig. 11; pl. v, figs. 1-4; pl. vi, figs. 3-7, 9, 10; pl.
+     viii, figs. 8, 11; pl. ix (1744).
+
+     R�sel von Rosenhof, Insekt.-Belustigung, iii, Hist. Polyp.,
+     pls. lxxxiv-lxxxvi (1755).
+
+     _Hydra socialis_, Linn�, Fauna Sueica, p. 542 (1761).
+
+     _Hydra oligactis_, Pallas, Elench. Zooph. p. 29 (1766).
+
+     ? _Hydra attenuata_, _id._, _ibid._ p. 32.
+
+     _Hydra fusca_, Linn�, Syst. Nat. (ed. 13), p. 3870 (1782).
+
+     _Hydra oligactis_, Johnston, Brit. Zooph. i, p. 124, fig. 27
+     (p. 120) (1847).
+
+     _Hydra oligactis_, Hincks, Hist. Brit. Hydr. Zooph. i, p.
+     315, fig. 42 (1868).
+
+     _Hydra roeselii_, Haacke, Jena Zeitschr. Naturwiss. xiv, p.
+     135 (1880).
+
+     ? _Hydra rh�tica_, Asper, Zool. Anz. 1880, p. 204, figs.
+     1-3.
+
+     _Hydra vulgaris_, Jickeli (_nec_ Pallas), Morph. Jahrb.
+     viii, p. 391, pl. xviii, fig. 3 (1882).
+
+     _Hydra fusca_, Nussbaum, Arch. mikr. Anat. Bonn, xxix, p.
+     273, pl. xiv, figs. 34-36, pl. xv, figs. 48-51, &c. (1887).
+
+     _Hydra fusca_, Brauer, Zeit. wiss. Zool. Leipzig, lii, p.
+     177, pl. xi, figs. 2, 5, 6; pl. xii, fig. 6 (1891).
+
+     _Hydra_ sp. ? _id._, _ibid._ pl. xi, figs. 3, 3a, 4, 7, 8;
+     pl. xii, figs. 1, 2, 5-13.
+
+     _Hydra fusca_, Chun in Br�nn's Thier-Reichs, ii (2), pl. ii,
+     figs. 2(_a_), 4, 6 (1892).
+
+     _Hydra monoecia_, Downing, Science* (5) xii, p. 228.
+
+     _Hydra fusca_, _id._, Zool. Jahrb. (Anat.) xxi, p. 382
+     (1905).
+
+     _Hydra dioecia_, _id._, _ibid._ pl. xxiii, figs. 6, 7, &c.
+
+     _Hydra fusca_, Hertwig, Biol. Centralbl. xxvi, p. 489
+     (1906).
+
+     _Hydra oligactis_, Brauer, Zool. Anz. xxxiii, p. 792, fig. 2
+     (1908).
+
+     _Hydra polypus_, _id._, _ibid._
+
+     _Hydra fusca_, Frischholz, Ann. Zool. (W�rzburg), iii, p.
+     114, figs. 2-9 (1909).
+
+     _Hydra oligactis_, Brauer, S�sswasserfauna Deutschl. xix, p.
+          193, figs. 339-341 (1909).
+
+     _Hydra polypus_, _id._, _ibid._ figs. 342-344.
+
+This species differs from _H. vulgaris_ in the following characters:--
+
+     (1) Even when the gastral cavity is empty, the basal part of
+     the column is distinctly more slender than the upper part;
+     (2) even when the animal is at rest, the tentacles are much
+     longer than the column;
+     (3) the nettle-cells of both types are usually smaller and
+     more uniform in size than in the other species; those with
+     barbed threads (fig. 27, p. 131) are always flask-shaped and
+     somewhat narrower in proportion to their length, while those
+     with simple threads are pointed or almost pointed at their
+     distal end;
+     (4) the stinging threads of the more complex form are
+     comparatively stout and short;
+     (5) there are comparatively few nettle-cells in the column;
+     (6) the egg-shell is nearly smooth or covered more or less
+     completely with short, simple spines (fig. 28, p. 137).
+
+_H. oligactis_ is usually a more vigorous form than _H. vulgaris_ and,
+in spite of its name, has often a considerable number of tentacles. The
+few Indian specimens examined have, however, been small and have not had
+more than six tentacles. I have not seen an Indian specimen with more
+than two buds, but European specimens sometimes produce a great many,
+and as the daughter buds do not always separate from the parent until
+they have themselves produced buds, temporary colonies of some
+complexity arise; Chun figures a specimen with nineteen daughter and
+granddaughter buds[AV].
+
+     [Footnote AV: Pallas writes as regards this "pulcherrime
+     vegetantem varietatem" with his usual critical insight, "Vix
+     tamen peculiaris speciei nomine salutanda videtur." It is
+     probably the _Hydra socialis_ of Linn�.]
+
+In Europe and N. America there appear to be two races or phases of the
+species. To avoid ambiguity they may be called form A and form B and
+described as follows:--
+
+   Form A is of vigorous growth. It is as a rule dioecious, and
+     its reproductive organs may be borne practically at any
+     level on the surface of the column. Its eggs are spherical
+     and as a rule covered almost uniformly with spines.
+
+   Form B is smaller and has smaller and more variable
+     nettle-cells. Its reproductive organs are borne only on the
+     distal third or at the base of its column and it is often
+     monoecious. The lower surface of its egg is flattened,
+     adherent, and devoid of spines.
+
+The larger form (A) was originally named _Hydra monoecia_ by Downing,
+who in 1904 expressed a wish to substitute for the specific name, which
+had been given through inadvertence, the more appropriate one _dioecia_.
+As, however, it appears to be the commoner of the two in northern
+Europe, we may regard it as probably being the one named _Hydra
+oligactis_ by Pallas and therefore may accept it as the _forma typica_
+of that species. According to Brauer (1908) the smaller form is Linn�'s
+_Hydra polypus_; but the original description of the "species" hardly
+bears out this view. As reproductive organs have not yet been found in
+Indian specimens, it is impossible to say to which of the two forms they
+belong.
+
+A red form of _H. oligactis_ occurs in Tibet in the lake Rham-tso, at an
+altitude of about 15,000 feet and has been reported from various small
+lakes in mountainous parts of Europe. It is probably the form called
+_Hydra rh�tica_ by Asper, but his figures are lacking in detail and
+appear to have been drawn from specimens in a state of partial
+contraction. _H. rubra_, Lewes (Ann. Mag. Nat. Hist. (3) v, p. 71,
+1860), may also be identical with this form. Roux, indeed, states that
+_H. rubra_ is only found living unattached at considerable depths (Ann.
+Biol. lacustre ii, p. 266, 1907); but this statement does not accord
+with the fact that Lewes's specimens were found in ponds on Wimbledon
+Common.
+
+TYPE not in existence.
+
+GEOGRAPHICAL DISTRIBUTION.--_H. oligactis_ is widely distributed in
+Europe and N. America, but in India has only been found in and near the
+city of Lahore in the Punjab.
+
+BIOLOGY.--This species was found by Major J. Stephenson, I.M.S., in the
+basin of a fountain at Lahore and in an ornamental canal in the Shalimar
+Gardens on the outskirts of the same city. Nothing is known as regards
+its habits in this country. In N. America, according to Downing, form B
+breeds in September and October and form A from October to December. The
+eggs of form B remain attached to the parent until the two cellular
+layers are formed and then drop off, whereas those of form A are fixed
+by the parent to some extraneous object, its column contracting until
+they are in a favourable position for attachment.
+
+The colour of Indian examples of _H. oligactis_ apparently resembles
+that of the Calcutta winter brood of _H. vulgaris_ so far as visual
+effect is concerned, but I have noticed in specimens from Lahore and the
+neighbourhood that very minute spherical bodies of a dark green colour
+are present in the endoderm cells.
+
+
+
+
+  PART III.
+
+  FRESHWATER POLYZOA
+
+  (CTENOSTOMATA & PHYLACTOL�MATA).
+
+
+
+
+INTRODUCTION TO PART III.
+
+
+I.
+
+STATUS AND STRUCTURE OF THE POLYZOA.
+
+The Polyzoa constitute a class in the third great division of the animal
+kingdom, the so-called Triploblastea. In this division are included also
+the worms, molluscs, insects, crustacea, spiders, vertebrates, etc.; for
+heterogeneous as its elements appear, all these animals may be
+considered to have essential features in common, in particular a body
+consisting primarily of three cellular layers. Most of them also possess
+a body cavity distinct from the alimentary canal. Some authors regard
+the position of the polyzoa as near that of the higher worms, but the
+group is an isolated one.
+
+In considering the anatomy of simple forms of animal life such as the
+sponges it is necessary to pay attention mainly to individual cells, but
+in discussing more complicated forms our notice is first attracted to
+tissues and organs, for the cells of which these tissues and organs are
+composed have each a definite position, a definite structure, and a
+definite function. The most characteristic feature of the polyzoa,
+considered from this point of view, is the fact that most of their
+organs fall into one of two categories and are connected either with
+what is called the "zooecium" or with what is known as the "polypide."
+The zooecium is a cage in which the polypide is enclosed, but it is a
+living cage, differing from the shell of a snail or the tubes in which
+many worms encase themselves in being part of the animal itself. The
+polypide consists mainly of the organs connected directly and indirectly
+with nutrition and of part of the muscular system; its name is derived
+from the fact that it bears a superficial resemblance to a polyp such as
+_Hydra_.
+
+The shape and structure of the zooecium differs greatly in different
+groups of polyzoa. In its simplest form it is merely a cylindrical tube
+of living matter which secretes an outer horny or gelatinous covering.
+It is open at the end furthest from its base, at which it is attached
+either to another zooecium or to some kind of supporting structure.
+Certain parts of the polypide can always be extruded from the aperture,
+which is known technically as the "orifice," or withdrawn through it
+into the zooecium. When the polypide is retracted it draws in with it a
+portion of the zooecium. The dead outer layer or ectocyst lines part of
+the portion thus invaginated and forms the walls of a cavity within the
+orifice. The base of this cavity consists in many forms of a transverse
+partition pierced in the middle by a circular hole and known as the
+"diaphragm." The diaphragm, however, does not constitute the limit of
+the invaginated portion of the zooecium, for the living inner wall or
+endocyst is dragged in still further and forms a sheath round the
+retracted tentacles. When the tentacles are protruded they emerge
+through the hole in the diaphragm, carrying with them their sheath of
+endocyst. The invagination above the diaphragm, consisting of both
+endocyst and ectocyst, is then everted.
+
+The tentacles are a characteristic feature of the polypide. Together
+with the base to which they are attached they are known as the
+"lophophore"; they surround the mouth, usually in a circle. They differ
+widely from the tentacles of _Hydra_ in both structure and function,
+although they too serve as organs for the capture of prey; they are not
+highly contractile and are not provided with nettle-cells but are
+covered with cilia, which are in constant motion. When extruded they
+form a conspicuous calix-like crown to the zooecium, but in the
+retracted condition they are closely pressed together and lie parallel
+to one another. They are capable individually of motion in all
+directions but, although they usually move in concert, they cannot as a
+rule seize objects between them.
+
+The mouth is a hole situated in the midst of the tentacles. It leads
+directly into a funnel-shaped oesophagus, the upper part of which is
+lined with cilia and is sometimes distinguished as the "pharynx," while
+the lower part, the oesophagus proper, is a thin-walled tube that
+connects the pharynx with the stomach, which it enters on the dorsal
+side. The stomach is a bulky organ that differs markedly in form and
+structure in different groups of polyzoa. It is lined internally with
+glandular cells and the inner wall is sometimes thrown into folds or
+"rug�." The part with which the oesophagus communicates is known as the
+"cardiac" portion, while the part whence the intestine originates is
+called the "pylorus" or "pyloric" portion. The intestine commences on
+the ventral side opposite the entrance of the oesophagus and nearly on a
+level with it, the bulk of the stomach depending between the two tubes.
+This part of the stomach is often produced into a blind tube, the fundus
+or c�cum. The alimentary canal may therefore be described as distinctly
+Y-shaped. The proximal part of the intestine is in some forms lined with
+cilia, and the tube as a whole is usually divided into two parts--the
+intestine proper, which is nearest the stomach, and the rectum, which
+opens by the anus not far from the mouth.
+
+The nervous system consists of a central ganglion or brain, which is
+situated at the base of the tentacles on the side nearest the anus and
+gives out radiating nerves in all directions. Close to the brain and
+providing a communication between the cavity of the zooecium and the
+cavity in which the tentacles are contained (or, in the case of an
+expanded polyp, the external world) is a ciliated tube known as the
+"intertentacular organ." Apparently it acts as a passage through which
+the genital products are expelled; but contradictory statements have
+been made regarding it, and perhaps it is present only at certain
+seasons or in certain conditions of the polypide.
+
+[Illustration: Fig. 30.--Vertical section through a polypide of
+_Alcyonidium_ with the polypide retracted (after Prouho).
+
+A=orifice; B=contracted collar; C=diaphragm; D=parieto-vaginal muscles;
+E=tentacles; F=pharynx; G=oesophagus; H=stomach; J=intestine; K=rectum;
+L=intertentacular organ; M=retractor muscle; N=testes; O=ovary;
+P=funiculus; Q=parietal muscles; R=ectocyst; S=endocyst.]
+
+The muscular system is often of a complicated nature, but three sets of
+muscles may be distinguished as being of peculiar importance, viz., (i)
+the retractor muscles, which are fixed to the base of the lophophore at
+one end and to the base of the zooecium at the other, and by contracting
+pull the former back into the zooecium; (ii) the parieto-vaginal
+muscles, which connect the upper part of the invaginated portion of the
+zooecium with the main wall thereof; and (iii) the parietal muscles,
+which run round the inner wall of the zooecium and compress the zooecium
+as a whole. The parietal muscles are not developed in the
+Phylactol�mata, the most highly specialized group of freshwater polyzoa.
+
+The cavity between the polypide and the zooecium contains a reticulate
+tissue of cells known as the "funicular" tissue, and this tissue is
+usually concentrated to form a hollow strand or strands ("funiculi")
+that connect the outer wall of the alimentary canal with the endocyst.
+
+This rapid sketch of the general anatomy of a simple polyzoon will be
+the best understood by comparing it with fig. 30, which represents, in a
+somewhat diagrammatic fashion, a vertical section through a single
+zooecium and polypide of the order Ctenostomata, to which some of the
+freshwater species belong. The polypide is represented in a retracted
+condition in which the Y-shaped disposition of the alimentary canal is
+somewhat obscured.
+
+In the great majority of cases the polyzoa form permanent colonies or
+polyparia, each of which consists of a number of individual zooecia and
+polypides connected together by threads of living tissue. These colonies
+are formed by budding, not by independent individuals becoming
+associated together. In a few cases compound colonies are formed owing
+to the fact that separate simple colonies congregate and secrete a
+common investment; but in these cases there is no organic connection
+between the constituent colonies. It is only in the small subclass
+Entoprocta, the polypides and zooecia of which are not nearly so
+distinct from one another as they are in other polyzoa (the Ectoprocta),
+that mature solitary individuals occur.
+
+As representatives of both subclasses of polyzoa and of more than one
+order of Ectoprocta occur in fresh water, I have prefaced my description
+of the Indian species with a synopsis of the more conspicuous characters
+of the different groups (pp. 183-186).
+
+
+CAPTURE AND DIGESTION OF FOOD: ELIMINATION OF WASTE PRODUCTS.
+
+The food of all polyzoa consists of minute living organisms, but its
+exact nature has been little studied as regards individual species and
+genera. In _Victorella bengalensis_ it consists largely of diatoms,
+while the species of _Hislopia_ and _Arachnoidea_ possess an alimentary
+canal modified for the purpose of retaining flagellate organisms until
+they become encysted. Similar organisms form a large part of the food of
+the phylactol�mata.
+
+Although the tentacles may be correctly described as organs used in
+capturing prey, they do not themselves seize it but waft it by means of
+the currents set up by their cilia to the mouth, into which it is swept
+by the currents produced by the cilia lining the pharynx. The tentacles
+are also able in some species to interlace themselves in order to
+prevent the escape of prey. Apparently they have the power of rejecting
+unsuitable food, for they may often be observed to bend backwards and
+forwards and thrust particles that have approached them away, and if the
+water contains anything of a noxious nature in solution the lophophore
+is immediately retracted, unless it has been completely paralysed. In
+the phylactol�mata the peculiar organ known as the epistome is capable
+of closing the mouth completely, and probably acts as an additional
+safeguard in preventing the ingestion of anything of an injurious
+nature.
+
+In many genera and larger groups the food commonly passes down the
+pharynx into the stomach without interruption, although it is probable
+that in all species the oesophagus can be closed off from the stomach by
+a valve at its base. In some forms, however, a "gizzard" is interposed
+between the oesophagus and the stomach. This gizzard has not the same
+function in all cases, for whereas in some forms (_e. g._, in
+_Bowerbankia_) it is lined with horny projections and is a powerful
+crushing organ, in others (_e. g._, in _Hislopia_ or _Victorella_) it
+acts as an antechamber in which food can be preserved without being
+crushed until it is required for digestion, or rough indigestible
+particles can be retained which would injure the delicate walls of the
+stomach.
+
+Digestion takes place mainly in the stomach, the walls of which are of a
+glandular nature. The excreta are formed into oval masses in the rectum
+and are extruded from the anus in this condition.
+
+Although the gross non-nutritious parts of the food are passed _per
+anum_, the waste products of the vital processes are not eliminated so
+easily, and a remarkable process known as the formation of brown bodies
+frequently takes place. This process cannot be described more clearly
+and succinctly than by quoting Dr. Harmer's description of it from pp.
+471 and 472 of vol. ii. of the Cambridge Natural History, a volume to
+which I have been much indebted in the preparation of this introduction.
+The description is based very largely on Dr. Harmer's own
+observations[AW].
+
+     [Footnote AW: Q. J. Micr. Sci. xxxiii, p. 123 (1892).]
+
+"The tentacles, alimentary canal, and nervous system break down, and the
+tentacles cease to be capable of being protruded. The degenerating
+organs become compacted into a rounded mass, known from its colour as
+the 'brown body.' This structure may readily be seen in a large
+proportion of the zooecia of transparent species. In active parts of the
+colony of the body-wall next develops an internal bud-like structure,
+which rapidly acquires the form of a new polypide. This takes the place
+originally occupied by the old polypide, while the latter may either
+remain in the zooecium in the permanent form of a 'brown body,' or pass
+to the exterior. In _Flustra_ the young polypide-bud becomes connected
+with the 'brown body' by a funiculus. The apex of the blind pouch or
+'c�cum' of the young stomach is guided by this strand to the 'brown
+body,' which it partially surrounds. The 'brown body' then breaks up,
+and its fragments pass into the cavity of the stomach, from which they
+reach the exterior by means of the anus."
+
+Brown bodies are rarely if ever found in the phylactol�mata, in which
+the life of the colony is always short; but they are not uncommon in
+_Hislopia_ and _Victorella_, although in the case of the former they may
+easily escape notice on account of the fact that they are much paler in
+colour than is usually the case. When they are found in a ctenostome the
+collar-like membrane characteristic of the suborder is extruded from the
+orifice (which then disappears) and remains as a conspicuous external
+addition to the zooecium, the ectocyst of which, at any rate in
+_Bowerbankia_ and _Victorella_, sometimes becomes thickened and dark in
+colour.
+
+It is noteworthy that the colouring matter of the brown bodies is
+practically the only colouring matter found in the polypides of most
+polyzoa. Young polypides are practically colourless in almost all cases.
+
+
+REPRODUCTION: BUDDING.
+
+Polyzoa reproduce their species in three ways--(i) by means of eggs,
+(ii) by budding, and (iii) by means of bodies developed asexually and
+capable of lying dormant in unfavourable conditions without losing their
+vitality.
+
+Most, if not all species are hermaphrodite, eggs and spermatozoa being
+produced either simultaneously or in succession by each individual, or
+by certain individuals in each zoarium. The reproductive organs are
+borne on the inner surface of the endocyst, as a rule in a definite
+position, and often in connection with the funiculus or funiculi. It is
+doubtful to what extent eggs are habitually fertilized by spermatozoa of
+the individual that has borne them, but in some cases this is
+practically impossible and spermatozoa from other individuals must be
+introduced into the zooecium.
+
+Budding as a rule does not result in the formation of independent
+organisms, but is rather comparable to the proliferation that has become
+the normal method of growth in sponges, except of course that
+individuality is much more marked in the component parts of a polyzoon
+colony than it is in a sponge. In the genera described in this volume
+budding takes place by the outgrowth of a part of the body-wall and the
+formation therein of a new polypide, but the order in which the buds
+appear and their arrangement in reference to the parent zooecium is
+different in the different groups. In the freshwater ctenostomes three
+buds are typically produced from each zooecium, one at the anterior end
+and one at either side, the two latter being exactly opposite one
+another. The parent zooecium in this formation arises from another
+zooecium situated immediately behind it, so that each zooecium, except
+at the extremities of the zoarium, is connected with four other zooecia,
+the five together forming a cross. The two lateral buds are, however,
+frequently suppressed, or only one of them is developed, and a linear
+series of zooecia with occasional lateral branches is formed instead of
+a series of crosses. In the phylactol�mata, on the other hand, the
+linear method of budding is the typical one, but granddaughter-buds are
+produced long before the daughter-buds are mature, so that the zooecia
+are frequently pressed together, and lateral buds are produced
+irregularly. In _Victorella_ additional adventitious buds are produced
+freely near the tip of the zooecium.
+
+Reproduction by spontaneous fission sometimes occurs, especially in the
+Lophopin�, but the process differs from that which takes place when a
+_Hydra_ divides into two, for there is no division of individual zooecia
+or polypides but merely one of the whole zoarium.
+
+The production of reproductive bodies analogous to the gemmules of
+sponges appears to be confined in the polyzoa to the species that
+inhabit fresh or brackish water, nor does it occur in all of these.
+
+All the phylactol�mata produce, within their zooecia, the bodies known
+as statoblasts. These bodies consist essentially of masses of cells
+containing abundant food-material and enclosed in a capsule with thick
+horny walls. In many cases the capsule is surrounded by a "swim-ring"
+composed of a mass of horny-walled chambers filled with air, which
+renders the statoblast extremely light and enables it to float on the
+surface of the water; while in some genera the margin of the swim-ring
+bears peculiar hooked processes, the function of which is obscure. The
+whole structure first becomes visible as a mass of cells (the origin of
+all of which is not the same) formed in connection with the funiculus,
+and the statoblast may be regarded as an internal bud. Its origin and
+development in different genera has been studied by several authors,
+notably by Oka[AX] in _Pectinatella_, and by Braem[AY] in _Cristatella_.
+
+     [Footnote AX: Journ. Coll. Sci. Tokyo, iv, p. 124 (1891).]
+
+     [Footnote AY: Bibliotheca Zoologica, ii, pt. 6, p. 17
+     (1890).]
+
+The external form of the statoblasts is very important in the
+classification of the phylactol�mata, to which these structures are
+confined. In all the genera that occur in India they are flattened and
+have an oval, circular, or approximately oval outline.
+
+In temperate climates statoblasts are produced in great profusion at the
+approach of winter, but in India they occur, in most species, in
+greatest numbers at the approach of the hot weather.
+
+[Illustration: Fig. 31.--Part of the zoarium of _Victorella bengalensis_
+entirely transformed into resting buds, � 25. (From an aquarium in
+Calcutta.)]
+
+In the family Paludicellid� (ctenostomata) external buds which resemble
+the statoblasts in many respects are produced at the approach of
+unfavourable climatic conditions, but no such buds are known in the
+family Hislopiid�, the zoaria of which appear to be practically
+perennial. The buds consist of masses of cells formed at the points at
+which ordinary buds would naturally be produced, but packed with
+food-material and protected like statoblasts by a thick horny coat. It
+seems also that old zooecia and polypides are sometimes transformed into
+buds of the kind (fig. 31), and it is possible that there is some
+connection between the formation of brown bodies and their production.
+Like the statoblasts of the phylactol�mata the resting buds of the
+Paludicellid� are produced in Europe at the approach of winter, and in
+India at that of the hot weather.
+
+
+DEVELOPMENT.
+
+(a) _From the Egg._
+
+Some polyzoa are oviparous, while in others a larva is formed within the
+zooecium and does not escape until it has attained some complexity of
+structure. Both the ctenostomatous genera that are found in fresh water
+in India are oviparous, but whereas in _Victorella_ the egg is small and
+appears to be extruded soon after its fertilization, in _Hislopia_ it
+remains in the zooecium for a considerable time, increases to a
+relatively large size, and in some unknown manner accumulates a
+considerable amount of food-material before escaping. Unfortunately the
+development is unknown in both genera.
+
+In the phylactol�mata the life-history is much better known, having been
+studied by several authors, notably by Allman, by Kraepelin, and by
+Braem (1908). The egg is contained in a thin membrane, and while still
+enclosed in the zooecium, forms by regular division a hollow sphere
+composed of similar cells. This sphere then assumes an ovoid form,
+becomes covered with cilia externally, and breaks its way through the
+egg-membrane into the cavity of the zooecium. Inside the embryo, by a
+process analogous to budding, a polypide or a pair of polypides is
+formed. Meanwhile the embryo has become distinctly pear-shaped, the
+polypide or polypides being situated at its narrow end, in which a pore
+makes its appearance. The walls are hollow in the region occupied by the
+polypide, the cavity contained in them being bridged by slender threads
+of tissue. The larva thus composed makes its way out of the zooecium,
+according to Kraepelin through the orifice of a degenerate bud formed
+for its reception, and swims about for a short time by means of the
+cilia with which it is covered. Its broad end then affixes itself to
+some solid object, the polypide is everted through the pore at the
+narrow end and the whole of that part of the larva which formerly
+enclosed it is turned completely inside out. A zoarium with its included
+polypides is finally produced from the young polypide by the rapid
+development of buds.
+
+(b) _From the Statoblast and Resting Buds._
+
+There is little information available as regards the development of the
+young polyzoon in the resting buds of the freshwater ctenostomes. In
+_Paludicella_ and _Pottsiella_ the capsule of the bud splits
+longitudinally into two valves and the polypide emerges between them;
+but in _Victorella bengalensis_ one of the projections on the margin of
+the bud appears to be transformed directly into the tip of a new
+zooecium and the capsule is gradually absorbed.
+
+Contradictory statements have been made as regards several important
+points in the development of the statoblast and it is probable that
+considerable differences exist in different species. The following facts
+appear to be of general application. The cellular contents of the
+capsule consist mainly of a mass of cells packed with food-material in a
+granular form, the whole enclosed in a delicate membrane formed of flat
+cells. When conditions become favourable for development a cavity
+appears near one end of the mass and the cells that form its walls
+assume a columnar form in vertical section. The cavity increases rapidly
+in size, and, as it does so, a young polypide is budded off from its
+walls. Another bud may then appear in a similar fashion, and the
+zooecium of the first bud assumes its characteristic features. The
+capsule then splits longitudinally into two disk-like valves and the
+young polypide, in some cases already possessing a daughter bud, emerges
+in its zooecium, adheres by its base to some external object and
+produces a new polyparium by budding. The two valves of the statoblast
+often remain attached to the zoarium that has emerged from between them
+until it attains considerable dimensions (see Plate IV, fig. 3 _a_).
+
+What conditions favour development is a question that cannot yet be
+answered in a satisfactory manner. Statoblasts can lie dormant for
+months and even for years without losing their power of germinating, and
+it is known that in Europe they germinate more readily after being
+subjected to a low temperature. In tropical India this is, of course, an
+impossible condition, but perhaps an abnormally high temperature has the
+same effect. At any rate it is an established fact that whereas the
+gemmules of most species germinate in Europe in spring, in Bengal they
+germinate either at the beginning of the "rains" or at that of our mild
+Indian winter.
+
+
+MOVEMENTS.
+
+[Illustration: Fig. 32.--Zoarium of _Lophopodella carteri_ moving along
+the stem of a water plant, � 4. (From Igatpuri Lake.)]
+
+In the vast majority of the polyzoa, marine as well as freshwater,
+movement is practically confined to the polypide, the external walls of
+the zooecium being rigid, the zooecia being closely linked together and
+the whole zoarium permanently fixed to some extraneous object. In a few
+freshwater species belonging to the genera _Cristatella_, _Lophopus_,
+_Lophopodella_ and _Pectinatella_, the whole zoarium has the power of
+progression. This power is best developed in _Cristatella_, which glides
+along with considerable rapidity on a highly specialized "sole" provided
+with abundant mucus and representing all that remains of the ectocyst.
+It is by no means clear how the zoaria of the other genera move from one
+place to another, for the base is not modified, so far as can be seen,
+for the purpose, and the motion is extremely slow. It is probable,
+however, that progression is effected by alternate expansions and
+contractions of the base, and in _Lophopodella_ (fig. 32), which moves
+rather less slowly than its allies, the anterior part of the base is
+raised at times from the surface along which it is moving. The whole
+zoarium can be released in this way and occasionally drops through the
+water, and is perhaps carried by currents from one place to another in
+so doing.
+
+So far as the polypides are concerned, the most important movements are
+those which enable the lophophore and the adjacent parts to be extruded
+from and withdrawn into the zooecium. The latter movement is executed by
+means of the retractor muscles, which by contracting drag the extruded
+parts back towards the posterior end of the endocyst, but it is not by
+any means certain how the extrusion of the lophophore is brought about.
+In most ctenostomes the action of the parietal muscles doubtless assists
+in squeezing it out when the retractor and parieto-vaginal muscles
+relax, but Oka states that protrusion can be effected in the
+phylactol�mata even after the zooecium has been cut open. Possibly some
+hydrostatic action takes place, however, and allowance must always be
+made for the natural resilience of the inverted portion of the ectocyst.
+
+Even when the polypide is retracted, muscular action does not cease, for
+frequent movements, in some cases apparently rhythmical, of the
+alimentary canal may be observed, and in _Hislopia_ contraction of the
+gizzard takes place at irregular intervals.
+
+When the lophophore is expanded, the tentacles in favourable
+circumstances remain almost still, except for the movements of their
+cilia; but if a particle of matter too large for the mouth to swallow or
+otherwise unsuitable is brought by the currents of the cilia towards it,
+individual tentacles can be bent down to wave it away and similar
+movements are often observed without apparent cause.
+
+In the cheilostomes certain individuals of each zoarium are often
+profoundly modified in shape and function and exhibit almost constant
+rhythmical or convulsive movements, some ("avicularia") being shaped
+like a bird's beak and snapping together, others ("vibracula") being
+more or less thread-like and having a waving motion.
+
+
+DISTRIBUTION OF THE FRESHWATER POLYZOA.
+
+Fifteen genera of freshwater Polyzoa are now recognized, one
+entoproctous and fourteen ectoproctous; five of the latter are
+ctenostomatous and nine phylactol�matous. Of the fourteen ectoproctous
+genera seven are known to occur in India, viz., _Victorella_,
+_Hislopia_, _Fredericella_, _Plumatella_, _Stolella_, _Lophopodella_,
+and _Pectinatella_. Except _Stolella_, which is only known from northern
+India, these genera have an extremely wide geographical range;
+_Victorella_ occurs in Europe, India, Africa, and Australia; _Hislopia_
+in India, Indo-China, China, and Siberia; _Fredericella_ in Europe, N.
+America, Africa, India, and Australia; _Plumatella_ in all geographical
+regions; _Lophopodella_ in E. and S. Africa, India, and Japan;
+_Pectinatella_ in Europe, N. America, Japan, and India.
+
+Two genera, _Paludicella_ and _Lophopus_, have been stated on
+insufficient grounds to occur in India. The former is known from Europe
+and N. America, and is said to have been found in Australia, while the
+latter is common in Europe and N. America and also occurs in Brazil.
+
+Of the genera that have not been found in this country the most
+remarkable are _Urnatella_ and _Cristatella_. The former is the only
+representative in fresh water of the Entoprocta and has only been found
+in N. America. Each individual is borne upon a segmented stalk the
+segments of which are enclosed in strong horny coverings and are
+believed to act as resting buds. _Cristatella_, which is common in
+Europe and N. America, is a phylactol�matous genus of highly specialized
+structure. It possesses a creeping "sole" or organ of progression at the
+base of the zoarium.
+
+The other phylactol�matous genera that do not occur in India appear to
+be of limited distribution, for _Australella_ is only known from N. S.
+Wales, and _Stephanella_ from Japan. The ctenostomatous _Arachnoidea_
+has only been reported from Lake Tanganyika, and _Pottsiella_ only from
+a single locality in N. America.
+
+As regards the exotic distribution of the Indian species little need be
+said. The majority of the _Plumatell�_ are identical with European
+species, while the only species of _Fredericella_ that has been
+discovered is closely allied to the European one. The Indian species of
+_Lophopodella_ occurs also in E. Africa and Japan, while that of
+_Pectinatella_ is apparently confined to India, Burma and Ceylon, but is
+closely allied to a Japanese form.
+
+
+POLYZOA OF BRACKISH WATER.
+
+With the exception of _Victorella_, which occurs more commonly in
+brackish than in fresh water and has been found in the sea, the genera
+that occur in fresh water are confined or practically confined to that
+medium; but certain marine ctenostomes and cheilostomes not uncommonly
+make their way, both in Europe and in India, into brackish water, and in
+the delta of the Ganges an entoproctous genus also does so. The
+ctenostomatous genera that are found occasionally in brackish water
+belong to two divisions of the suborder, the Vesicularina and the
+Alcyonellea. To the former division belongs _Bowerbankia_, a form of
+which (_B. caudata_ subsp. _bengalensis_, p. 187) is often found in the
+Ganges delta with _Victorella bengalensis_. No species of Alcyonellea
+has, however, as yet been found in Indian brackish waters. The two
+Indian cheilostomes of brackish water belong to a genus (_Membranipora_)
+also found in similar situations in Europe. One of them (_M.
+lacroixii_[AZ]) is, indeed, identical with a European form that occurs
+in England both in the sea and in ditches of brackish water. I have
+found it in the Cochin backwaters, in ponds of brackish water at the
+south end of the Chilka Lake (Ganjam, Madras), on the shore at Puri in
+Orissa, and in the Mutlah River at Port Canning. The second species (_M.
+bengalensis_, Stoliczka) is peculiar to the delta of the Ganges[BA] and
+has not as yet been found in the open sea. The two species are easily
+recognized from one another, for whereas the lip of _M. bengalensis_
+(fig. 33) bears a pair of long forked spines, there are no such
+structures on that of _M. lacroixii_, the dorsal surface of which is
+remarkably transparent. _M. lacroixii_ forms a flat zoarium, the only
+part visible to the naked eye being often the beaded margin of the
+zooecia, which appears as a delicate reticulation on bricks, logs of
+wood, the stems of rushes and of hydroids, etc.; but the zoarium of _M.
+bengalensis_ is as a rule distinctly foliaceous and has a peculiar
+silvery lustre.
+
+     [Footnote AZ: There is some doubt as to the proper name of
+     this species, which may not be the one originally described
+     as _Membranipora lacroixii_ by Andouin. I follow Busk and
+     Hincks in my identification (see Cat. Polyzoa Brit. Mus. ii,
+     p. 60, and Hist. Brit. Polyzoa, p. 129). Levinsen calls it
+     _M. hippopus_, sp. nov. (see Morphological and Systematic
+     Studies on the Cheilostomatous Bryozoa, p. 144; Copenhagen,
+     1909).]
+
+     [Footnote BA: Miss Thornely (Rec. Ind. Mus. i, p. 186, 1907)
+     records it from Mergui, but this is an error due to an
+     almost illegible label. The specimens she examined were the
+     types of the species from Port Canning. Since this was
+     written I have obtained specimens from Bombay--_April_,
+     1911.]
+
+[Illustration: Fig. 33.--Outline of four zooecia of _Membranipora
+bengalensis_, Stoliczka (from type specimen, after Thornely). In the
+left upper zooecium the lip is shown open.]
+
+_Loxosomatoides_[BB] (fig. 34), the Indian entoproctous genus found in
+brackish water, has not as yet been obtained from the open sea, but has
+recently been introduced, apparently from a tidal creek, into isolated
+ponds of brackish water at Port Canning. It is easily recognized by the
+chitinous shield attached to the ventral (posterior) surface.
+
+     [Footnote BB: Annandale, Rec. Ind. Mus. ii, p. 14 (1908).]
+
+[Illustration: Fig. 34.--_Loxosomatoides colonialis_, Annandale.
+
+A and B, a single individual of form A, as seen (A) in lateral, and (B)
+in ventral view; C, outline of a similar individual with the tentacles
+retracted, as seen from in front (dorsal view); D, ventral view of an
+individual and bud of form B. All the figures are from the type
+specimens and are multiplied by about 70.]
+
+
+II.
+
+HISTORY OF THE STUDY OF THE FRESHWATER POLYZOA.
+
+The naturalists of the eighteenth century were acquainted with more than
+one species of freshwater polyzoon, but they did not distinguish these
+species from the hydroids. Trembley discovered _Cristatella_, which he
+called "Polype � Panache," in 1741, and Linn� described a species of
+_Plumatella_ under the name _Tubipora repens_ in 1758, while ten years
+later Pallas gave a much fuller description (under the name _Tubularia
+fungosa_) of the form now known as _Plumatella fungosa_ or _P. repens_
+var. _fungosa_. Although Trembley, Baker, and other early writers on the
+fauna of fresh water published valuable biological notes, the first
+really important work of a comprehensive nature was that of Dumortier
+and van Beneden, published in 1848. All previous memoirs were, however,
+superseded by Allman's Monograph of the Fresh-Water Polyzoa, which was
+issued in 1857, and this memoir remains in certain respects the most
+satisfactory that has yet been produced. In 1885 Jullien published a
+revision of the phylactol�mata and freshwater ctenostomes which is
+unfortunately vitiated by some curious lapses in observation, but it is
+to Jullien that the recognition of the proper position of _Hislopia_ is
+due. The next comprehensive monograph was that of Kraepelin, which
+appeared in two parts (1887 and 1892) in the Abhandlungen des Naturwiss.
+Vereins of Hamburg. In its detailed information and carefully executed
+histological plates this work is superior to any that preceded it or has
+since appeared, but the system of classification adopted is perhaps less
+liable to criticism than that followed by Braem in his "Untersuchungen,"
+published in the Bibliotheca Zoologica in 1888.
+
+During the second half of the nineteenth century and the first decade of
+the twentieth several authors wrote important works on the embryology
+and anatomy of the phylactol�mata, notably Kraepelin, Braem, and Oka;
+but as yet the ctenostomes of fresh water have received comparatively
+little attention from anything but a systematic point of view.
+
+From all points of view both the phylactol�mata and the ctenostomes of
+Asia have been generally neglected, except in the case of the Japanese
+phylactol�mata, which have been studied by Oka. Although Carter made
+some important discoveries as regards the Indian forms, he did not
+devote to them the same attention as he did to the sponges. In the case
+of the only new genus he described he introduced a serious error into
+the study of the two groups by placing _Hislopia_ among the
+cheilostomes, instead of in its true position as the type genus of a
+highly specialized family of ctenostomes.
+
+For fuller details as to the history of the study of the freshwater
+Polyzoa the student may refer to Allman's and to Kraepelin's monographs.
+An excellent summary is given by Harmer in his chapter on the freshwater
+Polyzoa in vol. ii. of the Cambridge Natural History; and Loppens has
+recently (1908) published in the Annales de Biologie lacustre a concise
+survey of the systematic work that has recently been undertaken.
+Unfortunately he perpetuates Carter's error as regards the position of
+_Hislopia_.
+
+
+BIBLIOGRAPHY OF THE FRESHWATER POLYZOA.
+
+A very full bibliography of the freshwater Polyzoa will be found in pt.
+i. of Kraepelin's "Die Deutschen S�sswasserbryozoen" (1887), while
+Loppens, in his survey of the known species (Ann. Biol. lacustre, ii,
+1908), gives some recent references. The following list contains the
+titles of some of the more important works of reference, of memoirs on
+special points such as reproduction and of papers that have a special
+reference to Asiatic species. Only the last section is in any way
+complete.
+
+(a) _Works of Reference._
+
+1847. VAN BENEDEN, "Recherches sur les Bryozoaires fluviatiles de
+Belgique," M�m. Ac. Roy. Belgique, xxi.
+
+1850. DUMORTIER and VAN BENEDEN, "Histoire Naturelle des Polypes
+compos�s d'eau douce," 2^e partie, M�m. Ac. Roy. Bruxelles, xvi
+(compl�ment).
+
+1856. ALLMAN, "A Monograph of the Fresh-Water Polyzoa" (London).
+
+1866-1868. HYATT, "Observations on Polyzoa, suborder Phylactol�mata,"
+Comm. Essex Inst. iv, p. 197, v, p. 97.
+
+1880. HINCKS, "A History of the British Marine Polyzoa."
+
+1885. JULLIEN, "Monographie des Bryozoaires d'eau douce," Bull. Soc.
+zool. France, x, p. 91.
+
+1887 & 1892. KRAEPELIN, "Die deutschen S�sswasserbryozoen," Abhandl.
+Nat. Vereins Hamburg, x & xii.
+
+1890. BRAEM, "Untersuchungen des Bryozoen des s�ssen Wassers," Bibl.
+Zool. ii, Heft 6 (Cassel).
+
+1896. HARMER, Cambridge Natural History, ii, Polyzoa, chap. xviii.
+
+1899. KORSCHELT and HEIDER, "Embryology of Invertebrates," vol. ii,
+chap. xvi. (English edition by Bernard and Woodward, 1899.)
+
+1908. LOPPENS, "Les Bryozoaires d'eau douce," Ann. Biol. lacustre, iii.
+p. 141.
+
+(b) _Special Works on Embryology, etc._
+
+1875. NITSCHE, "Beitr�ge zur Kenntniss der Bryozoen," Zeitschr. f. wiss.
+Zool. xxv (supplement), p. 343.
+
+1880. REINHARD, "Zur Kenntniss der S�sswasser-Bryozoen," Zool. Anz. iii,
+p. 208.
+
+1888. BRAEM, "Untersuchungen �ber die Bryozoen des s�ssen Wassers,"
+Zool. Anz. xi, pp. 503, 533.
+
+1891. OKA, "Observations on Freshwater Polyzoa," J. Coll. Sci. Tokyo,
+iv, p. 89.
+
+1906. WILCOX, "Locomotion in young colonies of _Pectinatella
+magnifica_," Biol. Bull. Wood's Hole, ii.
+
+1908. BRAEM, "Die geschlechtliche Entwickelung von Fredericella sultana
+nebst Beobachtungen �ber die weitere Lebensgeschichte der Kolonien,"
+Bibl. Zool. xx, Heft 52.
+
+(c) _Papers that refer specifically to Asiatic species._
+
+1851. LEIDY described _Plumatella diffusa_ in Proc. Ac. Philad. v, p.
+261 (1851).
+
+1858. CARTER, "Description of a Lacustrine Bryozoon allied to
+_Flustra_," Ann. Nat. Hist. (3) i, p. 169.
+
+1859. CARTER, "On the Identify in Structure and Composition of the
+so-called Seed-like Body of _Spongilla_ with the Winter-egg of the
+Bryozoa: and the presence of Starch-granules in each," Ann. Nat. Hist.
+(3) iii, p. 331. (Statoblast of _Lophopodella_ described and figured.)
+
+1862. MITCHELL, "Freshwater Polyzoa," Q. J. Micr. Sci. (new series) ii,
+p. 61. ("_Lophopus_" recorded from Madras.)
+
+1866. HYATT, "Observations on Polyzoa, suborder Phylactol�mata," Comm.
+Essex Inst. iv, p. 197. ("_Pectinatella carteri_" named.)
+
+1869. STOLICZKA, "On the Anatomy of _Sagartia schilleriana_ and
+_Membranipora bengalensis_, a new coral and a bryozoon living in
+brackish water at Port Canning," J. As. Soc. Bengal, xxxviii, ii, p. 28.
+
+1880. JULLIEN, "Description d'un nouveau genre de Bryozoaire
+Cheilostomien des eaux douces de la Chine et du Cambodge et de deux
+esp�ces nouvelles," Bull. Soc. zool. France, v, p. 77. ("_Norodonia_"
+described.)
+
+1885. JULLIEN, "Monographie des Bryozoaires d'eau douce," Bull. Soc.
+zool. France, x, p. 91. (_Hislopia_ assigned to the ctenostomes.)
+
+1887. KRAEPELIN, "Die deutschen S�sswasserbryozoen," Abh. Ver. Hamburg,
+x. (_Plumatella philippinensis._)
+
+1891. OKA, "Observations on Freshwater Polyzoa," J. Coll. Sci. Tokyo,
+iv, p. 89.
+
+1898. MEISSNER, "Die Moosthiere Ost-Afrikas," in Mobius's
+Deutsch-Ost-Afrika, iv. (_Lophopodella carteri_ recorded from E.
+Africa.)
+
+1901. KOROTNEFF, "Faunistische Studien am Baikalsee," Biol. Centrbl.
+xxi, p. 305. ("_Echinella_" described.)
+
+1904-1906. ROUSSELET, "On a new Freshwater Polyzoon from Rhodesia,
+_Lophopodella thomasi_, gen. et sp. nov.", J. Quekett Club (2) ix, p.
+45. (Genus _Lophopodella_ described.)
+
+1906. ANNANDALE, "Notes on the Freshwater Fauna of India. No. II. The
+Affinities of _Hislopia_," J. As. Soc. Bengal (new series) ii, p. 59.
+
+1906. KRAEPELIN, "Eine S�sswasser-bryozo� (_Plumatella_) aus Java,"
+Mitth. Mus. Hamburg, xxiii, p. 143.
+
+1907. ANNANDALE, "Notes on the Freshwater Fauna of India. No. XII. The
+Polyzoa occurring in Indian Fresh and Brackish Pools," J. As. Soc. Bengal
+(new series) iii, p. 83.
+
+1907. ANNANDALE, "Statoblasts from the surface of a Himalayan Pond,"
+Rec. Ind. Mus. i, p. 177.
+
+1907. ANNANDALE, "The Fauna of Brackish Ponds at Port Canning, Lower
+Bengal: I.--Introduction and Preliminary Account of the Fauna," Rec.
+Ind. Mus. i, p. 35.
+
+1907. ANNANDALE, "The Fauna of Brackish Ponds at Port Canning, Lower
+Bengal: VI.--Observations on the Polyzoa, with further notes on the
+Ponds," Rec. Ind. Mus. i, p. 197.
+
+1907. ANNANDALE, "Further Note on a Polyzoon from the Himalayas," Rec.
+Ind. Mus. i, p. 145.
+
+1907. ROUSSELET, "Zoological Results of the Third Tanganyika Expedition,
+conducted by Dr. W. A. Cunnington, 1904-1905.--Report on the Polyzoa,"
+P. Z. Soc. London, i, p. 250. (_Plumatella tanganyik�._)
+
+1907. OKA, "Eine dritte Art von _Pectinatella_ (_P. davenporti_, n.
+sp.)," Zool. Anz. xxxi, p. 716.
+
+1907. APSTEIN, "Das Plancton im Colombo-See auf Ceylon," Zool. Jahrb.
+(Syst.) xxv, p. 201. (_Plumatella_ recorded.)
+
+1907. WALTON, "Notes on _Hislopia lacustris_, Carter," Rec. Ind. Mus. i,
+p. 177.
+
+1907-1908. OKA, "Zur Kenntnis der S�sswasser-Bryozoenfauna von Japan,"
+Annot. Zool. Japon, vi, p. 117.
+
+1907-1908. OKA, "Ueber eine neue Gattung von S�sserwasserbryozoen,"
+Annot. Zool. Japon, vi, p. 277.
+
+1908. ANNANDALE, "The Fauna of Brackish Ponds at Port Canning, Lower
+Bengal: VII.--Further Observations on the Polyzoa with the description
+of a new genus of Entoprocta," Rec. Ind. Mus. ii, p. 11.
+
+1908. ANNANDALE, "Corrections as to the Identity of Indian
+Phylactol�mata," Rec. Ind. Mus. ii, p. 110.
+
+1908. ANNANDALE, "Three Indian Phylactol�mata," Rec. Ind. Mus. ii, p.
+169.
+
+1908. KIRKPATRICK, "Description of a new variety of _Spongilla
+loricata_, Weltner," Rec. Ind. Mus. ii, p. 97. (_Hislopia_ recorded from
+Burma.)
+
+1909. ANNANDALE, "Preliminary Note on a new genus of Phylactol�matous
+Polyzoa," Rec. Ind. Mus. iii, p. 279.
+
+1909. ANNANDALE, "A new species of _Fredericella_ from Indian Lakes,"
+Rec. Ind. Mus. iii. p. 373.
+
+1909. WALTON, "Large Colonies of _Hislopia lacustris_," Rec. Ind. Mus.
+iii, p. 295.
+
+1910. ANNANDALE, "Materials for a Revision of the Phylactol�matous
+Polyzoa of India," Rec. Ind. Mus. v, p. 37.
+
+1911. WEST and ANNANDALE, "Descriptions of Three Species of Alg�
+associated with Indian Freshwater Polyzoa," J. As. Soc. Bengal
+(_ined._).
+
+
+
+
+GLOSSARY OF TECHNICAL TERMS USED IN PART III.
+
+
+  _Brown body_            A body formed in a zooecium by the degeneration
+                          of a polypide as a preparation
+                          for its regeneration.
+
+  _Cardiac portion_ (of   That part which communicates with the
+   the stomach).          oesophagus.
+
+  _Collar_                A longitudinally pleated circular membrane
+                          capable of being thrust out of the orifice
+                          in advance of the lophophore and of
+                          closing together inside the zooecium above
+                          the tentacles when they are retracted.
+
+  _Dorsal surface_        (_Of zooecium_ or _polypide_) the surface
+                          nearest the mouth; (_of statoblast_) the
+                          surface furthest from that by which the
+                          statoblast is attached to the funiculus
+                          during development.
+
+  _Ectocyst_              The outer, structureless layer of the zooecium.
+
+  _Emarginate_            Having a thin or defective triangular area
+  (of a zooecium)         in the ectocyst at the tip.
+
+  _Endocyst_              The inner, living (cellular) layer of the
+                          zooecium.
+
+  _Epistome_              A leaf-like ciliated organ that projects
+                          upwards and forwards over the mouth
+                          between it and the anus.
+
+  _Funiculus_             A strand of tissue joining the alimentary
+                          canal to the endocyst.
+
+  _Furrowed_              Having a thin or defective longitudinal
+  (of a zooecium)         linear streak in the ectocyst on the dorsal
+                          surface.
+
+  _Gizzard_               A chamber of the alimentary canal situated
+                          at the cardiac end of the stomach and
+                          provided internally with a structureless
+                          lining.
+
+  _Intertentacular organ_ A ciliated tube running between the cavity
+                          of the zooecium and the external base of
+                          the lophophore.
+
+  _Keeled_                Having a longitudinal ridge on the dorsal
+  (of a zooecium)         surface.
+
+  _Lophophore_            The tentacles with the base to which they
+                          are attached.
+
+  _Marginal processes_    Chitinous hooked processes on the margin
+  (of statoblast).        of the swim-ring (_q. v._).
+
+  _OEsophagus_            That part of the alimentary canal which
+                          joins the mouth to the stomach.
+
+  _Orifice_               The aperture through which the lophophore
+                          can be protruded from or retracted into
+                          the zooecium.
+
+  _Parietal muscles_      Transverse muscles running round the inner
+                          wall of the zooecium.
+
+  _Parieto-vaginal_       Muscles that surround the orifice, running
+  _muscles_               between the folds of the zooecium in an
+                          oblique direction.
+
+  _Polyparium_            The whole body of zooecia and polypides
+                          which are in organic connection.
+
+  _Polypide_              The tentacular crown, alimentary canal,
+                          and retractor muscles of a polyzoon-individual.
+
+  _Pyloric portion_       That part which communicates with the
+  (of the stomach).       intestine.
+
+  _Resting bud_           An external bud provided with food-material
+                          in its cells, with a horny external
+                          coat and capable of lying dormant in
+                          unfavourable conditions.
+
+  _Retractor muscles_     The muscles by the action of which the
+                          lophophore can be pulled back into the
+                          zooecium.
+
+  _Statoblast_            An internal bud arising from the funiculus,
+                          containing food-material in its cells,
+                          covered with a horny coat and capable
+                          of lying dormant in unfavourable conditions.
+
+  _Swim-ring_             A ring of polygonal air-spaces surrounding
+                          the statoblast.
+
+  _Ventral surface_       (_Of zooecium_ or _polypide_) the surface
+                          nearest the anus; (_of statoblast_) the surface
+                          by which the statoblast is attached
+                          to the funiculus during development.
+
+  _Zoarium_               The whole body of zooecia which are in
+                          organic connection.
+
+  _Zooecium_              Those parts of the polyzoon-individual
+                          which constitute a case or "house" for
+                          the polypide.
+
+
+
+
+SYNOPSIS OF THE CLASSIFICATION OF THE POLYZOA.
+
+
+
+
+I.
+
+SYNOPSIS OF THE SUBCLASSES, ORDERS, AND SUBORDERS.
+
+Class POLYZOA.
+
+Small coelomate animals, each individual of which consists of a
+polyp-like organism or polypide enclosed in a "house" or zooecium
+composed partly of living tissues. The mouth is surrounded by a circle
+of ciliated tentacles that can be retracted within the zooecium; the
+alimentary canal, which is suspended in the zooecium, is Y-shaped and
+consists of three parts, the oesophagus, the stomach, and the intestine.
+
+
+Subclass ENTOPROCTA.
+
+The anus as well as the mouth is enclosed in the circle of tentacles and
+the zooecium is not very distinctly separated from the polypide. Some
+forms are solitary or form temporary colonies by budding.
+
+Most Entoprocta are marine, but a freshwater genus (_Urnatella_) occurs
+in N. America, while the Indian genus _Loxosomatoides_ (fig. 34, p. 176)
+is only known from brackish water.
+
+
+Subclass ECTOPROCTA.
+
+The anus is outside the circle of tentacles and the zooecium can always
+be distinguished from the polypide. All species form by budding
+permanent communities the individuals in which remain connected together
+by living tissue.
+
+
+Order I. GYMNOL�MATA.
+
+Ectoproctous polyzoa the polypides of which have no epistome; the
+zooecia are in nearly all cases distinctly separated from one another by
+transverse perforated plates.
+
+Most of the Gymnol�mata are marine, but species belonging to two of the
+three suborders into which they are divided often stray into brackish
+water, while a few genera that belong to one of these two suborders are
+practically confined to fresh water. The three suborders are
+distinguished as follows:--
+
+
+Suborder A. _CHEILOSTOMATA._
+
+The zooecia are provided with a "lip" or lid hinged to the posterior
+margin of the orifice (see fig. 33, p. 175). This lid closes
+automatically outside the zooecium or in a special chamber on the
+external surface (the "peristome") when the polypide retracts and is
+pushed open by the tentacles as they expand. The majority of the zooecia
+in each zoarium are more or less distinctly flattened, but some of them
+are often modified to form "vibracula" and "avicularia."
+
+The Cheilostomata are essentially a marine group, but some species are
+found in estuaries and even in pools and ditches of brackish water (fig.
+33).
+
+
+Suborder B. _CTENOSTOMATA._
+
+The zooecia are provided with a collar-like membrane which is pleated
+vertically and closes together above the polypide inside the zooecium
+when the former is retracted; it is thrust out of the zooecium and
+expands into a ring-shaped form just before the tentacles are extruded.
+The zooecia are usually more or less tubular, but in some genera and
+species are flattened.
+
+The majority of the Ctenostomata are marine, but some genera are found
+in estuaries, while those of one section of the suborder live almost
+exclusively in fresh water.
+
+
+Suborder C. _CYCLOSTOMATA._
+
+The zooecia are provided neither with a lip nor with a collar-like
+membrane. They are tubular and usually have circular orifices.
+
+The Cyclostomata are exclusively marine.
+
+
+Order II. PHYLACTOL�MATA.
+
+Ectoproctous polyzoa the polypides of which have a leaf-shaped organ
+called an epistome projecting upwards and forwards within the circle of
+tentacles and between the mouth and the anus. The zooecia are not
+distinct from one another, but in dendritic forms the zoarium is divided
+irregularly by chitinous partitions.
+
+The Phylactol�mata are, without exception, freshwater species.
+
+
+
+
+II.
+
+SYNOPSIS OF THE LEADING CHARACTERS OF THE DIVISIONS OF THE SUBORDER
+CTENOSTOMATA.
+
+
+Suborder B. _CTENOSTOMATA._
+
+The suborder has been subdivided in various ways by different authors.
+The system here adopted is essentially the same as that proposed in a
+recent paper by Waters (Journ. Linn. Soc. London, Zool. xxi, p. 231,
+1910), but I have thought it necessary to add a fourth division to the
+three adopted by that author, namely, the Alcyonellea, Stolonifera, and
+Vesicularina. This new division includes all the freshwater genera and
+may be known as the Paludicellina. In none of these divisions are the
+tentacles webbed at the base.
+
+The four divisions may be recognized from the following synopsis of
+their characteristic features:--
+
+
+Division I. ALCYONELLEA.
+
+The zooecia arise directly from one another in a fleshy or gelatinous
+mass. The polypide has no gizzard. The species are essentially marine,
+but a few are found in brackish water in estuaries.
+
+
+Division II. STOLONIFERA.
+
+The zooecia arise from expansions in a delicate creeping rhizome or
+root-like structure, the order in which they are connected together
+being more or less irregular. As a rule (perhaps always) there is no
+gizzard. The species are marine.
+
+
+Division III. VESICULARINA.
+
+The zooecia grow directly from a tubular stem which is usually free and
+vertical, their arrangement being alternate, spiral or irregular. There
+is a stout gizzard which bears internal chitinous projections and is
+tightly compressed when the polypide is retracted. The species are
+essentially marine, but a few are found in brackish water.
+
+
+Division IV. PALUDICELLINA, nov.
+
+The zooecia are arranged in a regular cruciform manner and arise either
+directly one from another or with the intervention of tubular processes.
+If the polypide has a gizzard it does not bear internal chitinous
+projections. Most of the species are confined to fresh water, but a few
+are found in brackish water or even in the sea.
+
+Although all true freshwater Ctenostomes belong to the fourth of these
+divisions, species of a genus (_Bowerbankia_) included in the third are
+so frequently found in brackish water and in association with one
+belonging to the fourth, and are so easily confounded with the latter,
+that I think it necessary to include a brief description of the said
+genus and of the form that represents it in ponds of brackish water in
+India.
+
+
+
+
+SYSTEMATIC LIST OF THE INDIAN FRESHWATER POLYZOA.
+
+[The types have been examined in the case of all species, etc., whose
+names are marked thus, *.]
+
+
+  Order I. GYMNOL�MATA.
+
+  Suborder I. _CTENOSTOMATA._
+
+  [Division III. Vesicularina.]
+
+  [Genus BOWERBANKIA, Farre (1837).]
+
+  [_B. caudata_ subsp. _bengalensis_*, Annandale (1907).
+  (Brackish water).]
+
+
+  Division IV. Paludicellina, nov.
+
+  Family I. PALUDICELLID�.
+
+  Genus 1. PALUDICELLA, Gervais (1836).
+
+  ? _Paludicella_ sp. (_fide_ Carter).
+
+  Genus 2. VICTORELLA, Kent (1870).
+
+  26._V. bengalensis_*, Annandale (1907).
+
+
+  Family II. HISLOPIID�.
+
+  Genus HISLOPIA, Carter (1858).
+
+  27. _H. lacustris_, Carter (1858).
+  27 _a._ _H. lacustris_ subsp. _moniliformis_*, nov.
+
+
+  Order II. PHYLACTOL�MATA.
+
+  Division I. Plumatellina.
+
+  Family 1. FREDERICELLID�.
+
+  Genus FREDERICELLA, Gervais (1836).
+
+  28. _F. indica_*, Annandale (1909).
+
+
+  Family 2. PLUMATELLID�.
+
+  Subfamily A. PLUMATELLIN�.
+
+  Genus 1. PLUMATELLA, Lamarck (1816).
+
+  29. _P. fruticosa_, Allman (1844).
+  30. _P. emarginata_, Allman (1844).
+  31. _P. javanica_*, Kraepelin (1905).
+  32. _P. diffusa_, Leidy (1851).
+  33. _P. allmani_, Hancock (1850).
+  34. _P. tanganyik�_*, Rousselet (1907).
+  35. _P. punctata_, Hancock (1850).
+
+  Genus 2. STOLELLA, Annandale (1909).
+
+  36. _S. indica_*, Annandale (1909).
+
+
+  Subfamily B. LOPHOPIN�.
+
+  Genus 1. LOPHOPODELLA, Rousselet (1904).
+
+  37. _L. carteri_* (Hyatt) (1865).
+  37 _a._ _L. carteri_ var. _himalayana_* (Annandale) (1907).
+
+  Genus 2. PECTINATELLA, Leidy (1851).
+
+  38. _P. burmanica_*, Annandale (1908).
+
+
+  Order CTENOSTOMATA.
+
+  [Division VESICULARINA.
+
+  Family VESICULARID�.
+
+  VESICULARID�, Hincks, Brit. Marine Polyzoa, p. 512 (1880).
+
+Zooecia constricted at the base, deciduous, attached to a stem that is
+either recumbent or vertical.
+
+
+Genus BOWERBANKIA, _Farre_.
+
+     _Bowerbankia_, Farre, Phil. Trans. Roy. Soc. cxxvii, p. 391 (1837).
+
+     _Bowerbankia_, Hincks, _op. cit._ p. 518.
+
+_Zoarium_ vertical or recumbent. _Zooecia_ ovate or almost cylindrical,
+arranged on the stem singly, in clusters or in a subspiral line.
+_Polypide_ with 8 or 10 tentacles.
+
+
+Bowerbankia caudata, _Hincks_.
+
+     _Bowerbankia caudata_, Hincks, _op. cit._ p. 521, pl. lxxv,
+     figs. 7, 8.
+
+This species is easily distinguished from all others by the fact that
+mature zooecia have always the appearance of being fixed to the sides of
+a creeping, adherent stem and are produced, below the point at which
+they are thus fixed, into a pointed "tail."
+
+
+Subsp. bengalensis, _Annandale_.
+
+     _Bowerbankia caudata_, Thornely, Rec. Ind. Mus. i, p. 196
+       (1907).
+
+     _Bowerbankia caudata_, Annandale, _ibid._ p. 203.
+
+     _Bowerbankia caudata_ race _bengalensis_, _id._, _ibid._
+       ii. p. 13 (1908).
+
+The Indian race is only distinguished from the typical form by its
+greater luxuriance of growth and by the fact that the "tail" of the
+zooecia is often of relatively great length, sometimes equaling or
+exceeding the rest of the zooecium. The stem, which is divided at
+irregular intervals by partitions, often crosses and recrosses its own
+course and even anastomoses, and a fur-like structure is formed in which
+the zooecia representing the hairs become much elongated; but upright
+branches are never formed. The zoarium has a greenish or greyish tinge.
+
+TYPE in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--_B. caudata_ subsp. _bengalensis_ is common
+in brackish water in the Ganges delta, where it often occurs in close
+association with _Victorella bengalensis_, and also at the south end of
+the Chilka Lake in the north-east of the Madras Presidency. Although it
+has not yet been found elsewhere, it probably occurs all round the
+Indian coasts.]
+
+
+Division PALUDICELLINA, nov.
+
+This division consists of two very distinct families, the species of
+which are easily distinguished at a glance by the fact that in one (the
+Paludicellid�) the zooecia are tubular, while in the other (the
+Hislopiid�) they are broad and flattened. The anatomical and
+physiological differences between the two families are important, and
+they are associated together mainly on account of the method of budding
+by means of which their zoaria are produced.
+
+[Illustration: Fig. 35.--Single zooecia of _Victorella_ and _Hislopia_
+(magnified).
+
+A, zooecium of _Victorella pavida_, Kent, with the polypide retracted
+(after Kraepelin).
+
+B, zooecium of _Hislopia lacustris_, Carter (typical form from the
+United Provinces), with the collar completely and the tentacles partly
+protruded.
+
+A=collar; B=orifice; C=tentacles; D=pharynx; E=oesophagus proper;
+F=gizzard; G=stomach; G'=cardiac portion of stomach; H=intestine;
+J=rectum; K=anus; L=young egg; M=green cysts in gizzard; N=testes;
+O=ovary; O'=funiculus.
+
+The muscles are omitted except in fig. B.]
+
+
+Family PALUDICELLID�.
+
+     PALUDICELLID�, Allman, Mon. Fresh-Water Polyzoa, p. 113
+     (1857).
+
+     HOMODI�TID�, Kent, Q. J. Micr. Sci. x, p. 35 (1870).
+
+     VICTORELLID�, Hincks, Brit. Marine Polyzoa, p. 558 (1880).
+
+     PALUDICELLID�ES, Jullien, Bull. Soc. zool. France, x, p. 174
+     (1885).
+
+     PALUDICELLIDES, Loppens, Ann. Biol. lacustre, iii, p. 170
+     (1908).
+
+     VICTORELLIDES, _id._, _ibid._ p. 171.
+
+_Zoarium._ The zoarium is recumbent or erect, and is formed typically
+either of zooecia arising directly in cruciform formation from one
+another, or of zooecia joined together in similar formation with the
+intervention of tubules arising from their own bases. Complications
+often arise, however, either on account of the suppression of the
+lateral buds of a zooecium, so that the formation becomes linear instead
+of cruciform, or by the production in an irregular manner of additional
+tubules and buds from the upper part of the zooecia. A confused and
+tangled zoarium may thus be formed, the true nature of which can only be
+recognized by the examination of its terminal parts.
+
+_Zooecia._ The zooecia are tubular and have a terminal or subterminal
+orifice, which is angulate or subangulate as seen from above. Owing to
+this fact, to the stiff nature of the external ectocyst, to the action
+of circular muscles that surround the tentacular sheath, and to the
+cylindrical form of the soft inverted part, the orifice, as seen from
+above, appears to form four flaps or valves, thus [illustration: sketch,
+similar to a cloverleaf inside a square with rounded corners].
+
+_Polypide._ The alimentary canal is elongate and slender as a whole, the
+oesophagus (including the pharynx) being of considerable length. In
+_Paludicella_ and _Pottsiella_ the oesophagus opens directly into the
+cardiac limb of the stomach, which is distinctly constricted at its
+base; but in _Victorella_ the base of the oesophagus is constricted off
+from the remainder to form an elongate oval sac the walls of which are
+lined with a delicate structureless membrane. _Victorella_ may therefore
+be said to possess a gizzard, but the structure that must be so
+designated has not the function (that of crushing food) commonly
+associated with the name, acting merely as a chamber for the retention
+of solid particles. In this genus the cardiac limb of the stomach is
+produced and vertical but not constricted at the base. The tentacles in
+most species number 8, but in _Paludicella_ there are 16.
+
+_Resting buds._ The peculiar structures known in Europe as "hibernacula"
+are only found in this family. The name hibernacula, however, is
+inappropriate to the only known Indian species as they are formed in
+this country at the approach of summer instead of, as in Europe and N.
+America, at that of winter. It is best, therefore, to call them "resting
+buds." They consist of masses of cells congregated at the base of the
+zooecia, gorged with food material and covered with a resistant horny
+covering.
+
+The family Paludicellid� consists of three genera which may be
+distinguished as follows:--
+
+   I. Orifice terminal; main axis of the zooecium
+      vertical; zooecia separated from one another
+      by tubules.
+    [A. Base of the zooecia not swollen; no
+        adventitious buds                          POTTSIELLA.]
+     B. Base of the zooecium swollen; adventitious
+        buds produced near the tip                 VICTORELLA, p. 194.
+  II. Orifice subterminal, distinctly on the dorsal
+      surface; main axis of the zooecium horizontal
+      (the zoarium being viewed from the dorsal
+      surface); buds not produced at the tip of the
+      zooecia                                      PALUDICELLA, p. 192.
+
+Of these three genera, _Pottsiella_ has not yet been found in India and
+is only known to occur in N. America. It consists of one species, _P.
+erecta_ (Potts) from the neighbourhood of Philadelphia in the United
+States.
+
+_Victorella_ includes four species, _V. pavida_ known from England and
+Germany and said to occur in Australia, _V. m�lleri_ from Germany
+(distinguished by possessing parietal muscles at the tip of the
+zooecia), _V. symbiotica_ from African lakes and _V. bengalensis_ from
+India. These species are closely related.
+
+_Paludicella_ is stated by Carter to have been found in Bombay, but
+probably what he really found was the young stage of _V. bengalensis_. A
+single species is known in Europe and N. America, namely _P.
+ehrenbergi_, van Beneden (=_Alcyonella articulata_, Ehrenberg).
+
+I have examined specimens of all the species of this family as yet
+known.
+
+
+Genus 1. PALUDICELLA, _Gervais_.
+
+     _Paludicella_, Gervais, Compt. Rend. iii, p. 797 (1836).
+
+     _Paludicella_, Allman, Mon. Fresh-Water Polyzoa, p. 113
+     (1857).
+
+     ? _Paludicella_, Carter, Ann. Nat. Hist. (3) iii, p. 333
+     (1859).
+
+     _Paludicella_, Jullien, Bull. Soc. zool. France, x, p. 174
+     (1885).
+
+     _Paludicella_, Kraepelin, Deutsch. S�sswasserbryozoen, i, p.
+     96 (1887).
+
+     _Paludicella_, Loppens, Ann. Biol. lacustre, iv, p. 14
+     (1910).
+
+_Zoarium._ The nature of the zoarium in this genus is well expressed by
+Ehrenberg's specific name "_articulata_," although the name was given
+under a false impression. The zooecia arise directly from one another in
+linear series with occasional side-branches. The side-branches are,
+however, often suppressed. The zoarium as a whole is either recumbent
+and adherent or at least partly vertical.
+
+_Zooecia._ Although the zooecia are distinctly tubular as a whole, two
+longitudinal axes may be distinguished in each, for the tip is bent
+upwards in a slanting direction, bearing the orifice at its extremity.
+The main axis is, however, at right angles to the dorso-ventral axis,
+and the dorsal surface, owing to the position of the aperture, can
+always be readily distinguished from the ventral, even when the position
+of the zooecium is vertical. Each zooecium tapers towards the posterior
+extremity. Parietal muscles are always present.
+
+[Illustration: Fig. 36.--Structure of _Paludicella ehrenbergi_ (A and B
+after Allman).
+
+A=a single zooecium with the polypide retracted. B=the base of the
+lophophore as seen from above with the tentacles removed. C=the orifice
+of a polypide with the collar expanded and the tentacles partly
+retracted. _a_=tentacles; _c_=collar; _d_=mouth; _e_=oesophagus;
+_f_=stomach; _g_=intestine; _k_=parieto-vaginal muscles; _p_=parietal
+muscles; _o_=cardiac part of the stomach; _r_=retractor muscle;
+_s_=funiculus.]
+
+_Polypide._ The most striking features of the polypide are the absence
+of any trace of a gizzard and the highly specialized form assumed by the
+cardiac part of the stomach. There are two funiculi, both connecting the
+pyloric part of the stomach with the endocyst. The ovary develops at the
+end of the upper, the testis at that of the lower funiculus.
+
+_Resting buds._ The resting buds are spindle-shaped.
+
+Kraepelin recognized two species in the genus mainly by their method of
+growth and the number of tentacles. In his _P. m�lleri_ the zoarium is
+always recumbent and the polypide has 8 tentacles, whereas in _P.
+articulata_ or _ehrenbergi_ the tentacles number 16 and upright branches
+are usually developed. It is probable, however, that the former species
+should be assigned to _Victorella_, for it is often difficult to
+distinguish _Paludicella_ from young specimens of _Victorella_ unless
+the latter bear adventitious terminal buds. The gizzard of _Victorella_
+can be detected in well-preserved material even under a fairly low power
+of the microscope, and I have examined specimens of what I believe to be
+the adult of _m�lleri_ which certainly belong to that genus.
+
+It is always difficult to see the collar of _Paludicella_, because of
+its transparency and because of the fact that its pleats are apparently
+not strengthened by chitinous rods as is usually the case. Allman
+neither mentions it in his description of the genus nor shows it in his
+figures, and Loppens denies its existence, but it is figured by
+Kraepelin and can always be detected in well-preserved specimens, if
+they are examined carefully. If the collar were actually absent, its
+absence would separate _Paludicella_ not only from _Victorella_ and
+_Pottsiella_, but also from all other ctenostomes. In any case,
+_Victorella_ is distinguished from _Paludicella_ and _Pottsiella_ by
+anatomical peculiarities (_e. g._, the possession of a gizzard and the
+absence of a second funiculus) that may ultimately be considered
+sufficiently great to justify its recognition as the type and only genus
+of a separate family or subfamily.
+
+The description of _Paludicella_ is included here on account of Carter's
+identification of the specimens he found at Bombay; but its occurrence
+in India is very doubtful.
+
+
+Genus 2. _VICTORELLA_, _Kent_.
+
+     _Victorella_, Kent, Q. J. Micr. Sci. x, p. 34 (1870).
+
+     _Victorella_, Hincks, Brit. Marine Polyzoa, p. 559 (1880).
+
+     _Victorella_, Kraepelin, Deutsch. S�sswasserbryozoen, i, p.
+     93 (1887).
+
+TYPE, _Victorella pavida_, Kent.
+
+_Zoarium._ The zoarium consists primarily of a number of erect or
+semi-erect tubular zooecia joined together at the base in a cruciform
+manner by slender tubules, but complications are introduced by the fact
+that adventitious buds and tubules are produced, often in large numbers,
+round the terminal region of the zooecia, and that these buds are often
+separated from their parent zooecium by a tubule of considerable length,
+and take root among other zooecia at a distance from their point of
+origin. A tangled mass may thus be formed in which it is difficult to
+recognize the regular arrangement of the zooecia that can be readily
+detached at the growing points of the zoarium.
+
+_Zooecia._ The zooecia when young closely resemble those of
+_Paludicella_, but as they grow the terminal upturned part increases
+rapidly, while the horizontal basal part remains almost stationary and
+finally appears as a mere swelling at the base of an almost vertical
+tube, in which by far the greater part, if not the whole, of the
+polypide is contained. Round the terminal part of this tube adventitious
+buds and tubules are arranged more or less regularly. There are no
+parietal muscles.
+
+_Polypide._ The polypide has 8 slender tentacles, which are thickly
+covered with short hairs. The basal part of the oesophagus forms a
+thin-walled sac (the "gizzard") constricted off from the upper portion
+and bearing internally a thin structureless membrane. Circular muscles
+exist in its wall but are not strongly developed on its upper part.
+There is a single funiculus, which connects the posterior end of the
+stomach with the base of the zooecium. The ovaries and testes are borne
+on the endocyst, not in connection with the funiculus.
+
+_Resting buds._ The resting buds are flattened or resemble young zooecia
+in external form.
+
+_Victorella_, although found in fresh water, occurs more commonly in
+brackish water and is known to exist in the littoral zone of the sea.
+
+
+26. Victorella bengalensis, _Annandale_.
+
+     _Victorella pavida_, Annandale (_nec_ Kent), Rec. Ind. Mus.
+     i, p. 200, figs. 1-4 (1907).
+
+     _Victorella bengalensis_, _id._, _ibid._ ii, p. 12, fig. 1
+     (1908).
+
+_Zoarium._ _The mature zoarium resembles a thick fur_, the hairs of
+which are represented by elongate, erect, slender tubules (the zooecia),
+the arrangement of the whole being very complicated and irregular. The
+base of the zoarium often consists of an irregular membrane formed of
+matted tubules, which are sometimes agglutinated together by a gummy
+secretion. The zoarium as a whole has a faint yellowish tinge.
+
+_Zooecia._ The zooecia when young are practically recumbent, each being
+of an ovoid form and having a stout, distinctly quadrate orificial
+tubule projecting upwards and slightly forwards near the anterior margin
+of the dorsal surface. At this stage a single tubule, often of great
+relative length, is often given off near the orifice, bearing a bud at
+its free extremity. As the zooecium grows the tubular part becomes much
+elongated as compared with the basal part and assumes a vertical
+position. Its quadrate form sometimes persists but more often
+disappears, so that it becomes almost circular in cross-section
+throughout its length. Buds are produced near the tip in considerable
+profusion. As a rule, if they appear at this stage, the tubule
+connecting them with the parent zooecium is short or obsolete; sometimes
+they are produced only on one side of the zooecium, sometimes on two.
+The buds themselves produce granddaughter and great-granddaughter buds,
+often connected together by short tubules, while still small and
+imperfectly developed. The swelling at the base of the zooecium, when
+the latter is fully formed, is small.
+
+_Polypide._ The polypide has the features characteristic of the genus.
+The base of the gizzard is surrounded by a strong circular muscle.
+
+[Illustration: Fig. 37.--_Victorella bengalensis_ (type specimens).
+
+A=single zooecium without adventitious buds but with a young resting bud
+(_b_), � 70 (dorsal view); B=lateral view of a smaller zooecium without
+buds, � 70; C=upper part of a zooecium with a single adventitious bud, �
+70; D=outline of the upper part of a zooecium with adventitious buds of
+several generations, � 35; E=remains of a zooecium with two resting buds
+(_b_) attached. All the specimens figured are from Port Canning and,
+except D, are represented as they appear when stained with borax carmine
+and mounted in canada balsam.]
+
+_Resting buds._ The resting buds (fig. 31, p. 170) are somewhat variable
+in shape but are always flat with irregular cylindrical or
+subcylindrical projections round the margin, on which the horny coat is
+thinner than it is on the upper surface. This surface is either smooth
+or longitudinally ridged.
+
+TYPE in the Indian Museum.
+
+This species differs from the European _V. pavida_ in very much the same
+way as, but to a greater extent than, the Indian race of _Bowerbankia
+caudata_ does from the typical English one (see p. 189). The growth of
+the zoarium is much more luxuriant, and the form of the resting buds is
+different.
+
+GEOGRAPHICAL DISTRIBUTION.--_V. bengalensis_ is abundant in pools of
+brackish water in the Ganges delta and in the Salt Lakes near Calcutta;
+it also occurs in ponds of fresh water near the latter. I have received
+specimens from Madras from Dr. J. R. Henderson, and it is probable that
+the form from Bombay referred by Carter to _Paludicella_ belonged to
+this species.
+
+BIOLOGY.--In the Ganges delta _V. bengalensis_ is usually found coating
+the roots and stems of a species of grass that grows in and near
+brackish water, and on sticks that have fallen into the water. It also
+spreads over the surface of bricks, and I have found a specimen on a
+living shell of the common mollusc _Melania tuberculata_. Dr. Henderson
+obtained specimens at Madras from the surface of a freshwater shrimp,
+_Pal�mon malcolmsonii_. In the ponds at Port Canning the zoaria grow
+side by side with, and even entangled with those of _Bowerbankia
+caudata_ subsp. _bengalensis_, to the zooecia of which their zooecia
+bear a very strong external resemblance so far as their distal extremity
+is concerned. This resemblance, however, disappears in the case of
+zooecia that bear terminal buds, for no such buds are borne by _B.
+caudata_; and the yellowish tint of the zoaria of _V. bengalensis_ is
+characteristic. Zoaria of the entoproct _Loxosomatoides colonialis_ and
+colonies of the hydroid _Irene ceylonensis_ are also found entangled
+with the zoaria of _V. bengalensis_, the zooecia of which are often
+covered with various species of Vorticellid protozoa and small rotifers.
+The growth of _V. bengalensis_ is more vigorous than that of the other
+polyzoa found with it, and patches of _B. caudata_ are frequently
+surrounded by large areas of _V. bengalensis_.
+
+The food of _V. bengalensis_ consists largely of diatoms, the siliceous
+shells of which often form the greater part of its excreta. Minute
+particles of silt are sometimes retained in the gizzard, being
+apparently swallowed by accident.
+
+There are still many points to be elucidated as regards the production
+and development of the resting buds in _V. bengalensis_, but two facts
+are now quite clear as regards them: firstly, that these buds are
+produced at the approach of the hot weather and germinate in November or
+December; and secondly, that the whole zoarium may be transformed at the
+former season into a layer of resting buds closely pressed together but
+sometimes exhibiting in their arrangement the typical cruciform
+formation. Resting buds may often be found in vigorous colonies as late
+as the beginning of December; these buds have not been recently formed
+but have persisted since the previous spring and have not yet
+germinated. Sometimes only one or two buds are formed at the base of an
+existing zooecium (fig. 37 _a_), but apparently it is possible not only
+for a zooecium to be transformed into a resting bud but for it to
+produce four other buds round its base before undergoing the change.
+Young polypides are formed inside the buds and a single zooecium sprouts
+out of each, as a rule by the growth of one of the basal projections,
+when conditions are favourable.
+
+Polypides of _V. bengalensis_ are often transformed into brown bodies.
+When this occurs the orifice closes together, with the collar expanded
+outside the zooecium. I have occasionally noticed that the ectocyst of
+such zooecia was distinctly thicker and darker in colour than that of
+normal zooecia.
+
+Eggs and spermatozoa are produced in great numbers, as a rule
+simultaneously in the same zooecia, but individuals kept in captivity
+often produce spermatozoa only. The eggs are small and are set free as
+eggs. Nothing is known as regards their development.
+
+Polypides are as a rule found in an active condition only in the cold
+weather, but I have on one occasion seen them in this condition in
+August, in a small zoarium attached to a shell of _Melania tuberculata_
+taken in a canal of brackish water near Calcutta.
+
+
+Family HISLOPIID�.
+
+     HISLOPID�ES, Jullien, Bull. Soc. zool. France, x, p. 180
+     (1885).
+
+     HISLOPIID�, Annandale, Rec. Ind. Mus. i, p. 200 (1907).
+
+_Zoarium_ recumbent, often forming an almost uniform layer on solid
+subjects.
+
+_Zooecia_ flattened, adherent; the orifice dorsal, either surrounded by
+a chitinous rim or situated at the tip of an erect chitinous tubule; no
+parietal muscles.
+
+_Polypide_ with an ample gizzard which possesses a uniform chitinous
+lining and does not close together when the polypide is retracted.
+
+_Resting bud_, not produced.
+
+Only two genera can be recognized in this family, _Arachnoidea_, Moore,
+from Central Africa, and _Hislopia_, Carter, which is widely distributed
+in Eastern Asia. The former genus possesses an upright orificial tubule
+and has zooecia separated by basal tubules. Its anatomy is imperfectly
+known, but it certainly possesses a gizzard of similar structure to that
+of _Hislopia_, between which and _Victorella_ its zooecium is
+intermediate in form.
+
+
+Genus HISLOPIA, _Carter_.
+
+     _Hislopia_, Carter, Ann. Nat. Hist. (3) i, p. 169 (1858).
+
+     _Hislopia_, Stolickza, J. As. Soc. Bengal, xxxviii (2), p.
+     61 (1869).
+
+     _Norodonia_, Jullien, Bull. Soc. zool. France, v, p. 77
+     (1880).
+
+     _Hislopia_, _id._, _ibid._ x, p. 183 (1885).
+
+     _Norodonia_, _id._, _ibid._ p. 180.
+
+     _Echinella_, Korotneff, Biol. Centrbl. xxi, p. 311 (1901).
+
+     _Hislopia_, Annandale, J. As. Soc. Bengal (new series) ii,
+     p. 59 (1906).
+
+     _Hislopia_, Loppens, Ann. Biol. lacustre, iii, p. 175
+     (1908).
+
+TYPE, _Hislopia lacustris_, Carter.
+
+_Zoarium._ The zoarium consists primarily of a main axis running in a
+straight line, with lateral branches that point forwards and outwards.
+Further proliferation, however, often compacts the structure into an
+almost uniform flat area.
+
+_Zooecia._ The zooecia (fig. 35 B, p. 190) are flat and have the orifice
+surrounded by a chitinous rim but not much raised above the dorsal
+surface. They arise directly one from another.
+
+_Polypide._ The polypide possesses from 12 to 20 tentacles. Its
+funiculus is rudimentary or absent. Neither the ovaries nor the testes
+have any fixed position on the lateral walls of the zooecium to which
+they are confined.
+
+The position of this genus has been misunderstood by several zoologists.
+Carter originally described _Hislopia_ as a cheilostome allied to
+_Flustra_; in 1880 Jullien perpetuated the error in describing his
+_Norodonia_, which was founded on dried specimens of Carter's genus;
+while Loppens in 1908 still regarded the two "genera" as distinct and
+placed them both among the cheilostomes. In 1885, however, Jullien
+retracted his statement that _Norodonia_ was a cheilostome and placed
+it, together with _Hislopia_, in a family of which he recognized the
+latter as the eponymic genus. Carter's mistake arose from the fact that
+he had only examined preserved specimens, in which the thickened rim of
+the orifice is strongly reminiscent of the "peristome" of certain
+cheilostomes, while the posterior of the four folds into which the
+tentacle sheath naturally falls (as in all ctenostomes, _cf._ the
+diagram on p. 191) is in certain conditions rather larger than the other
+three and suggests the "lip" characteristic of the cheilostomes. If
+living specimens are examined, however, it is seen at once that the
+posterior fold, like the two lateral folds and the anterior one, changes
+its form and size from time to time and has no real resemblance to a
+"lip."
+
+That there is a remarkable, if superficial, resemblance both as regards
+the form of the zooecium and as regards the method of growth between
+_Hislopia_ and certain cheilostomes cannot be denied, but the structure
+of the orifice and indeed of the whole organism is that of a ctenostome
+and the resemblance must be regarded as an instance of convergence
+rather than of genetic relationship.
+
+The most striking feature of the polypide of _Hislopia_ is its gizzard
+(fig. 38, p. 201) which is perhaps unique (except for that of
+_Arachnoidea_) both in structure and function. In structure its
+peculiarities reside mainly in three particulars: (i), it is not
+constricted off directly from the thin-walled oesophageal tube, but
+possesses at its upper extremity a thick-walled tubular portion which
+can be entirely closed from the oesophagus at its upper end but always
+remains in communication with the spherical part of the gizzard; (ii),
+this spherical part of the gizzard is uniformly lined with a thick
+chitinous or horny layer which in optical section has the appearance of
+a pair of ridges; and (iii), there is a ring of long and very powerful
+cilia round the passage from the gizzard to the stomach. The cardiac
+limb of the stomach, which is large and heart-shaped, is obsolete. The
+wall of the spherical part of the gizzard consists of two layers of
+cells, an outer muscular layer consisting of powerful circular muscles
+and an inner glandular layer, which secretes the chitinous lining. The
+inner walls of the tubular part consist of non-ciliated columnar cells,
+and when the polypide is retracted it lies almost at right angles to the
+main axis of the zooecium.
+
+The spherical part of the gizzard invariably contains a number of green
+cells, which lie free in the liquid it holds and are kept in motion by
+the cilia at its lower aperture. The majority of these cells can be seen
+with the aid of a high power of the microscope to consist of a hard
+spherical coat or cyst containing green protoplasm in which a spherical
+mass of denser substance (the nucleus) and a number of minute
+transparent granules can sometimes be detected. The external surface of
+many of the cysts is covered with similar granules, but some are quite
+clean.
+
+There can be no doubt that these cysts represent a stage in the
+life-history of some minute unicellular plant or animal. Indeed,
+although it has not yet been found possible to work out this
+life-history in detail, I have been able to obtain much evidence that
+they are the resting stage of a flagellate organism allied to _Euglena_
+which is swallowed by the polyzoon and becomes encysted in its gizzard,
+extruding in so doing from its external surface a large proportion of
+the food-material that it has stored up within itself in the form of
+transparent granules. It may also be stated that some of the organisms
+die and disintegrate on being received into the gizzard, instead of
+encysting themselves.
+
+So long as the gizzard retains its spherical form the green cells and
+its other contents are prevented from entering the stomach by the
+movements of the cilia that surround its lower aperture, but every now
+and then, at irregular intervals, the muscles that form its outer wall
+contract. The chitinous lining although resilient and not inflexible is
+too stiff to prevent the lumen of the gizzard being obliterated, but the
+action of the muscles changes its contents from a spherical to an ovoid
+form and in so doing presses a considerable part of them down into the
+stomach, through the ring of the cilia.
+
+[Illustration: Fig. 38.--Optical section of gizzard of _Hislopia
+lacustris_, with contained green cysts, � 240.]
+
+The contraction of the gizzard is momentary, and on its re-expansion
+some of the green cysts that have entered the stomach are often
+regurgitated into it. Some, however, remain in the stomach, in which
+they are turned round and round by the action of the cilia at both
+apertures. They are apparently able to retain their form for some hours
+in these circumstances but finally disintegrate and disappear, being
+doubtless digested by the juices poured out upon them by the glandular
+lining of the stomach. In polypides kept under observation in clean
+tap-water all the cysts finally disappear, and the f�ces assume a green
+colour. In preserved specimens apparently unaltered cysts are sometimes
+found in the rectum, but this is exceptional: I have observed nothing of
+the kind in living polypides. Cysts often remain for several days
+unaltered in the gizzard.
+
+Imperfect as these observations are, they throw considerable light on
+the functions of the gizzard in _Hislopia_. Primarily it appears to act
+as a food-reservoir in which the green cysts and other minute organisms
+can be kept until they are required for digestion. When in the gizzard
+certain organisms surrender a large proportion of the food-material
+stored up for their own uses, and this food-material doubtless aids in
+nourishing the polyzoon. Although the cysts in the gizzard are
+frequently accompanied by diatoms, the latter are not invariably
+present. The cysts, moreover, are to be found in the zooecia of
+polypides that have formed brown bodies, often being actually enclosed
+in the substance of the brown body. The gizzards of the specimens of
+_Arachnoidea_ I have examined contain cysts that resemble those found in
+the same position in _Hislopia_.
+
+_Hislopia_ is widely distributed in the southern part of the Oriental
+Region, and, if I am right in regarding _Echinella_, Korotneff as a
+synonym, extends its range northwards to Lake Baikal. It appears to be a
+highly specialized form but is perhaps related, through _Arachnoidea_,
+to _Victorella_.
+
+
+27. Hislopia lacustris, _Carter_.
+
+     _Hislopia lacustris_, Carter, Ann. Nat. Hist. (3) i, p. 170,
+     pl. vii, figs. 1-3 (1858).
+
+     _Norodonia cambodgiensis_, Jullien, Bull. Soc. zool. France,
+     v, p. 77, figs. 1-3 (1880).
+
+     _Norodonia sinensis_, _id._, _ibid._ p. 78, figs. 1-3.
+
+     _Norodonia cambodgiensis_, _id._, _ibid._ x, p. 181, figs.
+     244, 245 (1885).
+
+     _Norodonia sinensis_, _id._, _ibid._ p. 182, figs. 246, 247.
+
+     _Hislopia lacustris_, Annandale, J. As. Soc. Bengal (new
+     series) iii, p. 85 (1907).
+
+     _Hislopia lacustris_, Walton, Rec. Ind. Mus. i, p. 177
+     (1907).
+
+     _Hislopia lacustris_, Kirkpatrick, _ibid._ ii, p. 98 (1908).
+
+     _Hislopia lacustris_, Walton, _ibid._ iii, p. 295 (1909).
+
+_Zoarium._ The zoarium forms a flat, more or less solid layer and is
+closely adherent to foreign objects. As a rule it covers a considerable
+area, with radiating branches at the edges; but when growing on slender
+twigs or the stems of water-plants it forms narrow, closely compressed
+masses. One zooecium, however, never grows over another.
+
+_Zooecia._ The zooecia are variable in shape. In zoaria which have space
+for free expansion they are as a rule irregularly oval, the posterior
+extremity being often narrower than the anterior; but small triangular
+zooecia and others that are almost square may often be found. When
+growing on a support of limited area the zooecia are smaller and as a
+rule more elongate. The orifice is situated on a slight eminence nearer
+the anterior than the posterior margin of the dorsal surface. It is
+surrounded by a strong chitinous rim, which is usually square or
+subquadrate but not infrequently circular or subcircular. Sometimes a
+prominent spine is borne at each corner of the rim, but these spines are
+often vestigial or absent; they are rarely as long as the transverse
+diameter of the orifice. The zooecium is usually surrounded by a
+chitinous margin, and outside this margin there is often a greater or
+less extent of adherent membrane. In some zooecia the margin is obsolete
+or obsolescent. The dorsal surface is of a glassy transparency but by no
+means soft.
+
+[Illustration: Fig. 39.--_Hislopia lacustris._
+
+A=part of a zoarium of the subspecies _moniliformis_ (type specimen,
+from Calcutta), � 15; A=green cysts in gizzard; E=eggs.
+
+B=outline of part of a zoarium of the typical form of the species from
+the United Provinces, showing variation in the form of the zooecia and
+of the orifice, � 15.]
+
+_Polypide._ The polypide has from 12 to 20 tentacles, 16 being a common
+number.
+
+TYPE probably not in existence. It is not in the British Museum and
+Prof. Dendy, who has been kind enough to examine the specimens from
+Carter's collection now in his possession, tells me that there are none
+of _Hislopia_ among them.
+
+
+27 _a._ Subsp. moniliformis, nov.
+
+     _Hislopia lacustris_, Annandale, J. As. Soc. Bengal (new
+     series) ii, p. 59, fig. 1 (1906).
+
+In this race, which is common in Calcutta, the zooecia are almost
+circular but truncate or concave anteriorly and posteriorly. They form
+linear series with few lateral branches. I have found specimens
+occasionally on the shell of _Vivipara bengalensis_, but they are much
+more common on the leaves of _Vallisneria spiralis_.
+
+TYPE in the Indian Museum.
+
+The exact status of the forms described by Jullien as _Norodonia
+cambodgiensis_ and _N. sinensis_ is doubtful, but I see no reason to
+regard them as specifically distinct from _H. lacustris_, Carter, of
+which they may be provisionally regarded as varieties. The variety
+_cambodgiensis_ is very like my subspecies _moniliformis_ but has the
+zooecia constricted posteriorly, while var. _sinensis_, although the
+types were found on _Anodonta_ shells on which there was plenty of room
+for growth, resemble the confined phase of _H. lacustris_ so far as the
+form of their zooecia and of the orifice is concerned.
+
+GEOGRAPHICAL DISTRIBUTION.--The typical form is common in northern India
+and occurs also in Lower Burma; the subspecies _moniliformis_ appears to
+be confined to Lower Bengal, while the varieties _cambodgiensis_ and
+_sinensis_ both occur in China, the former having been found also in
+Cambodia and Siam. Indian and Burmese localities are:--BENGAL, Calcutta
+(subsp. _moniliformis_); Berhampur, Murshidabad district (_J. Robertson
+Milne_): CENTRAL PROVINCES, Nagpur (_Carter_): UNITED PROVINCES,
+Bulandshahr (_H. J. Walton_): BURMA, Pegu-Sittang Canal (_Kirkpatrick_).
+
+BIOLOGY.--Regarding the typical form of the species Major Walton writes
+(Rec. Ind. Mus. iii, p. 296):--"In volume i (page 177) of the Records of
+the Indian Museum, I described the two forms of colonies of _Hislopia_
+that I had found in the United Provinces (Bulandshahr). Of these, one
+was a more or less linear arrangement of the zooecia on leaves and
+twigs, and the other, and more common, form was an encrusting sheath on
+the outer surface of the shells of _Paludina_. During the present
+'rains' (July 1908) I have found many examples of what may be considered
+a much exaggerated extension of the latter form. These colonies have
+been on bricks, tiles, and other submerged objects. The largest colony
+that I have seen so far was on a tile; one side of the tile was exposed
+above the mud of the bottom of the tank, and its area measured about 120
+square inches; the entire surface was almost completely covered by a
+continuous growth of _Hislopia_. Another large colony was on a piece of
+bark which measured 7 inches by 3 inches; both sides were practically
+everywhere covered by _Hislopia_."
+
+Major Walton also notes that in the United Provinces the growth of
+_Hislopia_ is at its maximum during "rains," and that at that time of
+year almost every adult _Paludina_ in a certain tank at Bulandshahr had
+its shell covered with the zooecia. The Calcutta race flourishes all the
+year round but never forms large or closely compacted zoaria, those on
+shells of _Vivipara_ exactly resembling those on leaves of
+_Vallisneria_.
+
+In Calcutta both eggs and spermatozoa are produced at all times of the
+year simultaneously in the same zooecia, but the eggs in one zooecium
+often vary greatly in size. When mature they reach relatively
+considerable dimensions and contain a large amount of food material; but
+they are set free from the zooecium as eggs. They lie loose in the
+zooecium at a comparatively small size and grow in this position.
+Nothing is known as regards the development of _Hislopia_.
+
+Both forms of the species appear to be confined to water that is free
+from all traces of contamination with brine.
+
+
+Order PHYLACTOL�MATA.
+
+The polypide in this order possesses a leaf-like ciliated organ (the
+epistome) which arises within the lophophore between the mouth and the
+anus and projects upwards and forwards over the mouth, which it can be
+used to close. The zooecia are never distinct from one another, but in
+dendritic forms such as _Plumatella_ the zoarium is divided at irregular
+intervals by chitinous partitions. The lophophore in most genera is
+horseshoe-shaped instead of circular, the part opposite the anus being
+deeply indented. There are no parietal muscles. The orifice of the
+zooecium is always circular, and there is no trace of any structure
+corresponding to the collar of the ctenostomes. The tentacles are always
+webbed at the base.
+
+All the phylactol�mata produce the peculiar reproductive bodies known as
+statoblasts.
+
+The phylactol�mata, which are probably descended from ctenostomatous
+ancestors, are confined to fresh or slightly brackish water. Most of the
+genera have a wide geographical distribution, but (with the exception of
+a few statoblasts of almost recent date) only one fossil form
+(_Plumatellites_, Fric. from the chalk of Bohemia) has been referred to
+the order, and that with some doubt.
+
+It is convenient to recognize two main divisions of the phylactol�mata,
+but these divisions hardly merit the distinction of being regarded as
+suborders. They may be called Cristatellina and Plumatellina and
+distinguished as follows:--
+
+Division I, PLUMATELLINA, nov.--Ectocyst well developed; zoaria without
+a special organ of progression; polypides contained in tubes.
+
+Division II, CRISTATELLINA, nov.--Ectocyst absent except at the base of
+the zoarium which is modified to form a creeping "sole"; polypides
+embedded in a common synoecium of reticulate structure.
+
+The Cristatellina consist of a single genus and probably of a single
+species (_Cristatella mucedo_, Cuvier), which is widely distributed in
+Europe and N. America, but has not been found in the Oriental Region.
+Eight genera of Plumatellina are known, and five (possibly six) of these
+genera occur in India.
+
+
+Division PLUMATELLINA, nov.
+
+The structure of the species included in this division is very uniform
+as regards the internal organs (see fig. 40 opposite and fig. 47 _a_, p.
+236). The alimentary canal is simpler than that of the Paludicellid�. A
+short oesophagus leads directly into the stomach, the cardiac portion of
+which is produced as a vertical limb almost cylindrical in form and not
+constricted at the base. This limb is as a rule of greater length than
+the oesophagus. The pyloric part of the stomach is elongated and narrow,
+and the intestine short, straight, and of ovoid form. There are no cilia
+at the pyloric opening. A single funiculus joins the posterior end of
+the stomach to the wall of the zooecium, bearing the statoblasts. Sexual
+organs are often absent.
+
+[Illustration: Fig. 40.--Structure of the Plumatellina (after Allman).
+
+A=a zooecium of _Fredericella_ with the polypide extruded. B=the
+lophophore of _Lophopus_ (tentacles removed) as seen obliquely from the
+right side. C=larva of _Plumatella_ as seen in optical section.
+_a_=tentacles; _b_=velum; _c_=epistome; _d_=mouth; _e_=oesophagus;
+_f_=stomach; _g_=intestine; _h_=anus; _j_=retractor muscle;
+_k_=parieto-vaginal muscles; _l_=funiculus.]
+
+Two families may be recognized as constituting the division, _viz._,
+(_a_) the Fredericellid�, which have a circular or oval lophophore and
+simple statoblast without a swim-ring, and (_b_) the Plumatellid�, in
+which the lophophore is shaped like a horseshoe and some or all of the
+statoblasts are provided with a ring of air-spaces.
+
+
+Family 1. FREDERICELLID�.
+
+     FREDERICELLID�, Kraepelin, Deutsch. S�sswasserbryozoen, i,
+     p. 168 (1887).
+
+_Zoaria_ dendritic; _zooecia_ distinctly tubular, with the ectocyst well
+developed; _statoblasts_ of one kind only, each surrounded by a
+chitinous ring devoid of air-spaces; _polypides_ with the lophophore
+circular or oval when expanded.
+
+The Fredericellid� consist of a single genus (_Fredericella_) which
+includes several closely-allied forms and has a wide geographical
+distribution.
+
+
+Genus FREDERICELLA, _Gervais_ (1838).
+
+     _Fredericella_, Allman, Mon. Fresh-Water Polyzoa, p. 11
+     (1857).
+
+     _Plumatella_, ("arr�t de d�veloppement") Jullien, Bull. Soc.
+     zool. France, x, p. 121 (1885).
+
+       _Fredericella_, Kraepelin, Deutsch. S�sswasserbryozoen,
+     i, p. 99 (1887).
+
+     _Fredericella_, Goddard, Proc. Linn. Soc. N. S. Wales,
+     xxxiv, p. 489 (1909).
+
+This genus has the characters of the family. Its status has been much
+disputed, some authors regarding the shape of the lophophore as of great
+morphological importance, while Jullien believed that _Fredericella_ was
+merely an abnormal or monstrous form of _Plumatella_. The latter belief
+was doubtless due to the fact that the zoaria of the two genera bear a
+very close external resemblance to one another and are sometimes found
+entangled together. The importance of the shape of the lophophore may,
+however, easily be exaggerated, for, as both Jullien and Goddard have
+pointed out, it assumes an emarginate form when retracted.
+
+The best known species is the European and N. American _F. sultana_
+(Blumenbach), of which several varieties or phases have been described
+as distinct. This form is stated to occur also in S. Africa. _F.
+australiensis_, Goddard[BC] from N. S. Wales is said to differ from this
+species in having an oval instead of a circular lophophore and in other
+small anatomical characters; but it is doubtful how far these characters
+are valid, for the lophophore appears to be capable of changing its
+shape to some slight extent and has been stated by Jullien to be
+habitually oval in specimens from France. _F. cunningtoni_,
+Rousselet[BD] from Lake Tanganyika has stout zooecia encrusted with
+relatively large sand-grains.
+
+     [Footnote BC: Proc. Linn. Soc. N. S. Wales, xxxiv, p. 489
+     (1909).]
+
+     [Footnote BD: Rousselet, Proc. Zool. Soc. London, 1907 (1),
+     p. 254.]
+
+The zoaria of _Fredericella_ are usually found attached to solid objects
+in shallow water, but a form described as _F. duplessisi_, Ford has been
+found at a depth of 40 fathoms embedded in mud at the bottom of the Lake
+of Geneva. _F. cunningtoni_ was dredged from depths of about 10 and
+about 25 fathoms.
+
+The statoblasts of this genus do not float and often germinate in the
+parent zooecium after its polypides have died. They are produced in
+smaller numbers than is usually the case in other genera of the order.
+The polypides sometimes undergo a process of regeneration, but without
+the formation of brown bodies.
+
+[Illustration: Fig. 41.--_Fredericella indica._
+
+A=statoblast, � 120. B=outline of expanded lophophore and adjacent
+parts, � 75; a=anus, r=rectum. C=outline of zoarium on leaf of
+water-plant, � 3.
+
+(A and B are from specimens from Igatpuri, C from specimen from
+Shasthancottah).]
+
+
+28. Fredericella indica, _Annandale_.
+
+     _Fredericella indica_, Annandale, Rec. Ind. Mus. iii, p. 373,
+     fig. (1909).
+
+     _Fredericella indica_, _id._, _ibid._ v, p. 39 (1910).
+
+_Zoarium._ The zoarium is of delicate appearance and branches sparingly.
+It is often entirely recumbent but sometimes produces short, lax
+branches that consist of two or three zooecia only.
+
+_Zooecia._ The zooecia are very slender and almost cylindrical; they are
+slightly emarginate and furrowed, the keel in which the furrow runs
+being sometimes prominent. The external surface is minutely roughened
+and apparently soft, for small grains of sand and other d�bris cling to
+it, but never thickly. The ectocyst is practically colourless but not
+transparent.
+
+_Statoblasts._ The statoblasts are variable in size and form but most
+commonly have a regular broad oval outline; sometimes they are
+kidney-shaped. The dorsal surface is covered with minute star-shaped
+prominences, which sometimes cover it almost uniformly and are sometimes
+more numerous in the centre than towards the periphery. The ventral
+surface is smooth.
+
+_Polypide._ The lophophore bears about 20-25 tentacles, which are very
+slender and of moderate length; the velum at their base is narrow; as a
+rule the lophophore is accurately circular.
+
+TYPE in the Indian Museum.
+
+The most definite character in which this species differs from _F.
+sultana_ and _F. australiensis_ is the ornamentation of one surface of
+the statoblast, both surfaces of which are smooth in the two latter
+species. From _F. cunningtoni_, the statoblasts of which are unknown, it
+differs in having almost cylindrical instead of depressed zooecia and in
+not having the zooecia densely covered with sand-grains.
+
+GEOGRAPHICAL DISTRIBUTION.--Western India (the Malabar Zone): Igatpuri
+Lake, W. Ghats (alt. ca. 2,000 feet), Bombay Presidency, and
+Shasthancottah Lake near Quilon, Travancore.
+
+BIOLOGY.--In both the lakes in which the species has yet been found it
+was collected in November. The specimens obtained in Travancore were
+found to be undergoing a process of regeneration due at least partly to
+the fact that most of the polypides had perished and that statoblasts
+were germinating in the old zooecia. Specimens from the Bombay
+Presidency, which were obtained a little later in the month, were in a
+more vigorous condition, although even they contained many young
+polypides that were not yet fully formed. It seems, therefore, not
+improbable that _F. indica_ dies down at the beginning of the hot
+weather and is regenerated by the germination of its statoblasts at the
+beginning of the cold weather.
+
+At Shasthancottah zoaria were found entangled with zoaria of a delicate
+form of _Plumatella fruticosa_ to which they bore a very close external
+resemblance.
+
+
+Family 2. PLUMATELLID�.
+
+     PLUMATELLID�, Allman (_partim_), Mon. Fresh-Water Polyzoa,
+     pp. 76, 81 (1857).
+
+Phylactol�mata which have horseshoe-shaped lophophores and a
+well-developed ectocyst not specialized to form an organ of progression.
+Some or all of the statoblasts are provided with a "swim-ring"
+consisting of symmetrically disposed, polygonal chitinous chambers
+containing air.
+
+It is convenient to divide the Plumatellid� as thus defined into
+subfamilies (the Plumatellin� and the Lophopin�), which may be defined
+as follows:--
+
+
+Subfamily A. PLUMATELLIN�.
+
+Zoarium dendritic or linear, firmly fixed to extraneous objects; zooecia
+tubular, not fused together to form a gelatinous mass.
+
+
+Subfamily B. LOPHOPIN�.
+
+Zoarium forming a gelatinous mass in which the tubular nature of the
+zooecia almost disappears, capable to a limited extent of progression
+along a smooth surface.
+
+Both these subfamilies are represented in the Indian fauna, the
+Plumatellin� by two of the three genera known to exist, and the
+Lophopin� by two (or possibly three) of the four that have been
+described. The following key includes all the known genera, but the
+names of those that have not been recorded from India are enclosed in
+square brackets.
+
+
+_Key to the Genera of_ Plumatellid�.
+
+  I.  Statoblasts without marginal processes.
+    A. Zooecia cylindrical, not embedded in a gelatinous
+       investment (Plumatellin�).
+      _a_.  Zooecia arising directly from one another;
+            no stolon; free statoblast oval          PLUMATELLA, p. 212.
+      _a'_. Zooecia arising singly or in groups from
+            an adherent stolon; free statoblasts oval. STOLELLA, p. 229.
+    B. Zooecia cylindrical, embedded in a structureless
+       gelatinous investment.
+       Zooecia arising from a ramifying stolon;
+       statoblasts circular                               [STEPHANELLA.]
+    C. Polypides embedded in a hyaline synoecium
+       that conceals the cylindrical form of the
+       zooecia (Lophopin�).
+      _c_.  Polypides upright, their base far removed
+            from that of the zoarium when they are
+            expanded                                   LOPHOPUS, p. 231.
+      _c'_. Polypides recumbent for the greater
+            part of their length at the base of
+            the zoarium                               [AUSTRALELLA[BE].]
+  II. Statoblasts armed (normally) with hooked
+      processes (Lophopin�).
+     A. Processes confined to the extremities of
+        the statoblast; zoaria remaining separate
+        throughout life                            LOPHOPODELLA, p. 231.
+     B. Processes entirely surrounding the
+        statoblast; many zoaria embedded in a
+        common gelatinous investment so as to
+        form large compound colonies               PECTINATELLA, p. 235.
+
+     [Footnote BE: See Rec. Ind. Mus. v, p. 40, footnote (1910).]
+
+
+Subfamily A. PLUMATELLIN�.
+
+Of the two Indian genera of this subfamily, one (_Plumatella_) is almost
+universally distributed, while the other (_Stolella_) has only been
+found in the valley of the Ganges. The third genus of the subfamily
+(_Stephanella_) is only known from Japan.
+
+It should be noted that zoaria of different species and genera of this
+subfamily are often found in close proximity to one another and to
+zoaria of _Fredericella_, and that the branches of the different species
+are sometimes entangled together in such a way that they appear, unless
+carefully separated, to belong to the same zoarium.
+
+
+Genus 1. PLUMATELLA, _Lamarck_.
+
+     _Plumatella_, Lamarck, Animaux sans Vert. (ed. 1re) ii, p.
+     106 (1816).
+
+     _Alcyonella_, _id_., _ibid_. p. 100.
+
+     _Plumatella_, Allman, Mon. Fresh-Water Polyzoa, p. 92
+     (1857).
+
+     _Alcyonella_, _id_., _ibid_. p. 86.
+
+     _Plumatella_, Hyatt, Comm. Essex Inst. iv, p. 207, pl. viii
+     (1866).
+
+     _Plumatella_, Jullien (_partim_), Bull. Soc. zool. France,
+     x, p. 100 (1885).
+
+     _Hyalinella_, _id_., _ibid_. p. 133.
+
+     _Plumatella_, Kraepelin, Deutsch. S�sswass. Bryozoen, i, p.
+     104 (1887).
+
+     _Plumatella_, Braem, Unter. �. Bryozoen des s�ssen Wassers,
+     p. 2 (Bibliotheca Zoologica, ii, 1890).
+
+_Zoarium_ dendritic, recumbent, erect, or partly recumbent and partly
+erect.
+
+_Zooecia_ tubular, not confined in a gelatinous synoecium; the ectocyst
+usually horny.
+
+_Statoblasts_ often of two kinds, free and stationary, the latter
+without air-cells and as a rule adherent by one surface, the former
+provided with a well-developed ring of air-cells but without marginal
+processes, oval in form, never more than about 0.6 mm. in length.
+
+_Polypide_ with less than 65 tentacles.
+
+[Illustration: Fig. 42.--Outlines of free statoblasts of _Plumatella_
+(enlarged).
+
+A, of _P. fruticosa_ (Calcutta); B, of _P. emarginata_ (Calcutta); C, of
+_P. javanica_ (Travancore); D, of _P. diffusa_ (Sikhim); E, of _P.
+allmani_ (Bhim Tal); F, of _P. diffusa_ (Rajshahi, Bengal); G, G', of
+_P. punctata_ (Calcutta); H, of _P. diffusa_ (Sikhim), statoblast
+further enlarged: A=outline of capsule; B=limit of swim-ring on
+ventral surface; C=limit of swim-ring on dorsal surface. [The dark
+area represents the capsule of the statoblast.]]
+
+Certain forms of this genus are liable to become compacted together in
+such a way as to constitute solid masses consisting of elongate vertical
+zooecia closely parallel to one another and sometimes agglutinated by
+means of a gummy substance. These forms were given by Lamarck in 1816
+the name _Alcyonella_, and there has been much dispute as to whether
+they represent a distinct genus, distinct species, or merely varieties
+or phases of more typical forms. It appears to be the case that all
+species which produce vertical branches are liable to have these
+branches closely packed together and the individual zooecia of which
+they are composed more or less greatly elongated. It is in this way that
+the form known to Allman as _Alcyonella benedeni_ is produced from the
+typical _Plumatella emarginata_. Other forms go further and secrete a
+gummy substance that glues the upright zooecia together and forces them
+to elongate themselves without branching. In these conditions the
+zooecia become polygonal in cross-section. It is probable that such
+forms (_e. g._, _Plumatella fungosa_ (Pallas)) should rank as distinct
+species, for the gummy secretion is present in great profusion even in
+young zoaria in which the zooecia have not yet assumed a vertical
+position. No such form, however, has as yet been found in India, and in
+any case it is impossible to regard _Alcyonella_ as a distinct genus.
+
+
+  _Key to the Indian Species of_ Plumatella.
+
+   I.  Ectocyst more or less stiff, capable of
+       transverse wrinkling only near the tips of
+       the zooecia, never contractile or greatly
+       swollen; zooecia rounded[BF] at the tip when
+       the polypide is retracted. Free statoblasts
+       elongate; the free portion of their swim-ring
+       distinctly narrower at the sides than at
+       the ends.
+      A. Ectocyst by no means rigid, of a uniform
+         pale colour; zooecia never emarginate or
+         furrowed, straight, curved or sinuous,
+         elongate, cylindrical                      _fruticosa_, p. 217.
+      B. Ectocyst rigid; zooecia (or at any rate
+         some of the zooecia) emarginate and furrowed.
+       _b_.   Ectocyst darkly pigmented over the
+              greater part of each zooecium, white
+              at the tip; branching of the zoarium
+              practically dichotomous, profuse, as
+              a rule both horizontal and vertical;
+              zooecia straight or slightly curved
+              or sinuous                           _emarginata_, p. 220.
+       _b'_.  Ectocyst colourless and hyaline;
+              branching of the zoarium sparse,
+              lateral, irregular, horizontal;
+              zooecia nearly straight, strongly
+              emarginate and furrowed                _javanica_, p. 221.
+       _b''_. The majority of the zooecia distinctly
+              L-shaped, one limb being as a rule
+              adherent; ectocyst never densely
+              pigmented.
+          beta.  Zooecia cylindrical, their furrowed
+                 keel never prominent                 _diffusa_, p. 223.
+          beta'. Zooecia (or at any rate some of the
+                 zooecia) constricted or tapering at
+                 the base, their emargination and
+                 furrow conspicuous                   _allmani_, p. 224.
+
+   II. Ectocyst stiff; zooecia truncated when the
+       polypide is retracted. Surface of zooecia
+       minutely roughened, distinctly annulate on
+       the distal part                             _tanganyik�_, p. 225.
+  III. Ectocyst swollen and contractile, capable
+       of transverse wrinkling all over the
+       zooecium; zooecia never emarginate            _punctata_, p. 227.
+
+     [Footnote BF: In specimens preserved in spirit they are apt
+     to collapse and therefore to become somewhat concave.]
+
+There has always been much difficulty in separating the species of
+_Plumatella_, and even now there is no general consensus of opinion as
+to the number that should be recognized. The difficulty, however, is
+much reduced if the following precautions are observed:--
+
+     (1) If the zoarium appears to be tangled, if the branches
+     intertwine or overlap, or if the zooecia are closely pressed
+     together, the whole mass should be carefully dissected out.
+     This is necessary not only because zoaria belonging to
+     different species are sometimes found entangled together but
+     also because it is often difficult to recognize the
+     characteristic method of branching and shape of the zooecia
+     unless it is done.
+
+     (2) As large a part as possible of each zoarium should be
+     examined, preferably with a binocular microscope, and
+     allowance should be made for irregularities and
+     abnormalities of all kinds. What must be observed is the
+     rule rather than the exceptions.
+
+     (3) When the statoblasts are being examined, care must be
+     taken that they lie flat and that their surface is parallel
+     to that of the nose-piece of the microscope. If they are
+     viewed obliquely it is impossible to see their true outlines
+     and proportions.
+
+     (4) In order to see the relative proportions of the capsule
+     and the swim-ring it is necessary that the statoblast should
+     be rendered transparent. This is often difficult owing to
+     the presence of air in the air-cells, but strong nitric acid
+     applied judiciously will render it possible (p. 240).
+
+In supervising the preparation of the plates that illustrate this genus
+I have impressed upon the artist the importance of representing what he
+saw rather than what he thought he ought to see, and the figures are
+very close copies of actual specimens. I have deliberately chosen for
+representation specimens of _Plumatella_ preserved by the simple methods
+which are often the only ones that it is possible for a traveller to
+adopt, for the great majority of naturalists will probably have no
+opportunity of examining living specimens or specimens preserved by
+special methods, and the main object, I take it, of this series is to
+enable naturalists first to distinguish the species described and then
+to learn something of their habitat and habits.
+
+GEOGRAPHICAL DISTRIBUTION.--Of the seven species included in this key
+five have been found in Europe (namely _P. fruticosa_, _P. emarginata_,
+_P. diffusa_, _P. allmani_, and _P. punctata_), while of these five all
+but _P. allmani_ are known to occur in N. America also. _P. javanica_ is
+apparently peculiar to the Oriental Region, while _P. tanganyik�_ has
+only been taken in Central Africa and in the Bombay Presidency.
+
+TYPES.--Very few of the type-specimens of the older species of
+_Plumatella_ are in existence. Allman's are neither in Edinburgh nor in
+London, and Mr. E. Leonard Gill, who has been kind enough to go through
+the Hancock Collection at Newcastle-on-Tyne, tells me that he cannot
+trace Hancock's. Those of the forms described by Kraepelin are in
+Hamburg and that of _P. tanganyik�_ in the British Museum, and there are
+schizotypes or paratypes of this species and of _P. javanica_ in
+Calcutta. The types of Leidy's species were at one time in the
+collection of the Philadelphia Academy of Science.
+
+BIOLOGY.--The zoaria of the species of _Plumatella_ are found firmly
+attached to stones, bricks, logs of wood, sticks, floating seeds, the
+stems and roots of water-plants, and occasionally to the shells of
+molluscs such as _Vivipara_ and _Unio_. Some species shun the light, but
+all are apparently confined to shallow water.
+
+Various small oligoch�te worms (e. g., _Ch�togaster spongill�_,[BG]
+_Nais obtusa_, _Nais elinguis_, _Slavina appendiculata_ and _Pristina
+longiseta_[BH]), take shelter amongst them; dipterous larv� of the genus
+_Chironomus_ often build their protective tubes at the base of the
+zoaria, and the surface of the zooecia commonly bears a more or less
+profuse growth of such protozoa as _Vorticella_ and _Epistylis_. I have
+seen a worm of the genus _Ch�togaster_ devouring the tentacles of a
+polypide that had been accidentally injured, but as a rule the movements
+of the lophophore are too quick to permit attacks of the kind, and I
+know of no active enemy of the genus. The growth of sponges at the base
+of the zoaria probably chokes some species, but one form (_F.
+fruticosa_) is able to surmount this difficulty by elongating its
+zooecia (p. 219). A small worm (_Aulophorus tonkinensis_) which is
+common in ponds in Burma and the east of India as far west as Lucknow,
+often builds the tube in which it lives mainly of the free statoblasts
+of this genus. It apparently makes no selection in so doing but merely
+gathers the commonest and lightest objects it can find, for small seeds
+and minute fragments of wood as well as sponge gemmules and statoblasts
+of other genera are also collected by it. I know of no better way of
+obtaining a general idea as to what sponges and phylactol�mata are
+present in a pond than to examine the tubes of _Aulophorus tonkinensis_.
+
+     [Footnote BG: Annandale, J. As. Soc. Bengal (n. s.) ii, p.
+     188, pl. i (1906).]
+
+     [Footnote BH: See Michaelsen, Mem. Ind. Mus. i, pp. 131-135
+     (1908).]
+
+I am indebted to Mr. F. H. Gravely, Assistant Superintendent in the
+Indian Museum, for an interesting note regarding the food of
+_Plumatella_. His observations, which were made in Northamptonshire,
+were unfortunately interrupted at a critical moment, but I have
+reproduced them with his consent in order that other observers may
+investigate the phenomena he saw. Mr. Gravely noted that a small green
+flagellate which was abundant in water in which _Plumatella repens_ was
+growing luxuriantly, was swallowed by the polypides, and that if the
+polyparium was kept in a shallow dish of water, living flagellata of the
+same species congregated in a little pile under the anus of each
+polypide. His preparations show very clearly that the flagellates were
+passing through the alimentary canal without apparent change, but the
+method of preservation does not permit the retractile granules, which
+were present in large numbers in the cell-substance of the flagellates,
+to be displayed and it is possible that these granules had disappeared
+from those flagellates which are present in the recta of his specimens.
+It is clear, therefore, either that certain flagellates must pass
+through the alimentary canal of _Plumatella_ unchanged, or that the
+polyzoon must have the power of absorbing the stored food material the
+flagellates contain without doing them any other injury.
+
+The free statoblasts of _Plumatella_ are as a rule set free before the
+cells they contain become differentiated, and float on the surface of
+the water for some time before they germinate; but occasionally a small
+polypide is formed inside the capsule while it is still in its parent
+zooecium. I have, however, seen only one instance of this premature
+development, in a single statoblast contained in a small zoarium of _P.
+fruticosa_ found in Lower Burma in March. The fixed statoblasts usually
+remain fixed to the support of the zoarium, even when their
+parent-zooecium decays, and germinate _in situ_.
+
+The larva (fig. 40 C, p. 207) that originates from the egg of
+_Plumatella_ is a minute pear-shaped, bladder-like body covered
+externally with fine vibratile threads (cilia) and having a pore at the
+narrow end. At the period at which it is set free from the parent
+zooecium it already contains a fully formed polypide or pair of
+polypides with the tentacles directed towards the narrow end. After a
+brief period of active life, during which it moves through the water by
+means of its cilia, it settles down on its broad end, which becomes
+adhesive; the polypide or pair of polypides is everted through the pore
+at the narrow end, the whole of this end is turned inside out, and a
+fresh polyparium is rapidly formed by budding.
+
+
+29. Plumatella fruticosa, _Allman_. (Plate III, fig. 1; plate IV, fig.
+4; plate V, fig. 1.)
+
+     _Plumatella fruticosa_, Allman, Ann. Nat. Hist. xiii, p. 331
+     (1844).
+
+     _Plumatella repens_, van Beneden (? _nec_ Linn�), M�m. Acad.
+     Roy. Belg. 1847, p. 21, pl. i, figs. 1-4.
+
+     _Plumatella fruticosa_, Johnston, Brit. Zooph. (ed. 2), p.
+     404 (1847).
+
+     _Plumatella coralloides_, Allman, Rep. Brit. Assoc. 1850, p.
+     335.
+
+     _Plumatella stricta_, _id._, Mon. Fresh-Water Polyzoa, p.
+     99, fig. 14 (1857).
+
+     _Plumatella fruticosa_, _id._, _ibid._ p. 102, pl. vi, figs.
+     3-5.
+
+     _Plumatella coralloides_, _id._, _ibid._ p. 103, pl. vii,
+     figs. 1-4.
+
+     _Plumatella repens_ and _P. stricta_, Carter, Ann. Nat.
+     Hist. (3) iii, p. 341 (1859).
+
+     _Plumatella lucifuga_, Jullien (_partim_), Bull. Soc. zool.
+     France, x, p. 114 (1885).
+
+     _Plumatella princeps_ var. _fruticosa_, Kraepelin, Deutsch.
+     S�sswasserbryozoen, i, p. 120, pl. vii, fig. 148 (1887).
+
+     _Plumatella fruticosa_, Braem, Unter. ii. Bryozoen des
+     s�ssen Wassers, p. 9, pl. i, fig. 15 (Bibl. Zool. ii)
+     (1890).
+
+     _Plumatella repens_, Annandale, J. As. Soc. Bengal (new
+     series) iii, 1907, p. 88.
+
+     _Plumatella emarginata_, Loppens (_partim_), Ann. Biol.
+     lacustre, iii, p. 161 (1908).
+
+     _Plumatella fruticosa_, Annandale, Rec. Ind. Mus. v, p. 45
+     (1910).
+
+_Zoarium._ The zoarium in the typical form has a loose appearance due to
+the fact that the branches are far apart and the ectocyst by no means
+rigid. When young the zoarium is adherent, but in well-grown polyparia
+vertical branches, often an inch or more in length, are freely produced.
+As a rule they have not the strength to stand upright if removed from
+the water. Branching is ordinarily lateral and as a rule occurs chiefly
+on one side of a main branch or trunk. In certain circumstances upright
+zooecia are pressed together and reach a great length without branching,
+and in this form (_P. coralloides_, Allman) daughter-zooecia are often
+produced at the tip of an elongated mother-zooecium in fan-like
+formation. A depauperated form (_P. stricta_, Allman), occurs in which
+the vertical branches are absent or very short. In all forms internal
+partitions are numerous and stout.
+
+_Zooecia._ The zooecia are cylindrical and bear a simple keel on their
+dorsal surface. They are never emarginate or furrowed. In the typical
+form their diameter is more than half a millimetre, and they are always
+of considerable length. The ectocyst is thin and never very rigid or
+deeply pigmented, the colour usually being an almost uniform pale
+pinkish brown and fading little towards the tip of the zooecium.
+
+_Statoblasts._ Both free and stationary statoblasts are formed, but the
+latter are rare and do not always adhere. They resemble the free
+statoblasts in general form but have a solid margin instead of a
+swim-ring and are often minutely serrated round the edge. The free
+statoblasts are at least considerably, sometimes very elongate; in all
+zoaria it is possible to find specimens that are more than twice as long
+as broad. The capsule is relatively large and resembles the swim-ring in
+outline, so that the free portion of the latter is not much narrower at
+the sides than at the ends. The sides are distinctly convex and the ends
+rounded; the swim-ring encroaches little on the surface of the capsule.
+
+_Polypide._ The tentacles number between 40 and 50 and are not festooned
+at the base. The stomach is slender and elongate.
+
+TYPE not in existence.
+
+SYSTEMATIC REMARKS.--_P. fruticosa_ is closely allied to _P. repens_
+(European and N. American) but always has much longer statoblasts. Three
+phases of the species may be distinguished as follows:--
+
+     A. (_Forma typica_). Zooecia stout in form, not greatly
+     elongate; free branches produced in profusion.
+
+     B. (_P. stricta_, Allman, _P. repens_, van Beneden). Zooecia
+     slender; free branches absent or consisting of two or three
+     zooecia only.
+
+     C. (_P. coralloides_, Allman). Vertical zooecia pressed
+     together and greatly elongated.
+
+Indian specimens of the typical form agree well with German specimens
+labelled by Prof. Kraepelin _P. princeps_ var. _fruticosa_, and
+specimens of the _coralloides_ phase could hardly be distinguished from
+similar specimens from Scotland.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. fruticosa_ is widely distributed in
+Europe and probably in N. America. I have seen Indian specimens from the
+Punjab (Lahore, _Stephenson_), from Bombay, from Travancore, from
+Calcutta and other places in the Ganges delta, from Rajshahi (Rampur
+Bhoolia) on the R. Ganges, from Kurseong in the E. Himalayas (alt. 4,500
+feet), and from Kawkareik in Tenasserim. Statoblasts found on the
+surface of a pond near Simla in the W. Himalayas (alt. _ca._ 8,000
+feet), probably belong to this species.
+
+BIOLOGY.--Allman states that in England _P. fruticosa_ is fond of still
+and slowly-running water. The typical form and the _coralloides_ phase
+grow abundantly in the Calcutta tanks, the former often attaining an
+extraordinary luxuriance. I have found the var. _stricta_ only in water
+in which there was reason to suspect a lack of minute life (and
+therefore of food), viz. in Shasthancottah Lake in Travancore, in a
+swamp in Lower Burma, and in a small jungle stream near the base of the
+Western Ghats in Travancore. The species is the only one that I have
+seen in running water in India, and the specimens obtained in the jungle
+stream in Travancore are the only specimens I have taken in these
+circumstances. _P. fruticosa_ always grows near the surface or near the
+edge of water; it is found attached to the stems of bulrushes and other
+aquatic plants, to floating seeds and logs and (rarely) to stones and
+bricks. So far as my experience goes it is only found, at any rate in
+Calcutta, in the cold weather and does not make its appearance earlier
+than October.
+
+The form Allman called _P. coralloides_ was found by him, "attached to
+floating logs of wood, together with _P. repens_ and _Cordylophora
+lacustris_, and generally immersed in masses of _Spongilla
+fluviatilis_." I have always found it immersed in sponges (_S.
+lacustris_, _S. alba_, _S. carteri_, and _S. crassissima_), except when
+the sponge in which it had been immersed had decayed. Indeed, the
+peculiar form it has assumed appears to be directly due to the pressure
+of the growing sponge exerted on the zooecia, for it is often possible
+to find a zoarium that has been partially overgrown by a sponge and has
+retained its typical form so long as it was free but has assumed the
+_coralloides_ form where immersed.[BI] In Shasthancottah Lake,
+Travancore, I found specimens of the _stricta_ phase embedded in the
+gelatinous mass formed by a social rotifer and to some extent
+assimilated to the _coralloides_ form.
+
+     [Footnote BI: Braem (_op. cit._, p. 3, pl. i, fig. 1), has
+     described and figured under the name _P. fungosa_ var.
+     _coralloides_, Allman, a dense form that somewhat resembles
+     this phase of _P. fruticosa_ but has become compacted
+     without external pressure. It is, however, probably a form
+     of _P. repens_ rather than _P. fungosa_ and differs in its
+     broad statoblasts from any form of _P. fruticosa_. I have
+     examined specimens of the same form from England.]
+
+
+30. Plumatella emarginata, _Allman_. (Plate III, fig. 2; plate IV, figs.
+1, 1 _a._)
+
+     _Plumatella emarginata_, Allman, Ann. Nat. Hist. xiii, p.
+     330 (1844).
+
+     _Plumatella emarginata_, Johnston, Brit. Zooph. (ed. 2), p.
+     404 (1847).
+
+     _Alcyonella benedeni_, Allman, Mon. Fresh-Water Polyzoa, p.
+     89, pl. iv, figs. 5-11 (1857).
+
+     _Plumatella emarginata_, _id._, _ibid._ p. 104, pl. vii,
+     figs. 5-10.
+
+     _Plumatella lucifuga_, Jullien, Bull. Soc. zool. France, x,
+     figs. 89, 90, p. 114 (1885).
+
+     _Plumatella princeps_ var. _emarginata_, Kraepelin
+     (_partim_), Deutsch. S�sswasserbryoz. p. 120, pl. iv, fig.
+     108, pl. v, fig. 123 (1887).
+
+     _Plumatella emarginata_, Braem, Unter. ii. Bryoz. s�ssen
+     Wassers, p. 9, pl. i, figs. 12, 14 (Bibl. Zool. ii) (1890).
+
+     _Plumatella emarginata_, Annandale (_partim_), J. As. Soc.
+     Bengal, (new series) iii, 1907, p. 89.
+
+     _Plumatella princeps_, Loppens (_partim_), Ann. Biol.
+     lacustre, iii, p. 162, fig. 7 (1908).
+
+     _Plumatella emarginata_, Annandale, Rec. Ind. Mus. v, p. 47
+     (1910).
+
+_Zoarium._ The zoarium often covers a considerable area on flat surfaces
+and is sometimes entirely recumbent. More usually, however, the younger
+part is vertical. In either case the branching is practically
+dichotomous, two young zooecia arising almost simultaneously at the tip
+of a mother-zooecium and diverging from one another at a small angle.
+When the zoarium becomes vertical, rigid branches of as much as an inch
+in length are sometimes produced in this way and, arising parallel to
+one another, are pressed together to form an almost solid mass
+(=_Alcyonella benedeni_, Allman). In such cases the basal zooecium or at
+any rate the basal part of each upright branch is considerably
+elongated. In recumbent zooecia the main branches often radiate outwards
+from a common centre.
+
+_Zooecia._ The zooecia are of almost equal width throughout, slender,
+and moderately elongate when recumbent. Their ectocyst is stiff; they
+are emarginate at the tip and more or less distinctly furrowed on the
+dorsal surface, the keel in which the furrow runs not being prominent.
+The orifice is often on the dorsal surface even in upright branches.
+Each zooecium is of a dark brown or almost black colour for the greater
+part of its length but has a conspicuous white tip which is extended
+down the dorsal surface in the form of a triangle, its limits being
+rather more extensive than and parallel to those of the emargination.
+
+_Statoblast._ The majority of the free statoblasts are elongate and
+truncate or subtruncate at the extremities, the sides being as a rule
+straight and parallel. In every polyparium specimens will be found that
+are between twice and thrice as long as broad. The capsule is, however,
+relatively much broader than the swim-ring, often being nearly circular,
+and there is therefore at either end a considerable extent of free
+air-cells, while the extent of these cells at the sides of the capsule
+is small. The air-cells cover a considerable part of the dorsal surface
+of the capsule. Fixed statoblasts are usually found in old colonies,
+especially at the approach of the hot weather. They have an oval form
+and are surrounded by a membranous margin on which traces of
+reticulation can often be detected. As a rule statoblasts of both types
+are produced in considerable but not in excessive numbers.
+
+_Polypide._ There are about 40 tentacles, the velum at the base of which
+extends upwards for a considerable distance without being festooned. The
+stomach is elongate and slender and narrowly rounded at the base.
+
+The method of branching, the coloration of the zooecia and the form of
+the free statoblast are all characteristic. Luxuriant or closely
+compressed zoaria of _P. diffusa_ often bear a superficial resemblance
+to those of _P. emarginata_, but the resemblance disappears if they are
+carefully dissected out. Indian specimens of _P. emarginata_ agree
+closely with European ones.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. emarginata_ is a common species in
+Europe, N. America, and southern Asia and probably also occurs in Africa
+and Australia. I have examined specimens from Calcutta, Rangoon, and
+Mandalay in Indian territory, and also from Jalor in the Patani States
+(Malay Peninsula) and the Tal� Noi, Lakon Sitamarat, Lower Siam.
+Gemmules found by Apstein (Zool. Jahrb. (Syst.) xxv, 1907, p. 201) in
+plankton from the Colombo lake may belong to this species or to any of
+the others included by Kraepelin in his _P. princeps_.
+
+BIOLOGY.--In Ireland Allan found _P. emarginata_ in streams and
+rivulets, but it also occurs in European lakes. In India I have only
+found it in ponds. It prefers to adhere to the surface of stones or
+bricks, but when these are not available is found on the stems of
+water-plants. In the latter position the form called _Alcyonella
+benedeni_ by Allman is usually produced, owing to the fact that the
+upright branches are crowded together through lack of space, very much
+in the same way (although owing to a different cause) as those of _P.
+fruticosa_ are crowded together in the _coralloides_ phase, to which the
+_benedeni_ phase of _P. emarginata_ is in many respects analogous.
+
+Although it is essentially a cold-weather species in Calcutta, _P.
+emarginata_ is sometimes found in a living condition during the "rains."
+Zoaria examined at this season, however, contains few living polypides,
+the majority of the zooecia having rotted away and left fixed
+statoblasts only to mark their former position.
+
+
+31. Plumatella javanica, _Kraepelin_.
+
+     _Plumatella javanica_, Kraepelin, Mitt. Nat. Mus. Hamb.
+     xxiii, p. 143, figs. 1-3 (1903).
+
+     _Plumatella emarginata_ var. _javanica_, Loppens, Ann. Biol.
+     lacustre, iii, p. 162 (1908).
+
+     _Plumatella javanica_, Annandale, Rec. Ind. Mus. v, p. 50
+     (1910).
+
+     _Plumatella allmani_ var. _dumortieri_, _id._ (_partim_)
+     (_nec_ Allman), _ibid._ p. 49.
+
+This species is related to _P. emarginata_, from which it may be
+distinguished by the following characters:--
+
+_Zoarium._ The zoarium is always entirely recumbent and branches
+sparingly; its method of branching does not approach the dichotomous
+type but is lateral and irregular. Linear series of zooecia without
+lateral branches are often formed.
+
+_Zooecia._ The zooecia are slender and often very long; they are
+strongly emarginate and furrowed, and the keel that contains the furrow
+is conspicuous. The ectocyst is hyaline and as a rule absolutely
+colourless.
+
+_Statoblasts._ The free statoblasts are variable in length, sometimes
+distinctly elongate, sometimes elongate only to a moderate degree; they
+are rounded at the extremities and have the sides slightly or distinctly
+convex outwards. The capsule is relatively large, and the free portion
+of the swim-ring is not much broader at the ends than at the sides. The
+fixed statoblasts are elongate and surrounded by an irregularly shaped
+chitinous membrane, which is often of considerable extent. The whole of
+the dorsal surface is covered with what appear to be rudimentary
+air-spaces some of which even contain air.
+
+The transparent glassy ectocyst and strong furrowed keel of this species
+are very characteristic, but the former character is apt to be obscured
+by staining due to external causes, especially when the zoarium is
+attached to dead wood. The shape of the free statoblasts is too variable
+to be regarded as a good diagnostic character, but the fixed
+statoblasts, when they are to be found, are very characteristic in
+appearance. _P. javanica_ appears to be closely related to Allman's _P.
+dumortieri_, with which stained zoaria are apt to be confused. The
+character of the ectocyst is, however, different, and the free part of
+the swim-ring is distinctly narrower at the sides of the free
+statoblasts. Dr. Kraepelin has been kind enough to send me one of the
+types.
+
+TYPES in the Hamburg and Indian Museums.
+
+GEOGRAPHICAL DISTRIBUTION.--Java, Penang, India. Indian localities
+are:--BENGAL, Calcutta; Berhampore, Murshidabad; R. Jharai, Siripur,
+Saran district, Tirhut: E. HIMALAYAS, Kurseong, Darjiling district (alt.
+4,500 feet): MADRAS PRESIDENCY, canal near Srayikaad, Travancore. Mr. C.
+W. Beebe has recently sent me a specimen taken by him in the Botanical
+Gardens at Penang.
+
+BIOLOGY.--Very little is known about the biology of this species.
+Kraepelin took it in Java on the leaves of water-lilies. It is not
+uncommon during the cold weather in the Calcutta Zoological Gardens on
+floating seeds and sticks and on the stems of bulrushes; in Travancore I
+took it in November on the submerged leaves of _Pandani_ growing at the
+edge of a canal of slightly brackish water. Mr. Hodgart, the collector
+of the Indian Museum, found it in the R. Jharai on the stems of
+water-plants at a time of flood in the "rains." In Calcutta it is often
+found entangled with _P. fruticosa_ and _P. emarginata_.
+
+
+32. Plumatella diffusa, _Leidy_. (Plate IV, fig. 2.)
+
+     _Plumatella diffusa_, Leidy, P. Ac. Philad. v, p. 261
+     (1852).
+
+     _Plumatella diffusa_, Allman, Mon. Fresh-Water Polyzoa, p.
+     105 (1857).
+
+     _Plumatella diffusa_, Hyatt, Comm. Essex Inst. iv, pl. viii,
+     figs. 11, 12 (1866).
+
+     _Plumatella diffusa_, _id._, _ibid._ v, p. 107, fig. 12
+     (1868).
+
+     _Plumatella repens_, Jullien, Bull. Soc. zool. France, x,
+     fig. 37 (_lapsus_ for 73), p. 110 (1885).
+
+     _Plumatella diffusa_, _id._, _ibid._ figs. 155, 157, pp.
+     130, 131.
+
+     _Plumatella allmani_ var. _diffusa_, Annandale, Rec. Ind.
+     Mus. v, p. 49 (1910).
+
+_Zoarium._ The zoarium often covers a considerable area on flat surfaces
+and is sometimes found crowded together on the stems of plants. In the
+latter case the arrangement of the main branches is distinctly radiate.
+Upright branches occur rarely and never consist of more than three
+zooecia. The characteristic method of branching is best represented by
+the following diagram:--
+
+[Illustration: Fig. 43.]
+
+The partitions are stout and numerous.
+
+_Zooecia._ The great majority of the zooecia in each zoarium are
+distinctly L-shaped, the long limb being usually adherent. The vital
+organs of the polypide are contained in the vertical limb, while the
+horizontal one, in mature polyparia, is packed full of free statoblasts.
+The zooecia are cylindrical and as a rule obscurely emarginate and
+furrowed. The ectocyst is stiff; it is never deeply pigmented but is
+usually of a transparent horn-colour at the base of each zooecium and
+colourless at the tip, the contrast between the two portions never being
+very strong. The basal portion is rough on the surface, the distal
+portion smooth.
+
+_Statoblasts._ Free statoblasts are produced in very great profusion and
+fixed statoblasts are also to be found as a rule. The latter resemble
+those of _P. emarginata_. The free statoblasts are never very large or
+relatively broad, but they vary considerably as regards size and
+outline. The capsule is large, the sides convex outwards and the
+extremity more or less broadly rounded. The air-cells are unusually
+large and extend over a great part of the dorsal surface of the
+statoblast.
+
+_Polypide._ The polypide is shorter and stouter than that of _P.
+emarginata_ and as a rule has fewer tentacles.
+
+The most characteristic feature of this species is the form of the
+zooecia, which differ greatly from those of any other Indian species but
+_P. allmani_. In the latter they are distinctly "keg-shaped" (_i. e._,
+constricted at the base and swollen in the middle), and the zoarium
+never spreads out over large surfaces in the way in which that of _P.
+diffusa_ does.
+
+TYPE--? in the Philadelphia Academy of Sciences.
+
+GEOGRAPHICAL DISTRIBUTION.--This species was originally described from
+North America (in which it is apparently common) and occurs also in
+Europe. I have seen Indian specimens from the following
+localities:--BENGAL, Calcutta and neighbourhood; Rajshahi (Rampur
+Bhulia): E. HIMALAYAS, Gangtok, Native Sikhim (alt. 6,150 feet)
+(_Kirkpatrick_, _Stewart_): PUNJAB, Lahore (_Stephenson_).
+
+BIOLOGY.--_P. diffusa_ in Lower Bengal is a cold-weather species. It is
+remarkable for the enormous number of gemmules it produces and is
+usually found either on floating objects such as the stems of certain
+water-plants, or on stones or bricks at the edge of ponds.
+
+
+33. Plumatella allmani, _Hancock_. (Plate IV, figs. 3, 3 _a_.)
+
+     _Plumatella allmani_, Hancock, Ann. Nat. Hist. (2) v, p.
+     200, pl. v, fig. 3-4, pl. iii, fig. 2-3 (1850).
+
+     _Plumatella allmani_, Allman, Mon. Fresh-Water Polyzoa, p.
+     106, fig. 16 (1857).
+
+     _Plumatella elegans_, _id._, _ibid._ p. 107, pl. viii, figs.
+     6-10.
+
+     _Plumatella lucifuga_ ("forme rampante") Jullien, Bull. Soc.
+     zool. France, x, p. 114 (1885).
+
+This species is closely allied to _P. diffusa_, from which it differs in
+the following characters:--
+
+     (1) The zoarium never covers a large area and as a rule
+     grows sparingly and mainly in two directions.
+
+     (2) The zooecia are more irregular in shape, not so
+     distinctly elbowed, smaller; they have a much more
+     prominently keeled ridge. The great majority of them are
+     constricted at the base and taper towards the orifice. In
+     young zoaria they are almost colourless but in older ones
+     there is a band of not very dense pigment round the base of
+     the vertical limb.
+
+     (3) The free statoblasts are comparatively large and usually
+     show a tendency to taper at the extremities, often being
+     almost rhomboidal in form. The swim-ring does not extend so
+     far over the dorsal surface as it does in those of _P.
+     diffusa_; the "cells" of which it is composed are small.
+
+TYPE not in existence.
+
+I have seen every gradation between this form and Allman's _P. elegans_.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. allmani_ is apparently a rare species to
+which there are few references in literature. It was originally
+described from England and is stated by Jullien to occur in France. I
+have found specimens only in the lake Bhim Tal (alt. 4,500 feet) in the
+W. Himalayas.
+
+BIOLOGY.--The original specimens were found by Hancock on stones. My own
+were growing on the leaves of water-plants, usually on the under side.
+When the zooecia were forced to stretch across from one leaflet to
+another they assumed the sinuous form characteristic of Allman's _P.
+elegans_.
+
+
+34. Plumatella tanganyik�, _Rousselet_.
+
+     _Plumatella tanganyik�_, Rousselet, Proc. Zool. Soc. London,
+     1907 (i), p. 252, pl. xiv, figs. 1-4.
+
+     _Plumatella bombayensis_, Annandale, Rec. Ind. Mus. ii, p.
+     169, figs. 1, 2 (1908).
+
+     _Plumatella bombayensis_, _id._, _ibid._ v, p. 51 (1910).
+
+_Zoarium._ The whole colony is recumbent but branches freely and at
+short intervals in a horizontal plane, so that the zooecia become
+crowded together and the branches sometimes overlap one another. The
+zoarium often covers a considerable area, but growth seems to be mainly
+in two directions. When growing on the stems of water-plants the
+branches are often parallel and closely pressed together but remain
+recumbent in this position. A stout membrane sometimes extends between
+branches and individual zooecia.
+
+_Zooecia._ The walls of the zooecia are thick, stiff, and more or less
+darkly but not opaquely pigmented; the external surface, although not
+very smooth, is always clean. The two most noteworthy characters of the
+zooecia are (i) their truncated appearance when the polypide is
+retracted, and (ii) the conspicuous, although often irregular external
+annulation of their walls. The tip of each zooecium, owing to the fact
+that the invaginated part of the ectocyst is soft and sharply separated
+from the stiffened wall of the tube, terminates abruptly and is not
+rounded off gradually as is the case in most species of the genus;
+sometimes it expands into a trumpet-like mouth. The annulation of the
+external surface is due to numerous thickened areas of the ectocyst
+which take the form of slender rings surrounding the zooecium; they are
+most conspicuous on its distal half. On the dorsal surface of the base
+of each zooecium there is a conspicuous furrowed keel, which, however,
+does not usually extend to the distal end; the latter is oval in
+cross-section. The zooecia are short and broad; their base is always
+recumbent, and, when the zoarium is attached to a stone or shell, often
+seems to be actually embedded in the support; the distal part turns
+upwards and is free, so that the aperture is terminal; the zooecia of
+the older parts of the zoarium exhibit the specific characters much more
+clearly than those at the growing points.
+
+_Polypide._ The lophophore bears 20 to 30 tentacles, which are long and
+slender; the velum at their base extends up each tentacle in the form of
+a sharply pointed projection, but these projections do not extend for
+more than one-fifth of the length of the tentacles. Both the velum and
+the tentacular sheath bear numerous minute tubercles on the external
+surface. The base of the stomach is rounded, and the whole of the
+alimentary canal has a stout appearance.
+
+[Illustration: Fig. 44.--_Plumatella tanganyik�_ from Igatpuri Lake.
+
+A=outline of part of zoarium from a stone, � 16; B=outline of the tip of
+a single zooecium, � 70; C=free statoblast, � 70.]
+
+_Statoblasts._ Both fixed and free statoblasts are produced, but not in
+very large numbers. The latter are broadly oval and are surrounded by a
+stout chitinous ring, which often possesses irregular membranous
+projections; the surface is smooth. The free statoblasts are small and
+moderately elongate, the maximum breadth as a rule measuring about 2/3
+of the length; the capsule is relatively large and the ring of air-cells
+is not very much broader at the ends than at the sides; the dorsal
+surface of the central capsule is profusely tuberculate. The outline of
+the whole structure is often somewhat irregular.
+
+In deference to Mr. Rousselet's opinion expressed in a letter I have
+hitherto regarded the Bombay form of this species as distinct from the
+African one, and there certainly is a great difference in the appearance
+of specimens taken on the lower surface of stones in Igatpuri Lake and
+of the types of _P. tanganyik�_, one of which is now in the collection
+of the Indian Museum. The dark colour of the former, however, and their
+vigorous growth appear to be directly due to environment, for these
+characters disappear to a large extent in specimens growing on the stems
+of water-plants in the same lake. Indeed, such specimens are exactly
+intermediate between the form "_bombayensis_" and the typical form of
+the species. _P. tanganyik�_ is closely allied to _P. philippinensis_,
+Kraepelin, from the island of Luzon, but the latter has a smooth and
+polished ectocyst devoid of annulations, and zooecia of a more elongate
+and regular form.
+
+TYPES of the species in the British and Indian Museums, those of _P.
+bombayensis_ in the latter collection.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. tanganyik�_ is only known as yet from L.
+Tanganyika in Central Africa and from Igatpuri in the Bombay Presidency.
+
+BIOLOGY.--In both localities the zoaria were found in shallow water. In
+L. Tanganyika they were encrusting stones and shells, while at Igatpuri
+they were fixed for the most part to the lower surface of stones but
+were also found on the stems of water-plants. My specimens from the
+Bombay Presidency were taken, on two separate occasions, at the end of
+November. At that date the zoaria were already decaying and large
+blanks, marked out by fixed statoblasts, were often observed on the
+stones. Probably, therefore, the species flourishes during the "rains."
+
+
+35. Plumatella punctata, _Hancock_. (Plate IV, fig. 5.)
+
+    _Plumatella punctata_, Hancock, Ann. Nat. Hist. (2) v, p. 200, pl. iii,
+    fig. 1, and pl. v, figs. 6, 7 (1850).
+
+    _Plumatella vesicularis_, Leidy, P. Ac. Philad. vii, p. 192 (1854).
+
+    _Plumatella vitrea_, Hyatt, Comm. Essex Inst. iv, pl. ix, figs. 1, 2
+    (1866).
+
+    _Plumatella punctata_, Allman, Mon. Fresh-Water Polyzoa, p. 100,
+    fig. 15 (1857).
+
+    _Plumatella vesicularis_, _id._, _ibid._ p. 101.
+
+     _Plumatella vitrea_, Hyatt, Proc. Essex Inst. v, p. 225,
+     figs. 18, 19 (1868).
+
+     _Plumatella vesicularis_, _id._, _ibid._ p. 225.
+
+     _Hyalinella vesicularis_, Jullien, Bull. Soc. zool. France,
+     x, p. 133, figs. 165-172 (1885).
+
+     _Hyalinella vitrea_, _id._, _ibid._ p. 134, figs. 173-179.
+
+     _Plumatella punctata_, Kraepelin, Deutsch.
+     S�sswasserbryozoen, i, p. 126, pl. iv, figs. 115, 116; pl.
+     v, figs. 124, 125; pl. vii, figs. 153, 154 (1887).
+
+     _Plumatella vesicularis_, Braem, Unters. �. Bryozoen s�ssen
+     Wassers, p. 8, pl. i, fig. 8 (Bibl. Zool. ii) (1890).
+
+     _Hyalinella punctata_, Loppens, Ann. Biol. lacustre, iii, p.
+     163 (1908).
+
+     _Plumatella punctata_, Annandale, Rec. Ind. Mus. v, p. 52
+     (1910).
+
+_Zoarium._ The zoarium is entirely recumbent and often appears to form
+an almost uniform flat layer instead of a dendritic body. Sometimes,
+however, it is distinctly linear, with lateral branches produced
+irregularly at considerable distances apart.
+
+_Zooecia._ The zooecia differ from those of all other species in having
+a greatly swollen, soft ectocyst which can be transversely wrinkled all
+over the zooecium by the action of the muscles of the polypide and is
+distinctly contractile. It is mainly owing to the swollen and almost
+gelatinous nature of the ectocyst that the dendritic character of the
+zoarium is frequently concealed, for the method of branching is
+essentially the same as that of _P. diffusa_, although the zooecia are
+not so distinctly elbowed. The ectocyst is colourless or faintly tinted
+with brown; as a rule it is not quite hyaline and the external surface
+is minutely roughened or tuberculate. The zooecia are not emarginate or
+furrowed.
+
+_Statoblasts._ Stationary statoblasts are not found.  The free
+statoblasts are variable and often asymmetrical in outline, but the free
+portion of the swim-ring is always of nearly equal diameter all round
+the periphery and the capsule relatively large. Some of the statoblasts
+are always broad in comparison with their length.
+
+_Polypide._ The polypide is comparatively short and stout. European
+specimens are said to have from 30 to 40 tentacles, but Indian specimens
+have only from 20 to 30.
+
+Shrunken specimens of the less congested forms of this species closely
+resemble specimens of _P. repens_, but the statoblasts are more variable
+in shape and the ectocyst, even in such specimens, is thicker. Living or
+well-preserved specimens cannot be mistaken for those of any other
+species. Jullien regarded _P. punctata_ as the type of a distinct genus
+(_Hyalinella_) but included in _Plumatella_ at least one form (P.
+"_arethusa_") which probably belongs to this species. Kraepelin
+distinguishes as "varieties" two phases, a summer phase ("var.
+_prostrata_") and an autumn phase ("var. _densa_"). The former often
+forms linear series of considerable length with only an occasional
+side-branch, while in the autumn phase branching is so profuse and the
+branches are so closely pressed together that the zoarium comes to
+resemble a uniform gelatinous patch rather than a dendritic growth. A
+phase resembling the European autumn form is the commonest in Calcutta
+and I have also found one intermediate between this and Kraepelin's
+"var. _prostrata_," neither having any seasonal significance in India.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. punctata_ is widely distributed in
+Europe and N. America, but in the Oriental Region it has only been found
+in Calcutta and the neighbourhood.
+
+BIOLOGY.--In this part of India _P. punctata_ flourishes both during the
+"rains" and in winter. I have found specimens in June and July and also
+in December and January. The majority of them were attached to bricks,
+but some were on the roots of duckweed, the stems of water-plants, and
+the tips of creepers falling into water. The species is often found
+together with _Stolella indica_ and also with other species of its own
+genus. It is most common, in the neighbourhood of Calcutta, in that part
+of the town which is near the Salt Lakes, and occurs in ponds the water
+of which is slightly brackish.
+
+
+Genus 2. STOLELLA, _Annandale_.
+
+    _Stolella_, Annandale, Rec. Ind. Mus. iii, p. 279 (1909).
+
+    _Stolella_, _id._, _ibid._ v, p. 53 (1910).
+
+TYPE, _Stolella indica_, Annandale.
+
+_Zoarium_. The zoarium consists of groups of zooecia (or occasionally of
+single zooecia) joined together by an adherent rhizome. There is no
+gelatinous investment.
+
+_Zooecia._ The adult zooecia resemble those of _Plumatella_ except in
+being sometimes more or less upright.
+
+_Polypide_ and _Statoblasts._ The polypide and statoblasts resemble
+those of _Plumatella_. Fixed as well as free statoblasts occur.
+
+This genus is closely allied to _Plumatella_, from which it is probably
+derived. The root-like tube from which the zooecia arise is formed by
+the great elongation of the basal part of a zooecium, and the zoaria
+closely resemble those of _P. punctata_, for it is not until several
+zooecia have been produced that the characteristic mode of growth
+becomes apparent.
+
+_Stolella_ has only been found in India and is monotypic[BJ].
+
+     [Footnote BJ: But see p. 246 (addenda).]
+
+
+36. Stolella indica, _Annandale_. (Plate V, figs. 3, 4.)
+
+    _Stolella indica_, Annandale, Rec. Ind. Mus. iii, p. 279, fig. (1909).
+
+    _Stolella indica_, _id._, _ibid._ v, p. 53 (1910).
+
+_Zoarium._ The zoarium is adherent and linear, having neither lateral
+nor vertical branches.
+
+_Zooecia._ The zooecia are short and slender, erect or nearly so,
+distinctly emarginate and furrowed. Their ectocyst is soft, colourless
+and transparent but minutely roughened on the surface.
+
+_Polypide._ The tentacles number from 30 to 35 and are rather short and
+stout, sometimes being slightly expanded at the tips. The stomach is
+comparatively short and abruptly truncated posteriorly.
+
+_Statoblasts._ Both free and fixed statoblasts are found, and both are
+variable in form, the latter varying in outline from the circular to the
+broadly oval. The free statoblasts resemble those of _Plumatella
+punctata_, but are sometimes rather more elongate.
+
+TYPE in the Indian Museum.
+
+[Illustration: Fig. 45.--Zoarium of _Stolella indica_ on stem of
+water-plant (from Calcutta), � 6.]
+
+GEOGRAPHICAL DISTRIBUTION.--So far as we know, this species is confined
+to the Indo-Gangetic Plain. Major Walton found it at Bulandshahr in the
+United Provinces, and it is not uncommon in the neighbourhood of
+Calcutta.
+
+BIOLOGY.--The zoaria of _S. indica_ are usually fixed to the roots of
+duckweed or to the stems of other plants. They are often found together
+with those of _P. punctata_. A slight infusion of brackish water into
+the ponds in which it lives does not seem to be inimical to this
+species, but I have found it in ponds in which nothing of the kind was
+possible. It flourishes during the "rains" and, to judge from specimens
+kept in an aquarium, is very short-lived. Major Walton found it growing
+over a zoarium of _Hislopia lacustris_.
+
+
+Subfamily B. LOPHOPIN�.
+
+The zoaria of this subfamily are never dendritic but form gelatinous
+masses which, except in _Australella_, are cushion-shaped or sack-like.
+With the possible exception of _Australella_, they possess to a limited
+extent the power of moving along vertical or horizontal surfaces, but it
+is by no means clear how they do so (see p. 172). The statoblasts are
+remarkable for their large size, and it is noteworthy that
+_Australella_, which is intermediate in structure between the
+Plumatellin� and the Lophopin�, possesses statoblasts of intermediate
+size. The swim-ring is always well developed, and fixed statoblasts are
+unknown.
+
+Only two genera (_Lophopodella_ and _Pectinatella_) have been definitely
+proved to occur in India, but a third (_Lophopus_[BK]) is stated to have
+been found in Madras. Should it be met with it will easily be recognized
+by the upright position of its polypides when their tentacles are
+expanded and by the fact that the statoblasts never bear marginal
+processes.
+
+     [Footnote BK: Only two species are known, _L. crystallinus_
+     (Pallas) from Europe and N. America, with oval statoblasts
+     that are produced and pointed at the two ends, and _L.
+     jheringi_, Meissner from Brazil, with irregularly polygonal
+     or nearly circular statoblasts.]
+
+
+Genus 3. LOPHOPODELLA, _Rousselet_.
+
+     _Lophopodella_, Rousselet, Journ. Quek. Micr. Club (2) ix,
+     p. 45 (1904).
+
+     _Lophopodella_, Annandale, Rec. Ind. Mus. v, p. 54 (1910).
+
+TYPE, _Pectinatella carteri_, Hyatt.
+
+_Zoarium._ The zoarium consists of a circular or oval mass of no great
+size. Polyparia do not form compound colonies.
+
+_Polypides._ The polypides lie semi-recumbent in the mass and never
+stand upright in a vertical position.
+
+_Statoblasts._ The statoblasts are of considerable size and normally
+bear at both ends a series of chitinous processes armed with double rows
+of small curved spinules.
+
+As a rule the genus is easily recognized by means of the statoblasts,
+but sometimes the processes at the ends of these structures are absent
+or abortive and it is then difficult to distinguish them from those of
+_Lophopus_. There is, however, no species of that genus known that has
+statoblasts shaped like those of the Indian species of _Lophopodella_.
+
+Three species of _Lophopodella_, all of which occur in Africa, have been
+described; _L. capensis_ from S. Africa, which has the ends of the
+statoblast greatly produced, _L. thomasi_ from Rhodesia, in which they
+are distinctly concave, and _L. carteri_ from E. Africa, India and
+Japan, in which they are convex or truncate.
+
+The germination of the gemmule and the early stages in the development
+of the polyparium of _L. capensis_ have been described by Miss Sollas
+(Ann. Nat. Hist. (8) ii, p. 264, 1908).
+
+
+37. Lophopodella carteri (_Hyatt_). (Plate III, figs. 4, 4_a_.)
+
+     _Lophopus_ sp., Carter, Ann. Nat. Hist. (3) iii, p. 335, pl.
+     viii, figs. 8-15 (1859).
+
+     ? _Lophopus_ sp., Mitchell, Q. J. Micr. Sci. London (3) ii,
+     p. 61 (1862).
+
+     _Pectinatella carteri_, Hyatt, Comm. Essex Inst. iv, p. 203
+     (footnote) (1866).
+
+     _Pectinatella carteri_, Meissner, Die Moosthiere
+     Ost-Afrikas, p. 4 (in Mobius's Deutsch-Ost-Afrika, iv,
+     1898).
+
+     _Lophopodella carteri_, Rousselet, Journ. Quek. Micr. Club,
+     (2) ix, p. 47, pl. iii, figs. 6, 7 (1904).
+
+     _Lophopus carteri_, Annandale, Rec. Ind. Mus. ii, p. 171,
+     fig. 3 (1908).
+
+     _Lophopodella carteri_, _id._, _ibid._ v, p. 55 (1910).
+
+_Zoarium._ The zoarium as a rule has one horizontal axis longer than the
+other so that it assumes an oval form when the polypides are expanded;
+when they are retracted its outline is distinctly lobular. Viewed from
+the side it is mound-shaped. The polypides radiate, as a rule in several
+circles, from a common centre. The ectocyst is much swollen, hyaline and
+colourless.
+
+_Polypide._ The polypide has normally about 60 tentacles, the velum at
+the base of which is narrow and by no means strongly festooned. The
+stomach is yellow or greenish in colour. The extended part of the
+polypide measures when fully expanded rather less than 3 mm., and each
+limb of the lophophore about the same.
+
+_Statoblast._ The statoblast is variable in shape and size but measures
+on an average about 0.85 � 0.56 mm. The ends are truncate or
+subtruncate; the capsule is small as compared with the swim-ring and as
+a rule circular or nearly so. The processes at the two ends are variable
+in number; so also are their spinules, which are arranged in two
+parallel rows, one row on each side of the process, and are neither very
+numerous nor set close together; as a rule they curve round through the
+greater part of a circle and are absent from the basal part of the
+process.
+
+[Illustration: Fig. 46.--Lophopodella carteri (from Igatpuri Lake).
+
+A=outline of a zoarium with the polypides expanded, as seen from below
+through glass to which it was attached, � 4; B=outline of a zoarium with
+the polypides highly contracted, as seen from above, � 4; C=statoblast,
+� 75.]
+
+
+37 _a._ Var. himalayana.
+
+     _Lophopus lendenfeldi_, Annandale (_nec_ Ridley), J. As.
+     Soc. Bengal, (n. s.) iii, 1907, p. 92, pl. ii, figs. 1-4
+     (1907).
+
+     _Lophopus lendenfeldi_ var. _himalayanus_, _id._, Rec. Ind.
+     Mus. i, p. 147, figs. 1, 2 (1907).
+
+     _Lophopus himalayanus_, _id._, _ibid._ ii, p. 172, fig. 4
+     (1908).
+
+This variety differs from the typical form in having fewer tentacles and
+in the fact that the marginal processes of the statoblast are abortive
+or absent.
+
+_Pectinatella davenporti_, Oka[BL] from Japan is evidently a local race
+of _L. carteri_, from the typical form of which it differs in having the
+marginal processes of the statoblast more numerous and better developed.
+The abortive structure of these processes in var. _himalayana_ points to
+an arrest of development, for they are the last part of the statoblast
+to be formed.
+
+     [Footnote BL: Zool. Anz. xxxi, p. 716 (1907), and Annot.
+     Zool. Japon. vi, p. 117 (1907).]
+
+TYPES. The statoblasts mounted in Canada balsam by Carter and now in the
+British Museum must be regarded as the types of the species named but
+not seen by Hyatt. The types of the var. _himalayana_ are in the Indian
+Museum and those of the subspecies _davenporti_ presumably in the
+possession of Dr. Oka in Tokyo.
+
+GEOGRAPHICAL DISTRIBUTION.--The typical form occurs in Bombay, the W.
+Himalayas and possibly Madras, and its statoblasts have been found in E.
+Africa; the var. _himalayana_ has only been taken in the W. Himalayas
+and the subspecies _davenporti_ in Japan. Indian localities are:--BOMBAY
+PRESIDENCY, Igatpuri Lake, W. Ghats (alt. _ca._ 2,000 feet); the Island
+of Bombay (_Carter_): W. HIMALAYAS, Bhim Tal, Kumaon (alt. 4,500 feet).
+
+BIOLOGY.--_L. carteri_ is found on the lower surface of stones and on
+the stems and leaves of water-plants, usually in lakes or large ponds.
+Although the zoaria do not form compound colonies by secreting a common
+membrane or investment, they are markedly gregarious. The most closely
+congregated and the largest zoaria I have seen were assembled amongst a
+gelatinous green alga of the genus _Tolypothrix_[BM] (Myxophyce�) that
+grows on the vertical stems of a plant at the edge of Igatpuri Lake; it
+is noteworthy that in this case the alga seemed to take the place of the
+common investment of _Pectinatella burmanica_, in which green cells are
+present in large numbers (p. 237). The zoaria of _L. carteri_ are able
+to change their position, and I found that if a number of them were
+placed in a bottle of water they slowly came together at one spot, thus
+apparently forming temporary compound colonies. Before a movement of the
+whole zoarium commences its base becomes detached from its support at
+the anterior end (fig. 32, p. 172), but the whole action is extremely
+slow and I have not been able to discover any facts that cast light on
+its exact method of production. At Igatpuri statoblasts are being
+produced in considerable numbers at the end of November, but many young
+zoaria can be found in which none have as yet been formed.
+
+     [Footnote BM: Prof. W. West will shortly describe this alga,
+     which represents a new species, in the Journ. Asiat. Soc.
+     Bengal, under the name _Tolypothrix
+     lophopodellophila_.--_April 1911_.]
+
+The larva of a fly of the genus _Chironomus_ is often found inhabiting a
+tube below zoaria of _L. carteri_. It is thus protected from its enemies
+but can protrude its head from beneath the zoarium and seize the small
+animals on which it preys.
+
+
+Genus 4. PECTINATELLA, _Leidy_.
+
+     _Cristatella_, Leidy, P. Ac. Philad. v, p. 265 (1852).
+
+     _Pectinatella_, _id._, _ibid._, p. 320.
+
+     _Pectinatella_, Allman, Mon. Fresh-Water Polyzoa, p. 81
+     (1857).
+
+     _Pectinatella_, Hyatt, Proc. Essex Inst. v, p. 227, fig. 20
+     (1867).
+
+     _Pectinatella_, Kraepelin, Deutsch. S�sswasserbryozoen, i,
+     p. 133 (1887).
+
+     _Pectinatella_, Oka, Journ. Coll. Sci. Tokyo, iv, p. 89
+     (1891).
+
+TYPE, _Pectinatella magnifica_, Leidy.
+
+This genus is closely allied to _Lophopodella_, from which it is often
+difficult to distinguish young specimens. Adult zoaria are, however,
+always embedded together in groups in a gelatinous investment which they
+are thought to secrete in common[BN], and the statoblasts are entirely
+surrounded by processes that bear curved spinules at their tips only.
+The polypides have the same semi-recumbent position as those of
+_Lophopodella_ but are larger than those of any species of
+_Lophopodella_ or _Lophopus_ yet known. The statoblasts are larger than
+those of any other Plumatellid�.
+
+     [Footnote BN: It is now perhaps open to doubt whether the
+     investment is actually secreted by the polyzoon, for Prof.
+     W. West has discovered in it the cells of an alga belonging
+     to a genus which habitually secretes a gelatinous investment
+     of its own (see p. 238, _post._).--_April 1911._]
+
+The type-species was originally found in N. America but has since been
+taken in several localities in continental Europe. Except this and the
+Indian form only one species is known, namely _P. gelatinosa_ from
+Japan. _P. magnifica_ has circular statoblasts with long marginal
+processes, while in _P. gelatinosa_ the statoblasts are subquadrate and
+in _P. burmanica_ almost circular, both Asiatic forms having very short
+marginal processes.
+
+The compound colonies formed by _Pectinatella_ are often of great size.
+Those of _P. gelatinosa_ are sometimes over 2 metres in length, while
+those of _P. burmanica_ in the Sur Lake appeared to be only limited as
+regards their growth by the shallowness of the water in which the reeds
+to which they were attached were growing. Some were observed that were
+over 2 feet long.
+
+
+38. Pectinatella burmanica, _Annandale_. (Plate III, fig. 5.)
+
+     _Pectinatella burmanica_, Annandale, Rec. Ind. Mus. ii,
+     p. 174, fig. 5 (1908).
+
+     _Pectinatella burmanica_, _id._, _ibid._ v, p. 56 (1910).
+
+     _Pectinatella burmanica_, _id._, Spol. Zeyl. vii, p. 63,
+     pl. i, fig. 3 (1910).
+
+_Zoarium._ The zoaria are circular or nearly so except when about to
+undergo division, in which case they are constricted in the middle. As a
+rule they measure nearly an inch (2 cm.) in diameter. The polypides have
+a definite arrangement in each zoarium, being divided into four groups,
+each of which has a fan-like form. In the first place they are separated
+into two main divisions in a line running through the centre of the
+zoarium, and secondly each main division is separated into two
+subordinate ones in a line running across the other at right angles. The
+number of zoaria joined together in a single compound colony is very
+variable; sometimes there are only about half a dozen and sometimes
+several hundreds. The common investment in living colonies is often as
+much as two inches thick and has a translucent dark greenish colour due
+to the presence in it of green cells.
+
+[Illustration: Fig. 47.--_Pectinatella burmanica._
+
+A=polypide with the lophophore expanded, � 15; _a_=oesophagus;
+_b_=cardiac limb of stomach; _c_=stomach; _d_=rectum; _e_=anus;
+_f_=funiculus. [The muscles are omitted and the external tubercles are
+only shown on part of the polypide. The specimen is from the Sur Lake,
+Orissa.] B=statoblast from Ceylon, � 35.]
+
+_Polypide._ The polypide can be extruded for a distance of at least 5
+mm. Its whole external surface is covered with minute tubercles. There
+are about 90 tentacles, which are long and slender, the velum at their
+base being narrow and almost straight. The stomach is of considerable
+stoutness.
+
+_Statoblast._ The statoblasts are of large size, measuring from 1 to
+1.75 mm. in diameter. In form they are almost circular, but one side is
+always slightly flattened. The marginal processes are very short and
+bear a single pair of hooks at the tip. The capsule is circular and
+small as compared with the free part of the swim-ring.
+
+TYPE in the Indian Museum.
+
+_P. burmanica_ is evidently a near relation of _P. gelatinosa_, Oka,
+from Japan, differing from that species in the shape of the statoblasts
+and in having much longer tentacles. The arrangement of the polypides in
+the zoarium and the general structure of the statoblasts are very
+similar in the two species.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. burmanica_ was originally described from
+a swamp at Kawkareik in the Amherst district of Tenasserim but has also
+been found in the Sur Lake near Puri in Orissa. Dr. A. Willey obtained
+specimens from a pool by the roadside between Maradankadewela and
+Galapitagala, at the foot of Ritigala, N. Central Province, Ceylon.
+
+BIOLOGY.--The first specimen obtained was a statoblast fixed to a tube
+of the oligoch�te worm _Aulophorus tonkinensis_ taken at Kawkareik in
+March. At the same time young zoaria, which did not yet possess a common
+investment, were found on a leaf growing on a twig which drooped into
+the water. Large compound colonies were taken in Orissa in October. They
+completely encased the stems of reeds, thus forming hollow cylinders,
+but slipped from their supports when the reeds were pulled out of the
+water. In life they resembled gelatinous alg� rather than animals and
+exhibited a striking similarity to masses of zoaria of _Lophopodella
+carteri_ surrounded by such alg�. Some of the colonies were evidently
+dying and contained few polypides in a living condition, but many
+statoblasts; others were in a flourishing condition and were producing
+larv� and statoblasts simultaneously.
+
+A piece of a colony full of larv� was placed before midday in an
+aquarium, which was kept in a shady verandah. Large numbers of larv�
+were set free almost immediately. They measured about 2 mm. in length
+and were distinctly pear-shaped; each contained a pair of polypides,
+which occupied a comparatively small part of the interior, the whole of
+the broader half being hollow. The larv� swam slowly, broad-end-first,
+by means of the cilia with which their surface was covered, occasionally
+gyrating on their long axis and always adopting an erratic course.
+Towards evening they showed signs of settling down, frequently touching
+the glass of the aquarium with their broad ends and sometimes remaining
+still in this position for some minutes. Many attempts were, however,
+made before fixation was completed, and this did not occur until after
+nightfall. By next morning every larva was fixed to the glass and had
+everted its two polypides. Unfortunately I was not able to trace the
+development further, but young compound colonies were found in which the
+secretion of the common investment had just commenced. The zoaria in
+these colonies measured about 1 cm. in diameter and already contained
+many polypides each.
+
+Oka has described the development from the statoblast of the allied
+Japanese species. He found that each statoblast produced in the first
+instance a single polypide, and that the statoblasts, which were
+produced in autumn, lay dormant through the winter and germinated in
+spring. As the Sur Lake begins to undergo desiccation as soon as the
+"rains" cease, the statoblasts in it probably do not germinate until the
+break of the next "rains" about the middle of June. I have had dried
+statoblasts in my possession for over two years. Their cellular contents
+appear to be in good condition, although the cells show no signs of
+development; but they have not germinated in my aquarium, in which some
+of them have now been kept for more than six months.
+
+The green cells of the common investment are peculiar bodies that
+deserve further study than it has yet been possible to devote to them.
+Each cell is of ovoid form, varying somewhat in size but as a rule
+measuring about 0.03 � 0.008 mm. There can be no doubt that these bodies
+represent a stage in the life-history of an alga[BO]. Diatoms, bacilli
+and other minute plants are often present in the membrane as well as the
+characteristic green cells, but do not form a constant feature of it.
+
+     [Footnote BO: Professor W. West identifies this alg� as
+     _Dactylococcopsis pectinatellophila_, new species. It will
+     be described, before the publication of this book, in the
+     Journ. As. Soc. Bengal (1911). Prof. West has found,
+     associated more or less fortuitously with _P. burmanica_,
+     another alga, namely _Microcystis orissica_, also a new
+     species.--_April 1911._]
+
+
+
+
+APPENDIX TO THE VOLUME.
+
+
+HINTS ON THE PREPARATION OF SPECIMENS.
+
+_To preserve Spongillid�._--Spongillid� must be preserved dry or in very
+strong alcohol. Formalin should not be used.
+
+_To clean siliceous sponge spicules._--Place small fragments of the
+dried sponge (if alcohol is present, the reaction is apt to be violent)
+in a test tube, cover them with strong nitric acid and boil over the
+flame of a Bunsen burner or small spirit lamp until the solid particles
+disappear. Add a large quantity of water to the acid and filter through
+pure cellulose filter-paper, agitating the liquid repeatedly. Pass clean
+water in considerable quantities through the filter-paper and dry the
+latter carefully; place it in a spirally coiled wire and ignite with a
+match, holding the wire in such a way that the spicules released by the
+burning of the paper fall into a suitable receptacle. They may then be
+picked up with a camel's-hair brush and mounted in Canada balsam.
+
+_To examine the skeleton of a Spongillid._--Cut thin hand-sections with
+a sharp scalpel, dehydrate if necessary, and mount in Canada balsam.
+
+_To prepare gemmules for examination._--Place the gemmules dry in a
+watch-glass with a few drops of strong nitric acid. When gas is given
+off freely add water in considerable quantities. Remove the gemmules
+with a camel's-hair brush to clean water, then to 50%, 70%, 90% and
+absolute alcohol in succession, leaving them for an hour in each
+strength of spirit. Clear with oil of cloves and mount in Canada balsam.
+
+_To ascertain the presence of bubble-cells in the parenchyma of a
+Spongillid._--Tease up a small piece of the sponge with a pair of
+needles, mount under a thin cover-slip in strong spirit, and examine
+under a high power of the microscope.
+
+_To preserve Hydra in an expanded condition._--Place the polyp in a
+watch-glass of clean water and wait until its tentacles are expanded.
+Heat a few drops of commercial formaldehyde and squirt the liquid while
+still hot at the _Hydra_, which will be killed instantaneously. Remove
+it to a solution of formaldehyde and spirit of the following formula:--
+
+     Commercial formaldehyde      1 part.
+     Absolute alcohol             3 parts.
+     Distilled water              7 parts.
+
+Then pass the _Hydra_ through 50% and 70% alcohol and keep in 90%.
+
+_To examine the capsules of the nettle-cells._--Place a living _Hydra_
+in a small drop of water on a slide and press a thin cover-slip down
+upon it.
+
+_To preserve freshwater polyzoa in an expanded condition._--Place the
+polyzoa in a glass tube full of clean water and allow them to expand
+their tentacles. Drop on them gradually when they are fully expanded a
+2% aqueous solution of cocaine, two or three drops at a time, until
+movement ceases in the tentacles. Then pour commercial formaldehyde into
+the tube in considerable quantities. Allow the whole to stand for half
+an hour. If it is proposed to stain the specimens for anatomical
+investigation, they should then be removed through 50% and 70% to 90%
+alcohol. If, on the other hand, it is desired to keep them in a
+life-like condition they may be kept permanently in a solution of one
+part of commercial formaldehyde in four parts of water. Care must be
+taken that the process of paralyzing the polypides is not unduly
+prolonged, and it is always as well to preserve duplicate specimens in
+spirit or formalin with the lophophore retracted.
+
+_To prepare statoblasts for examination._--Place the statoblasts for a
+few minutes in strong nitric acid. Then remove the acid with water, pass
+through alcohol, clear with oil of cloves, and mount in a small quantity
+of Canada balsam under a cover-slip, taking care that the statoblasts
+lie parallel to the latter.
+
+
+
+
+ADDENDA.
+
+
+The following addenda are due mainly to an expedition to the lakes of
+Kumaon in the W. Himalayas undertaken by Mr. S. W. Kemp in May, 1911.
+
+
+PART I.
+
+
+Genus SPONGILLA.
+
+
+Subgenus EUSPONGILLA (p. 69).
+
+1 a. Spongilla lacustris, subsp. reticulata (p. 71).
+
+Specimens were taken in the lake Malwa Tal (alt. 3600 feet) in Kumaon,
+while others have recently been obtained from the Kalichedu
+irrigation-tank in the Pagnor _talug_ of the Nellore district, Madras
+(_G. H. Tipper_).
+
+4. Spongilla cinerea (p. 79).
+
+Specimens were taken in Naukuchia Tal (alt. 4200 feet) in Kumaon. They
+have a pale yellow colour when dry. This sponge has not hitherto been
+found outside the Bombay Presidency.
+
+
+Subgenus EUNAPIUS (p. 86).
+
+8. Spongilla carteri (p. 87).
+
+Specimens were taken in Bhim Tal (alt. 4450 feet) and Sat Tal (alt. 4500
+feet). Some of them approach the variety _cava_ in structure.
+
+
+Subgenus STRATOSPONGILLA (p. 100).
+
+12. Spongilla bombayensis (p. 102).
+
+Add a new variety:--
+
+13 a. Var. pneumatica, nov.
+
+  (i.)   The sponge forms a flat layer of a pale brownish colour
+         as a rule with short and very delicate vertical branches.
+         In one specimen it takes the form of an elegant cup
+         attached, only at the base, to a slender twig.
+
+  (ii.)  The gemmules are covered, outside the spicules, by a
+         thick pneumatic coat of irregular formation and with
+         comparatively large air-spaces.
+
+  (iii.) The gemmule-spicules are regularly sausage-shaped.
+
+TYPES in the Indian Museum.
+
+HABITAT. Naukuchia Tal (alt. 4200 feet), Kumaon, W. Himalayas (_S. W.
+Kemp_).
+
+
+Genus EPHYDATIA (p. 108).
+
+After _Ephydatia meyeni_, p. 108, add:--
+
+
+Ephydatia fluviatilis, _auct._
+
+     ? _Ephydatia fluviatilis_, Lamouroux, Encyclop. M�thod. ii,
+     p. 327 (1824).
+
+     _Spongilla fluviatilis_, Bowerbank (_partim_), Proc. Zool.
+     Soc. London, 1863, p. 445, pl. xxxviii, fig. 1.
+
+     _Ephydatia fluviatilis_, J. E. Gray (_partim_), Proc. Zool.
+     Soc. London, 1867, p. 550.
+
+     _Meyenia fluviatilis_, Carter (_partim_), Ann. Nat. Hist.
+     (5) vii, p. 92, pl. vi, fig. 11 _a_, _b_ (1881).
+
+     _Ephydatia fluviatilis_, Vejdovsky, Abh. k. B�hm.
+     Gesellschaft Wiss. xii, p. 24, pl. i, figs. 1, 2, 7, 10, 14,
+     19 (1883).
+
+     _Ephydatia fluviatilis_, _id._, P. Ac. Philad. 1887, p. 178.
+
+     _Meyenia fluviatilis_ var. _gracilis_, Potts, _ibid._, p.
+     224.
+
+     _Meyenia robusta_, _id._, _ibid._, p. 225, pl. ix, fig. 5.
+
+     _Ephydatia fluviatilis_, Weltner, Arch. Naturg. Berlin, 1895
+     (i) p. 122.
+
+     _Ephydatia robusta_, Annandale, Journ. As. Soc. Bengal,
+     1907, p. 24, fig. 7.
+
+     _Ephydatia fluviatilis_, Weltner, in Brauer's
+     S�sswasserfauna Deutschlands xix, S�sswasserschw�mme, p.
+     185, figs. 316, 317 (1909).
+
+     _Ephydatia fluviatilis_, Annandale, P. U. S. Mus. xxxviii,
+     p. 649 (1910).
+
+[Many more references to this common species might be cited, but those
+given above will be sufficient.]
+
+This species only differs from _E. meyeni_ in the following
+characters:--
+
+  (i.)   there are no bubble-cells in the parenchyma;
+
+  (ii.)  there is less spongin in the skeleton, which is less compact;
+
+  (iii.) the gemmule-spicules are longer, the shafts being as a rule
+         longer than the diameter of the rotul�;
+
+  (iv.)  the gemmules are armed with a single row of regularly
+         arranged spicules embedded in pneumatic tissue with
+         minute air-spaces.
+
+The sponge is a variable one and several "varieties" have been described
+from different parts of the world. My Indian specimens come nearest to
+the form described by Potts as _Meyenia robusta_, but have rather more
+slender skeleton-spicules and more elongate gemmule-spicules. The latter
+also appear to be less frequently "monstrous."
+
+TYPE ?
+
+GEOGRAPHICAL DISTRIBUTION.--_E. fluviatilis_ is widely distributed in
+Europe and occurs in N. America,[BP] S. Africa (var. _capensis_,
+Kirkpatrick), Australia, and Japan. Specimens were obtained by Mr. Kemp
+from several lakes in Kumaon, namely Naukuchia Tal (alt. 4200 feet),
+Bhim Tal (4450 feet), Sat Tal (4500 feet), and Naini Tal (6300 feet).
+The gemmules from Bhim Tal referred by me to _E. robusta_ (Potts) also
+belong to this species.
+
+     [Footnote BP: Most of the forms assigned by Potts to this
+     species belong to the closely allied _E. m�lleri_
+     (Lieberk�hn).]
+
+_Biology._ The external form of the sponge is due in great part to its
+environment. Specimens on small stones from the bottom of the Kumaon
+Lakes consist of thin disk-like films, often not more than a few
+centimetres in diameter and a few millimetres thick: others, growing on
+thin twigs, are elevated and compressed, resembling a cockscomb in
+appearance, while others again form nodules and masses of irregular form
+among the branches of delicate water-weeds. Some of these last are
+penetrated by zoaria of _Fredericella indica_.
+
+Weltner has published some very interesting observations on the seasonal
+variation of minute structure in European representatives of the species
+(Arch. Naturg. Berlin, lxxiii (i), p. 273 1907) and has discussed the
+formation of the abnormal spicules that sometimes occur (_ibid._ lxvii
+(Special Number), p. 191, pls. vi, vii, figs. 27-59, 1901).
+
+
+Genus CORVOSPONGILLA (p. 122).
+
+After _Corvospongilla burmanica_, p. 123, add a new species:--
+
+
+Corvospongilla caunteri, nov.
+
+_Sponge_ forming thin films of considerable area not more than 3 or 4
+mm. thick, of a bright green colour, moderately hard but friable. The
+surface smooth; oscula inconspicuous, surrounded by shallow and
+ill-defined radiating furrows; a very stout basal membrane present.
+
+[Illustration: Fig. 48.--_Corvospongilla caunteri_ (type, from Lucknow).
+
+A=Gemmule; B=gemmule-spicules; C=flesh-spicules; D=Skeleton-spicules.]
+
+_Skeleton_ reticulate but almost devoid of spongin, the reticulations
+close but formed mainly by single spicules; skeleton-fibres barely
+distinguishable. A close layer of spicules lying parallel to the basal
+membrane.
+
+_Spicules._ Skeleton-spicules variable in size and shape, almost
+straight, as a rule smooth, moderately stout, blunt or abruptly pointed;
+sometimes roughened or spiny at the tips, often sharply pointed.
+Flesh-spicules minute, few in number, with smooth, slender shafts which
+are variable in length, never very strongly curved; the terminal spines
+relatively short, not strongly recurved. Gemmule-spicules
+amphistrongylous or amphioxous, irregularly spiny, slender, of variable
+length.
+
+_Gemmules_ free in the substance of the sponge, spherical or somewhat
+depressed, very variable in size but never large, having a thick
+external pneumatic coat in which the air-spaces are extremely small and,
+inside this coat, a single rather sparse layer of spicules lying
+parallel to the gemmule. A single depressed aperture present.
+
+TYPE in the Indian Museum.
+
+HABITAT. Hazratganj, Lucknow; on piers of bridge in running water (_J.
+Caunter_, 29-30. iv. 11).
+
+The structure of the gemmules of this species differs considerably from
+that in any other known species of the genus, in which these structures
+are usually adherent and devoid of a true pneumatic coat. In some of the
+gemmules before me this coat measures in thickness about 1/9 of the
+total diameter of the gemmule. _C. caunteri_ is the first species of
+_Corvospongilla_ to be found in the Indo-Gangetic plain.
+
+
+PART II.
+
+
+Genus HYDRA (p. 147).
+
+
+25. Hydra oligactis (p. 158).
+
+Mr. Kemp found this species common in Bhim Tal in May. His specimens,
+which were of a reddish-brown colour in life, appear to have been of
+more vigorous constitution than those taken by Major Stephenson in
+Lahore. Some of them had four buds but none were sexually mature.
+
+
+PART III.
+
+
+Genus FREDERICELLA (p. 208).
+
+
+28. Fredericella indica (p. 210).
+
+This species is common in some of the Kumaon lakes, in which it grows,
+at any rate at the beginning of summer, much more luxuriantly than it
+does in the lakes of the Malabar Zone in autumn, forming dense bushy
+masses on the under surface of stones, on sticks, &c. The vertical
+branches often consist of many zooecia. Mr. Kemp took specimens in Malwa
+Tal, Sath Tal, and Naini Tal (alt. 3600-6300 feet).
+
+
+Genus PLUMATELLA (p. 212).
+
+
+30. Plumatella emarginata (p. 220).
+
+Mr. Kemp took bushy masses of this species in Malwa Tal and Bhim Tal.
+
+
+32. Plumatella diffusa (p. 223).
+
+This species is common in Malwa Tal and Bhim Tal in May.
+
+
+33. Plumatella allmani (p. 224).
+
+Mr. Kemp only found this species in Malwa Tal, in which (at any rate in
+May) it appears to be less abundant than it is in Bhim Tal in autumn.
+Mr. Kemp's specimens belong to the form called _P. elegans_ by Allman.
+
+
+34. Plumatella tanganyik� (p. 225).
+
+Specimens taken by Mr. Kemp, somewhat sparingly, in Bhim Tal and Sath
+Tal in May exhibit a somewhat greater tendency towards uprightness of
+the zooecia than those I found in autumn in Igatpuri lake. The ectocyst
+is, in the former specimens, of a deep but bright reddish-brown. The
+zoaria are attached to twigs and small stones.
+
+
+Genus STOLELLA (p. 229).
+
+After Stolella indica, p. 229, add a new species:--
+
+
+Stolella himalayana, nov.
+
+This species may be distinguished from _S. indica_ by (i) its entirely
+recumbent zooecia, and (ii) the lateral branches of its zoarium.
+
+[Illustration: Fig. 49.--_Stolella himalayana_ (types, from the Kumaon
+lakes).
+
+A. The greater part of a young zoarium. B. Part of a much older
+zoarium.]
+
+_Zoarium_ entirely recumbent, consisting of zooecia joined together,
+often in groups of three, by slender, transparent, tubular processes.
+These processes are often of great relative length; they are formed by a
+modification of the posterior or proximal part of the zooecia, from
+which they are not separated by a partition, and they increase in length
+up to a certain point more rapidly than the zooecia proper. A zooecium
+often gives rise first to an anterior daughter-zooecium, the proximal
+part of which becomes elongate and attenuated in due course, and then to
+a pair of lateral daughter-zooecia situated one on either side. As a
+result of this method of budding a zoarium with a close superficial
+resemblance to that of _Paludicella_ is at first produced, but as the
+colony increases in age and complexity this resemblance largely
+disappears, for the zooecia and their basal tubules grow over one
+another and often become strangely contorted (fig. 49).
+
+_Zooecia_ elongate and slender, flattened on the ventral, strongly
+convex on the dorsal surface; rather deep in proportion to their
+breadth; the ectocyst colourless, not very transparent except on the
+stolon-like tubular part; dorsal keel and furrow as a rule absent;
+orifice unusually inconspicuous, situated on a tubercle on the dorsal
+surface.
+
+_Polypide_ stout and short; the tip of the fundus of the stomach capable
+of very complete constriction; the retractor muscles unusually short and
+stout.
+
+_Statoblasts._ Only free statoblasts have been observed. They resemble
+those of _S. indica_, but are perhaps a little longer and more elongate.
+
+TYPES in the Indian Museum.
+
+The discovery of this species makes it necessary to modify the diagnosis
+of the genus, the essential character of which, as distinguishing it
+from _Plumatella_, is the differentiation of the proximal part of some
+or all of the zooecia to form stolon-like tubules. From _Stephanella_,
+Oka, it is distinguished by the absence of a gelatinous covering, and by
+the fact that all the zooecia are attached, at least at the base, to
+some extraneous object.
+
+HABITAT. Malwa Tal, Kumaon (alt. 3600 feet), W. Himalayas (_Kemp_, May
+1911).
+
+BIOLOGY. Mr. Kemp took three specimens, all attached to the lower
+surface of stones. They contained few statoblasts and were evidently in
+a condition of vigorous growth. Between the lateral branches new
+polyparia were developing in several instances from free statoblasts,
+each of which appeared to contain two polypides.
+
+
+
+
+ALPHABETICAL INDEX.
+
+
+All names printed in italics are synonyms.
+
+When more than one reference is given, the page on which the description
+occurs is indicated by thickened numerals.
+
+  alba (Euspongilla) (Spongilla), 8, 9.
+  alba (Spongilla), 4, 22, 63, ~76~.
+  alba _var._ bengalensis (Spongilla), 4, 22, 63, ~77~.
+  alba _var_. cerebellata (Spongilla), 22, 63, ~76~.
+  _alba_ var. _marina_ (_Spongilla_), ~77~.
+  _Alcyonella_, 212.
+  Alcyonellea, 185.
+  allmani (Plumatella), 7, 8, 9, 23, 188, ~224~, 246.
+  _allmani_ var. _diffusa_ (_Plumatella_), 223.
+  _allmani_ var. _dumortieri_ (_Plumatella_), 222.
+  _attenuata_ (_Hydra_), 148, 158.
+  _aurantiaca_ (_Hydra_), 148.
+  aurea (Pectispongilla), 9, 22, 63, ~106~.
+  aurea _var._ subspinosa (Pectispongilla), 63, ~107~.
+
+  _benedeni_ (_Alcyonella_), 220.
+  bengalensis (Bowerbankia), 189.
+  bengalensis (Membranipora), 23.
+  bengalensis (Spongilla), 77.
+  bengalensis (Victorella), 4, 8, 9, 23, 187, ~195~.
+  blembingia (Ephydatia), 54.
+  bogorensis (Ephydatia), 54.
+  _bombayensis_ (_Plumatella_), 225.
+  bombayensis (Spongilla), 22, 63, 100, ~102~, 241.
+  bombayensis (Stratospongilla) (Spongilla), 8, 9.
+  Bowerbankia, 187, ~189~.
+  _brunnea_ (_Hydra_), 148.
+  burmanica (Corvospongilla), 8, 22, 64, ~122~.
+  burmanica (Pectinatella), 8, 10, 23, 188, ~235~.
+
+  calcuttana (Spongilla), 96.
+  _cambodgiensis_ (_Norodonia_), 202.
+  _Carterella_, 108.
+  carteri (Eunapius) (Spongilla), 7, 8, 9, 10.
+  _carteri_ (_Eunapius_), 87.
+  carteri (Lophopodella), 7, 8, 23, 188, ~232~, 233.
+  _carteri_ (_Lophopus_), 232.
+  _carteri_ (_Pectinatella_), 231,
+  carteri (Spongilla), 4, 22, 63, 86, ~87~, 241.
+  carteri _var._ cava (Spongilla), 22, 63.
+  carteri _var._ himalayana (Lophopodella), 23, 188.
+  carteri _var._ lobosa (Spongilla), 22, 63.
+  carteri _var._ mollis (Spongilla), 22, 63.
+  caudata (Bowerbankia), 189.
+  caudata _subsp._ bengalensis (Bowerbankia), 23, 189.
+  caunteri (Corvospongilla), 243.
+  cava (Spongilla), 88.
+  cerebellata (Spongilla), 76.
+  ceylonensis (Irene), 22, 140.
+  Cheilostomata, 184.
+  Chlorella, 50.
+  cinerea (Euspongilla) (Spongilla), 9.
+  cinerea (Spongilla), 22, 63, 72, 79, 241.
+  clementis (Stratospongilla) (Spongilla), 53.
+  coggini (Stratospongilla) (Spongilla), 53.
+  colonialis (Loxosomatoides), 23.
+  _contecta_ (_Spongilla_), 95.
+  _coralloides_ (_Plumatella_), 217.
+  Corvospongilla, 64, ~122~, 243.
+  crassior (Spongilla), 98.
+  crassissima (Eunapius) (Spongilla), 9.
+  crassissima (Spongilla), 4, 22, 63, ~98~.
+  crassissima _var._ crassior (Spongilla), 23, 63.
+  _crateriformis_ (_Meyenia_), 83.
+  _crateriformis_ (_Ephydatia_), 83, 84.
+  crateriformis (Euspongilla) (Spongilla), 8, 9.
+  _crateriformis_ (_Meyenia_), 83.
+  crateriformis (Spongilla), 22, 63, ~83~.
+  _Cristatella_, 235.
+  Cristatellina, 206.
+  Ctenostomata, 184, 185, 187, ~189~.
+  Cyclostomata, 184.
+
+  decipiens (Spongilla), 54, 96, ~97~.
+  diffusa (Plumatella), 7, 8, 9, 23, 188, ~223~, 245.
+  _di[oe]cia_ (_Hydra_), 158.
+  Dosilia, 64, ~110~.
+
+  _Echinella_, 199.
+  _elegans_ (_Plumatella_), 224.
+  Eleutheroblastea, 146, 147.
+  emarginata (Plumatella), 4, 8, 9, 10, 23, 188, 218, ~220~, 245.
+  _emarginata_ var. _javanica_ (_Plumatella_), 221.
+  Entoprocta, 183.
+  Ephydatia, 64, ~108~, 242.
+  _erinaceus_ (_Spongilla_), 114.
+  Eunapius, 63, ~86~, 241.
+  Euspongilla, 63, 67, ~69~, 241.
+
+  filamentata (Syncoryne), 22, 140.
+  fluviatilis (Ephydatia), 109, ~242~.
+  _fluviatilis_ (_Meyenia_), 242.
+  fluviatilis (Spongilla), 108, 242.
+  _fluviatilis_ var. _gracilis_ (_Meyenia_), 242.
+  fortis (Ephydatia), 52, 53.
+  fragilis (Spongilla), ~95~, 96.
+  fragilis _subsp._ calcuttana (Eunapius) (Spongilla), 9.
+  fragilis _subsp._ calcuttana (Spongilla), 22, 63.
+  fragilis _subsp._ decipiens (Spongilla), 22, 63.
+  Fredericella, 188, ~208~, 245.
+  FREDERICELLID�, 188, ~208~.
+  _friabilis_ (_Spongilla_), 87.
+  fruticosa (Plumatella), 4, 7, 8, 9, 23, 188, ~217~, 218.
+  _fusca_ (_Hydra_), 158, 159.
+
+  Gecarcinucus, 10.
+  gemina (Eunapius) (Spongilla), ~8~.
+  gemina (Spongilla), 22, 63, ~97~.
+  _glomerata_ (_Spongilla_), 95.
+  _grisea_ (_Hydra_), 148, 149.
+  Gymnol�mata, 184, 187.
+
+  Halichondrina, 65.
+  hemephydatia (Euspongilla) (Spongilla), 8.
+  hemephydatia (Spongilla), 22, 63, ~82~.
+  _hexactinella_ (_Hydra_), 148.
+  himalayana (Lophopodella), 233.
+  himalayana (Stolella), 246.
+  _himalayanus_ (_Lophopus_), 233.
+  Hislopia, 187, ~199~.
+  Hislopid�es, 199.
+  HISLOPIID�, 187, ~199~.
+  Homodi�tid�, 191.
+  _Hyalinella_, 212.
+  Hydra, 146, ~147~, 245.
+  Hydraid�, 147.
+  HYDRID�, 146, 147.
+  hydriforme (Polypodium), 142.
+  Hydrozoa, 146.
+
+  _indica_ (_Ephydatia_), 83.
+  indica (Fredericella), 9, 23, 188, ~209~, 245.
+  indica (Spongilla), 22, 63, ~100~.
+  indica (Stolella), 4, 9, 23, 188, ~229~.
+  indica (Stratospongilla), (Spongilla), 9.
+
+  javanica (Plumatella), 4, 8, 9, 23, 188, ~221~, 222.
+
+  kawaii (Limnocodium), 141.
+
+  lacroixii (Membranipora), 23.
+  lacustris (Cordylophora), 141.
+  _lacustris_ (_Euspongilla_), 69.
+  lacustris (Hislopia), 4, 8, 9, 23, 187, 199, ~202~, 204.
+  lacustris (Spongilla), 63, 67, ~69~.
+  lacustris _subsp._ moniliformis (Hislopia), 9, 23, 187.
+  lacustris _subsp._ reticulata (Spongilla), 4, 8, 9, 22, 63, ~71~, 241.
+  _lacustris_ var. _bengalensis_ (_Spongilla_), 77.
+  lapidosa (Corvospongilla), 9, 22, 64, ~124~.
+  _lapidosa_ (_Spongilla_), 124.
+  latouchiana (Trochospongilla), 4, 8, 9, 22, 64, ~115~.
+  _leidyi_ (_Trochospongilla_), 115.
+  _lendenfeldi_ (_Lophopus_), 233.
+  _lendenfeldi_ var. _himalayanus_ (_Lophopus_), 233.
+  lobosa (Spongilla), 89.
+  LOPHOPIN�, 188, 211, ~231~.
+  Lophopodella, 8, 188, ~231~.
+  _Lophopus_, 8, 232.
+  _lordii_ (_Spongilla_), 95.
+  loricata (Spongilla), ~122~.
+  _loricata_ var. _burmanica_, (_Spongilla_), 122.
+  _lucifuga_ (_Plumatella_), 217, 220, 224.
+
+  magnifica (Pectinatella), 235.
+  meyeni (Ephydatia), 7, 9, 17, 22, 64, ~108~.
+  _meyeni_ (_Spongilla_), 108.
+  _Meyenia_, 108, 113.
+  microsclerifera (Euspongilla) (Spongilla), 53.
+  mollis (Spongilla), 88.
+  moniliformis (Hislopia), 204.
+  _mon[oe]cia_ (_Hydra_), 158.
+  _morgiana_ (_Spongilla_), 95.
+  _m�lleri_ (_Ephydatia_), 109, 243.
+  _m�lleri_ subsp. _meyeni_ (_Ephydatia_), 109.
+
+  _Norodonia_, 199.
+
+  oligactis (Hydra), 7, 22, 146, ~158~, 159, 245.
+  _orientalis_ (_Hydra_), 148, 149.
+  _ottav�nsis_ (_Spongilla_), 95.
+
+  _pallens_ (_Hydra_), 148.
+  Paludicella, 187, ~192~.
+  PALUDICELLID�, 187, ~191~.
+  Paludicellid�es, 191.
+  Paludicellides, 191.
+  Paludicellina, 186, 187, ~190~.
+  paulula (Spongilla), 120.
+  _pavida_ (_Victorella_), 194, 195.
+  Pectinatella, 188, ~235~.
+  pectinatellophila (Dactyloccopsis), 238.
+  Pectispongilla, 63, ~106~.
+  pennsylvanica (Trochospongilla), 9, 22, 64, ~118~.
+  _pennsylvanica_ (_Tubella_), 118.
+  _pentactinella_ (_Hydra_), 149.
+  philippinensis (Euspongilla) (Spongilla), 53.
+  phillottiana (Trochospongilla), 4, 8, 9, 22, 64, ~117~.
+  Phylactol�mata, 185, 188, ~206~.
+  Plumatella, 188, 208, ~212~, 245.
+  PLUMATELLID�, 188, ~211~.
+  Plumatellina, 188, ~206~.
+  PLUMATELLIN�, 188, 211, ~212~.
+  plumosa (Dosilia), 8, 9, 22, 64, ~111~.
+  _plumosa_ (_Ephydatia_), 111.
+  _plumosa_ (_Meyenia_), 111.
+  _plumosa_ (_Spongilla_), 111.
+  pneumatica (Stratospongilla) (Spongilla), 241.
+  _polypus_ (_Hydra_), 148, 159.
+  Polyzoa, 183.
+  _princeps_ (_Plumatella_), 220.
+  _princeps_ var. _emarginata_ (_Plumatella_), 220.
+  _princeps_ var. _fruticosa_ (_Plumatella_), 217.
+  proliferens (Euspongilla) (Spongilla), 8, 9, 10.
+  proliferens (Spongilla), 4, 8, 22, 63, ~72~.
+  Proterospongia, 27.
+  _punctata_ (_Hyalinella_), 228.
+  punctata (Plumatella), 9, 188, ~227~.
+
+  _repens_ (_Plumatella_), 217, 223.
+  reticulata (Spongilla), 71.
+  _rh�tica_ (_Hydra_), 158.
+  _robusta_ (_Ephydatia_), 109, 242.
+  _robusta_ (_Meyenia_), 242.
+  _roeselii_ (_Hydra_), 158.
+  ryderi (Microhydra), 141.
+
+  schilleriana (Sagartia), 2, 22, 140.
+  schilleriana _subsp_. exul (Sagartia), 22.
+  _sibirica_ (_Spongilla_), 95.
+  _sinensis_ (_Norodonia_), 202.
+  sinensis (Stratospongilla) (Spongilla), 53.
+  _socialis_ (_Hydra_), 158.
+  sowerbii (Limnocodium), 141.
+  Spongilla, 63, ~67~, 86, 241.
+  Spongillad�, 65.
+  SPONGILLID�, 65.
+  Stolella, 188, ~229~, 246.
+  Stolonifera, 185.
+  Stratospongilla, 63, ~100~, 241.
+  _stricta_ (_Plumatella_), 217.
+  subspinosa (Pectispongilla), 107.
+  sumatrana (Stratospongilla) (Spongilla), 53.
+
+  tanganyik� (Limnocnida), 142.
+  tanganyik� (Plumatella), 9, 23, 188, ~225~, 246.
+  Trachospongilla, 64, ~113~.
+  _Trachyspongilla_, 108.
+  travancorica (Euspongilla) (Spongilla), 9.
+  travancorica (Spongilla), 22, 63, ~81~.
+  _trembleyi_ (_Hydra_), 148.
+  Tubella, 64, 113, ~120~.
+
+  ultima (Spongilla), 22, 63, ~105~.
+  ultima (Stratospongilla) (Spongilla), 9.
+
+  VESICULARID�, 189.
+  Vesicularina, 186, 187, ~189~.
+  _vesicularis_ (_Hyalinella_), 228.
+  _vesicularis_ (_Plumatella_), 227, 228.
+  vesparioides (Tubella), 8, 22, 64, ~120~.
+  vesparium (Tubella), 54.
+  vestita (Bimeria), 22, 139.
+  Victorella, 189, ~194~.
+  Victorellid�, 191.
+  Victorellides, 191.
+  viridis (Hydra), 147.
+  _vitrea_ (_Hyalinella_), 228.
+  _vitrea_ (_Plumatella_), 227, 228.
+  vulgaris (Hydra), 4, 8, 9, 10, 22, 130, 146, ~148~, 149, 158.
+
+  whiteleggei (Cordylophora), 141.
+
+  yunnanensis (Euspongilla) (Spongilla), 53.
+
+
+
+
+  PLATE I.
+
+  SPECIMENS OF _Spongilla_ PRESERVED IN SPIRIT.
+
+
+  Figs. 1-3. _S. (Euspongilla) alba_ var. _bengalensis_ (nat.
+     size) from ponds of brackish water at Port Canning in the
+     delta of the Ganges. Fig. 1 represents the type-specimen of
+     the variety, and was taken in the winter of 1905-6. Figs. 2
+     and 3 represent specimens taken in the same ponds in the
+     winters of 1907 and 1908 respectively.
+
+  Fig. 4. _Spongilla_ sp. (? abnormal form of _S. (Eunapius
+     carteri_)) from an aquarium in Calcutta (� 10).
+
+  [Illustration: Freshwater Sponges.                     Plate I.
+  A. C. Chowdhary, del.                               SPONGILLA.]
+
+
+
+
+  PLATE II.
+
+  PHOTOGRAPHS OF DRIED SPECIMENS OF _Spongilla_, _Tubella_, AND
+  _Corvospongilla_.
+
+
+  Fig. 1. Part of a large specimen of _S. (Eunapius) carteri_
+     from Calcutta, to show the conspicuous rounded oscula
+     (reduced).
+
+  Fig. 2. Gemmules of _S. (Stratospongilla) bombayensis_ on a
+     stone from the edge of Igatpuri Lake, Bombay Presidency
+     (nat. size).
+
+  Fig. 3. Part of one of the type-specimens of _S.
+     (Stratospongilla) ultima_ from Cape Comorin, Travancore, to
+     show the star-shaped oscula (slightly enlarged).
+
+  Fig. 4. Part of the type specimen of _T. vesparioides_
+     (external membrane destroyed), to show the reticulate
+     skeleton and the numerous gemmules (nat. size).
+
+  Fig. 5. Part of a schizotype of _C. burmanica_ to show the
+     elevated oscula (nat. size).
+
+  [Illustration: Freshwater Sponges.                    Plate II.
+  Photo by A. Chowdhary.     Spongilla, Tubella, Corvospongilla.]
+
+
+
+
+  PLATE III.
+
+  PHOTOGRAPHS OF SPECIMENS OF _Plumatella_, _Lophopodella_, AND
+  _Pectinatella_.
+
+  Fig. 1. Specimen in spirit of _P. fruticosa_ (typical
+     form) on the leaf of a bulrush from a pond in the Calcutta
+     Zoological Gardens (nat. size).
+
+  Fig. 2. A small zoarium of the _benedeni_ phase of _P.
+     emarginata_ from Rangoon (nat. size). Part of the mass has
+     been removed at one end to show the structure. The specimen
+     was preserved in spirit.
+
+  Fig. 3. Part of a large zoarium of _P. diffusa_ on a log
+     of wood from Gangtok, Sikhim (nat. size). An enlarged figure
+     of another part of the same specimen is given in fig. 2, Pl.
+     IV. The specimen was preserved in spirit.
+
+  Figs. 4, 4 _a_. Specimens of _L. carteri_ from Igatpuri
+     Lake, Bombay, preserved in formalin. Fig. 4 represents a
+     mass of polyparia surrounded by a green gelatinous alga on
+     the stem of a water-plant; fig. 4_a_ an isolated polyparium
+     with the polypides fully expanded from the under surface of
+     a stone in the same lake. Both figures are of natural size.
+
+  Fig. 5. Part of a compound colony of _P. burmanica_ on
+     the stem of a reed from the Sur Lake, Orissa (nat. size,
+     preserved in formalin).
+
+  [Illustration: Phylactolaematous Polyzoa.            Plate III.
+  Photo by A. Chowdhary. Plumatella, Lophopodella, Pectinatella.]
+
+
+
+
+  PLATE IV.
+
+  SPECIMENS OF _Plumatella_.
+
+  Fig. 1. Vertical branch of a polyparium of _P. emarginata_
+     from Calcutta, to show method of branching (� 8). The
+     specimen was preserved in formalin, stained with h�malum,
+     and after dehydration and clearing, mounted in canada
+     balsam.
+
+  Fig. 1 _a._ Part of a young, horizontal zoarium of _P.
+     emarginata_ from Rangoon (� 4, preserved in spirit).
+
+  Fig. 2. Part of a zoarium of _P. diffusa_ from Gangtok,
+     Sikhim (� 4). See Pl. III, fig. 3.
+
+  Figs. 3, 3 _a._ Specimens in spirit of _P. allmani_ from
+     Bhim Tal (lake), W. Himalayas. Fig. 3 represents a mature
+     polyparium; fig. 3 _a_ a young polyparium to which the
+     valves of the statoblast (�) whence it had arisen are still
+     attached.
+
+  Fig. 4. Part of a zoarium of the _coralloides_ phase of _P.
+     fruticosa_ (from Calcutta) preserved in spirit, as seen on
+     the surface of the sponge in which it is embedded (� 3).
+
+  Fig. 5. Part of the margin of a living polyparium of _P.
+     punctata_ from Calcutta (� 8) with the polypides fully
+     expanded.
+
+  [Illustration: Phylactolaematous Polyzoa.             Plate IV.
+  A. C. Chowdhary, del.                              PLUMATELLA.]
+
+
+
+
+  PLATE V.
+
+  SPECIMENS OF _Plumatella_, _Stolella_, AND _Pectinatella_.
+
+  Fig. 1. Part of a zoarium of the _coralloides_ phase of _P.
+     fruticosa_ (� 10) from Calcutta. The specimen, which was
+     preserved in spirit, had been removed from a sponge of
+     _Spongilla carteri_.
+
+  Fig. 2. Terminal branch of a polyparium of _P. punctata_
+     from Calcutta (� 30). The specimen was preserved in
+     formalin, stained with h�matoxylin, and finally mounted in
+     canada balsam.
+
+  Fig. 3. Part of an adult polyparium of _S. indica_ from
+     the United Provinces (� 30). The specimen was preserved in
+     formalin, stained with h�malum, and finally mounted in
+     canada balsam. The lower zooecium contains a mature free
+     statoblast, the upper one a fixed one.
+
+  Fig. 4. The growing point of a young polyparium of the
+     same species from Calcutta (� 30), to show the method of
+     formation of the stolon that connects the different groups
+     of zooecia. The specimen had been treated in the same way as
+     that represented in fig. 3.
+
+  Figs. 5, 5 _a_. Zoaria from a compound colony of _P.
+     burmanica_ from the Sur Lake, Orissa (� 2). The specimens,
+     which were preserved in formalin, are represented as seen
+     from the adherent surface of the colony.
+
+  [Illustration: Phylactolaematous Polyzoa.              Plate V.
+  A. C. Chowdhary, del.      Plumatella, Stolella, Pectinatella.]
+
+
+
+
+       *     *     *     *     *
+
+
+
+
+Transcriber's note:
+
+  In the Systematic Index, sub-family items were renumbered from 15.
+    through 38., to correspond to the numbers used in the text of the
+    book.
+  Greek letters used as symbols are spelled out, e.g. alpha, beta, etc.
+  Letters missing or mis-typeset were inserted, e.g. 'practica ly' to
+    'practically'
+  Footnotes were moved after the paragraph to which they pertain.
+  Raised dots were replaced with decimal points in numeric notations.
+  Bold page numbers in the index are surrounded by tildes, e.g. ~76~.
+  Punctuation was standardized.
+  Added a description of a sketch contained within one line of text.
+
+  Other changes:
+    'recognzied' to 'recognized' ... be recognized....
+    'benegalensis' to 'bengalensis' ... lacustris var. bengalensis,...
+    'pecular' to 'peculiar' ... the peculiar amphipod ...
+    'milar' to 'similar' ... similar in the two ...
+    'large' to 'larger' ... a little larger than the upper ...
+    'pennsylvania' to 'pennsylvanica' ...Tubella pennsylvanica...
+    'variely' to 'variety' ... specimens of the variety ...
+    'measurments' to 'measurements' ... the average measurements ...
+    'It' to 'Its' ... Its buds, however, possessed ...
+    'dispsition' to 'disposition' ... 'Y-shaped disposition of ...
+    'Wood's Holl' to 'Wood's Hole' ... Biol. Bull. Wood's Hole,...
+    '1852' to '1851' at the end of the citation of Leidy's paper, to
+       match date at the beginning of the citation paragraph.
+    'syoecium' to 'synoecium' ...in a gelatinous synoecium...
+    'Lacustre' to lower case ...Ann. Biol. lacustre,...
+    'Dactyloccopsis' to 'Dactylococcopsis' ... Dactylococcopsis
+       pectinatellophila ...
+    'amphioxus' to 'amphioxous' ... amphistrongylous or amphioxous ...
+    'Tr�da' and 'Trida' to 'Tr�da' for consistency ... Praze, Tr�da ...
+
+
+
+***END OF THE PROJECT GUTENBERG EBOOK FRESHWATER SPONGES, HYDROIDS &
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+<h1>The Project Gutenberg eBook, Freshwater Sponges, Hydroids &amp; Polyzoa, by
+Nelson Annandale</h1>
+<pre>
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at <a href = "http://www.gutenberg.org">www.gutenberg.org</a></pre>
+<p>Title: Freshwater Sponges, Hydroids &amp; Polyzoa</p>
+<p>Author: Nelson Annandale</p>
+<p>Release Date: June 24, 2011  [eBook #36504]</p>
+<p>Language: English</p>
+<p>Character set encoding: ISO-8859-1</p>
+<p>***START OF THE PROJECT GUTENBERG EBOOK FRESHWATER SPONGES, HYDROIDS &amp; POLYZOA***</p>
+<p>&nbsp;</p>
+<h4>E-text prepared by Bryan Ness, Carol Brown, Sharon Joiner,<br />
+    and the Online Distributed Proofreading Team<br />
+    (<a href="http://www.pgdp.net">http://www.pgdp.net</a>)<br />
+    from page images generously made available by<br />
+    Internet Archive<br />
+    (<a href="http://www.archive.org">http://www.archive.org</a>)</h4>
+<p>&nbsp;</p>
+<table border="0" style="background-color: #ccccff;margin: 0 auto;" cellpadding="10">
+  <tr>
+    <td valign="top">
+      Note:
+    </td>
+    <td>
+      Images of the original pages are available through
+      Internet Archive. See
+      <a href="http://www.archive.org/details/freshwatersponge00anna">
+      http://www.archive.org/details/freshwatersponge00anna</a>
+	</td>
+  </tr>
+</table>
+<p>&nbsp;</p>
+<hr class="full" />
+<p>&nbsp;</p>
+<p>&nbsp;</p>
+<p>&nbsp;</p>
+
+<h1>THE FAUNA OF BRITISH INDIA,</h1>
+
+<h4>INCLUDING</h4>
+
+<h1>CEYLON AND BURMA.</h1>
+
+<p class="center"><i><span class="smcap">Published under the authority
+of the Secretary of<br /> State for India in Council.</span></i></p>
+
+<p class="center"><span class="smcap">EDITED BY A. E. SHIPLEY, M.A.,
+Sc.D., HON. D.Sc., F.R.S.</span></p>
+
+<hr class="c10t" />
+
+<h1>FRESHWATER SPONGES,<br />
+HYDROIDS &amp; POLYZOA.</h1>
+
+<h4>BY</h4>
+
+<h2><span class="smcap">N. ANNANDALE, D.Sc.</span>,</h2>
+
+<p class="center"><span class="smcap">superintendent and trustee (<i>ex
+officio</i>) of the indian museum,<br /> fellow of the asiatic society
+of bengal and of the calcutta university.</span></p>
+<p>&nbsp;</p>
+<p>&nbsp;</p>
+
+<hr class="c10b" />
+
+<p class="p4 center">LONDON:<br />
+TAYLOR AND FRANCIS, RED LION COURT, FLEET STREET.</p>
+
+<table summary="Publisher locations">
+<tr><td align="center">CALCUTTA:</td><td> </td><td
+align="center">BOMBAY:</td></tr>
+<tr><td align="center"><span class="smcap">thacker, spink, &amp;
+co.</span></td><td> </td><td align="center"><span class="smcap">thacker
+&amp; co., limited.</span></td></tr>
+<tr><td> </td><td align="center">BERLIN:</td></tr>
+<tr><td> </td><td align="center"><span class="smcap">r. friedl�nder &amp;
+sohn, 11 carlstrasse.</span></td></tr>
+</table>
+
+<p class="p2 center"><i>August</i>, 1911.</p>
+
+<hr class="p4" />
+
+<p class="center">PRINTED AT TODAY &amp; TOMORROW'S PRINTERS &amp;
+PUBLISHERS, FARIDABAD</p>
+
+<h3 class="p4">CONTENTS.</h3>
+
+<table summary="Table of Contents">
+
+<tr><td> </td><td class="right">Page</td></tr>
+
+<tr><td><span class="smcap">Editor's Preface</span></td>
+    <td class="right"><a href="#Page_v">v</a></td></tr>
+
+<tr><td><span class="smcap">Systematic Index</span></td>
+    <td class="right"><a href="#Page_vii">vii</a></td></tr>
+
+<tr><td><span class="smcap">General Introduction</span></td>
+    <td class="right"><a href="#Page_1">1</a></td></tr>
+
+<tr><td class="indent1">Biological Peculiarities</td>
+    <td class="right"><a href="#Page_2">2</a></td></tr>
+
+<tr><td class="indent1">Geographical Distribution</td>
+    <td class="right"><a href="#Page_5">5</a></td></tr>
+
+<tr><td class="indent1">Geographical List</td>
+    <td class="right"><a href="#Page_7">7</a></td></tr>
+
+<tr><td class="indent1">Special Localities</td>
+    <td class="right"><a href="#Page_13">13</a></td></tr>
+
+<tr><td class="indent1">Nomenclature and Terminology</td>
+    <td class="right"><a href="#Page_17">17</a></td></tr>
+
+<tr><td class="indent1">Material</td>
+    <td class="right"><a href="#Page_20">20</a></td></tr>
+
+<tr><td><span class="smcap">Introduction to Part I.</span>
+(<i>Spongillid�</i>)</td>
+    <td class="right"><a href="#Page_27">27</a></td></tr>
+
+<tr><td class="indent1">The Phylum Porifera</td>
+    <td class="right"><a href="#Page_27">27</a></td></tr>
+
+<tr><td class="indent1">General Structure</td>
+    <td class="right"><a href="#Page_29">29</a></td></tr>
+
+<tr><td class="indent1">Skeleton and Spicules</td>
+    <td class="right"><a href="#Page_33">33</a></td></tr>
+
+<tr><td class="indent1">Colour and Odour</td>
+    <td class="right"><a href="#Page_35">35</a></td></tr>
+
+<tr><td class="indent1">External Form and Consistency</td>
+    <td class="right"><a href="#Page_37">37</a></td></tr>
+
+<tr><td class="indent1">Variation</td>
+    <td class="right"><a href="#Page_39">39</a></td></tr>
+
+<tr><td class="indent1">Nutrition</td>
+    <td class="right"><a href="#Page_41">41</a></td></tr>
+
+<tr><td class="indent1">Reproduction</td>
+    <td class="right"><a href="#Page_41">41</a></td></tr>
+
+<tr><td class="indent1">Development</td>
+    <td class="right"><a href="#Page_45">45</a></td></tr>
+
+<tr><td class="indent1">Habitat</td>
+    <td class="right"><a href="#Page_47">47</a></td></tr>
+
+<tr><td class="indent1">Animals and Plants commonly associated with
+Freshwater Sponges</td>
+    <td class="right"><a href="#Page_49">49</a></td></tr>
+
+<tr><td class="indent1">Freshwater Sponges in relation to Man</td>
+    <td class="right"><a href="#Page_50">50</a></td></tr>
+
+<tr><td class="indent1">Indian Spongillid� compared with those of other
+Countries</td>
+    <td class="right"><a href="#Page_51">51</a></td></tr>
+
+<tr><td class="indent1">Fossil Spongillid�</td>
+    <td class="right"><a href="#Page_52">52</a></td></tr>
+
+<tr><td class="indent1">Oriental Spongillid� not yet found in India</td>
+    <td class="right"><a href="#Page_52">52</a></td></tr>
+
+<tr><td class="indent1">History of the Study of Freshwater Sponges</td>
+    <td class="right"><a href="#Page_54">54</a></td></tr>
+
+<tr><td class="indent1">Literature</td>
+    <td class="right"><a href="#Page_55">55</a></td></tr>
+
+<tr><td><span class="smcap">Glossary of Technical Terms used in Part
+I.</span></td>
+    <td class="right"><a href="#Page_61">61</a></td></tr>
+
+<tr><td><span class="smcap">Systematic List of the Indian
+Spongillid�</span></td>
+    <td class="right"><a href="#Page_63">63</a></td></tr>
+
+<tr><td><span class="smcap">Introduction to Part II.</span>
+(<i>Hydrida</i>)</td>
+    <td class="right"><a href="#Page_129">129</a></td></tr>
+
+<tr><td class="indent1">The Phylum C&oelig;lenterata and the Class
+Hydrozoa</td>
+    <td class="right"><a href="#Page_129">129</a></td></tr>
+
+<tr><td class="indent1">Structure of Hydra</td>
+    <td class="right"><a href="#Page_130">130</a></td></tr>
+
+<tr><td class="indent1">Capture and Ingestion of Prey: Digestion</td>
+    <td class="right"><a href="#Page_133">133</a></td></tr>
+
+<tr><td class="indent1">Colour</td>
+    <td class="right"><a href="#Page_134">134</a></td></tr>
+
+<tr><td class="indent1">Behaviour</td>
+    <td class="right"><a href="#Page_135">135</a></td></tr>
+
+<tr><td class="indent1">Reproduction</td>
+    <td class="right"><a href="#Page_136">136</a></td></tr>
+
+<tr><td class="indent1">Development of the Egg</td>
+    <td class="right"><a href="#Page_139">139</a></td></tr>
+
+<tr><td class="indent1">Enemies</td>
+    <td class="right"><a href="#Page_139">139</a></td></tr>
+
+<tr><td class="indent1">C&oelig;lenterates of Brackish Water</td>
+    <td class="right"><a href="#Page_139">139</a></td></tr>
+
+<tr><td class="indent1">Freshwater C&oelig;lenterates other than
+Hydra</td>
+    <td class="right"><a href="#Page_141">141</a></td></tr>
+
+<tr><td class="indent1">History of the Study of Hydra</td>
+    <td class="right"><a href="#Page_142">142</a></td></tr>
+
+<tr><td class="indent1">Bibliography of Hydra</td>
+    <td class="right"><a href="#Page_143">143</a></td></tr>
+
+<tr><td><span class="smcap">Glossary of Technical Terms used in Part
+II.</span></td>
+    <td class="right"><a href="#Page_145">145</a></td></tr>
+
+<tr><td><span class="smcap">List of the Indian Hydrida</span></td>
+    <td class="right"><a href="#Page_146">146</a></td></tr>
+
+<tr><td><span class="smcap">Introduction to Part III.</span>
+(<i>Ctenostomata</i> and <i>Phylactol�mata</i>)</td>
+    <td class="right"><a href="#Page_163">163</a></td></tr>
+
+<tr><td class="indent1">Status and Structure of the Polyzoa</td>
+    <td class="right"><a href="#Page_163">163</a></td></tr>
+
+<tr><td class="indent1">Capture and Digestion of Food: Elimination of
+Waste Products</td>
+    <td class="right"><a href="#Page_166">166</a></td></tr>
+
+<tr><td class="indent1">Reproduction: Budding</td>
+    <td class="right"><a href="#Page_168">168</a></td></tr>
+
+<tr><td class="indent1">Development</td>
+    <td class="right"><a href="#Page_170">170</a></td></tr>
+
+<tr><td class="indent1">Movements</td>
+    <td class="right"><a href="#Page_172">172</a></td></tr>
+
+<tr><td class="indent1">Distribution of the Freshwater Polyzoa</td>
+    <td class="right"><a href="#Page_173">173</a></td></tr>
+
+<tr><td class="indent1">Polyzoa of Brackish Water</td>
+    <td class="right"><a href="#Page_174">174</a></td></tr>
+
+<tr><td class="indent1">History of the Study of Freshwater Polyzoa</td>
+    <td class="right"><a href="#Page_177">177</a></td></tr>
+
+<tr><td class="indent1">Bibliography of the Freshwater Polyzoa</td>
+    <td class="right"><a href="#Page_178">178</a></td></tr>
+
+<tr><td><span class="smcap">Glossary of Technical Terms used in Part
+III.</span></td>
+    <td class="right"><a href="#Page_181">181</a></td></tr>
+
+<tr><td><span class="smcap">Synopsis of the Classification of the
+Polyzoa</span></td>
+    <td class="right"><a href="#Page_183">183</a></td></tr>
+
+<tr><td><span class="smcap">Synopsis of the Subclasses, Orders, and
+Suborders</span></td>
+    <td class="right"><a href="#Page_183">183</a></td></tr>
+
+<tr><td><span class="smcap">Synopsis of the leading characters of the
+Divisions of the Suborder Ctenostomata</span></td>
+    <td class="right"><a href="#Page_185">185</a></td></tr>
+
+<tr><td><span class="smcap">Systematic List of the Indian Freshwater
+Polyzoa</span></td>
+    <td class="right"><a href="#Page_187">187</a></td></tr>
+
+<tr><td><span class="smcap">Appendix to the Volume</span></td>
+    <td class="right"><a href="#Page_239">239</a></td></tr>
+
+<tr><td class="indent1">Hints on the Preparation of Specimens</td>
+    <td class="right"><a href="#Page_239">239</a></td></tr>
+
+<tr><td><span class="smcap">Addenda</span></td>
+    <td class="right"><a href="#Page_242">242</a></td></tr>
+
+<tr><td class="indent1">Part I.</td>
+    <td class="right"><a href="#Page_242">242</a></td></tr>
+
+<tr><td class="indent1">Part II.</td>
+    <td class="right"><a href="#Page_245">245</a></td></tr>
+
+<tr><td class="indent1">Part III.</td>
+    <td class="right"><a href="#Page_245">245</a></td></tr>
+
+<tr><td><span class="smcap">Alphabetical Index</span></td>
+    <td class="right"><a href="#Page_249">249</a></td></tr>
+
+<tr><td><a href="#Plate_I"><span class="smcap">Explanation of
+Plates.</span></a></td></tr>
+
+</table>
+
+<p><span class='pagenum'><a name="Page_v" id="Page_v"></a></span></p>
+<h3 class="p4">EDITOR'S PREFACE.</h3>
+
+<p class="p2">Dr. N. Annandale's volume on the Freshwater <span
+class="smcap">Sponges</span>, <span class="smcap">Polyzoa</span>, and
+<span class="smcap">Hydrida</span> contains an account of three of the
+chief groups of freshwater organisms. Although he deals mainly with
+Indian forms the book contains an unusually full account of the
+life-history and bionomics of freshwater Sponges, Polyzoa, and
+Hydrozoa.</p>
+
+<p class="p2">I have to thank Dr. Annandale for the great care he has
+taken in the preparation of his manuscript for the press, and also the
+Trustees of the Indian Museum, Calcutta, for their kindness in placing
+material at the disposal of the Author.</p>
+
+<p class="quotesig">A. E. SHIPLEY.</p>
+
+<p>Christ's College, Cambridge,<br />
+March 1911.</p>
+
+<p><span class='pagenum'><a name="Page_vii"
+id="Page_vii"></a></span></p>
+
+<h3 class="p4">SYSTEMATIC INDEX.</h3>
+
+<table summary="Systematic Index">
+<tr><td></td><td></td><td class="right">Page</td></tr>
+
+<tr><td></td><td class='center'>PORIFERA.</td></tr>
+
+<tr><td>Order HALICHONDRINA</td><td> </td><td class="right"><a
+href="#Page_65">65</a></td></tr>
+
+<tr><td class='left'>Fam. 1. <span
+class="smcap">Spongillid�</span></td><td></td><td class="right"><a
+href="#Page_65">65</a></td></tr>
+
+<tr><td>1. Spongilla, <i>Lamarck</i></td><td> </td><td class="right"><a
+href="#Page_67">67</a></td></tr>
+
+<tr><td class="indent1">1<span class="smcap">a</span>. Euspongilla,
+<i>Vejdovsky</i></td><td> </td><td class="right"><a
+href="#Page_69">69</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;1. lacustris, <i>auct.</i></td><td>
+</td><td class="right"><a href="#Page_69">69</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;1 <i>a</i>. reticulata,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_71">71</a>, <a href="#Page_241">241</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;2. proliferens,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_72">72</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;3. alba, <i>Carter</i></td><td>
+</td><td class="right"><a href="#Page_76">76</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;3 <i>a</i>. cerebellata,
+<i>Bowerbank</i></td><td> </td><td class="right"><a
+href="#Page_76">76</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;3 <i>b</i>. bengalensis,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_77">77</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;4. cinerea, <i>Carter</i></td><td>
+</td><td class="right"><a href="#Page_79">79</a>, <a
+href="#Page_241">241</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;5. travancorica,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_81">81</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;6. hemephydatia,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_82">82</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;7. crateriformis
+(<i>Potts</i>)</td><td> </td><td class="right"><a
+href="#Page_83">83</a></td></tr>
+
+<tr><td class="indent1">1<span class="smcap">b</span>. Eunapius, <i>J.
+E. Gray</i></td><td> </td><td class="right"><a
+href="#Page_86">86</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;8. carteri, <i>Carter</i></td><td>
+</td><td class="right"><a href="#Page_87">87</a>, <a
+href="#Page_241">241</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;8 <i>a</i>. mollis,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_88">88</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;8 <i>b</i>. cava,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_88">88</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;8 <i>c</i>. lobosa,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_89">89</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;9. fragilis, <i>Leidy</i></td><td>
+</td><td class="right"><a href="#Page_95">95</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;9 <i>a</i>. calcuttana,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_96">96</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;9 <i>b</i>. decipiens,
+<i>Weber</i></td><td> </td><td class="right"><a
+href="#Page_97">97</a></td></tr>
+
+<tr><td class="indent2">10. gemina, <i>Annandale </i></td><td> </td><td
+class="right"><a href="#Page_97">97</a></td></tr>
+
+<tr><td class="indent2">11. crassissima, <i>Annandale</i></td><td>
+</td><td class="right"><a href="#Page_98">98</a></td></tr>
+
+<tr><td class="indent2">11 <i>a</i>. crassior, <i>Annandale</i></td><td>
+</td><td class="right"><a href="#Page_98">98</a></td></tr>
+
+<tr><td class="indent1">1<span class="smcap">c</span>. Stratospongilla,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_100">100</a></td></tr>
+
+<tr><td class="indent2">12. indica, <i>Annandale</i></td><td> </td><td
+class="right"><a href="#Page_100">100</a></td></tr>
+
+<tr><td class="indent2">13. bombayensis, <i>Carter</i></td><td> </td><td
+class="right"><a href="#Page_102">102</a>, <a
+href="#Page_241">241</a></td></tr>
+
+<tr><td class="indent2">13 <i>a</i>. pneumatica,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_241">241</a></td></tr>
+
+<tr><td class="indent2">14. ultima, <i>Annandale</i></td><td> </td><td
+class="right"><a href="#Page_104">104</a></td></tr>
+
+<tr><td>2. Pectispongilla, <i>Annandale</i></td><td> </td><td
+class="right"><a href="#Page_106">106</a></td></tr>
+
+<tr><td class="indent2">15. aurea, <i>Annandale</i></td><td> </td><td
+class="right"><a href="#Page_106">106</a></td></tr>
+
+<tr><td class="indent2">15 <i>a</i>. subspinosa,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_107">107</a></td></tr>
+
+<tr><td>3. Ephydatia, <i>Lamouroux</i></td><td> </td><td
+class="right"><a href="#Page_108">108</a></td></tr>
+
+<tr><td class="indent2">16. meyeni (<i>Carter</i>)</td><td> </td><td
+class="right"><a href="#Page_108">108</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;fluviatilis,
+<i>auct.</i></td><td> </td><td class="right"><a
+href="#Page_242">242</a></td></tr>
+
+<tr><td>4. Dosilia, <i>Gray</i></td><td> </td><td class="right"><a
+href="#Page_110">110</a></td></tr>
+
+<tr><td class="indent2">17. plumosa (<i>Carter</i>)</td><td> </td><td
+class="right"><a href="#Page_111">111</a></td></tr>
+
+<tr><td>5. Trochospongilla, <i>Vejdovsky</i></td><td> </td><td
+class="right"><a href="#Page_113">113</a></td></tr>
+
+<tr><td class="indent2">18. latouchiana, <i>Annandale</i></td><td>
+</td><td class="right"><a href="#Page_115">115</a></td></tr>
+
+<tr><td class="indent2">19. phillottiana, <i>Annandale</i></td><td>
+</td><td class="right"><a href="#Page_117">117</a></td></tr>
+
+<tr><td class="indent2">20. pennsylvanica (<i>Potts</i>)</td><td>
+</td><td class="right"><a href="#Page_118">118</a></td></tr>
+
+<tr><td>6. Tubella, <i>Carter</i></td><td> </td><td class="right"><a
+href="#Page_120">120</a></td></tr>
+
+<tr><td class="indent2">21. vesparioides, <i>Annandale</i></td><td>
+</td><td class="right"><a href="#Page_120">120</a></td></tr>
+
+<tr><td>7. Corvospongilla, <i>Annandale</i></td><td> </td><td
+class="right"><a href="#Page_122">122</a></td></tr>
+
+<tr><td class="indent2">22. burmanica (<i>Kirkpatrick</i>)</td><td>
+</td><td class="right"><a href="#Page_123">123</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;caunteri,
+<i>Annandale</i></td><td> </td><td class="right"><a
+href="#Page_243">243</a></td></tr>
+
+<tr><td class="indent2">23. lapidosa (<i>Annandale</i>)</td><td>
+</td><td class="right"><a href="#Page_124">124</a></td></tr>
+
+<tr><td></td><td class='center'>HYDROZOA.</td></tr>
+
+<tr><td>Order ELEUTHEROBLASTEA</td><td></td><td class="right"><a
+href="#Page_147">147</a></td></tr>
+
+<tr><td class='left'>Fam. 1. <span
+class="smcap">Hydrid�</span></td><td></td><td class="right"><a
+href="#Page_147">147</a></td></tr>
+
+<tr><td>1. Hydra, <i>Linn�</i></td><td></td><td class="right"><a
+href="#Page_147">147</a></td></tr>
+
+<tr><td class="indent2">24. vulgaris, <i>Pallas</i></td><td></td><td
+class="right"><a href="#Page_148">148</a></td></tr>
+
+<tr><td class="indent2">25. oligactis, <i>Pallas</i></td><td></td><td
+class="right"><a href="#Page_158">158</a>, <a
+href="#Page_245">245</a></td></tr>
+
+<tr><td></td><td class='center'>POLYZOA.</td></tr>
+
+<tr><td>Order CTENOSTOMATA</td><td></td><td class="right"><a
+href="#Page_189">189</a></td></tr>
+
+<tr><td class='left'>Div. 1. <span
+class="ls">Vesicularina</span></td><td></td><td class="right"><a
+href="#Page_189">189</a></td></tr>
+
+<tr><td class='left'>Fam. 1. <span
+class="smcap">Vesicularid�</span></td><td></td><td class="right"><a
+href="#Page_189">189</a></td></tr>
+
+<tr><td>1. Bowerbankia, <i>Farre</i></td><td></td><td class="right"><a
+href="#Page_189">189</a></td></tr>
+
+<tr><td class="indent2">1. &nbsp;&nbsp;&nbsp;&nbsp;caudata,
+<i>Hincks</i></td><td></td><td class="right"><a
+href="#Page_189">189</a></td></tr>
+
+<tr><td class="indent2">1. <i>a</i>. bengalensis,
+<i>Annandale</i></td><td></td><td class="right"><a
+href="#Page_189">189</a></td></tr>
+
+<tr><td class='left'>Div. 2. <span
+class="ls">Paludicellina</span></td><td></td><td class="right"><a
+href="#Page_190">190</a></td></tr>
+
+<tr><td class='left'>Fam. 1. <span
+class="smcap">Paludicellid�</span></td><td></td><td class="right"><a
+href="#Page_191">191</a></td></tr>
+
+<tr><td>1. Paludicella, <i>Gervais</i></td><td></td><td class="right"><a
+href="#Page_192">192</a></td></tr>
+
+<tr><td>2. Victorella, <i>Kent</i></td><td></td><td class="right"><a
+href="#Page_194">194</a></td></tr>
+
+<tr><td class="indent2">26. bengalensis,
+<i>Annandale</i></td><td></td><td class="right"><a
+href="#Page_195">195</a></td></tr>
+
+<tr><td class='left'>Fam. 2. <span
+class="smcap">Hislopiid�</span></td><td></td><td class="right"><a
+href="#Page_199">199</a></td></tr>
+
+<tr><td class='left'>1. Hislopia, <i>Carter</i></td><td></td><td
+class="right"><a href="#Page_199">199</a></td></tr>
+
+<tr><td class="indent2">27.&nbsp;&nbsp;&nbsp;&nbsp;lacustris,
+<i>Carter</i></td><td></td><td class="right"><a
+href="#Page_202">202</a></td></tr>
+
+<tr><td class="indent2">27 <i>a</i>. moniliformis,
+<i>Annandale</i></td><td></td><td class="right"><a
+href="#Page_204">204</a></td></tr>
+
+<tr><td>&nbsp;</td></tr>
+
+<tr><td>Order PHYLACTOL�MATA</td><td></td><td class="right"><a
+href="#Page_206">206</a></td></tr>
+
+<tr><td class='left'>Div. 1. <span
+class="ls">Plumatellina</span></td><td></td><td class="right"><a
+href="#Page_206">206</a></td></tr>
+
+<tr><td class='left'>Fam. 1. <span
+class="smcap">Fredericellid�</span></td><td></td><td class="right"><a
+href="#Page_208">208</a></td></tr>
+
+<tr><td>1. Fredericella, <i>Gervais</i></td><td></td><td
+class="right"><a href="#Page_208">208</a></td></tr>
+
+<tr><td class="indent2">28. indica, <i>Annandale</i></td><td></td><td
+class="right"><a href="#Page_210">210</a>, <a
+href="#Page_245">245</a></td></tr>
+
+<tr><td class='left'>Fam. 2. <span
+class="smcap">Plumatellid�</span></td><td></td><td class="right"><a
+href="#Page_211">211</a></td></tr>
+
+<tr><td class='left'>Subfam. A. <i>Plumatellin�</i></td><td></td><td
+class="right"><a href="#Page_212">212</a></td></tr>
+
+<tr><td>1. Plumatella, <i>Lamarck</i></td><td></td><td class="right"><a
+href="#Page_212">212</a></td></tr>
+
+<tr><td class="indent2">29. fruticosa, <i>Allman</i></td><td></td><td
+class="right"><a href="#Page_217">217</a></td></tr>
+
+<tr><td class="indent2">30. emarginata, <i>Allman</i></td><td></td><td
+class="right"><a href="#Page_220">220</a>, <a
+href="#Page_245">245</a></td></tr>
+
+<tr><td class="indent2">31. javanica, <i>Kraepelin</i></td><td></td><td
+class="right"><a href="#Page_221">221</a></td></tr>
+
+<tr><td class="indent2">32. diffusa, <i>Leidy</i></td><td></td><td
+class="right"><a href="#Page_223">223</a>, <a
+href="#Page_245">245</a></td></tr>
+
+<tr><td class="indent2">33. allmani, <i>Hancock</i></td><td></td><td
+class="right"><a href="#Page_224">224</a>, <a
+href="#Page_246">246</a></td></tr>
+
+<tr><td class="indent2">34. tanganyik�,
+<i>Rousselet</i></td><td></td><td class="right"><a
+href="#Page_225">225</a>, <a href="#Page_246">246</a></td></tr>
+
+<tr><td class="indent2">35. punctata, <i>Hancock</i></td><td></td><td
+class="right"><a href="#Page_227">227</a></td></tr>
+
+<tr><td>2. Stolella, <i>Annandale</i></td><td></td><td class="right"><a
+href="#Page_229">229</a></td></tr>
+
+<tr><td class="indent2">36. indica, <i>Annandale</i></td><td></td><td
+class="right"><a href="#Page_229">229</a></td></tr>
+
+<tr><td class="indent2">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;himalayana,
+<i>Annandale</i></td><td></td><td class="right"><a
+href="#Page_246">246</a></td></tr>
+
+<tr><td class='left'>Subfam. B. <i>Lophopin�</i></td><td></td><td
+class="right"><a href="#Page_231">231</a></td></tr>
+
+<tr><td>1. Lophopodella, <i>Rousselet</i></td><td></td><td
+class="right"><a href="#Page_231">231</a></td></tr>
+
+<tr><td class="indent2">37. carteri (<i>Hyatt</i>)</td><td></td><td
+class="right"><a href="#Page_232">232</a></td></tr>
+
+<tr><td class="indent2">37 <i>a</i>. himalayana
+(<i>Annandale</i>)</td><td></td><td class="right"><a
+href="#Page_233">233</a></td></tr>
+
+<tr><td>2. Pectinatella, <i>Leidy</i></td><td></td><td class="right"><a
+href="#Page_235">235</a></td></tr>
+
+<tr><td class="indent2">38. burmanica, <i>Annandale</i></td><td></td><td
+class="right"><a href="#Page_235">235</a></td></tr>
+
+</table>
+<p><span class='pagenum'><a name="Page_1" id="Page_1"></a></span></p>
+
+<h3 class="p4">GENERAL INTRODUCTION<br /> TO THE VOLUME.</h3>
+
+<p class="p2">Although some zoologists have recently revived the old
+belief that the sponges and the c&oelig;lenterates are closely allied,
+no one in recent times has suggested that there is any morphological
+relationship between either of these groups and the polyzoa. Personally
+I do not think that any one of the three groups is allied to any other
+so far as anatomy is concerned; but for biological reasons it is
+convenient to describe the freshwater representatives of the three
+groups in one volume of the "Fauna."</p>
+
+<p>Indeed, I originally proposed to the Editor that this volume should
+include an account not only of the freshwater species, but of all those
+that have been found in stagnant water of any kind. It is often
+difficult to draw a line between the fauna of brackish ponds and marshes
+and that of pure fresh water or that of the sea, and this is
+particularly the case as regards the estuarine tracts of India and
+Burma.</p>
+
+<p>Pelseneer<a name="fnanchor_A" id="fnanchor_A"></a><a
+href="#footnote_A" class="fnanchor"><sup>[A]</sup></a> has expressed the
+opinion that the Black Sea and the South-east of Asia are the two
+districts in the world most favourable for the study of the origin of a
+freshwater fauna from a marine one. The transition in particular from
+the Bay of Bengal, which is much less salt than most seas, to the
+lower<span class='pagenum'><a name="Page_2" id="Page_2">[Pg
+2]</a></span>reaches of the Ganges or the Brahmaputra is peculiarly
+easy, and we find many molluscs and other animals of marine origin in
+the waters of these rivers far above tidal influence. Conditions are
+unfavourable in the rivers themselves for the development and
+multiplication of organisms of many groups, chiefly because of the
+enormous amount of silt held in suspension in the water and constantly
+being deposited on the bottom, and a much richer fauna exists in ponds
+and lakes in the neighbourhood of the rivers and estuaries than in
+running water. I have only found three species of polyzoa and three of
+sponges in running water in India, and of these six species, five have
+also been found in ponds or lakes. I have, on the other hand, found
+three c&oelig;lenterates in an estuary, and all three species are
+essentially marine forms, but two have established themselves in ponds
+of brackish water, one (the sea-anemone <i>Sagartia schilleriana</i>)
+undergoing in so doing modifications of a very peculiar and interesting
+nature. It is not uncommon for animals that have established themselves
+in pools of brackish water to be found occasionally in ponds of fresh
+water; but I have not been able to discover a single instance of an
+estuarine species that is found in the latter and not in the former.</p>
+
+<p>For these reasons I intended, as I have said, to include in this
+volume descriptions of all the c&oelig;lenterates and polyzoa known to
+occur in pools of brackish water in the estuary of the Ganges and
+elsewhere in India, but as my manuscript grew I began to realize that
+this would be impossible without including also an amount of general
+introductory matter not justified either by the scope of the volume or
+by special knowledge on the part of its author. I have, however, given
+in the introduction to each part a list of the species found in stagnant
+brackish water with a few notes and references to descriptions.</p>
+
+<p class="p2 center"><span class="smcap">Biological Peculiarities of the
+Sponges, C&oelig;lenterates, and Polyzoa of Fresh Water.</span></p>
+
+<p>There is often an external resemblance between the representatives of
+the sponges, c&oelig;lenterates, and polyzoa that causes them to be
+classed together in popular phraseology as "zoophytes"; and this
+resemblance is not merely a superficial one, for it is based on a
+similarity in habits as well as of habitat, and is correlated with
+biological phenomena that lie deeper than what are ordinarily called
+habits. These phenomena are of peculiar interest with<span
+class='pagenum'><a name="Page_3" id="Page_3">[Pg 3]</a></span> regard to
+difficult questions of nutrition and reproduction that perhaps can only
+be solved by a close study of animals living together in identical
+conditions and exhibiting, apparently in consequence of so living,
+similar but by no means identical tendencies, either anatomical or
+physiological, in certain directions.</p>
+
+<p>One of the most important problems on which the study of the sponges,
+c&oelig;lenterates, and polyzoa of stagnant water throws light is that
+of the production of resting buds and similar reproductive bodies
+adapted to withstand unfavourable conditions in a quiescent state and to
+respond to the renewal of favourable conditions by a renewed growth and
+activity.</p>
+
+<p>Every autumn, in an English pond or lake, a crisis takes place in the
+affairs of the less highly organized inhabitants, and preparations are
+made to withstand the unfavourable conditions due directly or indirectly
+to the low winter temperature of the water: the individual must perish
+but the race may be preserved. At this season <i>Hydra</i>, which has
+been reproducing its kind by means of buds throughout the summer,
+develops eggs with a hard shell that will lie dormant in the mud until
+next spring; the phylactol�matous polyzoa produce statoblasts, the
+ctenostomatous polyzoa resting-buds ("hibernacula"), and the sponges
+gemmules. Statoblasts, hibernacula, and gemmules are alike produced
+asexually, but they resemble the eggs of <i>Hydra</i> in being provided
+with a hard, resistant shell, and in having the capacity to lie dormant
+until favourable conditions return.</p>
+
+<p>In an Indian pond or lake a similar crisis takes place in the case
+of most species, but it does not take place at the same time of year in
+the case of all species. Unfortunately the phenomena of periodic
+physiological change have been little studied in the freshwater fauna of
+most parts of the country, and as yet we know very little indeed of the
+biology of the Himalayan lakes and tarns, the conditions in which
+resemble those to be found in similar masses of water in Europe much
+more closely than they do those that occur in ponds and lakes in a
+tropical plain. In Bengal, however, I have been able to devote
+considerable attention to the subject, and can state definitely that
+some species flourish chiefly in winter and enter the quiescent stage at
+the beginning of the hot weather (that is to say about March), while
+others reach their maximum development during the "rains" (July to
+September) and as a rule die down during winter, which is the driest as
+well as the coolest time of year.</p>
+
+<p><span class='pagenum'><a name="Page_4" id="Page_4">[Pg
+4]</a></span>The following is a list of the forms that in Bengal are
+definitely known to produce hard-shelled eggs, gemmules, resting-buds,
+or statoblasts only or most profusely at the approach of the hot weather
+and to flourish during winter:&mdash;</p>
+
+<p class="indent5a"><i>Spongilla carteri.</i></p>
+<p class="indent5b"><i>Sponging alba.</i></p>
+<p class="indent5b"><i>Spongilla alba</i> var. <i>bengalensis</i>.</p>
+<p class="indent5b"><i>Spongilla crassissima.</i></p>
+<p class="indent5b"><i>Hydra vulgaris.</i></p>
+<p class="indent5b"><i>Victorella bengalensis.</i></p>
+<p class="indent5b"><i>Plumatella fruticosa.</i></p>
+<p class="indent5b"><i>Plumatella emarginata.</i></p>
+<p class="indent5c"><i>Plumatella javanica.</i></p>
+
+<p>The following forms flourish mainly during the "rains":&mdash;</p>
+
+<p class="indent5a"><i>Spongilla lacustris</i> subsp.
+   <i>reticulata</i>.</p>
+<p class="indent5b"><i>Trochospongilla latouchiana.</i></p>
+<p class="indent5b"><i>Trochospongilla phillottiana.</i></p>
+<p class="indent5c"><i>Stolella indica.</i></p>
+
+<p>The following flourish throughout the year:&mdash;</p>
+
+<p class="indent5a"><i>Spongilla proliferens.</i></p>
+<p class="indent5c"><i>Hislopia lacustris.</i></p>
+
+<p>It is particularly interesting to note that three of the species that
+flourish in the mild winter of Bengal, namely <i>Hydra vulgaris</i>,
+<i>Plumatella emarginata</i>, and <i>P. fruticosa</i>, are identical
+with species that in Europe perish in winter. There is evidence,
+moreover, that the statoblasts of the genus to which two of them belong
+burst more readily, and thus give rise to new colonies, after being
+subjected to a considerable amount of cold. In Bengal they only burst
+after being subjected to the heat of the hot weather. Does extreme heat
+have a similar effect on aquatic organisms as extreme cold? There is
+some evidence that it has.</p>
+
+<p>The species that flourish in India during the rains are all forms
+which habitually live near the surface or the edge of ponds or puddles,
+and are therefore liable to undergo desiccation as soon as the rains
+cease and the cold weather supervenes.</p>
+
+<p>The two species that flourish all the year round do not, properly
+speaking, belong to one category, for whereas <i>Hislopia
+lacustris</i><span class='pagenum'><a name="Page_5" id="Page_5">[Pg
+5]</a></span> produces no form of resting reproductive body but bears
+eggs and spermatozoa at all seasons, <i>Spongilla proliferens</i> is a
+short-lived organism that undergoes a biological crisis every few weeks;
+that is to say, it begins to develop gemmules as soon as it is fully
+formed, and apparently dies down as soon as the gemmules have attained
+maturity. The gemmules apparently lie dormant for some little time, but
+incessant reproduction is carried on by means of external buds, a very
+rare method of reproduction among the freshwater sponges.</p>
+
+<p>The facts just stated prove that considerable specific idiosyncrasy
+exists as regards the biology of the sponges, hydroids, and polyzoa of
+stagnant water in Bengal; but an even more striking instance of this
+phenomenon is afforded by the sponges <i>Spongilla bombayensis</i> and
+<i>Corvospongilla lapidosa</i> in Bombay. These two sponges resemble one
+another considerably as regards their mode of growth, and are found
+together on the lower surface of stones. In the month of November,
+however, <i>C. lapidosa</i> is in full vegetative vigour, while <i>C.
+bombayensis</i>, in absolutely identical conditions, is already reduced
+to a mass of gemmules, having flourished during the "rains." It is thus
+clear that the effect of environment is not identical in different
+species. This is more evident as regards the groups of animals under
+consideration in India (and therefore probably in other tropical
+countries) than it is in Europe. The subject is one well worthy of study
+elsewhere than in India, for it is significant that specimens of <i>S.
+bombayensis</i> taken in November in S. Africa were in a state of
+activity, thus contrasting strongly with specimens taken at the same
+time of year (though not at the same season from a climatic point of
+view) in the Bombay Presidency.</p>
+
+<p class="p2 center"><span class="smcap">Geographical Distribution of
+the Indian Species.</span></p>
+
+<p>The geographical distribution of the lower invertebrates of fresh and
+of stagnant water is often an extremely wide one, probably because the
+individual of many species exists at certain seasons or in certain
+circumstances in a form that is not only resistant to unfavourable
+environment, but also eminently capable of being transported by wind or
+currents. We therefore find that some genera and even species are
+practically cosmopolitan in their range, while others, so far as our
+knowledge goes, appear to have an extraordinarily discontinuous
+distribution. The latter<span class='pagenum'><a name="Page_6"
+id="Page_6">[Pg 6]</a></span> phenomenon may be due solely to our
+ignorance of the occurrence of obscure genera or species in localities
+in which they have not been properly sought for, or it may have some
+real significance as indicating that certain forms cannot always
+increase and multiply even in those localities that appear most suitable
+for them. As an example of universally distributed species we may take
+the European polyzoa of the genus <i>Plumatella</i> that occur in India,
+while of species whose range is apparently discontinuous better examples
+could not be found than the sponges <i>Trochospongilla pennsylvanica</i>
+and <i>Spongilla crateriformis</i>, both of which are only known from N.
+America, the British Isles, and India.</p>
+
+<p>My geographical list of the species of sponges, c&oelig;lenterates,
+and polyzoa as yet found in fresh water in India is modelled on Col.
+Alcock's recently published list of the freshwater crabs (Potamonid�) of
+the Indian Empire<a name="fnanchor_B" id="fnanchor_B"></a><a
+href="#footnote_B" class="fnanchor"><sup>[B]</sup></a>. I follow him in
+accepting, with slight modifications of my own, Blanford's
+physiographical rather than his zoogeographical regions, not because I
+think that the latter have been or ought to be superseded so far as the
+vertebrates are concerned, but rather because the limits of the
+geographical distribution of aquatic invertebrates appear to depend on
+different factors from those that affect terrestrial animals or even
+aquatic vertebrates.</p>
+
+<p>"Varieties" are ignored in this list, because they are not considered
+to have a geographical significance. The parts of India that are least
+known as regards the freshwater representatives of the groups under
+consideration are the valley of the Indus, the lakes of Kashmir and
+other parts of the Himalayas, the centre of the Peninsula, and the basin
+of the Brahmaputra. Those that are best known are the districts round
+Bombay, Calcutta, Madras and Bangalore, Travancore and Northern
+Tenasserim. Little is known as regards Ceylon, and almost nothing as
+regards the countries that surround the Indian Empire, a few species
+only having been recorded from Yunnan and the Malay Peninsula, none from
+Persia, Afghanistan, or Eastern Turkestan, and only one from Tibet.
+Professor Max Weber's researches have, however, taught us something as
+regards Sumatra and Java, while the results of various expeditions to
+Tropical Africa are beginning to cast light on the lower invertebrates
+of the great lakes in the centre of that continent and of the basin of
+the Nile.</p>
+
+<p><span class='pagenum'><a name="Page_7" id="Page_7">[Pg
+7]</a></span>It is not known to what altitude the three groups range in
+the Himalayas and the hills of Southern India. No sponge has been found
+in Indian territory at an altitude higher than that of Bhim Tal in
+Kumaon (4,500 feet), and <i>Hydra</i> is only known from the plains; but
+a variety of <i>H. oligactis</i> was taken by Capt. F. H. Stewart in
+Tibet at an altitude of about 15,000 feet. <i>Plumatella diffusa</i>
+flourishes at Gangtok in Sikhim (6,100 feet), and I have found
+statoblasts of <i>P. fruticosa</i> in the neighbourhood of Simla on the
+surface of a pond situated at an altitude of about 8,000 feet; Mr. R.
+Kirkpatrick obtained specimens of the genus in the Botanical Gardens at
+Darjiling (6,900 feet), and two species have been found at Kurseong
+(4,500-5,000 feet) in the same district.</p>
+
+<p class="p2 center">GEOGRAPHICAL LIST OF THE FRESHWATER SPONGES,
+HYDROIDS, AND POLYZOA OF INDIA, BURMA, AND CEYLON.</p>
+
+<p class="blockquote">[A * indicates that a species or subspecies has
+only been found in one physiographical region or subregion so far as the
+Indian Empire is concerned; a &#8224; that the species has also been
+found in Europe, a &#167; in North America, a &#10043; in Africa, and a
+&#664; in the Malay Archipelago.]</p>
+
+<p class="center">1. <b>Western Frontier Territory</b><a
+name="fnanchor_C" id="fnanchor_C"></a><a href="#footnote_C"
+class="fnanchor"><sup>[C]</sup></a>.</p>
+
+<p class="center">(Baluchistan, the Punjab, and the N.W. Frontier
+Province.)</p>
+<p><span class="smcap">Sponges</span>:&mdash;</p>
+<p class="indent1d">1. <i>Spongilla</i> (<i>Eunapius</i>)
+<i>carteri</i>&#8224;&#664; (Lahore).</p>
+
+<p><span class="smcap">Hydroids</span>:&mdash;</p>
+<p class="indent1d">1. <i>Hydra oligactis</i>&#8224;&#167; (Lahore).</p>
+
+<p><span class="smcap">Polyzoa</span>:&mdash;</p>
+<p class="indent1e">1. <i>Plumatella fruticosa</i>&#8224;&#167;
+(Lahore).</p>
+<p class="indent1c">2. <i>Plumatella diffusa</i>&#8224;&#167;
+(Lahore).</p>
+
+<p class="p2 center">2. <b>Western Himalayan Territory.</b></p>
+<p class="center">(Himalayas from Hazara eastwards as far as Nepal.)</p>
+
+<p><span class="smcap">Sponges</span>:&mdash;</p>
+<p class="indent1e">1. <i>Spongilla</i> (<i>Eunapius</i>)
+<i>carteri</i>&#8224;&#664; (Bhim Tal).</p>
+<p class="indent1c">2. <i>Ephydatia meyeni</i>&#664; (Bhim Tal).</p>
+
+<p><span class="smcap">Hydroids</span>:&mdash;None known (<i>Hydra
+oligactis</i> recorded from Tibet).</p>
+
+<p><span class="smcap">Polyzoa</span>:&mdash;</p>
+<p class="indent1e">1. <i>Plumatella allmani</i>&#8224; (Bhim Tal).</p>
+<p class="indent1b">2. <i>Plumatella fruticosa</i>&#8224;&#167;
+(Simla).</p>
+<p class="indent1c">3. <i>Lophopodella carteri</i>&#10043; (Bhim
+Tal).</p>
+
+<p class="p2 center">3. <b>North-Eastern Frontier Territory.</b><span
+class='pagenum'><a name="Page_8" id="Page_8">[Pg 8]</a></span></p>
+<p class="center">(Sikhim, Darjiling and Bhutan, and the Lower Brahmaputra
+Drainage-System.)</p>
+
+<p><span class="smcap">Sponges</span>:&mdash;</p>
+<p class="indent1d"><i>Spongilla proliferens</i>&#664; (Assam).</p>
+
+<p><span class="smcap">Hydroids</span>:&mdash;None known.</p>
+
+<p><span class="smcap">Polyzoa</span>:&mdash;</p>
+<p class="indent1e">1. <i>Plumatella fruticosa</i>&#8224; (Kurseong and
+Assam).</p>
+<p class="indent1b">2. <i>Plumatella diffusa</i>&#8224;&#167;
+(Sikhim).</p>
+<p class="indent1c">3. <i>Plumatella javanica</i>&#664; (Kurseong).</p>
+<p class="p2 center">4. <b>Burma Territory.</b></p>
+
+<p class="center">(Upper Burma, Arrakan, Pegu, Tenasserim.)</p>
+
+<p><span class="smcap">Sponges</span>:&mdash;</p>
+
+<p class="indent1e">1. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>proliferens</i>&#664; (Upper Burma, Pegu).</p>
+<p class="indent1b">2. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>crateriformis</i>&#8224;&#167; (Tenasserim).</p>
+<p class="indent1b">3.&nbsp;<i>Spongilla</i> (<i>Eunapius</i>)
+<i>carteri</i>&#8224;&#664; (Upper Burma, Pegu, Tenasserim).</p>
+<p class="indent1b">4. <i>Trochospongilla latouchiana</i>
+(Tenasserim).</p>
+<p class="indent1b">5. <i>Trochospongilla phillottiana</i>
+(Tenasserim).</p>
+<p class="indent1b">6. <i>Tubella vesparioides</i>* (Tenasserim).</p>
+<p class="indent1c">7. <i>Corvospongilla  burmanica</i>* (Pegu).</p>
+
+<p><span class="smcap">Hydroids</span>:&mdash;</p>
+<p class="indent1d">1. <i>Hydra vulgaris</i>&#8224;&#167; (Upper Burma
+and Tenasserim).</p>
+
+<p><span class="smcap">Polyzoa</span>:&mdash;</p>
+<p class="indent1e">1. <i>Plumatella emarginata</i>&#8224;&#167; (Pegu,
+Upper Burma).</p>
+<p class="indent1b">2. <i>Plumatella allmani</i>&#8224;
+(Tenasserim).</p>
+<p class="indent1b">3. <i>Pectinatella burmanica</i> (Tenasserim).</p>
+<p class="indent1c">4. <i>Hislopia lacustris</i> (Pegu).</p>
+<p class="p2 center">5 <i>a.</i> <b>Peninsular Province&mdash;Main
+Area.</b></p>
+
+<p class="center">(The Peninsula east of the Western Ghats.)</p>
+
+<p><span class="smcap">Sponges</span>:&mdash;</p>
+<p class="indent1e">1.&nbsp;<i>Spongilla</i> (<i>Euspongilla</i>)
+<i>lacustris</i> subsp. <i>reticulata</i> (Orissa, Madras).</p>
+<p class="indent1b">2. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>proliferens</i>&#664; (Madras).</p>
+<p class="indent1b">3. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>alba</i>&#10043; (N. Madras, Orissa, Hyderabad).</p>
+<p class="indent1b">4. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>hemephydatia</i>* (Orissa).</p>
+<p class="indent1b">5. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>crateriformis</i>&#8224;&#167;.</p>
+<p class="indent1b">6. <i>Spongilla</i> (<i>Eunapius</i>)
+<i>carteri</i>&#8224;&#664;.</p>
+<p class="indent1b">7. <i>Spongilla</i> (<i>Eunapius</i>) <i>gemina</i>*
+(Bangalore).</p>
+<p class="indent1b">8. <i>Spongilla</i> (<i>Stratospongilla</i>)
+<i>bombayensis</i>&#10043; (Mysore).</p>
+<p class="indent1c">9. <i>Dosilia plumosa</i> (N. Madras).</p>
+
+<p><span class="smcap">Hydroids</span>:&mdash;</p>
+<p class="indent1d">1. <i>Hydra vulgaris</i>&#8224;&#167;.</p>
+
+<p><span class="smcap">Polyzoa</span>:&mdash;</p>
+<p class="indent1e">1. <i>Plumatella fruticosa</i>&#8224; (Madras,
+Bangalore).</p>
+<p class="indent1b">2. <i>Lophopus</i> (?<i>Lophopodella</i>), sp.
+(Madras).</p>
+<p class="indent1b">3. <i>Pectinatella burmanica</i> (Orissa).</p>
+<p class="indent1b">4. <i>Victorella bengalensis</i> (Madras).</p>
+<p class="indent1c">5. <i>Hislopia lacustris</i> (Nagpur).</p>
+<p class="p2 center">5b. <b>Peninsular Province&mdash;Malabar
+Zone.</b><span class='pagenum'><a name="Page_9" id="Page_9">[Pg
+9]</a></span></p>
+
+<p class="center">(Western Ghats from Tapti R. to Cape Comorin and
+eastwards to the sea.)</p>
+
+<p><span class="smcap">Sponges</span>:&mdash;</p>
+<p class="indent1e">1. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>lacustris</i> subsp. <i>reticulata</i> (W. Ghats).</p>
+<p class="indent1b">2. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>proliferens</i>&#664; (Cochin).</p>
+<p class="indent1b">3. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>alba</i>&#10043;.</p>
+<p class="indent1b">4. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>cinerea</i>*.</p>
+<p class="indent1b">5. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>travancorica</i>* (Travancore).</p>
+<p class="indent1b">6. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>crateriformis</i>&#8224;&#167; (Cochin).</p>
+<p class="indent1b">7. <i>Spongilla</i> (<i>Eunapius</i>)
+<i>carteri</i>&#8224;&#664;.</p>
+<p class="indent1b">8. <i>Spongilla</i> (<i>Stratospongilla</i>)
+<i>indica</i>* (W. Ghats).</p>
+<p class="indent1b">9. <i>Spongilla </i> (<i>Stratospongilla</i>)
+<i>bombayensis</i>&#10043; (Bombay, W. Ghats).</p>
+<p class="indent1bb">10. <i>Spongilla</i> (<i>Stratospongilla</i>)
+<i>ultima</i>* (Travancore).</p>
+<p class="indent1bb">11. <i>Pectispongilla aurea</i>* (Travancore,
+Cochin).</p>
+<p class="indent1bb">12. <i>Ephydatia meyeni</i>&#664; (Bombay,
+Travancore).</p>
+<p class="indent1bb">13. <i>Dosilia plumosa</i> (Bombay).</p>
+<p class="indent1bb">14. <i>Trochospongilla
+pennsylvanica</i>*&#8224;&#167; (Travancore).</p>
+<p class="indent1cc">15. <i>Corvospongilla lapidosa</i>* (W. Ghats).</p>
+
+<p><span class="smcap">Hydroids</span>:&mdash;None recorded.</p>
+
+<p><span class="smcap">Polyzoa</span>:&mdash;</p>
+<p class="indent1e">1. <i>Fredericella indica</i>* (W. Ghats and
+Travancore).</p>
+<p class="indent1b">2. <i>Plumatella fruticosa</i>&#8224; (Bombay).</p>
+<p class="indent1b">3. <i>Plumatella javanica</i>&#664;
+(Travancore).</p>
+<p class="indent1b">4. <i>Plumatella tanganyik�</i>*&#10043; (W.
+Ghats).</p>
+<p class="indent1b">5. <i>Lophopodella carteri</i>&#10043; (Bombay, W.
+Ghats).</p>
+
+<p class="p2 center">6. <b>Indo-Gangetic Plain.</b></p>
+<p class="center">(From Sind to the Brahmaputra.)</p>
+
+<p><span class="smcap">Sponges</span>:&mdash;</p>
+<p class="indent1e">1.&nbsp;<i>Spongilla</i> (<i>Euspongilla</i>)
+<i>lacustris</i> subsp. <i>reticulata</i> (Gangetic delta).</p>
+<p class="indent1b">2. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>proliferens</i>&#664; (Lower Bengal, etc.).</p>
+<p class="indent1b">3. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>alba</i>&#10043; (Lower Bengal).</p>
+<p class="indent1b">4. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>crateriformis</i>&#8224;&#167;.</p>
+<p class="indent1b">5. <i>Spongilla</i> (<i>Eunapius</i>)
+<i>carteri</i>&#8224;&#664; (Lower Bengal, etc.).</p>
+<p class="indent1b">6. <i>Spongilla</i> (<i>Eunapius</i>)
+<i>fragilis</i> subsp. <i>calcuttana</i>* (Lower Bengal).</p>
+<p class="indent1b">7. <i>Spongilla</i> (<i>Eunapius</i>)
+<i>crassissima</i> (Bengal).</p>
+<p class="indent1b">8. <i>Ephydatia meyeni</i>&#664; (Lower Bengal).</p>
+<p class="indent1b">9. <i>Trochospongilla latouchiana</i> (Lower
+Bengal).</p>
+<p class="indent1cc">10. <i>Trochospongilla phillottiana</i> (Lower
+Bengal).</p>
+
+<p><span class="smcap">Hydroids</span>:&mdash;</p>
+<p class="indent1d">1. <i>Hydra vulgaris</i>&#8224;&#167;.</p>
+
+<p><span class="smcap">Polyzoa</span>:&mdash;</p>
+<p class="indent1e">1. <i>Plumatella fruticosa</i>&#8224;.</p>
+<p class="indent1b">2. <i>Plumatella emarginata</i>&#8224;&#167;.</p>
+<p class="indent1b">3. <i>Plumatella javanica</i>&#664; (Lower
+Bengal).</p>
+<p class="indent1b">4. <i>Plumatella diffusa</i>&#8224;&#167;.</p>
+<p class="indent1b">5. <i>Plumatella allmani</i>&#8224;.</p>
+<p class="indent1b">6. <i>Plumatella punctata</i>&#8224;&#167; (Lower
+Bengal).</p>
+<p class="indent1b">7. <i>Stolella indica</i>* (Lower Bengal, United
+Provinces).</p>
+<p class="indent1b">8. <i>Victorella bengalensis</i> (Lower Bengal).</p>
+<p class="indent1b">9. <i>Hislopia lacustris</i> (United Provinces, N.
+Bengal).</p>
+<p class="indent1b">9a. <i>Hislopia lacustris</i> subsp.
+<i>moniliformis</i>* (Lower Bengal).</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_10"
+id="Page_10">[Pg 10]</a></span>7. <b>Ceylon.</b></p>
+
+<p><span class="smcap">Sponges</span>:&mdash;</p>
+<p class="indent1e">1. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>proliferens</i>&#664;.</p>
+<p class="indent1c">2. <i>Spongilla</i> (<i>Eunapius</i>)
+<i>carteri</i>&#8224;&#664;.</p>
+
+<p><span class="smcap">Hydroids</span>:&mdash;</p>
+<p class="indent1d">1. <i>Hydra vulgaris</i>&#8224;&#167;.</p>
+
+<p><span class="smcap">Polyzoa</span>:&mdash;</p>
+<p class="indent1e">1. ? <i>Plumatella emarginata</i>&#8224;&#167;.</p>
+<p class="indent1c">2. <i>Pectinatella burmanica.</i></p>
+
+<p>The most striking feature of this list is the evidence it affords as
+to the distinct character of the fauna of the Malabar Zone, a feature
+that is also remarkably clear as regards the Potamonid�, one genus of
+which (<i>Gecarcinucus</i>) is peculiar, so far as India is concerned,
+to that zone. As regards the sponges we may note the occurrence of no
+less than three species of the subgenus <i>Stratospongilla</i>, which
+has not been found elsewhere in India except on one occasion in Mysore,
+and of a species of the genus <i>Corvospongilla</i>, which is unknown
+from the rest of Peninsular India and from the Himalayas. The genus
+<i>Pectispongilla</i> is only known from the Malabar Zone. Among the
+polyzoa the genus <i>Fredericella</i><a name="fnanchor_D"
+id="fnanchor_D"></a><a href="#footnote_D"
+class="fnanchor"><sup>[D]</sup></a> appears to be confined, so far as
+the Indian and Burmese fauna is concerned, to the Malabar Zone, and the
+same is true as regards the group of species to which <i>Plumatella
+tanganyik�</i>, an African form, belongs.</p>
+
+<p>A further examination of the list of Malabar species and a
+consideration of allied forms shows that the majority of the forms
+restricted to the Malabar Zone are either African or else closely allied
+to African forms. The genus <i>Corvospongilla</i>, except for one
+Burmese species, is otherwise peculiar to Tropical Africa; while
+<i>Stratospongilla</i>, although not confined to Africa, is more
+prolific in species in that continent than in any other. <i>Spongilla
+(Stratospongilla) bombayensis</i> has only been found in Bombay, the
+Western Ghats, Mysore, and Natal, and <i>Plumatella tanganyik�</i> only
+in the Western Ghats and Central Africa. The genus <i>Fredericella</i>
+(which also occurs in Europe, N. America, and Australia) is apparently
+of wide distribution in Africa, while <i>Lophopodella</i> (which in
+India is not confined to the Malabar Zone) is, except for a Japanese
+race of the Indian species, restricted outside India, so far as we know,
+to East Africa.</p>
+
+<p><span class='pagenum'><a name="Page_11" id="Page_11">[Pg
+11]</a></span> A less definite relationship between the sponges and
+polyzoa of the Malabar Zone and those of countries to the east of India
+is suggested by the following facts:&mdash;</p>
+
+<p class="blockquote_b">(1) The occurrence of the genus
+<i>Corvospongilla</i> in Burma;<br />
+
+(2) the occurrence of the subgenus <i>Stratospongilla</i> in Sumatra,
+China, and the Philippines;<br />
+
+(3) the occurrence of a race of <i>Lophopodella carteri</i> in Japan;<br
+/>
+
+(4) the occurrence of a species allied to <i>Plumatella tanganyik�</i>
+in the Philippines.</p>
+
+<p>It will be noted that in each of these instances the relationship
+extends to Africa as well as to the Eastern countries, and is more
+marked in the former direction. The species of <i>Stratospongilla</i>,
+moreover, that occurs in Sumatra (<i>S. sumatrensis</i>) also occurs in
+Africa, while those that have been found in China and the Philippines
+are aberrant forms.</p>
+
+<p>At first sight it might appear that these extra-Indian relationships
+might be explained by supposing that gemmules and statoblasts were
+brought to the Malabar Coast from Africa by the a�rial currents of the
+monsoon or by marine currents and carried from India eastwards by the
+same agency, this agency being insufficient to transport them to the
+interior and the eastern parts of the Peninsula. The work of La Touche<a
+name="fnanchor_E" id="fnanchor_E"></a><a href="#footnote_E"
+class="fnanchor"><sup>[E]</sup></a> on wind-borne foraminifera in
+Rajputana is very suggestive in this direction; but that the peculiar
+sponge and polyzoon fauna of Malabar is due to the agency either of wind
+or of marine currents may be denied with confidence, for it is a
+striking fact that most of the characteristic genera and subgenera of
+the Zone have resting reproductive bodies that are either fixed to solid
+objects or else are devoid of special apparatus to render them light.
+The former is the case as regards all species of <i>Corvospongilla</i>
+and all Indian and most other species of <i>Stratospongilla</i>, the
+gemmules of which not only are unusually heavy but also adhere firmly;
+while the statoblasts of <i>Fredericella</i> have no trace of the
+air-cells that render the free statoblasts of all other genera of
+phylactol�matous polyzoa peculiarly light and therefore peculiarly
+liable to be transported by wind.</p>
+
+<p><span class='pagenum'><a name="Page_12" id="Page_12">[Pg
+12]</a></span>A true <ins title="'geographica' in the
+original">geographical</ins> or geological explanation must therefore be
+sought for the relationship between the sponges and polyzoa of Malabar,
+of Africa, and of the Eastern countries&mdash;a relationship that is
+well known to exist as regards other groups of animals. No more
+satisfactory explanation has as yet been put forward than that of a
+former land connection between Africa and the Malaysia through Malabar
+at a period (probably late Cretaceous) when the Western Ghats were much
+higher than they now are<a name="fnanchor_F" id="fnanchor_F"></a><a
+href="#footnote_F" class="fnanchor"><sup>[F]</sup></a>.</p>
+
+<p>There is little to be said as regards the distribution of the
+sponges, hydroids, and polyzoa of fresh water in other parts of India.
+It may be noted, however, that the species known from the Punjab are all
+widely distributed Pal�arctic forms, and that the genus <i>Stolella</i>
+is apparently confined to the Indo-Gangetic Plain. Two species of sponge
+are peculiar to Lower Burma, one of them (<i>Corvospongilla
+burmanica</i>) representing the geographical alliance already discussed
+as regards the Malabar Zone, the other (<i>Tubella vesparioides</i>)
+closely related to a Malaysian species (<i>T. vesparium</i> from Borneo)
+and perhaps representing the northern limit of the Malaysian element
+well known in the fauna of Lower Burma. Of the sponges and polyzoa of
+Ceylon we know as yet too little to make it profitable to discuss their
+affinities. All that have as yet been discovered occur also in
+Peninsular India; nor do they afford any evidence of a connection with
+the Malabar Zone.</p>
+
+<p>The question of the geographical range of the sponges, hydroids, and
+polyzoa of brackish water may be considered briefly, for it is of
+importance in considering that of those which are confined to fresh
+water. Some of these species from brackish water (e.&nbsp;g.,
+<i>Membranipora lacroixii</i>) are identical with others (e.&nbsp;g.,
+<i>Victorella bengalensis</i> and <i>Bowerbankia caudata</i> subsp.
+<i>bengalensis</i>) closely related to European forms. Others again
+(e.&nbsp;g., <i>Loxosomatoides colonialis</i> and <i>Sagartia
+schilleriana</i>) are known as yet from the Ganges delta only. In our
+ignorance of the Indian representatives of the groups to which they
+belong, it is impossible to assert that their distribution is actually
+so restricted as it seems.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_13"
+id="Page_13">[Pg 13]</a></span><span class="smcap">Some Special
+Localities.</span></p>
+
+<p>In order to avoid constant repetition as regards the conditions that
+prevail at the places most frequently mentioned in this volume, a few
+details as regards them may be conveniently stated here.</p>
+
+<p class="center"><i>Lower Bengal.</i></p>
+
+<p><span class="smcap">Calcutta</span> is situated on the River Hughli
+at a point about 90 miles from the open sea. The water of the river is
+practically fresh, but is strongly affected by the tides; it is always
+turbid and of a brownish colour. The river, however, is not a good
+collecting ground for sponges, c&oelig;lenterates, and polyzoa, and none
+of the species described in this volume have been obtained from it. It
+is in the Calcutta "tanks" that most of my investigations have been
+made. These tanks are ponds, mostly of artificial origin, very numerous,
+of varying size but never very large or deep. Most of them contain few
+solid objects to which sedentary organisms can fix themselves, and such
+ponds are of course poor in sponges and polyzoa. Others, however,
+support a prolific growth of weeds such as <i>Pistia stratiotes</i>,
+<i>Lemna</i>, and <i>Limnanthemum</i>, and a few have brickwork or
+artificial stonework at their sides. In those parts of the town that
+approach the Salt Lakes (large lagoons and swamps of brackish water
+connected with the sea by the Mutlah River) the water of the ponds is
+slightly brackish and permits few plants except alg� to flourish. Few of
+the bigger tanks ever dry up. The best of the tanks from the
+sponge-collector's point of view, so far as I have been able to
+discover, is the one in the compound of the Indian Museum. It enjoys all
+the advantages of light and shade, solid supports, prolific aquatic
+vegetation, considerable depth, and the vicinity of human dwellings that
+seem to be favourable to the growth of sponges, no less than nine
+species of which, representing three genera and two subgenera, grow
+abundantly in it. <i>Hydra</i> also flourishes in this pond, but for
+some reasons there are few polyzoa. The phylactol�matous species of the
+latter group, however, are extraordinarily abundant in one of the tanks
+in the Zoological Gardens at Alipore. In this tank, which unlike the
+Museum tank is directly connected with the river, no less than six
+species and varieties of the genus <i>Plumatella</i> have been found
+growing together on sticks, floating seeds, and water-plants. Except
+<i>Hislopia</i>, which is common on <i>Vallisneria</i> in one tank on
+the<span class='pagenum'><a name="Page_14" id="Page_14">[Pg
+14]</a></span> Maidan (opposite the Bengal Club), the ctenostomes of
+stagnant water are only found in the tanks near the Salt Lakes.</p>
+
+<p><span class="smcap">Port Canning</span> is situated on the Mutlah
+River about 30 miles from Calcutta and about 60 from the open sea. The
+Mutlah is really a tidal creek rather than a river, in spite of the fact
+that it runs for a considerable number of miles, and its waters are
+distinctly brackish. Water taken from the edge at Port Canning in March
+was found to contain 25.46 per thousand of saline residue. The
+interesting feature of Port Canning, however, is from a zoological point
+of view not the Mutlah but certain ponds of brackish water now
+completely separated from it, except occasionally when the river is in
+flood, but communicating regularly with it in the memory of living
+persons. These ponds, which were apparently not in existence in 1855,
+have on an average an area of about half an acre each, and were
+evidently formed by the excavation of earth for the construction of an
+embankment along the Mutlah. They are very shallow and lie exposed to
+the sun. The salinity differs considerably in different ponds, although
+the fauna seems to be identical; the water of one pond was found to
+contain 22.88 per thousand of saline residue in May, 20.22 per thousand
+in March, and 12.13 in December. A second pond in the neighbourhood of
+the first and apparently similar to it in every way contained only 9.82
+per thousand in July, after the rains had broken. The fauna of these
+ponds includes not only a freshwater sponge (<i>Spongilla alba</i> var.
+<i>bengalensis</i>) but also many aquatic insects (<i>e.&nbsp;g.</i>,
+larv� of mosquitos and of <i>Chironomus</i> and several species of
+beetles and Rhynchota); while on the other hand essentially marine
+c&oelig;lenterates (<i>Irene ceylonensis</i>, etc.) and worms
+(<i>e.&nbsp;g.</i>, the gephyrean <i>Physcosoma lurco</i><a
+name="fnanchor_G" id="fnanchor_G"></a><a href="#footnote_G"
+class="fnanchor"><sup>[G]</sup></a>) form a part of it, together with
+forms of intermediate habitat such as <i>Bowerbankia caudata</i> subsp.
+<i>bengalensis</i>, <i>Victorella bengalensis</i>, and several fish and
+crustacea common in brackish water.</p>
+
+<p class="center"><i>Orissa.</i></p>
+
+<p>Orissa may be described in general terms as consisting of the coastal
+area of Bengal south of the Gangetic delta. It extends in inland,
+however, for a considerable distance and includes hilly tracts. There is
+no geographical boundary between it and the<span class='pagenum'><a
+name="Page_15" id="Page_15">[Pg 15]</a></span> north-eastern part of the
+Madras Presidency or the eastern part of the Central Provinces.</p>
+
+<p><span class="smcap">Chilka Lake.</span>&mdash;This marine lake is a
+shallow lagoon measuring about 40 miles in length and 10 miles in
+breadth, and formed in geologically recent times by the growth of a
+narrow sand-bank across the mouth of a wide bay. At its northern end it
+communicates with the sea by a narrow channel, and throughout its length
+it is strongly affected by the tides. At its south end, which is
+actually situated in the Ganjam district of Madras, the water is
+distinctly brackish and is said to be nearly fresh at certain times of
+year. At this end there are numerous small artificial pools of brackish
+water somewhat resembling those of Port Canning as regards their
+fauna.</p>
+
+<p><span class="smcap">Sur</span> (or <span class="smcap">Sar</span>)
+<span class="smcap">Lake</span>.&mdash;A shallow, freshwater lake of
+very variable size situated a few miles north of Puri on the Orissa
+coast. In origin it probably resembled the Chilka Lake, but it is now
+separated from the sea by about 3 miles of barren sand dunes, among
+which numerous little pools of rain-water are formed during the rains.
+These dry up completely in winter, and even the lake itself is said
+sometimes almost to disappear, although when it is full it is several
+miles in length. The fauna is essentially a freshwater one, but includes
+certain Mysid� and other crustacea usually found in brackish water.</p>
+
+<p class="center"><i>Bombay Presidency.</i></p>
+
+<p><span class="smcap">Bombay.</span>&mdash;The town of Bombay, built on
+an island near the mainland, is situated close to swamps and creeks of
+brackish water not unlike those that surround Calcutta. Its "tanks,"
+however, differ from those of Calcutta in having rocky bottoms and, in
+many cases, in drying up completely in the hot weather. Of the fauna of
+the swamps extremely little is known, but so far as the sponges and
+polyzoa of the tanks are concerned the work undertaken by Carter was
+probably exhaustive.</p>
+
+<p><span class="smcap">Igatpuri.</span>&mdash;Igatpuri is situated at an
+altitude of about 2000 feet, 60 miles north-east of Bombay. Above the
+town there is a lake of several square miles in area whence the
+water-supply of several stations in the neighbourhood is obtained. The
+water is therefore kept free from contamination. The bottom is composed
+of small stones and slopes gradually up at the edges. During the dry
+weather its level sinks considerably. Several interesting sponges<span
+class='pagenum'><a name="Page_16" id="Page_16">[Pg 16]</a></span> and
+polyzoa have been found in this lake, most of them also occurring in a
+small pond in the neighbourhood in which clothes are washed and the
+water is often full of soap-suds.</p>
+
+<p class="center"><i>Southern India.</i></p>
+
+<p><span class="smcap">Madras.</span>&mdash;The city of Madras is built
+by the sea, straggling over a large area of the sandy soil
+characteristic of the greater part of the east coast of India. In wet
+weather this soil retains many temporary pools of rain-water, and there
+are numerous permanent tanks of no great size in the neighbourhood of
+the town. The so-called Cooum River, which flows through the town, is
+little more than a tidal creek, resembling the Mutlah River of Lower
+Bengal on a much smaller scale. The sponges and polyzoa as yet found in
+the environs of Madras are identical with those found in the environs of
+Calcutta.</p>
+
+<p><span class="smcap">Bangalore.</span>&mdash;Bangalore (Mysore State)
+is situated near the centre of the Madras Presidency on a plateau about
+3000 feet above sea-level. The surrounding country is formed of laterite
+rock which decomposes readily and forms a fine reddish silt in the
+tanks. These tanks are numerous, often of large size, and as a rule at
+least partly of artificial origin. Their water supports few phanerogamic
+plants and is, as my friend Dr. Morris Travers informs me, remarkably
+free from salts in solution. The sponge fauna of the neighbourhood of
+Bangalore appears to be intermediate between that of Madras and that of
+Travancore.</p>
+
+<p><span class="smcap">The Backwaters of Cochin and
+Travancore.</span>&mdash;The "backwaters" of Cochin and Travancore were
+originally a series of shallow lagoons stretching along the coast of the
+southern part of the west coast of India for a distance of considerably
+over a hundred miles. They have now been joined together by means of
+canals and tunnels to form a tidal waterway, which communicates at many
+points directly with the sea. The salinity of the water differs greatly
+at different places and in different seasons, and at some places there
+is an arrangement to keep out sea-water while the rice-fields are being
+irrigated. The fauna is mainly marine, but in the less saline parts of
+the canals and lakes many freshwater species are found.</p>
+
+<p><i>Shasthancottah.</i>&mdash;There are two villages of this name, one
+situated on the backwater near Quilon (coast of Travancore), the<span
+class='pagenum'><a name="Page_17" id="Page_17">[Pg 17]</a></span> other
+about three miles inland on a large freshwater lake. This lake, which
+does not communicate with the backwater, occupies a narrow winding rift
+several miles in length at a considerable depth below the surrounding
+country. Its bottom is muddy and it contains few water-plants, although
+in some places the water-plants that do exist are matted together to
+form floating islands on which trees and bushes grow. The fauna, at any
+rate as regards mollusca and microscopic organisms, is remarkably poor,
+but two species of polyzoa (<i>Fredericella indica</i> and <i>Plumatella
+fruticosa</i>) and one of sponge (<i>Trochospongilla pennsylvanica</i>)
+grow in considerable abundance although not in great luxuriance.</p>
+
+<p class="center"><i>The Himalayas.</i></p>
+
+<p><span class="smcap">Bhim Tal</span><a name="fnanchor_H"
+id="fnanchor_H"></a><a href="#footnote_H"
+class="fnanchor"><sup>[H]</sup></a> is a lake situated at an altitude of
+4500 feet in that part of the Western Himalayas known as Kumaon, near
+the plains. It has a superficial area of several square miles, and is
+deep in the middle. Its bottom and banks are for the most part muddy.
+Little is known of its fauna, but two polyzoa (<i>Plumatella allmani</i>
+and <i>Lophopodella carteri</i>) and the gemmules of two sponges
+(<i>Spongilla carteri</i> and <i>Ephydatia meyeni</i>) have been found
+in it.</p>
+
+<p class="center">*     *     *     *     *</p>
+
+<p class="p2 center"><span class="smcap">Nomenclature and
+Terminology.</span></p>
+
+<p>The subject of nomenclature may be considered under four
+heads:&mdash;(I.) the general terminology of the various kinds of groups
+of individuals into which organisms must be divided; (II.) the general
+nomenclature of specimens belonging to particular categories, such as
+types, co-types, etc.; (III.) the nomenclature that depends on such
+questions as that of "priority"; and (IV.) the special terminology
+peculiar to the different groups. The special terminology peculiar to
+the different groups is dealt with in the separate introductions to each
+of the three parts of this volume.</p>
+
+<p class="center">(I.)</p>
+
+<p>No group of animals offers greater difficulty than the sponges,
+hydroids, and polyzoa (and especially the freshwater representatives of
+these three groups) as regards the question "What is a species?" and the
+kindred questions, "What is a subspecies?" "What is a variety?" and
+"What is a phase?" Genera can<span class='pagenum'><a name="Page_18"
+id="Page_18">[Pg 18]</a></span> often be left to look after themselves,
+but the specific and kindred questions are answered in so many different
+ways, if they are even considered, by different systematists, especially
+as regards the groups described in this volume, that I feel it necessary
+to state concisely my own answers to these questions, not for the
+guidance of other zoologists but merely to render intelligible the
+system of classification here adopted. The following definitions should
+therefore be considered in estimating the value of "species," etc.,
+referred to in the following pages.</p>
+
+<p><i>Species.</i>&mdash;A group of individuals differing in constant
+characters of a definite nature and of systematic<a name="fnanchor_I"
+id="fnanchor_I"></a><a href="#footnote_I"
+class="fnanchor"><sup>[I]</sup></a> importance from all others in the
+same genus.</p>
+
+<p><i>Subspecies.</i>&mdash;An isolated or local race, the individuals
+of which differ from others included in the same species in characters
+that are constant but either somewhat indefinite or else of little
+systematic importance.</p>
+
+<p><i>Variety.</i>&mdash;A group of individuals not isolated
+geographically from others of the same species but nevertheless
+exhibiting slight, not altogether constant, or indefinite differences
+from the typical form of the species (<i>i. e.</i>, the form first
+described).</p>
+
+<p><i>Phase.</i>&mdash;A peculiar form assumed by the individuals of a
+species which are exposed to peculiarities in environment and differ
+from normal individuals as a direct result.</p>
+
+<p>There are cases in which imperfection of information renders it
+difficult or impossible to distinguish between a variety and a
+subspecies. In such cases it is best to call the form a variety, for
+this term does not imply any special knowledge as regards its
+distribution or the conditions in which it is found.</p>
+
+<p>I use the term "form" in a general sense of which the meaning or
+meanings are clear without explanation.</p>
+
+<p class="center">(II.)</p>
+
+<p>The question of type specimens must be considered briefly. There are
+two schools of systematists, those who assert that one specimen and one
+only must be the type of a species, and those who are willing to accept
+several specimens as types. From the theoretical point of view it seems
+impossible to set up any one<span class='pagenum'><a name="Page_19"
+id="Page_19">[Pg 19]</a></span> individual as the ideal type of a
+species, but those who possess collections or are in charge of museums
+prefer, with the natural instinct of the collector, to have a definite
+single type (of which no one else can possibly possess a duplicate) in
+their possession or care, and there is always the difficulty that a
+zoologist in describing a species, if he recognizes more than one type,
+may include as types specimens that really belong to more than one
+species. These difficulties are met by some zoologists by the
+recognition of several specimens as paratypes, all of equal value; but
+this, after all, is merely a terminological means of escaping from the
+difficulty, calculated to salve the conscience of a collector who feels
+unwilling to give up the unique type of a species represented by other
+specimens in his collection. The difficulty as regards the confounding
+of specimens of two or more species as the types of one can always be
+adjusted if the author who discovers the mistake redescribes one of the
+species under the original name and regards the specimen that agrees
+with his description as the type, at the same time describing a new
+species with another of the specimens as its type. Personally I always
+desire to regard the whole material that forms the basis of an original
+description of a species as the type, but museum rules often render this
+impossible, and the best that can be done is to pick out one specimen
+that seems particularly characteristic and to call it the type, the rest
+of the material being termed co-types. A peculiar difficulty arises,
+however, as regards many of the sponges, c&oelig;lenterates, and
+polyzoa, owing to the fact that they are often either compound animals,
+each specimen consisting of more than one individual, or are easily
+divisible into equivalent fragments. If the single type theory were
+driven to its logical conclusion, it would be necessary to select one
+particular polyp in a hydroid colony, or even the part of a sponge that
+surrounded a particular osculum as the type of the species to which the
+hydroid or the sponge belonged. Either by accident or by design
+specimens of Spongillid�, especially if kept dry, are usually broken
+into several pieces. There is, as a matter of fact, no reason to
+attribute the peculiarly sacrosanct nature of a type to one piece more
+than another. In such cases the biggest piece may be called the type,
+while the smaller pieces may be designated by the term "schizotype."</p>
+
+<p>The more precise definition of such terms as topotype, genotype,
+<i>et hujus generis omnis</i> is nowadays a science (or at any rate a
+form of technical industry) by itself and need not be discussed
+here.</p>
+
+<p class="center"><span class='pagenum'><a name="Page_20"
+id="Page_20">[Pg 20]</a></span>(III.)</p>
+
+<p>In 1908 an influential committee of British zoologists drew up a
+strenuous protest against the unearthing of obsolete zoological names
+(see 'Nature,' Aug. 1908, p.&nbsp;395). To no group does this protest apply
+with greater force than to the three discussed in this volume. It is
+difficult, however, to adopt any one work as a standard of nomenclature
+for the whole of any one of them. As regards the Spongillid� it is
+impossible to accept any monograph earlier than Potts's "Fresh-Water
+Sponges" (P. Ac. Philad., 1887), for Bowerbank's and Carter's earlier
+monographs contained descriptions of comparatively few species. Even
+Potts's monograph I have been unable to follow without divergence, for
+it seems to me necessary to recognize several genera and subgenera that
+he ignored. The freshwater polyzoa, however, were dealt with in so
+comprehensive a manner by Allman in his "Fresh-Water Polyzoa" (London,
+1856) that no difficulty is experienced in ignoring, so far as
+nomenclature is concerned, any earlier work on the group; while as
+regards other divisions of the polyzoa I have followed Hincks's "British
+Marine Polyzoa" (1880), so far as recent researches permit. In most
+cases I have not attempted to work out an elaborate synonymy of species
+described earlier than the publication of the works just cited, for to
+do so is a mere waste of time in the case of animals that call for a
+most precise definition of species and genera and yet were often
+described, so far as they were known earlier than the dates in question,
+in quite general terms. I have been confirmed in adopting this course by
+the fact that few of the types of the earlier species are now in
+existence, and that a large proportion of the Indian forms have only
+been described within the last few years.</p>
+
+<p class="p2 center"><span class="smcap">Material.</span></p>
+
+<p>The descriptions in this volume are based on specimens in the
+collection of the Indian Museum, the Trustees of which, by the liberal
+manner in which they have permitted me to travel in India and Burma on
+behalf of the Museum, have made it possible not only to obtain material
+for study and exchange but also to observe the different species in
+their natural environment. This does not mean to say that specimens from
+other collections have been ignored, for many institutions and
+individuals have met us generously in the matter of gifts and exchanges,
+and our collection<span class='pagenum'><a name="Page_21"
+id="Page_21">[Pg 21]</a></span> now includes specimens of all the
+Indian forms, named in nearly all cases by the author of the species,
+except in those of species described long ago of which no authentic
+original specimens can now be traced. Pieces of the types of all of the
+Indian Spongillid� described by Carter have been obtained from the
+British Museum through the kind offices of Mr. R. Kirkpatrick. The
+Smithsonian Institution has sent us from the collection of the United
+States National Museum specimens named by Potts, and the Berlin Museum
+specimens named by Weltner, while to the Imperial Academy of Sciences of
+St. Petersburg we owe many unnamed but interesting sponges. Dr. K.
+Kraepelin and Dr. W. Michaelsen have presented us with specimens of most
+of the species and varieties of freshwater polyzoa described by the
+former in his great monograph and elsewhere. We owe to Dr. S. F. Harmer,
+formerly of the Cambridge University Museum and now Keeper in Zoology at
+the British Museum, to Professor Max Weber of Amsterdam, Professor Oka
+of Tokyo, and several other zoologists much valuable material. I would
+specially mention the exquisite preparations presented by Mr. C.
+Rousselet. Several naturalists in India have also done good service to
+the Museum by presenting specimens of the three groups described in this
+volume, especially Major H. J. Walton, I.M.S., Major J. Stephenson,
+I.M.S., Dr. J. R. Henderson and Mr. G. Matthai of Madras, and Mr. R.
+Shunkara Narayana Pillay of Trivandrum.</p>
+
+<p>The following list shows where the types of the various species,
+subspecies, and varieties are preserved, so far as it has been possible
+to trace them. I have included in this list the names of all species
+that have been found in stagnant water, whether fresh or brackish, but
+those of species not yet found in fresh water are enclosed in square
+brackets.</p>
+
+<p class="p4"><span class='pagenum'><a name="Page_22" id="Page_22">[Pg
+22]</a></span></p>
+
+<table summary="Stagnant water species types">
+
+<tr><th colspan="3"><span class="smcap">Indian
+Spongillid�.</span></th></tr>
+
+<tr><th><span class="smcap">Name.</span></th><th><span
+class="smcap">&nbsp;Type in Coll.</span></th><th><span
+class="smcap">Material<br />Examined.</span></th></tr>
+
+<tr><td class="left"><i>Spongilla lacustris</i> subsp.
+<i>reticulata</i></td><td class="left"> Ind. Mus.</td><td class="left">
+Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla proliferens</i></td><td class="left">
+Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla alba</i></td><td class="left"> Brit.
+and Ind. Mus.</td><td class="left"> Schizotype.</td></tr>
+
+<tr><td class="left">[<i>Spongilla alba</i> var.
+<i>bengalensis</i>]</td><td class="left"> Ind. Mus.</td><td
+class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla alba</i> var.
+<i>cerebellata</i></td><td class="left"> Brit. Mus.</td><td
+class="left">Specimens<br />compared with type.</td></tr>
+
+<tr><td class="left"><i>Spongilla cinerea</i></td><td class="left">
+Brit. and Ind. Mus.</td><td class="left"> Schizotype.</td></tr>
+
+<tr><td class="left">[<i>Spongilla travancorica</i>]</td><td
+class="left"> Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla hemephydatia</i></td><td class="left">
+Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla crateriformis</i></td><td
+class="left"> U.S. Nat. Mus.</td><td class="left"> Co-type.</td></tr>
+
+<tr><td class="left"><i>Spongilla carteri</i></td><td class="left">
+Brit. and Ind. Mus.</td><td class="left"> Schizotype.</td></tr>
+
+<tr><td class="left"><i>Spongilla carteri</i> var. <i>mollis</i></td><td
+class="left"> Ind. Mus.</td><td class="left">Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla carteri</i> var. <i>cava</i></td><td
+class="left"> Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla carteri</i> var. <i>lobosa</i></td><td
+class="left"> Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla fragilis</i> subsp.
+<i>calcuttana</i></td><td class="left"> Ind. Mus.</td><td class="left">
+Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla fragilis</i> subsp.
+<i>decipiens</i></td><td class="left"> Amsterdam Mus.</td><td
+class="left"> Co-type.</td></tr>
+
+<tr><td class="left"><i>Spongilla gemina</i></td><td class="left">  Ind.
+Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla crassissima</i></td><td class="left">
+Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla crassissima</i> var.
+<i>crassior</i></td><td class="left"> Ind. Mus.</td><td class="left">
+Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla bombayensis</i></td><td class="left">
+Brit. and Ind. Mus.</td><td class="left"> Schizotype.</td></tr>
+
+<tr><td class="left"><i>Spongilla indica</i></td><td class="left"> Ind.
+Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Spongilla ultima</i></td><td class="left"> Ind.
+Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Pectispongilla aurea</i></td><td class="left">
+Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Ephydatia meyeni</i></td><td class="left"> Brit.
+and Ind. Mus.</td><td class="left"> Schizotype.</td></tr>
+
+<tr><td class="left"><i>Dosilia plumosa</i></td><td class="left"> Brit.
+and Ind. Mus.</td><td class="left"> Schizotype.</td></tr>
+
+<tr><td class="left"><i>Trochospongilla latouchiana</i></td><td
+class="left"> Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Trochospongilla phillottiana</i></td><td
+class="left"> Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Trochospongilla pennsylvanica</i></td><td
+class="left"> U.S. Nat. Mus.</td><td class="left"> Co-type.</td></tr>
+
+<tr><td class="left"><i>Tubella vesparioides</i></td><td class="left">
+Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Corvospongilla burmanica</i></td><td
+class="left"> Brit. and Ind. Mus.</td><td class="left">
+Schizotype.</td></tr>
+
+<tr><td class="left"><i>Corvospongilla lapidosa</i></td><td
+class="left"> Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><th class="space" colspan="3"><span class="smcap">Indian
+C&oelig;lenterates of Stagnant Water.</span></th></tr>
+
+<tr><td class="center"><span class="smcap">Hydrozoa.</span></td></tr>
+
+<tr><td class="left"><i>Hydra oligactis</i></td><td class="left"> Not in
+existence.</td></tr>
+
+<tr><td class="left"><i>Hydra vulgaris</i></td><td class="left"> Not in
+existence.</td></tr>
+
+<tr><td class="left">[<i>Syncoryne filamentata</i>]</td><td
+class="left"> Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left">[<i>Bimeria vestita</i>]</td><td class="left"> ?
+Not in existence.</td></tr>
+
+<tr><td class="left">[<i>Irene ceylonensis</i>]</td><td class="left">
+Hydroid in Ind. Mus.,<br />Medusa in Brit. Mus.</td><td class="left">
+Hydroid type.</td></tr>
+
+<tr><td class="center"><span class="smcap">Actiniaria.</span></td></tr>
+
+<tr><td class="left">[<i>Sagartia schilleriana</i>]</td><td
+class="left"> Ind. Mus.</td><td class="left"> Types.</td></tr>
+
+<tr><td class="left">[<i>Sagartia schilleriana</i> subsp.
+<i>exul</i>]</td><td class="left"> Ind. Mus.</td><td class="left">
+Type.</td></tr>
+
+<tr><th class="space" colspan="3"><span class="smcap">Indian Polyzoa of
+Stagnant Water.</span><span class='pagenum'><a name="Page_23"
+id="Page_23">[Pg 23]</a></span></th></tr>
+
+<tr><td class="center"><span class="smcap">Entoprocta.</span></td></tr>
+
+<tr><td class="left">[<i>Loxosomatoides colonialis</i>]</td><td
+class="left"> Ind. Mus.</td><td class="left"> Types.</td></tr>
+
+<tr><td class="center"><span class="smcap">Ectoprocta
+Cheilostomata.</span></td></tr>
+
+<tr><td class="left">[<i>Membranipora lacroixii</i>]</td><td
+class="left"> ? Paris Mus.</td></tr>
+
+<tr><td class="left">[<i>Membranipora bengalensis</i>]</td><td
+class="left"> Ind. Mus.</td><td class="left"> Types.</td></tr>
+
+<tr><td class="center"><span class="smcap">Ectoprocta
+Stenostomata.</span></td></tr>
+
+<tr><td class="left">[<i>Bowerbankia caudata</i> subsp.
+<i>bengalensis</i>]</td><td class="left"> Ind. Mus.</td><td
+class="left"> Types.</td></tr>
+
+<tr><td class="left"><i>Victorella bengalensis</i></td><td class="left">
+ Ind. Mus.</td><td class="left"> Types.</td></tr>
+
+<tr><td class="left"><i>Hislopia lacustris</i></td><td class="left"> ?
+Not in existence.</td></tr>
+
+<tr><td class="left"><i>Hislopia lacustris</i> subsp.
+<i>moniliformis</i></td><td class="left"> Ind. Mus.</td><td
+class="left"> Types.</td></tr>
+
+<tr><td class="center"><span class="smcap">Ectoprocta
+Phylactol�mata.</span></td></tr>
+
+<tr><td class="left"><i>Fredericella indica</i></td><td class="left">
+Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Plumatella fruticosa</i></td><td class="left">
+Not in existence.</td></tr>
+
+<tr><td class="left"><i>Plumatella diffusa</i></td><td class="left"> ?
+Philadelphia Acad.<a name="fnanchor_J" id="fnanchor_J"></a><a
+href="#footnote_J" class="fnanchor"><sup>[J]</sup></a></td></tr>
+
+<tr><td class="left"><i>Plumatella allmani</i></td><td class="left"> Not
+in existence.</td></tr>
+
+<tr><td class="left"><i>Plumatella emarginata</i></td><td class="left">
+Not in existence.</td></tr>
+
+<tr><td class="left"><i>Plumatella javanica</i></td><td
+class="left">Hamburg and<br />Ind.  Mus.</td><td class="left">One of<br
+/>the types.</td></tr>
+
+<tr><td class="left"><i>Plumatella tanganyik�</i></td><td
+class="left">Brit. and Ind. Mus.</td><td class="left">One of<br />the
+types.</td></tr>
+
+<tr><td class="left"><i>Stolella indica</i></td><td class="left"> Ind.
+Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Lophopodella carteri</i></td><td class="left">
+Brit. Mus.</td><td class="left"> Type.</td></tr>
+
+<tr><td class="left"><i>Lophopodella carteri</i> var.
+<i>himalayana</i></td><td class="left"> Ind. Mus.</td><td class="left">
+Type.</td></tr>
+
+<tr><td class="left"><i>Pectinatella burmanica</i></td><td class="left">
+Ind. Mus.</td><td class="left"> Type.</td></tr>
+
+</table>
+
+<p>The literature dealing with the various groups described in
+the volume is discussed in the introductions to the three parts.
+Throughout the volume I have, so far as possible, referred to works that
+can be consulted in Calcutta in the libraries of the Indian Museum, the
+Geological Survey of India, or the Asiatic Society of Bengal. The names
+of works that are not to be found in India are marked with a *. The
+rarity with which this mark occurs says much for the fortunate position
+in which zoologists stationed in Calcutta find themselves as regards
+zoological literature, for I do not think that anything essential has
+been omitted.</p>
+
+<p>It remains for me to express my gratitude to those who have assisted
+me in the preparation of this volume. The names of<span
+class='pagenum'><a name="Page_24" id="Page_24">[Pg 24]</a></span> those
+who have contributed specimens for examination have already been
+mentioned. I have to thank the Trustees of the Indian Museum not only
+for their liberal interpretation of my duties as an officer of the
+Museum but also for the use of all the drawings and photographs and some
+of the blocks from which this volume is illustrated. Several of the
+latter have already been used in the "Records of the Indian Museum."
+From the Editor of the "Fauna" I have received valuable suggestions, and
+I am indebted to Dr. Weltner of the Berlin Museum for no less valuable
+references to literature. Mr. F. H. Gravely, Assistant Superintendent in
+the Indian Museum, has saved me from several errors by his
+criticism.</p>
+
+<p>The majority of the figures have been drawn by the draftsmen of the
+Indian Museum, Babu Abhoya Charan Chowdhary, and of the Marine Survey of
+India, Babu Shib Chandra Mondul, to both of whom I am much indebted for
+their accuracy of delineation.</p>
+
+<p>No work dealing with the sponges of India would be complete without a
+tribute to the memory of H. J. Carter, pioneer in the East of the study
+of lower invertebrates, whose work persists as a guide and an
+encouragement to all of us who are of the opinion that biological
+research on Indian animals can only be undertaken in India, and that
+even systematic zoological work can be carried out in that country with
+success. I can only hope that this, the first volume in the official
+Fauna of the Indian Empire to be written entirely in India, may prove
+not unworthy of his example.</p>
+
+<p class="p2">Indian Museum, Calcutta&nbsp;
+<span class="justr">Oct. 23rd, 1910.</span></p>
+
+<p class="p4 footnote">
+<a name="footnote_A" id="footnote_A"></a>
+<a href="#fnanchor_A">[A]</a> "L'origine des animaux d'eau douce," Bull.
+de l'Acad. roy. de Belgique (Classe des Sciences), No. 12, 1905, p.
+724.</p>
+
+<p class="footnote">
+<a name="footnote_B" id="footnote_B"></a>
+<a href="#fnanchor_B">[B]</a> Cat. Ind. Dec. Crust. Coll. Ind. Mus.,
+part i, fasc. ii (Potamonid�), 1910.</p>
+
+<p class="footnote">
+<a name="footnote_C" id="footnote_C"></a>
+<a href="#fnanchor_C">[C]</a> I include Baluchistan in this territory
+largely for climatic reasons.</p>
+
+<p class="footnote">
+<a name="footnote_D" id="footnote_D"></a>
+<a href="#fnanchor_D">[D]</a> Mr. S. W. Kemp recently obtained at
+Mangaldai, near the Bhutan frontier of Assam, a single specimen of what
+may be a species of <i>Fredericella</i>.</p>
+
+<p class="footnote">
+<a name="footnote_E" id="footnote_E"></a>
+<a href="#fnanchor_E">[E]</a> See Mem. Geol. Surv. Ind. <span
+class="smcap">xxxv</span> (1), p.&nbsp;39 (1902).</p>
+
+<p class="footnote">
+<a name="footnote_F" id="footnote_F"></a>
+<a href="#fnanchor_F">[F]</a> See Ortmann, "The Geographical
+Distribution of Freshwater Decapods and its bearing upon Ancient
+Geography," Proc. Amer. Phil. Soc. xli, p.&nbsp;380, fig. 6 (1902); also
+Suess, "The Face of the Earth" (English ed.) i, p.&nbsp;416 (1904).</p>
+
+<p class="footnote">
+<a name="footnote_G" id="footnote_G"></a>
+<a href="#fnanchor_G">[G]</a> I am indebted to Mr. W. F. Lanchester for
+the identification of this species.</p>
+
+<p class="footnote">
+<a name="footnote_H" id="footnote_H"></a>
+<a href="#fnanchor_H">[H]</a> The fauna of this lake and of others in
+the neighbourhood has recently been investigated by Mr. S. W. Kemp. See
+the addenda at the end of this volume.&mdash;<i>June 1911.</i></p>
+
+<p class="footnote">
+<a name="footnote_I" id="footnote_I"></a>
+<a href="#fnanchor_I">[I]</a> "What characters are of systematic
+importance?" is a question to which different answers must be given in
+the case of different groups.</p>
+
+<p class="footnote">
+<a name="footnote_J" id="footnote_J"></a>
+<a href="#fnanchor_J">[J]</a> I have failed to obtain from the
+Philadelphia Academy of Science a statement that the type of this
+species is still in existence.</p>
+
+<p class="p4"><span class='pagenum'><a name="Page_25" id="Page_25">[Pg
+25]</a></span></p>
+
+<h3>PART I.<br />
+FRESHWATER SPONGES<br />
+(SPONGILLID�).</h3>
+
+<p> <span class='pagenum'><a name="Page_26" id="Page_26">[Pg
+26]</a></span><br /><span class='pagenum'><a name="Page_27"
+id="Page_27">[Pg 27]</a></span></p>
+
+<h3 class="p4">INTRODUCTION TO PART I.</h3>
+
+<p class="p2 center">I.</p>
+
+<p class="center"><span class="smcap">The Phylum Porifera.</span></p>
+
+<p>The phylum Porifera or Spongi� includes the simplest of the Metazoa
+or multicellular animals. From the compound Protozoa its members are
+distinguished by the fact that the cells of which they are composed
+exhibit considerable differentiation both in structure and in function,
+and are associated together in a definite manner, although they are not
+combined to form organs and systems of organs as in the higher Metazoa.
+Digestion, for instance, is performed in the sponges entirely by
+individual cells, into the substance of which the food is taken, and the
+products of digestion are handed on to other cells without the
+intervention of an alimentary canal or a vascular system, while there is
+no structure in any way comparable to the nervous system of more highly
+organized animals.</p>
+
+<p>The simplest form of sponge, which is known as an olynthus, is a
+hollow vase-like body fixed at one end to some solid object, and with an
+opening called the osculum at the other. The walls are perforated by
+small holes, the pores, from which the name Porifera is derived.</p>
+
+<p>Externally the surface is protected by a delicate membrane formed of
+flattened cells and pierced by the pores, while the interior of the vase
+is covered with curious cells characteristic of the sponges, and known
+as choanocytes or collar-cells. They consist of minute oval or
+pear-shaped bodies, one end of which is provided with a rim or collar of
+apparently structureless membrane, while a flagellum or whip-like lash
+projects from the centre of the surface surrounded by the collar. These
+collar-cells are practically identical with those of which the Protozoa
+known as Choanoflagellata consist; but it is only in the sponges<a
+name="fnanchor_K" id="fnanchor_K"></a><a href="#footnote_K"
+class="fnanchor"><sup>[K]</sup></a> that they are found constantly
+associated with other cells unlike themselves.</p>
+
+<p>In addition to the collar-cells, which form what is called the
+gastral layer, and the external membrane (the derma or dermal<span
+class='pagenum'><a name="Page_28" id="Page_28">[Pg 28]</a></span>
+membrane), the sponge contains cells of various kinds embedded in a
+structureless gelatinous substance, through which they have the power of
+free movement. Most of these cells have also the power of changing their
+form in an "am&oelig;boid" manner; that is to say, by projecting and
+withdrawing from their margin mobile processes of a more or less
+finger-like form, but unstable in shape or direction. The protoplasm of
+which some of the cells are formed is granular, while that of others is
+clear and translucent. Some cells, which (for the time being at any
+rate) do not exhibit am&oelig;boid movements, are glandular in function,
+while others again give rise in various ways to the bodies by means of
+which the sponge reproduces its kind. There is evidence, however, that
+any one kind of cell, even those of the membrane and the gastral layer,
+can change its function and its form in case of necessity.</p>
+
+<p>Most sponges possess a supporting framework or skeleton. In some it
+is formed entirely of a horny substance called spongin (as in the
+bath-sponge), in others it consists of spicules of inorganic matter
+(either calcareous or siliceous) secreted by special cells, or of such
+spicules bound together by spongin. Extraneous objects, such as
+sand-grains, are frequently included in the skeleton. The spongin is
+secreted like the spicules by special cells, but its chemical structure
+is much more complicated than that of the spicules, and it is not
+secreted (at any rate in most cases) in such a way as to form bodies of
+a definite shape. In the so-called horny sponges it resembles the chitin
+in which insects and other arthropods are clothed.</p>
+
+<p class="center">*     *     *     *     *</p>
+
+<p>In no adult sponge do the collar-cells completely cover the whole of
+the internal surface, the olynthus being a larval form, and by no means
+a common larval form. It is only found in certain sponges with
+calcareous spicules. As the structure of the sponge becomes more
+complicated the collar-cells are tucked away into special pockets or
+chambers known as ciliated chambers, and finally the approach to these
+chambers, both from the external surface and from the inner or gastral
+cavity, takes the form of narrow tubes or canals instead of mere pores.
+With further complexity the simple internal cavity tends to disappear,
+and the sponge proliferates in such a way that more than one osculum is
+formed. In the class Demospongi�, to which the sponges described in this
+volume belong, the whole system is extremely complicated.</p>
+
+<p>The skeleton of sponges, when it is not composed wholly of spongin,
+consists of, or at any rate contains, spicules that have a definite
+chemical composition and definite shapes in accordance with the class,
+order, family, genus, and species of the sponge. Formerly sponges were
+separated into calcareous, siliceous, and horny sponges by the nature of
+their skeleton; and although the system of classification now adopted
+has developed into a much more complex one and a few sponges are known
+that have both calcareous and siliceous spicules, the question whether
+the spicules<span class='pagenum'><a name="Page_29" id="Page_29">[Pg
+29]</a></span> are formed of salts of lime or of silica (strictly
+speaking of opal) is very important. All Demospongi� that have spicules
+at all have them of the latter substance, and the grade Monaxonida, in
+which the freshwater sponges constitute the family Spongillid�, is
+characterized by the possession of spicules that have typically the form
+of a needle pointed at both ends. Although spicules of this simple form
+may be absent in species that belong to the grade, the larger spicules,
+which are called megascleres, have not normally more than one main axis
+and are always more or less rod-like in outline. They are usually
+arranged so as to form a reticulate skeleton. Frequently, however, the
+megascleres or skeleton-spicules are not the only spicules present, for
+we find smaller spicules (microscleres) of one or more kinds lying loose
+in the substance of the sponge and in the external membrane, or, in the
+Spongillid� only, forming a special armature for the reproductive bodies
+known as gemmules.</p>
+
+<p>All sponges obtain their food in the same way, namely by means of the
+currents of water set up by the flagella of the collar-cells. These
+flagella, although apparently there is little concerted action among
+them, cause by their rapid movements changes of pressure in the water
+contained in the cavities of the sponge. The water from outside
+therefore flows in at the pores and finally makes its way out of the
+oscula. With the water minute particles of organic matter are brought
+into the sponge, the collar-cells of which, and probably other cells,
+have the power of selecting and engulfing suitable particles. Inside the
+cells these particles undergo certain chemical changes, and are at least
+partially digested. The resulting substances are then handed on directly
+to other cells, or, as some assert, are discharged into the common
+jelly, whence they are taken up by other cells.</p>
+
+<p>Sponges reproduce their kind in more ways than one, <i>viz.</i>, by
+means of eggs (which are fertilized as in other animals by spermatozoa),
+by means of buds, and by means of the peculiar bodies called gemmules
+the structure and origin of which is discussed below (p.&nbsp;42). They are
+of great importance in the classification of the Spongillid�. Sponges
+can also be propagated artificially by means of fission, and it is
+probable that this method of reproduction occurs accidentally, if not
+normally, in natural circumstances.</p>
+
+<p class="p2 center"><span class="smcap">General Structure of the
+Spongillid�.</span></p>
+
+<p>It would be impracticable in this introduction to give a full account
+of the structure of the Spongillid�, which in some respects is still
+imperfectly known. Students who desire further information should
+consult Professor Minchin's account of the sponges in Lankester's
+'Treatise on Zoology,' part ii, or, if a less technical description is
+desired, Miss Sollas's contribution to the 'Cambridge Natural History,'
+vol. i, in which special attention is paid to <i>Spongilla</i>.</p>
+
+<p><span class='pagenum'><a name="Page_30" id="Page_30">[Pg
+30]</a></span>The diagram reproduced in fig. 1 gives a schematic view of
+a vertical section through a living freshwater sponge. Although it
+represents the structure of the organism as being very much simpler than
+is actually the case, and entirely omits the skeleton, it will be found
+useful as indicating the main features of the anatomy.</p>
+
+<div class="figcenter">
+<img src="images/fig_001.png" width="500" height="245"
+alt="Illustration: Diagram of a vertical section through a freshwater
+sponge (modified from K�kenthal)" title="Fig. 1.&mdash;Diagram of a
+vertical section through a freshwater sponge (modified from K�kenthal)"
+/>
+<p class="caption">Fig. 1.&mdash;Diagram of a vertical section through a
+freshwater sponge<br /> (<i>modified from K�kenthal)</i></p>
+</div>
+
+<p class="captionj">A=pores; B=subdermal cavity; C=inhalent canal;
+D=ciliated chamber; E=exhalent canal; F=osculum; G=dermal membrane;
+H=eggs; J=gemmule.</p>
+
+<p>It will be noted that the diagram represents an individual with a
+single osculum or exhalent aperture. As a rule adult Demospongi� have
+several or many oscula, but even in the Spongillid� sponges occur in
+which there is only one. New oscula are formed by a kind of
+proliferation that renders the structure still more complex than it is
+when only one exhalent aperture is present.</p>
+
+<p>The little arrows in the figure indicate the direction of the
+currents of water that pass through the sponge. It enters through small
+holes in the derma into a subdermal cavity, which separates the membrane
+from the bulk of the sponge. This space differs greatly in extent in
+different species. From the subdermal space the water is forced by the
+action of the flagella into narrow tubular canals that carry it into the
+ciliated chambers. Thence it passes into other canals, which communicate
+with what remains of the central cavity, and so out of the oscula.</p>
+
+<p>The ciliated chambers are very minute, and the collar-cells
+excessively so. It is very difficult to examine them owing to their
+small size and delicate structure. Fig. 2 D represents a collar-cell of
+a sponge seen under a very high power of the microscope in ideal
+conditions.</p>
+
+<div class="figcenter"><span class='pagenum'><a name="Page_31"
+id="Page_31">[Pg 31]</a></span>
+<img src="images/fig_002.jpg" width="346" height="500"
+alt="Illustration: Fig. 2.&mdash;Sponge cells." title="Fig.
+2.&mdash;Sponge cells." />
+<p class="caption">Fig. 2.&mdash;Sponge cells.</p>
+</div>
+
+<p class="captionj">A=bubble-cells of <i>Ephydatia m�lleri</i>, � 350
+(<i>after Weltner</i>). B=gemmule-cell of <i>Spongilla lacustris</i>
+containing green corpuscles (shaded dark), � 800 (<i>after Weltner</i>).
+C=gemmule-cell of <i>Ephydatia blembingia</i> showing "tabloids" of
+food-material, � 1150 (<i>after Evans</i>). D=collar-cell of
+<i>Esperella �gagrophila</i>, � 1600 (<i>after Vosmaer and
+Pekelharing</i>). E=three stages in the development of a gemmule-spicule
+of <i>E. blembingia</i> (<i>after Evans</i>), � 665. F=outline of
+porocytes of <i>S. proliferens</i>, � ca. 1290: <i>e</i>=dermal cell;
+<i>n</i>=nucleus; <i>p</i>=pore; <i>p.c.</i>=pore-cell.</p>
+
+<p>The nature of the inhalent apertures in the external membrane has
+been much discussed as regards the Demospongi�, but the truth seems to
+be that their structure differs considerably even in <span
+class='pagenum'><a name="Page_32" id="Page_32">[Pg 32]</a></span>
+closely allied species. At any rate this is the case as regards the
+Indian <i>Spongill�</i>. In all species the membrane is composed of
+flattened cells of irregular shape fitted together like the pieces of a
+puzzle-picture. In some species (e.&nbsp;g., <i>Spongilla carteri</i>)
+the apertures in the membrane consist merely of spaces between adjacent
+cells, which may be a little more crowded together than is usual. But in
+others (e.&nbsp;g., <i>Spongilla proliferens</i> and <i>Spongilla
+crassissima</i>) in which the pores are extremely small, each pore
+normally pierces the middle of a flat, ring-shaped cell or porocyte.
+Occasionally, however, a pore may be found that is enclosed by two
+narrow, crescent-shaped cells joined together at their tips to form a
+ring. The porocytes of sponges like <i>Spongilla carteri</i> are
+probably not actually missing, but instead of being in the external
+membrane are situated below the derma at the external entrance to the
+canals that carry water to the flagellated chambers or even at the
+entrance to the chambers themselves<a name="fnanchor_L"
+id="fnanchor_L"></a><a href="#footnote_L"
+class="fnanchor"><sup>[L]</sup></a>. Some authors object on theoretical
+grounds to the statement that porocytes exist in the Demospongia, and it
+is possible that these cells have in this grade neither the same origin
+as, nor a precisely similar function to, the porocytes of other sponges.
+When they occur in the dermal membrane no great difficulty is
+experienced in seeing them under a sufficiently high power of the
+microscope, if the material is well preserved and mounted and stained in
+a suitable manner<a name="fnanchor_M" id="fnanchor_M"></a><a
+href="#footnote_M" class="fnanchor"><sup>[M]</sup></a>. In most sponges
+the porocytes can contract in such a way that the aperture in their
+centre is practically closed, but this power appears to be possessed by
+the porocytes of <i>Spongilla</i> only to a very limited extent,
+although they closely resemble the porocytes of other sponges in
+appearance.</p>
+
+<p>The external membrane in many Spongillid� is prolonged round and
+above the oscula so as to form an oscular collar. This structure is
+highly contractile, but cannot close together. As a rule it is much more
+conspicuous in living sponges than in preserved specimens.</p>
+
+<p>It is not necessary to deal here with most of the cells that occur in
+the parenchyma or gelatinous part of the sponge. A full list of the
+kinds that are found is given by Dr. Weltner in his
+"Spongillidenstudien, V," p.&nbsp;276 (Arch. Naturg. Berlin, lxxiii (i),
+1907). One kind must, however, be briefly noticed as being of some
+systematic importance, namely the "bubble-cells" (fig. 2 A) that are
+characteristic of some species of <i>Ephydatia</i> and other genera.
+These cells are comparatively large, spherical in form; each of them
+contains a globule of liquid which not only occupies the greater part of
+the cell, but forces the protoplasm to assume the form of a delicate
+film lining the cell-wall and covering the<span class='pagenum'><a
+name="Page_33" id="Page_33">[Pg 33]</a></span> globule. In optical
+section "bubble-cells" have a certain resemblance to porocytes, but the
+cell is of course imperforate and not flattened.</p>
+
+<p class="p2 center"><span class="smcap">Skeleton and Spicules.</span></p>
+
+<div class="figcenter">
+<img src="images/fig_003.jpg" width="323" height="475"
+alt="Illustration: Radial sections of fragments of the skeletons of
+Spongill�" title="Radial sections of fragments of the skeletons of
+Spongill�" />
+<p class="caption">Radial sections of fragments of the skeletons of
+<i>Spongill�</i></p>
+</div>
+
+<p class="captionj">A, <i>S. crassissima</i> var. <i>crassior</i> (from
+Rajshahi); B, <i>S. carteri</i> (from Calcutta); <i>a</i>=transverse,
+<i>b</i>=radiating fibres; <i>e</i>=external surface of the sponge.</p>
+
+<p>In the Spongillid� the spicules and the skeleton are more important
+as regards the recognition of genera and species than<span
+class='pagenum'><a name="Page_34" id="Page_34">[Pg 34]</a></span> the
+soft parts. The skeleton is usually reticulate, but sometimes consists
+of a mass of spicules almost without arrangement. The amount of spongin
+present is also different in different species. The spicules in a
+reticulate skeleton are arranged so as to form fibres of two
+kinds&mdash;radiating fibres, which radiate outwards from the centre of
+the sponge and frequently penetrate the external membrane, and
+transverse fibres, which run across from one radiating fibre to another.
+The fibres are composed of relatively large spicules (megascleres)
+arranged parallel to one another, overlapping at the ends, and bound
+together by means of a more or less profuse secretion of spongin. In
+some species they are actually enclosed in a sheath of this substance.
+The radiating fibres are usually more distinct and stouter than the
+transverse ones, which are often represented by single spicules but are
+sometimes splayed out at the ends so as to assume in outline the form of
+an hour-glass (fig. 3 B). The radiating fibres frequently raise up the
+membrane at their free extremities just as a tent-pole does a tent.</p>
+
+<p>Normal spicules of the skeleton are always rod-like or needle-like,
+and either blunt or pointed at both ends; they are either
+smooth, granular, or covered with small spines. Sometimes
+spicules of the same type form a more or less irregular transverse
+network at the base or on the surface of the sponge.</p>
+
+<div class="figcenter">
+<img src="images/fig_004.png" width="500" height="215"
+alt="Illustration: Part of an oscular collar of Spongilla lacustris
+subsp. reticulata, showing arrangement of microscleres in the derma
+(magnified)." title="Part of an oscular collar of Spongilla lacustris
+subsp. reticulata, showing arrangement of microscleres in the derma
+(magnified)." />
+<p class="caption">Fig. 4.&mdash;Part of an oscular collar of
+<i>Spongilla lacustris</i> subsp. <i>reticulata</i>, showing arrangement
+of microscleres in the derma (magnified).</p>
+</div>
+
+<p>From the systematist's point of view, the structure of the free
+spicules found scattered in the substance and membrane of the sponge,
+and especially of those that form the armature of the gemmules, is of
+more importance than that of the skeleton-spicules. Free spicules are
+absent in many species; when present they are usually needle-like and
+pointed at the tips. In a few species, however, they are of variable or
+irregular form, or consist of several or many shafts meeting in a common
+central nodule. In one genus (<i>Corvospongilla</i>) they resemble a
+double grappling-iron in form, having a circle of strongly recurved
+hooks at both ends. The free microscleres, or flesh-spicules as they are
+often called, are either smooth, granular, or spiny.</p>
+
+<p><span class='pagenum'><a name="Page_35" id="Page_35">[Pg
+35]</a></span> Gemmule-spicules, which form a characteristic feature of
+the Spongillid�, are very seldom absent when the gemmules are mature.
+They are of the greatest importance in distinguishing the genera. In
+their simplest form they closely resemble the free microscleres, but in
+several genera they bear, either at or near one end or at or near both
+ends, transverse disks which are either smooth or indented round the
+edge. In one genus (<i>Pectispongilla</i>) they are provided at both
+ends not with disks but with vertically parallel rows of spines
+resembling combs in appearance.</p>
+
+<p>The simpler spicules of the Spongillid� are formed in single cells
+(see fig. 2 E), but those of more complicated shape are produced by
+several cells acting in concert. Each spicule, although it is formed
+mainly of hydrated silica (opal), contains a slender organic filament
+running along its main axis inside the silica. This filament, or rather
+the tube in which it is contained, is often quite conspicuous, and in
+some species (e.&nbsp;g., <i>Spongilla crassissima</i>) its termination
+is marked at both ends of the megasclere by a minute conical
+protuberance in the silica.</p>
+
+<p>Unless sponges are alchemists and can transmute one element into
+another, the material of which the spicules are made must ultimately
+come from the water in which the sponges live, or the rocks or other
+bodies to or near which they are attached. The amount of water that must
+pass through a large specimen of such a sponge as <i>Spongilla
+carteri</i> in order that it may obtain materials for its skeleton must
+be enormous, for silica is an insoluble substance. I have noticed,
+however, that this sponge is particularly abundant and grows with
+special luxuriance in ponds in which clothes are washed with soap, and
+my friend Mr. G. H. Tipper has suggested to me that possibly the alkali
+contained in the soap-suds may assist the sponge in dissolving out the
+silica contained in the mud at the bottom of the ponds. The question of
+how the mineral matter of the skeleton is obtained is, however, one
+about which we know nothing definite.</p>
+
+<p>The spongin that binds the skeleton-spicules together takes the form
+of a colourless or yellowish transparent membrane, which is often
+practically invisible. When very abundant it sometimes extends across
+the nodes of the skeleton as a delicate veil. In some sponges it also
+forms a basal membrane in contact with the object to which the sponge is
+attached, and in some such cases the spongin of the radiating fibres is
+in direct continuity with that of the basal membrane.</p>
+
+<p class="p2 center"><span class="smcap">Colour and Odour.</span></p>
+
+<p>Most freshwater sponges have a bad odour, which is more marked in
+some species than in others. This odour is not peculiar to the
+Spongillid�, for it is practically identical with that given out by the
+common marine sponge <i>Halichondria panicea</i>.<span
+class='pagenum'><a name="Page_36" id="Page_36">[Pg 36]</a></span> Its
+function is probably protective, but how it is produced we do not
+know.</p>
+
+<p>The coloration of freshwater sponges is usually dull and uniform, but
+<i>Pectispongilla aurea</i> is of the brilliant yellow indicated by its
+name, while many species are of the bright green shade characteristic of
+chlorophyll, the colouring matter of the leaves of plants. Many species
+are brown or grey, and some are almost white.</p>
+
+<p>These colours are due to one of three causes, or to a combination of
+more than one of them, viz.:&mdash;(1) the inhalation of solid inorganic
+particles, which are engulfed by the cells; (2) the presence in the
+cells of coloured substances, solid or liquid, produced by the vital
+activities of the sponge; and (3) the presence in the cells of peculiar
+organized living bodies known as "green corpuscles."</p>
+
+<p>Sponges living in muddy water are often nearly black. This is because
+the cells of their parenchyma are gorged with very minute solid
+particles of silt. If a sponge of the kind is kept in clean water for a
+few days, it often becomes almost white. An interesting experiment is
+easily performed to illustrate the absorption and final elimination of
+solid colouring matter by placing a living sponge (small specimens of
+<i>Spongilla carteri</i> are suitable) in a glass of clean water, and
+sprinkling finely powdered carmine in the water. In a few hours the
+sponge will be of a bright pink colour, but if only a little carmine is
+used at first and no more added, it will regain its normal greyish hue
+in a few days.</p>
+
+<p>The colouring matter produced by the sponge itself is of two
+kinds&mdash;pigment, which is probably a waste product, and the
+substances produced directly by the ingestion of food or in the process
+of its digestion. When pigment is produced it takes the form of minute
+granules lying in the cells of the parenchyma, the dermal membrane being
+as a rule colourless. Very little is known about the pigments of
+freshwater sponges, and even less about the direct products of
+metabolism. It is apparently the latter, however, that give many
+otherwise colourless sponges a slight pinkish or yellowish tinge
+directly due to the presence in cells of the parenchyma of minute liquid
+globules. In one form of <i>Spongilla carteri</i> these globules turn of
+a dark brown colour if treated with alcohol. The brilliant colour of
+<i>Pectispongilla aurea</i> is due not to solid granules but to a liquid
+or semi-liquid substance contained in the cells.</p>
+
+<p>The green corpuscles of the Spongillid� are not present in all
+species. There is every reason to think that they represent a stage in
+the life-history of an alga, and that they enter the sponge in an active
+condition (see p.&nbsp;49).</p>
+
+<p>A fourth cause for the coloration of freshwater sponges may be noted
+briefly. It is not a normal one, but occurs commonly in certain forms
+(e.&nbsp;g., <i>Spongilla alba</i> var. <i>bengalensis</i>). This cause
+is the growth in the canals and substance of the sponge of
+parasitic<span class='pagenum'><a name="Page_37" id="Page_37">[Pg
+37]</a></span> alga�, which turn the whole organism of a dull green
+colour. They do not do so, however, until they have reduced it to a
+dying state. The commonest parasite of the kind is a filamentous species
+particularly common in brackish water in the Ganges delta.</p>
+
+<p class="center p2"><span class="smcap">External Form and
+Consistency.</span></p>
+
+<div class="figcenter">
+<img src="images/fig_005.png" width="350"
+height="333"  alt="Illustration: Fig. 5.&mdash;Part of a type-specimen
+of Spongilla lacustris subsp. reticulata (nat. size)." title="Fig.
+5.&mdash;Part of a type-specimen of Spongilla lacustris subsp.
+reticulata (nat. size)." />
+<p class="caption">Fig. 5.&mdash;Part of a type-specimen of <i>Spongilla
+lacustris</i> subsp. <i>reticulata</i> (nat. size).</p>
+</div>
+
+<p>The external form of sponges is very variable, but each species,
+subspecies, or variety of the Spongillid� has normally a characteristic
+appearance. The European race of <i>Spongilla lacustris</i>, for
+example, consists in favourable circumstances of a flattened basal part
+from which long cylindrical branches grow out; while in the Indian race
+of the species these branches are flattened instead of being
+cylindrical, and anastomose freely. The structure of the branches is
+identical with that of the basal part. Many other species (for instance,
+<i>Spongilla bombayensis</i> and <i>S. ultima</i>) never produce
+branches but always consist of lichenoid<span class='pagenum'><a
+name="Page_38" id="Page_38">[Pg 38]</a></span> or cushion-shaped masses.
+The appearance of <i>Spongilla crateriformis</i>, when it is growing on
+a flattened surface which allows it to develop its natural form, is very
+characteristic, for it consists of little flattened masses that seem to
+be running out towards one another, just as though the sponge had been
+dropped, spoonful by spoonful, in a viscous condition from a teaspoon.
+Some species, such as <i>Trochospongilla phillottiana</i>, cover large
+areas with a thin film of uniform thickness, while others (e.&nbsp;g.,
+<i>Spongilla alba</i> and <i>Ephydatia meyeni</i>) consist of irregular
+masses, the surface of which bears numerous irregular ridges or conical,
+subquadrate, or digitate processes. In a few forms (e.&nbsp;g.,
+<i>Corvospongilla burmanica</i>) the surface is covered with small
+turret-like projections of considerable regularity, and some
+(e.&nbsp;g., <i>Spongilla crassissima</i>) naturally assume a spherical
+or oval shape with an absolutely smooth surface.</p>
+
+<p>The production of long branches is apparently rare in tropical
+freshwater sponges.</p>
+
+<p>The form of the oscula is characteristic in many cases. No other
+Indian species has them so large, or with such well-defined margins as
+<i>Spongilla carteri</i> (Pl. II, fig. 1). In many species (Pl. II, fig.
+3) they have a stellate appearance owing to the fact that grooves in the
+substance of the sponge radiate round them beneath the external
+membrane. In other species they are quite inconspicuous and very small.</p>
+
+<div class="figcenter">
+<img src="images/fig_006.png" width="550" height="390"
+alt="Illustration: Fig. 6.&mdash;Radial section through part of a dried
+sponge of Spongilla crassissima (from Calcutta), � 5." title="Fig.
+6.&mdash;Radial section through part of a dried sponge of Spongilla
+crassissima (from Calcutta), � 5." />
+<p class="caption">Fig. 6.&mdash;Radial section through part of a dried
+sponge of <i>Spongilla crassissima</i> (from Calcutta), � 5.</p>
+</div>
+
+<p>Spongillid� differ greatly in consistency. <i>Spongilla
+crassissima</i> and <i>Corvospongilla lapidosa</i> are almost stony,
+although the former is extremely light, more like pumice than true
+stone. Other species (e.&nbsp;g., <i>Trochospongilla latouchiana</i>)
+are hard but brittle, while others again are soft and easily compressed,
+as <i>Spongilla lacustris</i>, the variety <i>mollis</i> of <i>S.
+carteri</i>, and <i>S. crateriformis</i>. The consistency of a sponge
+depends on two factors&mdash;the number of spicules present, and the
+amount of spongin. In <i>Corvospongilla lapidosa</i> the number of
+spicules is very large indeed. They are not arranged so as to form a
+reticulate skeleton but interlock in<span class='pagenum'><a
+name="Page_39" id="Page_39">[Pg 39]</a></span> all directions, and there
+is hardly any spongin associated with them. In <i>Spongilla
+crassissima</i>, on the other hand, the number of spicules although
+large is not unusually so; but they form a very definitely reticulate
+skeleton, and are bound together by an unusually profuse secretion of
+spongin. In <i>S. carteri</i> var. <i>mollis</i> both spicules and
+spongin are reduced to a minimum, and the parenchyma is relatively more
+bulky than usual.</p>
+
+<p class="p2 center"><span class="smcap">Variation.</span></p>
+
+<p>Sponges are very variable organisms, and even a slight change in the
+environment of the freshwater species often produces a considerable
+change in form and structure. Some species vary in accordance with the
+season, and others without apparent cause. Not only have many given rise
+to subspecies and "varieties" that possess a certain stability, but most
+if not all are liable to smaller changes that apparently affect both the
+individual and the breed, at any rate for a period.</p>
+
+<p class="center">(a) <i>Seasonal Variation.</i></p>
+
+<p>Weltner has shown in a recent paper (Arch. Natg. Berlin, lxxiii (i),
+p.&nbsp;276, 1907) that in Europe those individuals of <i>Ephydatia</i> which
+are found (exceptionally) in an active condition in winter differ
+considerably both as regards the number of their cells and their anatomy
+from those found in summer. In Calcutta the majority of the individuals
+of <i>Spongilla carteri</i> that are found in summer have their external
+surface unusually smooth and rounded, and contain in their parenchyma
+numerous cells the protoplasm of which is gorged with liquid. These
+cells give the whole sponge a faint pinkish tinge during life; but if it
+is plunged in spirit, both the liquid in the cells and the spirit turn
+rapidly of a dark brown colour. Specimens of <i>Spongilla
+crateriformis</i> taken in a certain tank in Calcutta during the cold
+weather had the majority of the skeleton-spicules blunt, while the
+extremities of the gemmule-spicules were distinctly differentiated.
+Specimens of the same species taken from the same tank in July had the
+skeleton-spicules pointed, while the extremities of the gemmule-spicules
+were much less clearly differentiated. I have been unable to confirm
+this by observations made on sponges from other tanks, but it would
+certainly suggest that at any rate the breed of sponges in the tank
+first investigated was liable to seasonal variation.</p>
+
+<p class="center">(b) <i>Variation due directly to Environment.</i></p>
+
+<p>The characteristic external form of freshwater sponges is liable in
+most cases to be altered as a direct result of changes in the<span
+class='pagenum'><a name="Page_40" id="Page_40">[Pg 40]</a></span>
+environment. The following are two characteristic instances of this
+phenomenon.</p>
+
+<p>Certain shrubs with slender stems grow in the water at the edge of
+Igatpuri Lake. The stems of these shrubs support many large examples of
+<i>Spongilla carteri</i>, which are kept in almost constant motion owing
+to the action of the wind on those parts of the shrubs that are not
+under water. The surface of the sponges is so affected by the currents
+of water thus set up against it that it is covered with deep grooves and
+high irregular ridges like cockscombs. Less than a hundred yards from
+the lake there is a small pond in which <i>Spongilla carteri</i> is also
+abundant. Here it grows on stones at the bottom and has the
+characteristic and almost smooth form of the species.</p>
+
+<p>My second instance also refers in part to Igatpuri Lake.
+<i>Corvospongilla lapidosa</i> is common in the lake on the lower
+surface of stones, and also occurs at Nasik, about thirty miles away, on
+the walls of a conduit of dirty water. In the latter situation it has
+the form of large sheets of a blackish colour, with the surface
+corrugated and the oscula inconspicuous, while in the clear waters of
+the lake it is of a pale yellowish colour, occurs in small lichenoid
+patches, and has its oscula rendered conspicuous, in spite of their
+minute size, by being raised on little conical eminences in such a way
+that they resemble the craters of volcanoes in miniature.</p>
+
+<p>Both the European and the Indian races of <i>Spongilla lacustris</i>
+fail to develop branches if growing in unfavourable conditions. In
+specimens obtained from the River Spree near Berlin these structures are
+sometimes many inches in length; while in mature specimens taken under
+stones in Loch Baa in the Island of Mull the whole organism consisted of
+a minute cushion-shaped mass less than an inch in diameter, and was also
+deficient in spicules. Both these breeds belong to the same species, and
+probably differ as a direct result of differences in environment.</p>
+
+<p class="center">(c) <i>Variation without apparent cause.</i></p>
+
+<p><a href="#Plate_I">Plate I</a> in this volume illustrates an
+excellent example of variation in external form to which it is
+impossible to assign a cause with any degree of confidence. The three
+specimens figured were all taken in the same pond, and at the same
+season, but in different years. It is possible that the change in form,
+which was not peculiar to a few individuals but to all those in several
+adjacent ponds, was due to a difference in the salinity of the water
+brought about by a more or less abundant rainfall; but of this I have
+been able to obtain no evidence in succeeding years.</p>
+
+<p>Many Spongillid� vary without apparent cause as regards the shape,
+size, and proportions of their spicules. This is the case as regards
+most species of <i>Euspongilla</i> and <i>Ephydatia</i>, and is a fact
+to which careful consideration has to be given in separating the
+species.</p>
+
+<p class="p2 center"><span class="smcap">Nutrition.<span
+class='pagenum'><a name="Page_41" id="Page_41">[Pg 41]</a></span></span>
+</p>
+
+<p>Very little is known about the natural food of freshwater sponges,
+except that it must be of an organic nature and must be either in a very
+finely divided or in a liquid condition. The cells of the sponge seem to
+have the power of selecting suitable food from the water that flows past
+them, and it is known that they will absorb milk. The fact that they
+engulf minute particles of silt does not prove that they lack the power
+of selection, for extraneous matter is taken up by them not only as food
+but in order that it may be eliminated. Silt would soon block up the
+canals and so put a stop to the vital activity of the sponge, if it were
+not got rid of, and presumably it is only taken into the cells in order
+that they may pass it on and finally disgorge it in such a way or in
+such a position that it may be carried out of the oscula. The siliceous
+part of it may be used in forming spicules.</p>
+
+<p>It is generally believed that the green corpuscles play an important
+part in the nutrition of those sponges in which they occur, and there
+can be no doubt that these bodies have the power peculiar to all
+organisms that produce chlorophyll of obtaining nutritive substances
+direct from water and carbonic oxide through the action of sunlight.
+Possibly they hand on some of the nourishment thus obtained to the
+sponges in which they live, or benefit them by the free oxygen given out
+in the process, but many Spongillid� do well without them, even when
+living in identical conditions with species in which they abound.</p>
+
+<p class="p2 center"><span class="smcap">Reproduction.</span></p>
+
+<p>Both eggs and buds are produced by freshwater sponges (the latter
+rarely except by one species), while their gemmules attain an
+elaboration of structure not observed in any other family of
+sponges.</p>
+
+<p>Probably all Spongillid� are potentially mon&oelig;cious, that is to
+say, able to produce both eggs and spermatozoa. In one Indian species,
+however, in which budding is unusually common (viz. <i>Spongilla
+proliferens</i>), sexual reproduction takes place very seldom, if ever.
+It is not known whether the eggs of sponges are fertilized by
+spermatozoa from the individual that produces the egg or by those of
+other individuals, but not improbably both methods of fertilization
+occur.</p>
+
+<p>The egg of a freshwater sponge does not differ materially from that
+of other animals. When mature it is a relatively large spherical cell
+containing abundant food-material and situated in some natural cavity of
+the sponge. In the earlier stages of its growth, however, it exhibits
+am&oelig;boid movements, and makes its way through the common jelly. As
+it approaches maturity it is surrounded by other cells which contain
+granules of food-material. The food-material is apparently transferred
+by them<span class='pagenum'><a name="Page_42" id="Page_42">[Pg
+42]</a></span> in a slightly altered form to the egg. The egg has no
+shell, but in some species (e.&nbsp;g. <i>Ephydatia blembingia</i><a
+name="fnanchor_N" id="fnanchor_N"></a><a href="#footnote_N"
+class="fnanchor"><sup>[N]</sup></a>) it is surrounded, after
+fertilization, by gland-cells belonging to the parent sponge, which
+secrete round it a membrane of spongin. Development goes on within the
+chamber thus formed until the larva is ready to assume a free life.</p>
+
+<p>The spermatozoon is also like that of other animals, consisting of a
+rounded head and a lash-like tail, the movements of which enable it to
+move rapidly through the water. Spermatozoa are produced in
+<i>Spongilla</i> from spherical cells not unlike the eggs in general
+appearance. The contents of these cells divide and subdivide in such a
+way that they finally consist of a mass of spermatozoa surrounded by a
+single covering cell, which they finally rupture, and so escape.</p>
+
+<div class="figcenter">
+<img src="images/fig_007.jpg" width="300" height="295"
+alt="Illustration: Fig. 7.&mdash;Diagram of a vertical section through
+the gemmule of Spongilla proliferens." title="Fig. 7.&mdash;Diagram of a
+vertical section through the gemmule of Spongilla proliferens." />
+<p class="caption">Fig. 7.&mdash;Diagram of a vertical section through
+the gemmule of <i>Spongilla proliferens</i>.</p>
+</div>
+
+<p class="captionj">A=cellular contents; B=internal chitinous layer;
+C=external chitinous layer; D=pneumatic coat; E=gemmule-spicule;
+F=external membrane; G=foraminal tubule.</p>
+
+<p>Gemmules are asexual reproductive bodies peculiar to the sponges, but
+not to the Spongillid�. They resemble the statoblasts of the
+phylactol�matous polyzoa in general structure as well as in function,
+which is mainly that of preserving the race from destruction by such
+agencies as drought, starvation, and temperatures that are either too
+high or too low for its activities. This function they are enabled to
+perform by the facts that they are provided with coverings not only very
+hard but also fitted to resist the unfavourable agencies to which the
+gemmules are likely<span class='pagenum'><a name="Page_43"
+id="Page_43">[Pg 43]</a></span> to be exposed, and that they contain
+abundant food-material of which use can be made as soon as favourable
+conditions occur again.</p>
+
+<p>Internally the gemmule consists of a mass of cells containing
+food-material in what may be called a tabloid form, for it consists of
+minutely granular plate-like bodies. These cells are enclosed in a
+flask-like receptacle, the walls of which consist of two chitinous
+layers, a delicate inner membrane and an outer one of considerable
+stoutness. The mouth of the flask is closed by an extension of the inner
+membrane, and in some species is surrounded by a tubular extension of
+the external membrane known as the foraminal tubule. Externally the
+gemmule is usually covered by what is called a "pneumatic coat," also of
+"chitin" (spongin), but usually of great relative thickness and
+honeycombed by spaces which contain air, rendering the structure
+buoyant. The pneumatic coat also contains the microscleres
+characteristic of the species; it is often limited externally by a third
+chitinous membrane, on which more gemmule-spicules sometimes lie
+parallel to the surface.</p>
+
+<p>The cells from which those of the gemmules are derived are akin in
+origin to those that give rise to eggs and spermatozoa. Some zoologists
+are therefore of the opinion that the development of the gemmule is an
+instance of parthenogenesis&mdash;that is to say of an organism arising
+from an egg that has not been fertilized. But some of the collar-cells,
+although most of them originate from the external ciliated cells of the
+larva, have a similar origin. The building-up of the gemmule affords an
+excellent instance of the active co-operation that exists between the
+cells of sponges, and of their mobility, for the food-material that has
+to be stored up is brought by cells from all parts of the sponge, and
+these cells retire after discharging their load into those of the young
+gemmule.</p>
+
+<p>The formation of the gemmule of <i>Ephydatia blembingia</i>, a
+Malayan species not yet found in India, is described in detail by Dr. R.
+Evans (Q. J. Microsc. Sci. London, xliv, p.&nbsp;81, 1901).</p>
+
+<p>Gemmules are produced by the freshwater sponges of Europe, N. America
+and Japan at the approach of winter, but in the tropical parts of India
+they are formed more frequently at the approach of the hot weather (p.
+4). After they are fully formed the sponge that has produced them dies,
+and as a rule disintegrates more or less completely. In some species,
+however, the greater part of the skeleton remains intact, if it is not
+disturbed, and retains some of the gemmules in its meshwork, where they
+finally germinate. Other gemmules are set free. Some of them float on
+the surface of the water; others sink to the bottom. In any case all of
+them undergo a period of quiescence before germinating. It has been
+found that they can be kept dry for two years without dying.</p>
+
+<p>The function of the special spicules with which the gemmules<span
+class='pagenum'><a name="Page_44" id="Page_44">[Pg 44]</a></span> of the
+Spongillid� are provided appears to be not only to protect them but more
+especially to weight them to the extent suitable to the habits of each
+species. Species that inhabit running water, for example, in some cases
+have heavier gemmule-spicules than those that live in stagnant water,
+and their gemmules are the less easily carried away by the currents of
+the river. The gemmules of sponges growing in lakes are sometimes
+deficient in spicules. This is the case as regards the form of
+<i>Spongilla lacustris</i> found in Lake Baa, Isle of Mull, as regards
+<i>S. helvetica</i> from the Lake of Geneva, <i>S. moorei</i> from Lake
+Tanganyika, and <i>S. coggini</i> from Tali-Fu in Yunnan; also as
+regards the species of <i>Spongilla</i> and <i>Ephydatia</i> found in
+Lake Baikal, many of the sponges of which are said never to produce
+gemmules.</p>
+
+<p>Except in the genus <i>Corvospongilla</i> and the subgenus
+<i>Stratospongilla</i>, in both of which the air-spaces of the gemmules
+are usually no more than cavities between different chitinous membranes,
+the pneumatic coat is either "granular" or "cellular." Neither of these
+terms, however, must be understood in a physiological sense, for what
+appear to be granules in a granular coat are actually minute bubbles of
+air contained in little cavities in a foam-like mass of chitin (or
+rather spongin), while the cells in a cellular one are only larger and
+more regular air-spaces with thin polygonal walls and flat horizontal
+partitions. The walls of these spaces are said in some cases to contain
+a considerable amount of silica.</p>
+
+<p>The gemmules with their various coverings are usually spherical in
+shape, but in some species they are oval or depressed in outline. They
+lie as a rule free in the substance of the sponge, but in some species
+adhere at its base to the object to which it is attached. In some
+species they are joined together in groups, but in most they are quite
+free one from another.</p>
+
+<p>Reproductive buds<a name="fnanchor_O" id="fnanchor_O"></a><a
+href="#footnote_O" class="fnanchor"><sup>[O]</sup></a> are produced, so
+far as is known, by very few Spongillid�, although they are common
+enough in some other groups of sponges. In the only freshwater species
+in which they have been found to form a habitual means of reproduction,
+namely in <i>Spongilla proliferens</i>, they have much the appearance of
+abortive branches, and it is possible that they have been overlooked for
+this reason in other species, for they were noticed by Laurent in
+<i>Spongilla lacustris</i> as long ago as 1840 (CR. S�. Acad. Sci.
+Paris, xi, p.&nbsp;478). The buds noticed by Laurent, however, were only
+produced by very young sponges, and were of a different nature from
+those of <i>S. proliferens</i>, perhaps representing a form of fission
+rather than true budding (see 'Voyage de la Bonite: Zoophytologie,'
+Spongiaires, pl. i (Paris, 1844)).</p>
+
+<p>In <i>Spongilla proliferens</i>, a common Indian species, the buds
+arise<span class='pagenum'><a name="Page_45" id="Page_45">[Pg
+45]</a></span> as thickenings of the strands of cells accompanying the
+radiating spicule-fibres of the skeleton, which project outwards from
+the surface of the sponge. The thickenings originate beneath the surface
+and contain, at the earliest stage at which I have as yet examined them,
+all the elements of the adult organism (<i>i. e.</i> flesh-spicules,
+ciliated chambers, efferent and afferent canals, parenchyma-cells of
+various sorts) except skeleton fibres, gemmules, and a dermal membrane.
+A section at this period closely resembles one of an adult sponge,
+except that the structure is more compact, the parenchyma being
+relatively bulky and the canals of small diameter.</p>
+
+<p>Laurent observed reproduction by splitting in young individuals of
+<i>Spongilla</i>, but I have not been able to obtain evidence myself
+that this method of reproduction occurs normally in Indian species. In
+injured specimens of <i>Spongilla carteri</i>, however, I have observed
+a phenomenon that seems to be rather an abnormal form of budding, little
+rounded masses of cells making their way to the ends of the radiating
+skeleton fibres and becoming transformed into young sponges, which break
+loose and so start an independent existence. Possibly the buds observed
+by Laurent in <i>S. lacustris</i> were of a similar nature.</p>
+
+<p class="p2 center"><span class="smcap">Development.</span></p>
+
+<p class="center">(a) <i>From the Egg.</i></p>
+
+<p>After fertilization, the egg, lying in its cavity in the sponge,
+undergoes a complete segmentation; that is to say, becomes divided into
+a number of cells without any residuum remaining. The segmentation,
+however, is not equal, for it results in the formation of cells of two
+distinct types, one larger and less numerous than the other. As the
+process continues a pear-shaped body is produced, solid at the broader
+end, which consists of the larger cells, but hollow at the other.
+Further changes result in the whole of the external surface becoming
+ciliated or covered with fine protoplasmic lashes, each of which arises
+from a single small cell; considerable differentiation now takes place
+among the cells, and spicules begin to appear. At this stage or earlier
+(for there seem to be differences in different species and individuals
+as to the stage at which the young sponge escapes) the larva makes its
+way out of the parent sponge. After a brief period of free life, in
+which it swims rapidly through the water by means of its cilia, it fixes
+itself by the broad end to some solid object (from which it can never
+move again) and undergoes a final metamorphosis. During this process the
+ciliated cells of the external layer make their way, either by a
+folding-in of the whole layer or in groups of cells, into the interior,
+there change into collar-cells and arrange themselves in special
+cavities&mdash;the ciliated chambers of the adult. Finally an osculum,
+pores, &amp;c., are formed, and the sponge is complete.</p>
+
+<p><span class='pagenum'><a name="Page_46" id="Page_46">[Pg
+46]</a></span>This, of course, is the merest outline of what occurs;
+other changes that take place during the metamorphosis are of great
+theoretical interest, but cannot be discussed here. The student may
+refer to Dr. R. Evans's account of the larval development of
+<i>Spongilla lacustris</i> in the Q. J. Microsc. Sci. London, xlii, p.
+363 (1899).</p>
+
+<p class="center">(b) <i>From the Gemmule.</i></p>
+
+<p>The period for which the gemmule lies dormant probably depends to
+some extent upon environment and to some extent on the species to which
+it belongs. Carter found that if he cleaned gemmules with a handkerchief
+and placed them in water exposed to sunlight, they germinated in a few
+days; but in Calcutta gemmules of <i>Spongilla alba</i> var.
+<i>bengalensis</i> treated in this way and placed in my aquarium at the
+beginning of the hot weather, did not germinate until well on in the
+"rains." Even then, after about five months, only a few of them did so.
+Zykoff found that in Europe gemmules kept for two years were still alive
+and able to germinate.</p>
+
+<p>Germination consists in the cellular contents of the gemmule bursting
+the membrane or membranes in which they are enclosed, and making their
+way out of the gemmule in the form of a delicate whitish mass, which
+sometimes issues through the natural aperture in the outer chitinous
+coat and sometimes through an actual rent in this coat. In the latter
+case the development of the young sponge is more advanced than in the
+former.</p>
+
+<p>The fullest account of development from the gemmule as yet published
+is by Zykoff, and refers to <i>Ephydatia</i> in Europe (Biol. Centralbl.
+Berlin, xii, p.&nbsp;713, 1892).</p>
+
+<p>His investigations show that the bursting of the gemmule is not
+merely a mechanical effect of moisture or any such agency but is due to
+development of the cellular contents, which at the time they escape have
+at least undergone differentiation into two layers. Of the more
+important soft structures in the sponge the osculum is the first to
+appear, the ciliated chambers being formed later. This is the opposite
+of what occurs in the case of the bud, but in both cases the aperture
+appears to be produced by the pressure of water in the organism. The
+manner and order in which the different kinds of cells originate in the
+sponge derived from a gemmule give support to the view that the
+primitive cell-layers on which morphologists lay great stress are not of
+any great importance so far as sponges are concerned.</p>
+
+<p class="center">(c) <i>Development of the Bud.</i></p>
+
+<p>As the bud of <i>Spongilla proliferens</i> grows it makes its way up
+the skeleton-fibre to which it was originally attached, pushing the
+dermal membrane, which expands with its growth, before it. The<span
+class='pagenum'><a name="Page_47" id="Page_47">[Pg 47]</a></span>
+skeleton-fibre does not, however, continue to grow in the bud, in which
+a number of finer fibres make their appearance, radiating from a point
+approximately at the centre of the mass. As the bud projects more and
+more from the surface of the sponge the dermal membrane contracts at its
+base, so as finally to separate it from its parent. Further details are
+given on p.&nbsp;74.</p>
+
+<p class="p2 center"><span class="smcap">Habitat.</span></p>
+
+<p>Mr. Edward Potts<a name="fnanchor_P" id="fnanchor_P"></a><a
+href="#footnote_P" class="fnanchor"><sup>[P]</sup></a>, writing on the
+freshwater sponges of North America, says:&mdash;"These organisms have
+occasionally been discovered growing in water unfit for domestic uses;
+but as a rule they prefer pure water, and in my experience the finest
+specimens have always been found where they are subjected to the most
+rapid currents." True as this is of the Spongillid� of temperate
+climates, it is hardly applicable to those of tropical India, for in
+this country we find many species growing most luxuriantly and commonly
+in water that would certainly be considered unfit for domestic purposes
+in a country in which sanitation was treated as a science. Some species,
+indeed, are only found in ponds of water polluted by human agency, and
+such ponds, provided that other conditions are favourable, are perhaps
+the best collecting grounds. Other favourable conditions consist in a
+due mixture of light and shade, a lack of disturbance such as that
+caused by cleaning out the pond, and above all in the presence of
+objects suitable for the support of sponges.</p>
+
+<p>I do not know exactly why light and shade must be mixed in a habitat
+favourable for the growth of sponges, for most species prefer shade, if
+it be not too dense; but it is certainly the case that, with a few
+exceptions, Indian Spongillid� flourish best in water shaded at the
+edges by trees and exposed to sunlight elsewhere. One of the exceptions
+to this rule is the Indian race of <i>Spongilla lucustris</i>, which is
+found in small pools of water in sand-dunes without a particle of shade.
+Several species are only found on the lower surface of stones and roots
+in circumstances which do not suggest that their position merely
+protects them from mud, which, as Mr. Potts points out, is their "great
+enemy." A notable instance is <i>Trochospongilla pennsylvanica</i>,
+which is found hiding away from light in America and Europe as well as
+in India.</p>
+
+<p>It is curious that it should be easy to exterminate the sponges in a
+pond by cleaning it out, for one would have thought that sufficient
+gemmules would have remained at the edge, or would have been brought
+rapidly from elsewhere, to restock the water. Mr. Green has, however,
+noted that <i>Spongilla carteri</i> has disappeared for some years from
+a small lake at Peradeniya in which it was formerly abundant, owing to
+the lake having been cleaned<span class='pagenum'><a name="Page_48"
+id="Page_48">[Pg 48]</a></span> out, and I have made similar
+observations on several occasions in Calcutta.</p>
+
+<p>The question of the objects to which sponges attach themselves is one
+intimately connected with that of the injury done them by mud. The delta
+of the Ganges is one of the muddiest districts on earth. There are no
+stones or rocks in the rivers and ponds, but mud everywhere. If a sponge
+settles in the mud its canals are rapidly choked, its vital processes
+cease, and it dies. In this part of India, therefore, most sponges are
+found fixed either to floating objects such as logs of wood, to vertical
+objects such as the stems of bulrushes and other aquatic plants, or to
+the tips of branches that overhang the water and become submerged during
+the "rains." In Calcutta man has unwittingly come to the assistance of
+the sponges, not only by digging tanks but also by building
+"bathing-ghats" of brick at the edge, and constructing, with �sthetic
+intentions if not results, masses of artificial concrete rocks in or
+surrounding the water. There are at least two sponges (the typical form
+of <i>Spongilla alba</i> and <i>Ephydatia meyeni</i>) which in Calcutta
+are only found attached to such objects. The form of <i>S. alba</i>,
+however, that is found in ponds of brackish water in the Gangetic delta
+has not derived this artificial assistance from man, except in the few
+places where brick bridges have been built, and attaches itself to the
+stem and roots of a kind of grass that grows at the edge of brackish
+water. This sponge seems to have become immune even to mud, the
+particles of which are swallowed by its cells and finally got rid of
+without blocking up the canals.</p>
+
+<p>Several Indian sponges are only found adhering to stones and rocks.
+Among these species <i>Corvospongilla lapidosa</i> and our
+representatives of the subgenus <i>Stratospongilla</i> are noteworthy.
+Some forms (e.&nbsp;g. <i>Spongilla carteri</i> and <i>S.
+crateriformis</i>) seem, however, to be just as much at home in muddy as
+in rocky localities, although they avoid the mud itself.</p>
+
+<p>There is much indirect evidence that the larv� of freshwater sponges
+exercise a power of selection as regards the objects to which they affix
+themselves on settling down for life.</p>
+
+<p>Few Spongillid� are found in salt or brackish water, but <i>Spongilla
+alba</i> var. <i>bengalensis</i> has been found in both, and is abundant
+in the latter; indeed, it has not been found in pure fresh water.
+<i>Spongilla travancorica</i> has only been found in slightly brackish
+water, while <i>S. lacustris</i> subsp. <i>reticulata</i> and <i>Dosilia
+plumosa</i> occur in both fresh and brackish water, although rarely in
+the latter. The Spongillid� are essentially a freshwater family, and
+those forms that are found in any but pure fresh water must be regarded
+as aberrant or unusually tolerant in their habits, not as primitive
+marine forms that still linger halfway to the sea.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_49"
+id="Page_49">[Pg 49]</a></span><span class="smcap">Animals and Plants
+commonly associated with Freshwater Sponges.</span></p>
+
+<p class="center">(a) <i>Enemies.</i></p>
+
+<p>Freshwater sponges have few living enemies. Indeed, it is difficult
+to say exactly what is an enemy of a creature so loosely organized as a
+sponge. There can be little doubt, in any case, that the neuropteroid
+larva (<i>Sisyra indica</i>) which sucks the cells of several species
+should be classed in this category, and it is noteworthy that several
+species of the same genus also occur in Europe and N. America which also
+attack sponges. Other animals that may be enemies are a midge larva
+(<i>Tanypus</i> sp.) and certain worms that bore through the parenchyma
+(p.&nbsp;93), but I know of no animal that devours sponges bodily, so long as
+they are uninjured. If their external membrane is destroyed, they are
+immediately attacked by various little fish and also by snails of the
+genera <i>Limn�a</i> and <i>Planorbis</i>, and prawns of the genus
+<i>Pal�mon</i>.</p>
+
+<p>Their most active and obvious enemy is a plant, not an
+animal,&mdash;to wit, a filamentous alga that blocks up their canals by
+its rapid growth (p.&nbsp;79).</p>
+
+<p class="center">(b) <i>Beneficial Organisms.</i></p>
+
+<p>The most abundant and possibly the most important organisms that may
+be considered as benefactors to the Spongillid� are the green corpuscles
+that live in the cells of certain species (fig. 2, p.&nbsp;31), notably
+<i>Spongilla lacustris</i>, <i>S. proliferens</i>, and <i>Dosilia
+plumosa</i>. I have already said that these bodies are in all
+probability alg� which live free in the water and move actively at one
+stage of their existence, but some of them are handed on directly from a
+sponge to its descendants in the cells of the gemmule. In their
+quiescent stage they have been studied by several zoologists, notably by
+Sir Ray Lankester<a name="fnanchor_Q" id="fnanchor_Q"></a><a
+href="#footnote_Q" class="fnanchor"><sup>[Q]</sup></a> and Dr. W.
+Weltner<a name="fnanchor_R" id="fnanchor_R"></a><a href="#footnote_R"
+class="fnanchor"><sup>[R]</sup></a>, but the strongest light that has
+been cast on their origin is given by the researches of Dr. F. W. Gamble
+and Mr. F. Keeble (Q. J. Microsc. Sci. London, xlvii, p.&nbsp;363, 1904, and
+li, p.&nbsp;167, 1907). These researches do not refer directly to the
+Spongillid� but to a little flat-worm that lives in the sea,
+<i>Convoluta roscoffiensis</i>. The green corpuscles of this worm so
+closely resemble those of <i>Spongilla</i> that we are justified in
+supposing a similarity of origin. It has been shown by the authors cited
+that the green corpuscles of the worm are at one stage minute
+free-living organisms provided at one end with four flagella and at the
+other with a red pigment spot. The investigators are of the opinion that
+these organisms exhibit<span class='pagenum'><a name="Page_50"
+id="Page_50">[Pg 50]</a></span> the essential characters of the alg�
+known as Chlamydomonad�, and that after they have entered the worm they
+play for it the part of an excretory system.</p>
+
+<p>As they exist in the cells of <i>Spongilla</i> the corpuscles are
+minute oval bodies of a bright green colour and each containing a highly
+refractile colourless granule. A considerable number may be present in a
+single cell. It is found in European sponges that they lose their green
+colour if the sponge is not exposed to bright sunlight. In India,
+however, where the light is stronger, this is not always the case. Even
+when the colour goes, the corpuscles can still be distinguished as pale
+images of their green embodiment. They are called <i>Chlorella</i> by
+botanists, who have studied their life-history but have not yet
+discovered the full cycle. See Beyerinck in the Botan. Zeitung for 1890
+(vol. xlviii, p.&nbsp;730, pl. vii; Leipzig), and for further references
+West's 'British Freshwater Alg�,' p.&nbsp;230 (1904).</p>
+
+<p>The list of beneficent organisms less commonly present than the green
+corpuscles includes a <i>Chironomus</i> larva that builds parchment-like
+tubes in the substance of <i>Spongilla carteri</i> and so assists in
+supporting the sponge, and of a peculiar little worm (<i>Ch�togaster
+spongill�</i><a name="fnanchor_S" id="fnanchor_S"></a><a
+href="#footnote_S" class="fnanchor"><sup>[S]</sup></a>) that appears to
+assist in cleaning up the skeleton of the same sponge at the approach of
+the hot weather and in setting free the gemmules (p.&nbsp;93).</p>
+
+<p class="center">(c) <i>Organisms that take shelter in the Sponge or
+adhere to it externally.</i></p>
+
+<p>There are many animals which take shelter in the cavities of the
+sponge without apparently assisting it in any way. Among these are the
+little fish <i>Gobius alcockii</i>, which lays its eggs inside the
+oscula of <i>S. carteri</i>, thus ensuring not only protection but also
+a proper supply of oxygen for them (p.&nbsp;94); the molluscs
+(<i>Corbula</i>, spp.) found inside <i>S. alba</i> var.
+<i>bengalensis</i> (p.&nbsp;78); and the Isopod (<i>Tach�a spongillicola</i>)
+that makes its way into the oscula of <i>Spongilla carteri</i> and <i>S.
+crateriformis</i> (pp.&nbsp;86, 94).</p>
+
+<p>In Europe a peculiar ciliated Protozoon (<i>Trichodina spongill�</i>)
+is found attached to the external surface of freshwater sponges. I have
+noticed a similar species at Igatpuri on <i>Spongilla crateriformis</i>,
+but it has not yet been identified. It probably has no effect, good or
+bad, on the sponge.</p>
+
+<p class="p2 center"><span class="smcap">Freshwater Sponges in relation
+to Man.</span></p>
+
+<p>In dealing with <i>Spongilla carteri</i> I have suggested that
+sponges may be of some hygienic importance in absorbing putrid organic
+matter from water used both for ablutionary and for drinking purposes,
+as is so commonly the case with regard to ponds in India. Their bad
+odour has caused some species of Spongillid�<span class='pagenum'><a
+name="Page_51" id="Page_51">[Pg 51]</a></span> to be regarded as capable
+of polluting water, but a mere bad odour does not necessarily imply that
+they are insanitary.</p>
+
+<p>Unless my suggestion that sponges purify water used for drinking
+purposes by absorbing putrid matter should prove to be supported by
+fact, the Spongillid� cannot be said to be of any practical benefit to
+man. The only harm that has been imputed to them is that of polluting
+water<a name="fnanchor_T" id="fnanchor_T"></a><a href="#footnote_T"
+class="fnanchor"><sup>[T]</sup></a>, of blocking up water-pipes by their
+growth&mdash;a very rare occurrence,&mdash;and of causing irritation to
+the human skin by means of their spicules&mdash;a still rarer one. At
+least one instance is, however, reported in which men digging in a place
+where a pond had once been were attacked by a troublesome rash probably
+due to the presence of sponge-spicules in the earth, and students of the
+freshwater sponges should be careful not to rub their eyes after
+handling dried specimens.</p>
+
+<p class="p2 center"><span class="smcap">Indian Spongillid� Compared
+With Those of Other Countries.</span></p>
+
+<p>In Weltner's catalogue of the freshwater sponges (1895) seventy-six
+recent species of Spongillid� (excluding <i>Lubosmirskia</i>) are
+enumerated, and the number now known is well over a hundred. In India we
+have twenty-nine species, subspecies, and varieties, while from the
+whole of Europe only about a dozen are known. In the neighbourhood of
+Calcutta nine species, representing three genera and a subgenus, have
+been found; all of them occur in the Museum tank. The only other region
+of similar extent that can compare with India as regards the richness of
+its freshwater sponge fauna is that of the Amazon, from which about
+twenty species are known. From the whole of North America, which has
+probably been better explored than any other continent so far as
+Spongillid� are concerned, only twenty-seven or twenty-eight species
+have been recorded.</p>
+
+<p>The Indian species fall into seven genera, one of which
+(<i>Spongilla</i>) consists of three subgenera. With one exception (that
+of <i>Pectispongilla</i>, which has only been found in Southern India)
+these genera have a wide distribution over the earth's surface, and this
+is also the case as regards the subgenera of Spongilla. Four genera
+(<i>Heteromeyenia</i>, <i>Acalle</i>, <i>Parmula</i>, and
+<i>Uruguaya</i>) that have not yet been found in India are known to
+exist elsewhere.</p>
+
+<p>Five of the Indian species are known to occur in Europe, viz.,
+<i>Spongilla lacustris</i>, <i>S. crateriformis</i>, <i>S. carteri</i>,
+<i>S. fragilis</i>, <i>Trochospongilla pennsylvanica</i>; while
+<i>Ephydatia meyeni</i> is intermediate between the two commonest
+representatives of its genus in the Holarctic Zone, <i>Ephydatia
+fluviatilis</i> and <i>E. m�lleri</i>. Of the species that occur both in
+India and in Europe, two (<i>Spongilla</i><span class='pagenum'><a
+name="Page_52" id="Page_52">[Pg 52]</a></span> <i>lacustris</i> and
+<i>S. fragilis</i>) are found in this country in forms sufficiently
+distinct to be regarded as subspecies or local races. Perhaps this
+course should also be taken as regards the Indian forms of <i>S.
+carteri</i>, of which, however, the commonest of the Indian races would
+be the typical one; but <i>S. crateriformis</i> and <i>T.
+pennsylvanica</i> seem to preserve their specific characters free from
+modification, whether they are found in Europe, Asia, or America.</p>
+
+<p>The freshwater sponges of Africa have been comparatively little
+studied, but two Indian species have been discovered, <i>S.
+bombayensis</i> in Natal and <i>S. alba</i> var. <i>cerebellata</i> in
+Egypt. Several of the species from the Malabar Zone are, moreover,
+closely allied to African forms (p.&nbsp;11).</p>
+
+<p class="p2 center"><span class="smcap">Fossil Spongillid�.</span></p>
+
+<p>The Spongillid� are an ancient family. Young described a species
+(<i>Spongilla purbeckensis</i>) from the Upper Jurassic of Dorset (Geol.
+Mag. London (new series) v, p.&nbsp;220 (1878)), while spicules, assigned by
+Ehrenberg to various genera but actually those of <i>Spongilla
+lacustris</i> or allied forms, have been found in the Miocene of Bohemia
+(see Ehrenberg's 'Atlas f�r Micro-Geologie,' pl. xi (Leipzig, 1854), and
+Traxler in F�ldt. K�zl., Budapest, 1895, p.&nbsp;211). <i>Ephydatia</i> is
+also known in a fossil condition, but is probably less ancient than
+<i>Spongilla</i>.</p>
+
+<p>Ehrenberg found many sponge spicules in earth from various parts of
+the Indian Empire (including Baluchistan, Mangalore, Calcutta, the
+Nicobars and Nepal) and elsewhere, and it might be possible to guess at
+the identity of some of the more conspicuous species figured in his
+'Atlas.' The identification of sponges from isolated spicules is,
+however, always a matter of doubt, and in some cases Ehrenberg probably
+assigned spicules belonging to entirely different families or even
+orders to the same genus, while he frequently attributed the different
+spicules of the same species to different genera. Among his fossil (or
+supposed fossil) genera that may be assigned to the Spongillid� wholly
+or in part are <i>Aphidiscus</i>, <i>Spongolithis</i>,
+<i>Lithastericus</i> and <i>Lithosph�ridium</i>, many of the species of
+these "genera" certainly belonging to <i>Spongilla</i> and
+<i>Ephydatia</i>.</p>
+
+<p class="p2 center"><span class="smcap">Oriental Spongillid� not yet
+found in India.</span></p>
+
+<p>Few freshwater sponges that have not been found in India are as yet
+known from the Oriental Region, and there is positive as well as
+negative evidence that Spongillid� are less abundant in Malaysia than in
+this country. The following list includes the names of those that have
+been found, with notes regarding each species. It is quite possible that
+any one of them may be found at any time within the geographical
+boundaries laid down for this 'Fauna.' I have examined types or co-types
+in all cases except that of <i>Ephydatia fortis</i>, Weltner.</p>
+
+<p><span class='pagenum'><a name="Page_53" id="Page_53">[Pg
+53]</a></span>I. <i>Spongilla</i> (<i>Euspongilla</i>)
+<i>microsclerifera</i>*, Annandale (Philippines). P. U.S. Mus. xxxvii,
+p.&nbsp;131 (1909).</p>
+
+<p class="blockquote_b">This sponge is closely related to <i>S.
+lacustris</i>, but apparently does not produce branches. It is
+remarkable for the enormous number of microscleres in its
+parenchyma.</p>
+
+<p>II. <i>S.</i> (<i>Euspongilla</i>) <i>philippinensis</i>*, Annandale
+(Philippines). P. U.S. Mus. xxxvi, p.&nbsp;629 (1909).</p>
+
+<p class="blockquote_b">Related to <i>S. alba</i> and still more closely
+to <i>S. sceptrioides</i> of Australia. From the former it is readily
+distinguished by having minutely spined megascleres, green corpuscles,
+slender gemmule-spicules with short spines and no free microscleres.</p>
+
+<p>III. <i>S.</i> (? <i>Euspongilla</i>) <i>yunnanensis</i>*, Annandale
+(W. China). Rec. Ind. Mus. v, p.&nbsp;197 (1910).</p>
+
+<p class="blockquote_b">Apparently allied to <i>S. philippinensis</i>
+but with smooth skeleton-spicules and a more delicate skeleton.</p>
+
+<p>IV. <i>S.</i> (<i>Stratospongilla</i>) <i>sinensis</i>*, Annandale
+(Foochow, China). P. U.S. Mus. xxxviii, p.&nbsp;183 (1910).</p>
+
+<p class="blockquote_b">This species and <i>S. clementis</i> are
+referred to <i>Stratospongilla</i> with some doubt. Their gemmules are
+intermediate in structure between those of that subgenus and those of
+<i>Euspongilla</i>.  In <i>S. sinensis</i> the gemmules are packed
+together in groups at the base of the sponge, and their spicules are
+smooth, stout, and gradually pointed.</p>
+
+<p>V. <i>S.</i> (<i>Stratospongilla</i>) <i>clementis</i>*, Annandale
+(Philippines). P. U.S. Mus. xxxvi, p.&nbsp;631 (1909).</p>
+
+<p class="blockquote_b">The gemmules are single and closely adherent at
+the base of the sponge. Their spicules are very slender and minutely
+spined.</p>
+
+<p>VI. <i>S.</i> (? <i>Stratospongilla</i>) <i>coggini</i>*, Annandale
+(W. China). Rec. Ind. Mus. v, p.&nbsp;198 (1910).</p>
+
+<p class="blockquote_b">The gemmules apparently lack microscleres. They
+resemble those of <i>S. clementis</i>, to which the species is probably
+related, in other respects. The skeleton-spicules are spiny and rather
+stout, the species being strongly developed at the two ends.</p>
+
+<p>VII. <i>S.</i> (<i>Stratospongilla</i>) <i>sumatrana</i>*, Weber
+(Malay Archipelago). Zool. Ergebnisse einer Reise in Niederl�ndisch
+Ost-Indien, i. p.&nbsp;38 (1890).</p>
+
+<p class="blockquote_b">Closely allied to <i>S. indica</i> (p.&nbsp;100) but
+with pointed skeleton-spicules.</p>
+
+<p>VIII. <i>Ephydatia fortis</i>, Weltner (Philippines). Arch.
+Naturgesch. lxi(i), p.&nbsp;141 (1895).</p>
+
+<p class="blockquote_b">This species is remarkable for the great
+development of the spines on the shaft of the gemmule-spicules.</p>
+
+<p><span class='pagenum'><a name="Page_54" id="Page_54">[Pg
+54]</a></span>IX. <i>Ephydatia bogorensis</i>*, Weber (Malay
+Archipelago). Zool. Ergebnisse einer Reise in Niederl�ndisch Ost-Indien,
+i, p.&nbsp;33 (1890).</p>
+
+<p class="blockquote_b">The gemmule-spicules have rather narrow flattish
+disks, the edge of which is feebly but closely serrated.</p>
+
+<p>X. <i>E. blembingia</i>*, Evans (Malay Peninsula). Q. J. Microsc.
+Sci. London, xliv, p.&nbsp;81 (1901).</p>
+
+<p class="blockquote_b">The gemmules resemble those of <i>Dosilia
+plumosa</i> but are spherical. There are no free microscleres.</p>
+
+<p>XI. <i>Tubella vesparium</i>*, v. Martens (Borneo). Arch. Naturg.
+Berlin, xxxiv, p.&nbsp;62 (1868).</p>
+
+<p class="blockquote_b">Closely related to <i>T. vesparioides</i> (p.
+189), but with spiny megascleres.</p>
+
+<p>As regards <i>Spongilla decipiens</i>*, Weber, from the Malay
+Archipelago, see p.&nbsp;97.</p>
+
+<p class="p2 center">II.</p>
+
+<p class="center"><span class="smcap">History of the Study of Freshwater
+Sponges.</span></p>
+
+<p>The bath-sponge was known to the Greeks at an early date, and Homer
+refers to it as being used for cleansing furniture, for expunging
+writing, and for ablutionary purposes. He also mentions its peculiar
+structure, "with many holes." "Many things besides," wrote the English
+naturalist Ray in his 'Historia Plantarum' (1686), "regarding the powers
+and uses of sponges have the Ancients: to them refer." Ray himself
+describes at least one freshwater species, which had been found in an
+English river, and refers to what may be another as having been brought
+from America. In the eighteenth century Linn�, Pallas and other authors
+described the commoner European Spongillid� in general terms, sometimes
+as plants and sometimes as animals, more usually as zoophytes or
+"plant-animals" partaking of the nature of both kingdoms. The gemmules
+were noted and referred to as seeds. The early naturalists of the
+Linn�an Epoch, however, added little to the general knowledge of the
+Spongillid�, being occupied with theory in which theological disputes
+were involved rather than actual observation, and, notwithstanding the
+fact that the animal nature of sponges was clearly demonstrated by
+Ellis<a name="fnanchor_U" id="fnanchor_U"></a><a href="#footnote_U"
+class="fnanchor"><sup>[U]</sup></a> in 1765, it was not until the
+nineteenth century was well advanced that zoologists could regard
+sponges in anything like an impartial manner.</p>
+
+<p>One of the pioneers in the scientific study of the freshwater<span
+class='pagenum'><a name="Page_55" id="Page_55">[Pg 55]</a></span> forms
+was the late Dr. H. J. Carter, who commenced his investigations, and
+carried out a great part of them, in Bombay with little of the apparatus
+now considered necessary, and with a microscope that must have been
+grossly defective according to modern ideas. His long series of papers
+(1848-1887) published in the 'Annals and Magazine of Natural History' is
+an enduring monument to Indian zoology, and forms the best possible
+introduction to the study of the Spongillid�. Even his earlier mistakes
+are instructive, for they are due not so much to actual errors in
+observation as to a faithful transcription of what was observed with
+faulty apparatus.</p>
+
+<p>Contemporary with Carter were two authors whose monographs on the
+freshwater sponges did much to advance the study of the group, namely,
+J. S. Bowerbank, whose account of the species known at the time was
+published in the 'Proceedings of the Zoological Society of London' in
+1882, and the veteran American naturalist Mr. Edward Potts, whose study
+of the freshwater sponges culminated in his monograph published in the
+'Proceedings of the Academy of Natural Sciences of Philadelphia' in
+1887. Carter's own revision of the group was published in the 'Annals
+and Magazine of Natural History' in 1881. The names of Vejdovsky, who
+prefaced Potts's monograph with an account of the European species, and
+of Dybowsky, who published several important papers on classification,
+should also be mentioned, while Weltner's catalogue of the known species
+(1895) is of the greatest possible value to students of the group.</p>
+
+<p>Many authors have dealt with the physiology, reproduction and
+development of the Spongillid�, especially in recent years; Dr. R.
+Evans's description of the larva of <i>Spongilla lacustris</i> (1899),
+and his account of the development of the gemmule in <i>Ephydatia
+blembingia</i> (1901), Zykoff's account of the development of the
+gemmule and of the sponge from the gemmule (1892), and Weltner's
+observations on colour and other points (1893, 1907), may be mentioned
+in particular. Laurent's observations on development (1844), which were
+published in the 'Voyage de la Bonite,' and especially the exquisite
+plates which accompany them, have not received the notice they deserve,
+probably on account of their method of publication.</p>
+
+<p class="p2 center"><span class="smcap">Literature.</span></p>
+
+<p>The fullest account of the literature on the Spongillid� as yet
+published will be found in the first of Weltner's 'Spongillidenstudien'
+(Archiv f�r Naturgeschichte, lix (i), p.&nbsp;209, 1893). Unfortunately it
+contains no references of later date than 1892. The following list is
+not a complete bibliography, but merely a list of books and papers that
+should prove of use to students of the Oriental Spongillid�.</p>
+
+<p class="p2"><span class='pagenum'><a name="Page_56" id="Page_56">[Pg
+56]</a></span></p>
+
+<table summary="Works of Reference, Part 1 a">
+
+<tr><td></td><th class="normal">(a) <i>Works of Reference.</i></th></tr>
+
+<tr><td class="left_a">1863.</td><td><span
+class="smcap">Bowerbank</span>, "A Monograph of the Spongillid�," P.
+Zool. Soc. London, 1863, pp.&nbsp;440-472, pl. xxxviii.</td></tr>
+
+<tr><td class="left_a">1867.</td><td><span class="smcap">Gray, J.
+E.</span>, "Notes on the arrangement of Sponges, with the description of
+some new genera." <i>ibid.</i> 1867, pp.&nbsp;492-558.</td></tr>
+
+<tr><td class="left_a">1881.</td><td><span class="smcap">Carter</span>,
+"History and classification of the known species of <i>Spongilla</i>,"
+Ann. Nat. Hist. (5) vii, pp.&nbsp;77-107, pls. v, vi.</td></tr>
+
+<tr><td class="left_a">1883.</td><td><span
+class="smcap">Vejdovsky</span>, "Die S�sswasserschw�mme B�hmens," Abh.
+K�n. B�hm. Ges. Wiss. (math.-natur. Classe), xii, pp.&nbsp;1-43, pls.
+i-iii.</td></tr>
+
+<tr><td class="left_a">1887.</td><td><span class="smcap">Vosmaer</span>,
+"Spongien (Porifera)," in Bronn's Thier-Reichs.</td></tr>
+
+<tr><td class="left_a">1887.</td><td><span class="smcap">Potts</span>,
+"Contributions towards a synopsis of the American forms of Fresh-Water
+Sponges, with descriptions of those named by other authors and from all
+parts of the world," P. Ac. Philad. pp.&nbsp;158-279, pls.
+v-xii.</td></tr>
+
+<tr><td class="left_a">1887.</td><td><span
+class="smcap">Vejdovsky</span>, "Diagnosis of the European Spongillid�,"
+<i>ibid.</i> pp.&nbsp;172-180.</td></tr>
+
+<tr><td class="left_a">1888.</td><td><span
+class="smcap">Wierzejski</span>, "Beitrag zur Kenntnis der
+S�sswasserschw�mme," Verh. k.-k. zool.-bot. Ges. Wien, xxxviii,
+pp.&nbsp;529-536, pl. xii.</td></tr>
+
+<tr><td class="left_a">1891.</td><td><span class="smcap">Weltner</span>,
+in Zacharias's Die Tier- und Pflanzenwelt des S�sswassers: I, Die
+S�sswasserschw�mme.</td></tr>
+
+<tr><td class="left_a">1895.</td><td><span class="smcap">Weltner</span>,
+"Spongillidenstudien, III," Arch. Naturg. Berlin, lxi (i),
+pp.&nbsp;114-144.</td></tr>
+
+<tr><td class="left_a">1895.</td><td><span
+class="smcap">Korschelt</span> and <span class="smcap">Heider</span>,
+Text-book of the Embryology of Invertebrates: English edition, prepared
+by E. L. Mark and W. McM. Woodworth, Vol. I, chap. i.</td></tr>
+
+<tr><td class="left_a">1900.</td><td><span class="smcap">Minchin</span>,
+Sponges&mdash;Phylum Porifera in Lankester's "Treatise on Zoology,"
+ii.</td></tr>
+
+<tr><td class="left_a">1905.</td><td><span class="smcap">K�kenthal,
+W.</span>, Leitfaden f�r das Zoologische Praktikum (3rd Ed., Jena), 2.
+Kursus: Porifera, Schw�mme, p.&nbsp;31.</td></tr>
+
+<tr><td class="left_a">1906.</td><td><span class="smcap">Sollas, I. B.
+J.</span>, Cambridge Natural History&mdash;I. Porifera
+(Sponges).</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span class="smcap">Weltner</span>,
+"Spongillid�, S�sswasserschw�mme," in Brauer's "Die S�sswasserfauna
+Deutschlands," Heft xix, pp.&nbsp;177-190.</td></tr>
+
+<tr><td class="left_a">1910.</td><td><span class="smcap">Lloyd</span>,
+An Introduction to Biology for Students in India.</td></tr> </table>
+
+<table summary="Works of Reference, Part 1 b">
+
+<tr><td></td><th class="normal">(b) <i>Special Memoirs on Anatomy,
+Physiology, and Development.</i></th></tr>
+
+<tr><td class="left_a">1844.</td><td><span class="smcap">Laurent</span>,
+"Recherches sur l'Hydre et l'Eponge d'eau douce," Voyage de la Bonite,
+ii, pp.&nbsp;113-276.</td></tr>
+
+<tr><td class="left_a">1854.</td><td><span class="smcap">Carter</span>,
+"Zoosperms in <i>Spongilla</i>," Ann. Nat. Hist. (2) xiv, pp.&nbsp;334-336,
+pl. xi, figs. 1-6.</td></tr>
+
+<tr><td class="left_a">1857.</td><td><span class="smcap">Carter</span>,
+"On the ultimate structure of <i>Spongilla</i>, and additional notes on
+Freshwater Infusoria," Ann. Nat. Hist. (2) xx, pp.&nbsp;21-41, pl. i, figs.
+1-11.</td></tr>
+
+<tr><td class="left_a">1859.</td><td><span class="smcap">Carter</span>,
+"On the identity in structure and composition of the so-called
+'seed-like body' of <i>Spongilla</i> with the winter-egg of the Bryozoa,
+and the presence of starch-granules in each," Ann. Nat. Hist. (3) iii,
+pp.&nbsp;331-343, pl. viii.</td></tr>
+
+<tr><td class="left_a">1859.</td><td><span
+class="smcap">Lieberk�hn</span>, "Neue Beitr�ge zur Anatomie der
+Spongien," Arch. Anat. Phys. J. M�ller, pp.&nbsp;374-375, 526-528.<span
+class='pagenum'><a name="Page_57" id="Page_57">[Pg
+57]</a></span></td></tr>
+
+<tr><td class="left_a">1871.</td><td><span class="smcap">Carter</span>,
+"Discovery of the animal of the Spongiad� confirmed," Ann. Nat. Hist.
+(4) vii, p.&nbsp;445.</td></tr>
+
+<tr><td class="left_a">1871.</td><td><span class="smcap">Haeckel</span>,
+"Ueber die sexuelle Fortpflanzung und das nat�rliche System der
+Schw�mme," Jenaische Zeitschr. f. Naturw. vi, pp.&nbsp;643, 645.</td></tr>
+
+<tr><td class="left_a">1874.</td><td><span class="smcap">Carter</span>,
+"On the nature of the seed-like body of <i>Spongilla</i>; on the origin
+of the mother-cell of the spicule; and on the presence of spermatozoa in
+the <i>Spongida</i>," Ann. Nat. Hist. (4) xiv, pp.&nbsp;97-111.</td></tr>
+
+<tr><td class="left_a">1874.</td><td><span class="smcap">Lankester, E.
+Ray</span>, "The mode of occurrence of chlorophyll in <i>Spongilla</i>,"
+Q. J. Micr. Sci. xiv, pp.&nbsp;400-401.</td></tr>
+
+<tr><td class="left_a">1875.</td><td><span class="smcap">Sorby,
+H.</span>, "On the Chromatological relations of <i>Spongilla
+fluviatilis</i>," Q. J. Micr. Sci. xv, pp.&nbsp;47-52.</td></tr>
+
+<tr><td class="left_a">1878.</td><td><span class="smcap">Ganin</span>,
+"Zur Entwickelung der <i>Spongilla fluviatilis</i>," Zool. Anz. I, pp.
+195-199.</td></tr>
+
+<tr><td class="left_a">1882.</td><td><span class="smcap">Carter</span>,
+"Spermatozoa, polygonal cell-structure, and the green colour in
+<i>Spongilla</i>, together with a new species," Ann. Nat. Hist. (5) x,
+pp.&nbsp;362-372, pl. 16.</td></tr>
+
+<tr><td class="left_a">1882.</td><td><span class="smcap">Geddes</span>,
+"Further researches on animals containing chlorophyll," Nature, xxv, pp.
+303-305, 361-362.</td></tr>
+
+<tr><td class="left_a">1882.</td><td><span class="smcap">Lankester, E.
+Ray</span>, "On the chlorophyll-corpuscles and amyloid deposits of
+<i>Spongilla</i> and <i>Hydra</i>," Q. J. Micr. Sci. xxii (n. s.), pp.
+229-254, pl. xx.</td></tr>
+
+<tr><td class="left_a">1883.</td><td><span class="smcap">Marshall,
+W.</span>, "Einige vorl�utige Bemerkungen �ber die Gemmul� der
+S�sswasserschw�mme," Zool. Anz. vi, pp.&nbsp;630-634, 648-652.</td></tr>
+
+<tr><td class="left_a">1884.</td><td><span class="smcap">Carter</span>,
+"The branched and unbranched forms of the Freshwater Sponges considered
+generally," Ann. Nat. Hist. (5) xiii, pp.&nbsp;269-273.</td></tr>
+
+<tr><td class="left_a">1884.</td><td><span class="smcap">Marshall,
+W.</span>, "Vorl�utige Bemerkungen �ber die Fortpflanzungsverh�ltnisse
+von <i>Spongilla lacustris</i>," Ber. Naturf. Ges. Leipzig,* pp.
+22-29.</td></tr>
+
+<tr><td class="left_a">1884.</td><td><span class="smcap">Potts</span>,
+"Freshwater Sponges as improbable causes of the pollution of
+river-water," P. Ac. Philad. pp.&nbsp;28-30.</td></tr>
+
+<tr><td class="left_a">1885.</td><td><span class="smcap">Schulze, F.
+E.</span>, "�ber das Verh�ltniss der Spongien zu den Choanoflagellaten,"
+SB. preuss. Akad. Wiss. Berlin, pp.&nbsp;179-191.</td></tr>
+
+<tr><td class="left_a">1886.</td><td><span class="smcap">Goette</span>,
+Untersuchungen zur Entwickelungsgeschichte von <i>Spongilla
+fluviatilis</i>*, Hamburg und Leipzig (5 plates).</td></tr>
+
+<tr><td class="left_a">1886.</td><td><span
+class="smcap">Wierzejski</span>, "Le d�veloppement des Gemmules des
+Eponges d'eau douce d'Europe," Arch. Slaves Biologie, i, pp.&nbsp;26-47 (1
+plate).</td></tr>
+
+<tr><td class="left_a">1887.</td><td><span class="smcap">Carter</span>,
+"On the reproductive elements of the <i>Spongida</i>," Ann. Nat. Hist.
+(5) xix, pp.&nbsp;350-360.</td></tr>
+
+<tr><td class="left_a">1889.</td><td><span class="smcap">Maas</span>,
+"Zur Metamorphose der Spongillalarve," Zool. Anz. xii, pp.
+483-487.</td></tr>
+
+<tr><td class="left_a">1890.</td><td><span class="smcap">Maas</span>,
+"Ueber die Entwickelung des S�sswasserschw�mmes," Zeitschr. Wiss. Zool.
+1, pp.&nbsp;527-554, pls. xxii, xxiii.<span class='pagenum'><a name="Page_58"
+id="Page_58">[Pg 58]</a></span></td></tr>
+
+<tr><td class="left_a">1890.</td><td><span class="smcap">Weber,
+M.</span> et Mme. A., "Quelques nouveau cas de Symbiose," Zool. Ergebn.
+einer Reise Niederl�nd. Ost-Indien, i, pp.&nbsp;48-72, pl. v.</td></tr>
+
+<tr><td class="left_a">1892.</td><td><span class="smcap">Zykoff</span>,
+"Die Entwicklung der Gemmul� der <i>Ephydatia fluviatilis</i> auct.,"
+Zool. Anz. xv, pp.&nbsp;95-96.</td></tr>
+
+<tr><td class="left_a">1892.</td><td><span class="smcap">Zykoff</span>,
+"Die Bildung der Gemmul� bei <i>Ephydatia fluviatilis</i>," Revue Sc.
+Nat. Soc. St. P�tersbourg,* pp.&nbsp;342-344.</td></tr>
+
+<tr><td class="left_a">1892.</td><td><span class="smcap">Zykoff</span>,
+"Die Entwicklung der Gemmul� bei <i>Ephydatia fluviatilis</i> auct.,"
+Bull. Soc. Imp. Natur. Moscou, n. s. vi, pp.&nbsp;1-16, pl. i, ii.</td></tr>
+
+<tr><td class="left_a">1892.</td><td><span class="smcap">Zykoff</span>,
+"Entwickelungsgeschichte von <i>Ephydatia m�lleri</i>, Liebk. aus den
+Gemmul�," Biol. Centralbl. xii, pp.&nbsp;713-716.</td></tr>
+
+<tr><td class="left_a">1893.</td><td><span class="smcap">Weltner</span>,
+"Spongillidenstudien, II," Arch. Naturg. Berlin, lix (1), pp.&nbsp;245-282,
+pls. viii, ix.</td></tr>
+
+<tr><td class="left_a">1899.</td><td><span class="smcap">Evans,
+R.</span>, "The structure and metamorphosis of the larva of <i>Spongilla
+lacustris</i>," Q. J. Micr. Sci. xlii, pp.&nbsp;363-476, pls.
+xxxv-xli.</td></tr>
+
+<tr><td class="left_a">1901.</td><td><span class="smcap">Evans,
+R.</span>, "A description of <i>Ephydatia blembingia</i>, with an
+account of the formation and structure of the gemmule," Q. J. Micr. Sci.
+xliv, pp.&nbsp;71-109, pls. i-iv.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span class="smcap">Weltner</span>,
+"Spongillideustudien, V.: Zur Biologie von <i>Ephydatia fluviatilis</i>
+and die Bedeutung der Am�bocyten f�r die Spongilliden," Arch. Naturg.
+Berlin, lxxiii (i), pp.&nbsp;273-286.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "The buds of <i>Spongilla
+proliferens</i>, Annand.," Rec. Ind. Mus. i, pp.&nbsp;267, 268.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "Embryos of <i>Ephydatia blembingia</i>,
+Evans," <i>ibid.</i> p.&nbsp;269.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "The nature of the pores in
+<i>Spongilla</i>," <i>ibid.</i> pp.&nbsp;270-271.</td></tr> </table>
+
+<table summary="Works of Reference, part 1 c">
+
+<tr><td></td><th class="normal">(c) <i>Descriptions of Asiatic
+Species</i><a name="fnanchor_V" id="fnanchor_V"></a><a
+href="#footnote_V" class="fnanchor"><sup>[V]</sup></a> <i>and of Animals
+associated with them.</i></th></tr>
+
+<tr><td class="left_a">1847-<br />1848.</td><td><span
+class="smcap">Carter</span>, "Notes on the species, structure, and
+animality of the Freshwater Sponges in the tanks of Bombay (Genus
+<i>Spongilla</i>)," Trans. Bombay Med. &amp; Phys. Soc., 1847, and Ann.
+Nat. Hist. (2) i, pp.&nbsp;303-311, 1848.</td></tr>
+
+<tr><td class="left_a">1849.</td><td><span class="smcap">Carter</span>,
+"A descriptive account of the Freshwater Sponges (Genus
+<i>Spongilla</i>) in the Island of Bombay, with observations on their
+structure and development," Ann. Nat. Hist. (2) iv, pp.&nbsp;81-100, pls.
+iii-v.</td></tr>
+
+<tr><td class="left_a">1868.</td><td><span class="smcap">Martens, E.
+von</span>, "Ueber einige �stasiatische S�sswasserthiere," Arch. Naturg.
+Berlin, xxxiv, pp.&nbsp;1-67: IV., Ein S�sswasserschwamm aus Borneo, pp.
+61-64, pl. i, fig. 1.</td></tr>
+
+<tr><td class="left_a">1881.</td><td><span class="smcap">Carter</span>,
+"On <i>Spongilla cinerea</i>," Ann. Nat. Hist. (5) vii, p.
+263.</td></tr>
+
+<tr><td class="left_a">1890.</td><td><span class="smcap">Weber,
+M.</span>, "Zoologische Ergebnisse einer Reise in Niederl�ndisch
+Ost-Indien," i, pp.&nbsp;30-47, pl. iv.<span class='pagenum'><a
+name="Page_59" id="Page_59">[Pg 59]</a></span></td></tr>
+
+<tr><td class="left_a">1901.</td><td><span class="smcap">Evans,
+R.</span>, "A description of <i>Ephydatia blembingia</i>, with an
+account of the formation and structure of the gemmule," Q. J. Micr. Sci.
+xliv, pp.&nbsp;71-109, pls. i-iv.</td></tr>
+
+<tr><td class="left_a">1901.</td><td><span class="smcap">Weltner</span>,
+"S�sswasserspongien von Celebes (Spongillidenstudien, IV.)," Arch.
+Naturg. Berlin, lxvii (1) (Special Number), pp.&nbsp;187-204, pls. vi,
+vii.</td></tr>
+
+<tr><td class="left_a">1906.</td><td><span
+class="smcap">Annandale</span>, "A variety of <i>Spongilla lacustris</i>
+from brackish water in Bengal," J. As. Soc. Bengal, (n. s.) ii, pp.
+55-58.</td></tr>
+
+<tr><td class="left_a">1906.</td><td><span
+class="smcap">Annandale</span>, "Some animals found associated with
+<i>Spongilla carteri</i> in Calcutta," <i>ibid.</i> pp.
+187-196.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span class="smcap">Willey</span>,
+"Freshwater Sponge and Hydra in Ceylon," Spolia Zeylanica, iv, pp.
+184-185.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "On Freshwater Sponges from Calcutta and
+the Himalayas," J. As. Soc. Bengal, (n. s.) iii, pp.&nbsp;15-26.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "Gemmules of <i>Trochospongilla
+phillottiana</i>, Annand.," Rec. Ind. Mus. i, p.&nbsp;269.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "Description of two new Freshwater
+Sponges from Eastern Bengal, with remarks on allied forms," <i>ibid.</i>
+pp.&nbsp;387-392.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span
+class="smcap">Annandale</span>, "Preliminary notice of a collection of
+Sponges from W. India, with descriptions of two new species," Rec. Ind.
+Mus. ii, pp.&nbsp;25-28.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span
+class="smcap">Kirkpatrick</span>, "Description of a new variety of
+<i>Spongilla loricata</i>, Weltner," <i>ibid.</i> pp.&nbsp;97-99.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span
+class="smcap">Annandale</span>, "Preliminary notice of a collection of
+Sponges from Burma, with the description of a new species of
+<i>Tubella</i>," <i>ibid.</i> pp.&nbsp;157-158.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "Report on a small collection of Sponges
+from Travancore," Rec. Ind. Mus. iii, pp.&nbsp;101-104, pl. xii.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span class="smcap">Needham</span>,
+"Notes on the Neuroptera in the collection of the Indian Museum,"
+<i>ibid.</i> pp.&nbsp;206-207.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "Description of a new species of
+<i>Spongilla</i> from Orissa," <i>ibid.</i> p.&nbsp;275.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "Beitr�ge zur Kenntnis der Fauna von
+S�d-Afrika: IX. Freshwater Sponges," Zool. Jahrb. (Syst.) xxvii, pp.
+559-568.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "Report on a collection of Freshwater
+Sponges from Japan," Annot. Zool. Japon, vii, pp.&nbsp;105-112, pl.
+ii.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "Freshwater Sponges in the collection of
+the United States National Museum: Part I. Specimens from the
+Philippines and Australia," P. U.S. Mus. xxxvi, pp.&nbsp;627-632.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "Freshwater Sponges collected in the
+Philippines by the 'Albatross' Expedition," <i>ibid.</i> xxxvii, pp.
+131-132.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "Freshwater Sponges in the collection of
+the United States National Museum: Part II. Specimens from North and
+South America," <i>ibid.</i> pp.&nbsp;401-406.<span class='pagenum'><a
+name="Page_60" id="Page_60">[Pg 60]</a></span></td></tr>
+
+<tr><td class="left_a">1910.</td><td><span
+class="smcap">Annandale</span>, "Freshwater Sponges in the collection of
+the United States National Museum: Part III. Description of a new
+species of <i>Spongilla</i> from China," <i>ibid.</i> xxxviii, p.
+183.</td></tr>
+
+<tr><td class="left_a">1910.</td><td><span
+class="smcap">Annandale</span>, "Description of a new species of Sponge
+from Cape Comorin," Rec. Ind. Mus. v, p.&nbsp;31.</td></tr>
+
+<tr><td class="left_a">1910.</td><td><span
+class="smcap">Stephenson</span>, "On some aquatic Oligoch�te worms
+commensal in <i>Spongilla carteri</i>," <i>ibid.</i> pp.
+233-240.</td></tr>
+
+<tr><td class="left_a">1910.</td><td><span
+class="smcap">Annandale</span>, "Note on a Freshwater Sponge and
+Polyzoon from Ceylon," Spolia Zeylanica, vii. p.&nbsp;63, pl. i.</td></tr>
+
+</table>
+
+<p class="footnote">
+<a name="footnote_K" id="footnote_K"></a> <a href="#fnanchor_K">[K]</a>
+Except in "<i>Proterospongia</i>," an organism of doubtful affinities
+but not a sponge. It consists of a mass of jelly containing ordinary
+cells, with collar-cells <i>outside</i>.</p>
+
+<p class="footnote">
+<a name="footnote_L" id="footnote_L"></a> <a href="#fnanchor_L">[L]</a>
+<i>Cf.</i> Weltner, "Spongillidenstudien, V," Arch. Naturg. Berlin,
+lxxiii (i), p.&nbsp;273 (1907).</p>
+
+<p class="footnote">
+<a name="footnote_M" id="footnote_M"></a> <a href="#fnanchor_M">[M]</a>
+It is difficult to see any trace of them in thin microtome sections. A
+fragment of the membrane must be mounted whole.</p>
+
+<p class="footnote">
+<a name="footnote_N" id="footnote_N"></a> <a href="#fnanchor_N">[N]</a>
+Rec. Ind. Mus. i, p.&nbsp;269 (1907).</p>
+
+<p class="footnote">
+<a name="footnote_O" id="footnote_O"></a> <a href="#fnanchor_O">[O]</a>
+Proliferation whereby more than one osculum is produced is really a form
+of budding, but in most sponges this has become no longer a mode of
+reproduction but the normal method by which size is increased, and must
+therefore be considered merely as a vegetative process.</p>
+
+<p class="footnote">
+<a name="footnote_P" id="footnote_P"></a> <a href="#fnanchor_P">[P]</a>
+P. Ac. Philad. 1887, p.&nbsp;162.</p>
+
+<p class="footnote">
+<a name="footnote_Q" id="footnote_Q"></a> <a href="#fnanchor_Q">[Q]</a>
+Q. J. Microsc. Sci. London, xxii. p.&nbsp;229 (1882).</p>
+
+<p class="footnote">
+<a name="footnote_R" id="footnote_R"></a> <a href="#fnanchor_R">[R]</a>
+Arch. Naturg. Berlin, lix (i), p.&nbsp;260 (1893).</p>
+
+<p class="footnote">
+<a name="footnote_S" id="footnote_S"></a> <a href="#fnanchor_S">[S]</a>
+Journ. As. Soc. Beng. n. s. ii, 1906, p.&nbsp;189.</p>
+
+<p class="footnote">
+<a name="footnote_T" id="footnote_T"></a> <a href="#fnanchor_T">[T]</a>
+See Potts, Proc. Ac. Philad. 1884, p.&nbsp;28.</p>
+
+<p class="footnote">
+<a name="footnote_U" id="footnote_U"></a> <a href="#fnanchor_U">[U]</a>
+Phil. Trans. Roy. Soc. lv, p.&nbsp;280.</p>
+
+<p class="footnote">
+<a name="footnote_V" id="footnote_V"></a> <a href="#fnanchor_V">[V]</a>
+Descriptions of Siberian sponges are not included in these
+references.</p>
+
+<p><span class='pagenum'><a name="Page_61" id="Page_61">[Pg
+61]</a></span></p>
+
+<h3 class="p4">GLOSSARY OF TECHNICAL TERMS USED IN PART I.</h3>
+
+<table summary="Technical Terms Part I">
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Amphioxi</i>
+(adj. <i>amphioxous</i>)</span></td><td class="left_a">Rod-like spicules
+sharp at both ends.</td></tr>
+
+<tr><td class="left_a"><span
+style="white-space:nowrap;"><i>Amphistrongyli</i> (adj.</span>
+&nbsp;&nbsp;<i>amphistrongylous</i>)</td><td class="left_a">Rod-like
+spicules blunt at both ends.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Basal
+membrane</i></span></td><td class="left_a">A horny, structureless
+membrane found at the base of some sponges.</td></tr>
+
+<tr><td class="left_a"><span
+style="white-space:nowrap;"><i>Birotulate</i> (subst. or
+adj.)</span></td><td class="left_a">Spicule with a transverse disk at
+both ends.</td></tr>
+
+<tr><td class="left_a"><i>Bubble-cells</i></td><td
+class="left_a">Spherical cells of the parenchyma the contents of which
+consist of a drop of liquid covered by a thin film of
+protoplasm.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Ciliated</i>
+(or <i>flagellated</i>) <i>chamber</i></span></td><td class="left_a">A
+cavity lined with collar-cells.</td></tr>
+
+
+<tr><td class="left_a"><span
+style="white-space:nowrap;"><i>Collar-cell</i>
+(<i>choanocyte</i>)</span></td><td class="left_a">Cell provided at one
+end with a membranous collar and a vibratile lash or flagellum that
+springs from within the collar.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Derma</i> or
+<i>ectodermal layer</i></span></td><td class="left_a">A layer of flat
+cells arranged like a pavement on the surface of the sponge.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Exhalent</i>
+(or <i>efferent</i>) <i>canal</i></span></td><td class="left_a">A
+tubular canal through which water passes from a ciliated chamber towards
+the osculum.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Fibres</i>
+(skeleton)</span></td><td class="left_a">Thread-like structures that
+compose the skeleton of the sponge and are formed (in the Spongillid�)
+mainly of overlapping spicules.</td></tr>
+
+<tr><td class="left_a"><i>Flesh-spicules</i></td><td
+class="left_a">Microscleres (<i>q. v.</i>) that lie free in the
+parenchyma and the derma.</td></tr>
+
+<tr><td class="left_a"><i>Foramen</i></td><td class="left_a">An orifice
+of the gemmule.</td></tr>
+
+<tr><td class="left_a"><i>Foraminal tubule</i></td><td class="left_a">A
+horny tube that surrounds the foramina of some gemmules.</td></tr>
+
+<tr><td class="left_a"><i>Gemmule</i></td><td class="left_a">A mass of
+cells packed with food-material, surrounded by at least one horny coat,
+capable of retaining vitality in unfavourable conditions and finally of
+giving origin to a new sponge.</td></tr>
+
+<tr><td class="left_a"><i>Green corpuscles</i></td><td
+class="left_a">Minute green bodies found inside cells of sponges and
+other animals and representing a stage in the life-history of an alga
+(<i>Chlorella</i>).</td></tr>
+
+<tr><td class="left_a"><i>Inhalent</i> (or <i>afferent</i>)
+canal.</td><td class="left_a">A tubular canal through which water passes
+from the exterior towards a ciliated chamber.<span class='pagenum'><a
+name="Page_62" id="Page_62">[Pg 62]</a></span></td></tr>
+
+<tr><td class="left_a"><i>Megascleres</i></td><td class="left_a">The
+larger spicules that (in the Spongillid�) form the basis of the skeleton
+of the sponge.</td></tr>
+
+<tr><td class="left_a"><i>Microscleres</i></td><td
+class="left_a">Smaller spicules that lie free in the substance or the
+derma of the sponge, or are associated with the gemmule.</td></tr>
+
+<tr><td class="left_a"><i>Monaxon</i></td><td class="left_a">(Of
+spicules) having a single main axis; (of sponges) possessing skeleton
+spicules of this type.</td></tr>
+
+<tr><td class="left_a"><i>Osculum</i></td><td class="left_a">An aperture
+through which water is ejected from the sponge.</td></tr>
+
+<tr><td class="left_a"><i>Oscular collar</i></td><td class="left_a">A
+ring-shaped membrane formed by an extension of the derma round an
+osculum.</td></tr>
+
+<tr><td class="left_a"><i>Parenchyma</i></td><td class="left_a">The
+gelatinous part of the sponge.</td></tr>
+
+<tr><td class="left_a"><i>Pavement layer</i></td><td
+class="left_a">Adherent gemmules arranged close together in a single
+layer at the base of a sponge.</td></tr>
+
+<tr><td class="left_a"><i>Pneumatic coat</i></td><td class="left_a">A
+horny or chitinous layer on the surface of the gemmule containing
+air-spaces. If these spaces are of regular form and arrangement it is
+said to be <i>cellular</i>; if they are minute and irregular it is
+called <i>granular</i>.</td></tr>
+
+<tr><td class="left_a"><i>Pore</i></td><td class="left_a">A minute hole
+through which water is taken into the sponge.</td></tr>
+
+<tr><td class="left_a"><i>Pore-cell</i> (<i>porocyte</i>)</td><td
+class="left_a">A cell pierced by a pore.</td></tr>
+
+<tr><td class="left_a"><i>Radiating fibres</i></td><td
+class="left_a">Fibres in the skeleton of a sponge that are vertical or
+radiate from its centre.</td></tr>
+
+<tr><td class="left_a"><i>Rotula</i></td><td class="left_a">A transverse
+disk borne by a microsclere.</td></tr>
+
+<tr><td class="left_a"><i>Rotulate</i> (subst. or adj.)</td><td
+class="left_a">Spicule bearing one or two transverse disks.</td></tr>
+
+<tr><td class="left_a"><i>Spicule</i></td><td class="left_a">A minute
+mineral body of regular and definite shape due not to the forces of
+crystallization but to the activity of the living cell or cells in which
+it is formed.</td></tr>
+
+<tr><td class="left_a"><i>Spongin</i></td><td class="left_a">The horny
+substance found in the skeletal framework and the coverings of gemmules
+of sponges. Structures formed of this substance are often referred to as
+<i>chitinous</i>.</td></tr>
+
+<tr><td class="left_a"><i>Subdermal cavity</i></td><td class="left_a">A
+cavity immediately below the derma (<i>q. v.</i>).</td></tr>
+
+<tr><td class="left_a"><i>Transverse fibres</i></td><td
+class="left_a">Fibres in the skeleton of a sponge that run across
+between the radiating fibres.</td></tr>
+
+<tr><td class="left_a"><span
+style="white-space:nowrap;"><i>Tubelliform</i> (of
+spicule)</span></td><td class="left_a">Having a straight shaft with a
+transverse disk at one end and a comparatively small knob-like
+projection at the other.</td></tr> </table>
+
+<p><span class='pagenum'><a name="Page_63" id="Page_63">[Pg
+63]</a></span></p>
+
+<h3 class="p4">SYSTEMATIC LIST OF THE INDIAN SPONGILLID�.</h3>
+
+<p class="blockquote_b">[Types, schizotypes, or cotypes have been
+examined in the case of all species, &amp;c. , whose names are marked
+thus, *.]</p>
+
+<p>Genus 1. <span class="smcap">Spongilla</span>, Lamarck (1816).</p>
+
+<p class="indent2">Subgenus A. <span class="smcap">Euspongilla</span>,
+Vejdovsky (1883).</p>
+
+<p class="indent5a">1.</p>
+<p class="indent5aa">? <i>S. lacustris</i>, auct. (perhaps in N.W.
+India).</p>
+
+<p class="indent5b">1<i>a</i>.</p>
+<p class="indent5bb"><i>S. lacustris</i> subsp. <i>reticulata</i>*,
+Annandale (1907).</p>
+
+<p class="indent5b">2.</p>
+<p class="indent5bb"><i>S. proliferens</i>*, Annandale (1907).</p>
+
+<p class="indent5b">3.</p>
+<p class="indent5bb"><i>S. alba</i>*, Carter (1849).</p>
+
+<p class="indent5b">3<i>a</i>.</p>
+<p class="indent5bb"><i>S. alba</i> var. <i>cerebellata</i>, Bowerbank
+(1863).</p>
+
+<p class="indent5b">3<i>b</i>.</p>
+<p class="indent5bb"><i>S. alba</i> var. <i>bengalensis</i>*, Annandale
+(1906).</p>
+
+<p class="indent5b">4.</p>
+<p class="indent5bb"><i>S. cinerea</i>*, Carter (1849).</p>
+
+<p class="indent5b">5.</p>
+<p class="indent5bb"><i>S. travancorica</i>*, Annandale (1909).</p>
+
+<p class="indent5b">6.</p>
+<p class="indent5bb"><i>S. hemephydatia</i>*, Annandale (1909).</p>
+
+<p class="indent5c">7.</p>
+<p class="indent5cc"><i>S. crateriformis</i>* (Potts) (1882).</p>
+
+<p class="indent2">Subgenus B. <span class="smcap">Eunapius</span>, J.
+E. Gray (1867).</p>
+
+<p class="indent5a">8.</p>
+<p class="indent5aa"><i>S. carteri</i>*, Carter (1849).</p>
+
+<p class="indent5b">8<i>a</i>.</p>
+<p class="indent5bb"><i>S. carteri</i> var. <i>mollis</i>*, nov.</p>
+
+<p class="indent5b">8<i>b</i>.</p>
+<p class="indent5bb"><i>S. carteri</i> var. <i>cava</i>*, nov.</p>
+
+<p class="indent5b">8<i>c</i>.</p>
+<p class="indent5bb"><i>S. carteri</i> var. <i>lobosa</i>*, nov.</p>
+
+<p class="indent5b">9<i>a</i>.</p>
+<p class="indent5bb"><i>S. fragilis</i> subsp. <i>calcuttana</i>*,
+nov.</p>
+
+<p class="indent5b">9<i>b</i>.</p>
+<p class="indent5bb"><i>S. fragilis</i> var. <i>decipiens</i>, Weber</p>
+<p class="indent5bbb">(probably Malaysian, not Indian).</p>
+
+<p class="indent5_b">10.</p>
+<p class="indent5bb"><i>S. gemina</i>*, sp. nov.</p>
+
+<p class="indent5_b">11.</p>
+<p class="indent5bb"><i>S. crassissima</i>*, Annandale (1907).</p>
+
+<p class="indent5_c">11<i>a</i>.</p>
+<p class="indent5cc"><i>S. crassissima</i> var. <i>crassior</i>*,
+Annandale (1907).</p>
+
+<p class="indent2">Subgenus C. <span
+class="smcap">Stratospongilla</span>, Annandale (1909).</p>
+
+<p class="indent5_a">12.</p>
+<p class="indent5aa"><i>S. indica</i>*, Annandale (1908).</p>
+
+<p class="indent5_b">13.</p>
+<p class="indent5bb"><i>S. bombayensis</i>*, Carter (1882).</p>
+
+<p class="indent5_c">14.</p>
+<p class="indent5cc"><i>S. ultima</i>*, Annandale (1910).</p>
+
+<p>Genus 2. <span class="smcap">Pectispongilla</span>, Annandale
+(1909).</p>
+
+<p class="indent5_a">15.</p>
+<p class="indent5aa"><i>P. aurea</i>*, Annandale (1909).</p>
+
+<p class="indent5_c">15<i>a</i>.</p>
+<p class="indent5cc"><i>P. aurea</i> var. <i>subspinosa</i>*, nov.</p>
+
+<p><span class='pagenum'><a name="Page_64" id="Page_64">[Pg
+64]</a></span></p>
+
+<p>Genus 3. <span class="smcap">Ephydatia</span>, Lamouroux (1816).</p>
+
+<p class="indent5_a">16.</p>
+<p class="indent5aa"><i>E. meyeni</i>* (Carter) (1849).</p>
+
+<p>Genus 4. <span class="smcap">Dosilia</span>, J. E. Gray (1867).</p>
+
+<p class="indent5_a">17.</p>
+<p class="indent5aa"><i>D. plumosa</i>* (Carter) (1849).</p>
+
+<p>Genus 5. <span class="smcap">Trochospongilla</span>, Vejdovsky
+(1883).</p>
+
+<p class="indent5_a">18.</p>
+<p class="indent5aa"><i>T. latouchiana</i>*, Annandale (1907).</p>
+
+<p class="indent5_b">19.</p>
+<p class="indent5bb"><i>T. phillottiana</i>*, Annandale (1907).</p>
+
+<p class="indent5_c">20.</p>
+<p class="indent5cc"><i>T. pennsylvanica</i>* (Potts) (1882).</p>
+
+<p>Genus 6. <span class="smcap">Tubella</span>, Carter (1881).</p>
+
+<p class="indent5_a">21.</p>
+<p class="indent5aa"><i>T. vesparioides</i>*, Annandale (1908).</p>
+
+<p>Genus 7. <span class="smcap">Corvospongilla</span>, nov.</p>
+
+<p class="indent5_a">22.</p>
+<p class="indent5aa"><i>C. burmanica</i>* (Kirkpatrick) (1908).</p>
+
+<p class="indent5_c">23.</p>
+<p class="indent5cc"><i>C. lapidosa</i>* (Annandale) (1908).</p>
+
+<p class="p4"><span class='pagenum'><a name="Page_65" id="Page_65">[Pg
+65]</a></span></p>
+
+<p class="p2 center">Order <b>HALICHONDRINA</b>.</p>
+
+<p class="p2">Siliceous monaxon sponges in which the horny skeleton is
+much reduced or absent and the spicular skeleton is more or less
+definitely reticulate. The microscleres are usually rod-like and rarely
+have more than one main axis.</p>
+
+<p class="p2 center larger">Family <b>SPONGILLID�</b>.</p>
+
+<p class="center"><span class="smcap">Spongillad�</span>, J. E. Gray, P.
+Zool. Soc. London, 1867, p.&nbsp;550.</p>
+
+<p class="p2">Freshwater Halichondrina which at certain seasons produce
+gemmules armed with peculiar microscleres. Two distinct kinds of
+microsclere are often present, that associated with the gemmule
+sometimes consisting of a vertical shaft at the ends of which transverse
+disks or rotul� are borne. There is always at least a trace of a
+subdermal cavity.</p>
+
+<p>Many authors divide the Spongillid� into two
+subfamilies:&mdash;Spongillin� (or Euspongillin�), in which the
+gemmule-spicules have no transverse rotul�, and Meyenin� (or
+Ephydatiin�), in which they have rotules at one or both ends. So
+gradual, however, is the transition that I find it difficult to decide
+in one instance to which of two genera, typical respectively of the two
+"subfamilies," a species should be assigned. Minchin in his account of
+the Porifera in Lankester's "Treatise on Zoology" (1900) regards the
+Spongillid� merely as a subfamily of the Heterorrhaphid�, and there
+certainly are few differences of a definite nature between them and the
+marine family (or subfamily) Remerid�.</p>
+
+<p class="p2 center"><i>Key to the Indian Genera of</i> Spongillid�.</p>
+
+<table summary="Key to Indian Genera of Spongillid�">
+
+<tr><td class="left_a">I.</td><td class="left_a">Microscleres without
+transverse disks.</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Microscleres of the
+parenchyma similar in general structure to those or the gemmule; the
+latter without comb-like vertical rows of spines at the ends</td><td
+class="right"><span class="smcap">Spongilla</span>, p. <a
+href="#Page_67">67</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Microscleres of the
+gemmule with comb-like vertical rows of spines at both ends</td><td
+class="right"><span class="smcap">Pectispongilla</span>, p. <a
+href="#Page_106">106</a>.</td></tr>
+
+<tr><td class="left_a">II.</td><td class="left_a">Some or all
+of the microscleres birotulate. (Birotulate microscleres of one kind
+only.)<span class='pagenum'><a name="Page_66" id="Page_66">[Pg
+66]</a></span></td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Microscleres of the
+gemmule birotulate, the rotules with serrated or strongly sinuous edges;
+parenchyma spicules usually absent, never of complicated
+structure</td><td class="right"><span class="smcap">Ephydatia</span>,
+p. <a href="#Page_108">108</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Microscleres of the
+gemmule as in <i>Ephydatia</i>; microscleres of the parenchyma
+consisting of numerous shafts meeting in different planes in a central
+nodule</td><td class="right"><span class="smcap">Dosilia</span>, p. <a
+href="#Page_110">110</a>.</td></tr>
+
+<tr><td class="right_a">C.</td><td class="left_a">Microscleres as in
+<i>Ephydatia</i> except that the rotul� of the gemmule-spicules have
+smooth edges</td><td class="right"><span
+class="smcap">Trochospongilla</span>, p. <a
+href="#Page_113">113</a>.</td></tr>
+
+<tr><td class="right_a">D.</td><td class="left_a">Microscleres of the
+gemmule without a trace of rotules, those of the parenchyma
+birotulate</td><td class="right"><span
+class="smcap">Corvospongilla</span>, nov., p. <a
+href="#Page_122">122</a>.</td></tr>
+
+<tr><td class="left_a">III.</td><td class="left_a">Microscleres of the
+gemmule with a well-developed basal rotule and a vertical shaft ending
+above in a mere knob.</td><td class="right"><span
+class="smcap">Tubella</span>, p. <a href="#Page_120">120</a>.</td></tr>
+
+</table>
+
+<p>The most distinct genus of Spongillid� not yet found in India is
+<i>Heteromeyenia</i>, Potts. It is easily distinguished from all others
+by the fact that the birotulate spicules of the gemmule are of two quite
+distinct kinds, which occur together on every mature gemmule.
+<i>Heteromeyenia</i> is represented by several American species, one of
+which has been found in Europe. <i>Acalle</i>, J. E. Gray, which is
+represented by a single South American species (<i>Spongilla
+recurvata</i>, Bowerbank), is related to <i>Heteromeyenia</i> but has
+one kind of gemmule-spicule tubelliform, the other birotulate. Probably
+<i>Uraguaya</i>, Carter, should be regarded as a subgenus of
+<i>Trochospongilla</i> with an unusually solid skeleton; it is peculiar
+to S. America. <i>Parmula</i>, Carter (=<i>Drulia</i>, Gray) includes
+South American forms allied to <i>Tubella</i>, but with the shaft of the
+gemmule-spicule degenerate and consisting of a mere projection in the
+centre of a shield-like body, which represents the lower rotule. The
+status of <i>Potamolepis</i>, Marshall, originally described from the
+Lake of Galilee, is very doubtful; possibly some or all of its species
+belong to the subgenus of <i>Spongilla</i> here called
+<i>Stratospongilla</i> (p.&nbsp;100); but they are stated never to produce
+gemmules. The same is the case as regards <i>Pachydictyum</i>, Weltner,
+which consists of a single species from Celebes.</p>
+
+<p>The sponges from Lake Baikal assigned by Weltner (Arch. Naturg. lxi
+(i) p.&nbsp;131) to the subfamily Lubomirskin� are of doubtful position and
+need not be considered here; while <i>Lessepsia</i>, Keller, from one of
+the salt lakes on the Suez Canal, certainly does not belong to the
+family, although it is assigned to it by von Lendenfeld (Mon. Horny
+Sponges, p.&nbsp;904 (1889)) and subsequently by Minchin (Porifera, p.&nbsp;152,
+in Lankester's Treatise on Zoology, part ii (1900)).</p>
+
+<p><span class='pagenum'><a name="Page_67" id="Page_67">[Pg
+67]</a></span></p>
+
+<p class="p2 center">Genus 1. <b>SPONGILLA</b>, <i>Lamarck</i> (Carter
+<i>emend.</i>).</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla</i>, Lamarck, Histoire des Animaux sans
+Vert�bres, ii, p.&nbsp;111 (1836).</span>
+<span class="i0"><i>Spongilla</i>, Carter, Ann. Nat. Hist. (5) vii, p.
+86 (1881).</span>
+<span class="i0"><i>Euspongilla</i>, Vejdovsky, Abh. B�hm. Ges. xii, p.
+15 (1883).</span>
+<span class="i0"><i>Spongilla</i>, Potts, P. Ac. Philad. 1887, p.
+182.</span>
+</div>
+
+<p><span class="smcap">Type</span>, <i>Spongilla lacustris</i>,
+auctorum.</p>
+
+<p>Spongillid� in which the gemmules have (normally) cylindrical or
+subcylindrical spicules that are sharp or blunt at the ends, without a
+distinct transverse disk or disks and without comb-like vertical rows of
+spines.</p>
+
+<p>The skeleton is variable in structure, sometimes being almost
+amorphous, sometimes having well-defined radiating and transverse fibres
+firmly compacted with spongin. The skeleton-spicules are either sharp or
+blunt at the ends. Flesh-spicules are often absent; when present they
+are needle-like and resemble the gemmule-spicules in general structure;
+they have not even rudimentary rotules at their ends. The gemmules
+either lie free in the substance of the sponge or are attached to its
+support; sometimes they adhere together in free or attached groups.</p>
+
+<p><i>Spongilla</i> is undoubtedly the most primitive genus of the
+Spongillid�, its spicules showing less sign of specialization than those
+of any other genus included in the family. As a fossil it goes back at
+any rate to the Upper Jurassic (p.&nbsp;52).</p>
+
+<p><span class="smcap">Geographical
+Distribution.</span>&mdash;Cosmopolitan. In most countries the majority
+of the freshwater sponges belong to this genus, but in Japan
+<i>Ephydatia</i> seems to predominate.</p>
+
+<p class="p2 center"><i>Key to the Indian Species of</i> Spongilla.</p>
+
+<table summary="Key to Indian Species of Spongilla">
+
+<tr><td class="left_a">I.</td><td class="left_a">Gemmule provided with a
+thick, apparently granular pneumatic coat in which the gemmule-spicules
+are arranged tangentially or vertically. (Subgenus <i>Euspongilla</i>,
+p.&nbsp;<a href="#Page_69">69</a>.)</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">No foraminal
+tubule.</td></tr> <tr><td></td><td class="left_a"><i>a.</i> Sponge
+bright green, soft and compressible when fresh, very fragile dry</td><td
+class="right"> <i>lacustris</i>, p.&nbsp;<a
+href="#Page_69">69</a>.</td></tr>
+
+<tr><td></td><td class="left_a"><i>a'.</i> Sponge white or grey, hard
+both fresh and dry</td><td class="right"><i>alba</i>, p.&nbsp;<a
+href="#Page_76">76</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">A foraminal tubule
+present.</td></tr> <tr><td></td><td class="left_a"><i>b.</i>
+Skeleton-spicules smooth.</td></tr>
+
+<tr><td></td><td class="left_a">&nbsp;&nbsp;&nbsp;&nbsp;&#946;. Gemmules
+free; gemmule-spicules arranged tangentially and horizontally</td><td
+class="right"><i>proliferens</i>, p.&nbsp;<a
+href="#Page_72">72</a>.</td></tr>
+
+<tr><td></td><td class="left_a">&nbsp;&nbsp;&nbsp;&nbsp;&#946;'.
+Gemmules free; gemmule-spicules arranged vertically or nearly so in a
+single series</td><td class="right"><i>hemephydatia</i>, p.&nbsp;<a
+href="#Page_82">82</a>.<span class='pagenum'><a name="Page_68"
+id="Page_68">[Pg 68]</a></span></td></tr>
+
+<tr><td></td><td class="left_a">&nbsp;&nbsp;&nbsp;&nbsp;&#946;''.
+Gemmules firmly fixed to the support of the sponge; gemmule-spicules
+almost vertical, irregularly arranged, as a rule in more than one
+series</td><td  class="right"><i>travancorica</i>, p.&nbsp;<a
+href="#Page_81">81</a>.</td></tr>
+
+<tr><td></td><td class="left_a"><i>b'.</i> Skeleton-spicules spiny or
+irregular in outline.</td></tr>
+
+<tr><td></td><td class="left_a">&nbsp;&nbsp;&nbsp;&nbsp;&#946;'''.
+Gemmule-spicules tangential and horizontal, without rudimentary
+rotules</td><td class="right"><i>cinerea</i>, p.&nbsp;<a
+href="#Page_79">79</a>.</td></tr>
+
+<tr><td></td><td class="left_a">&nbsp;&nbsp;&nbsp;&nbsp;&#946;''''.
+Gemmule-spicules vertical or nearly so, often with rudimentary rotules
+at the tips</td><td class="right"><i>crateriformis</i>, p.&nbsp;<a
+href="#Page_83">83</a>.</td></tr>
+
+<tr><td class="left_a">II.</td><td class="left_a">Gemmules surrounded in
+several layers by distinct polygonal air-spaces with chitinous walls.
+(Subgenus <i>Eunapius</i>, p.&nbsp;<a href="#Page_86">86</a>.)</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Gemmules single.
+Skeleton- and gemmule-spicules smooth, pointed, not very stout</td><td
+class="right"><i>carteri</i>, p.&nbsp;<a
+href="#Page_87">87</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Gemmules bound
+together in pairs. Skeleton friable; skeleton-spicules slender</td><td
+class="right"><i>gemina</i>, nov., p.&nbsp;<a
+href="#Page_97">97</a>.</td></tr>
+
+<tr><td class="right_a">C.</td><td class="left_a">Gemmules bound
+together in free groups of more than two or forming a "pavement-layer"
+at the base of the sponge.</td></tr>
+
+<tr><td></td><td class="left_a"><i>c.</i> Skeleton friable;
+skeleton-spicules slender</td><td class="right"><i>fragilis</i>,
+p.&nbsp;<a href="#Page_95">95</a>.</td></tr>
+
+<tr><td></td><td class="left_a"><i>c'.</i> Skeleton very hard and
+resistant; skeleton-spicules stout</td><td
+class="right"><i>crassissima</i>, p.&nbsp;<a
+href="#Page_98">98</a>.</td></tr>
+
+<tr><td class="left_a">III.</td><td class="left_a">Gemmules without or
+with irregular pneumatic coat, covered by a chitinous membrane or
+membranes in which the gemmule-spicules lie parallel to the surface.
+(Subgenus <i>Stratospongilla</i>, p.&nbsp;<a
+href="#Page_100">100</a>.)</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Skeleton spicules
+spiny or irregular in outline.</td></tr>
+
+<tr><td></td><td class="left_a"><i>a.</i> Skeleton-spicules blunt;
+gemmules covered by a single chitinous membrane</td><td
+class="right"><i>indica</i>, p.&nbsp;<a
+href="#Page_100">100</a>.</td></tr>
+
+<tr><td></td><td class="left_a"><i>a'.</i> Skeleton-spicules sharp;
+gemmules covered by two chitinous membranes</td><td
+class="right"><i>bombayensis</i>, p.&nbsp;<a
+href="#Page_102">102</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Skeleton-spicules
+smooth. Skeleton-spicules sharp; gemmule spicules very irregular in
+form</td><td class="right"><i>ultima</i>, p.&nbsp;<a
+href="#Page_104">104</a>.</td></tr>
+
+</table>
+
+<p><span class='pagenum'><a name="Page_69" id="Page_69">[Pg
+69]</a></span></p>
+
+<p class="p2 center">Subgenus A. <b>EUSPONGILLA</b>,
+<i>Vejdovsky</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Euspongilla</i>, Vejdovsky, Abh. B�hm. Ges. xii, p.
+15 (1883).</span>
+<span class="i0"><i>Euspongilla</i>, <i>id.</i>, in Potts's "Fresh-Water
+Sponges," P. Ac. Philad. 1887, p.&nbsp;172.</span>
+<span class="i0"><i>Euspongilla</i>, Weltner, in Zacharias's Tier- und
+Pflanzenwelt des S�sswassers, i, p.&nbsp;210 (1891).</span>
+</div>
+
+<p><span class="smcap">Type</span>, <i>Spongilla lacustris</i>,
+auctorum.</p>
+
+<p>Spongill� in which the gemmules are covered with a thick, apparently
+granular pneumatic coat. A delicate membrane often occurs outside this
+coat, but it is never thick or horny. The gemmules usually lie free in
+the sponge but sometimes adhere to its support; rarely they are fastened
+together in groups (<i>e.&nbsp;g.</i> in <i>S. aspinosa</i>, Potts). The
+skeleton-spicules are never very stout and the skeleton is always
+delicate.</p>
+
+<p>The species in this subgenus are closely allied and must be
+distinguished rather by the sum of their peculiarities than by any one
+character. They occur in all countries in which Spongillid� are found.
+Seven Indian species may be recognized.</p>
+
+<p class="p2"><b>1. Spongilla lacustris</b>, <i>auctorum</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla lacustris</i>, Bowerbank, P. Zool. Soc.
+London, 1863, p.&nbsp;441, pl. xxxviii, fig. 14.</span>
+<span class="i0"><i>Spongilla lacustris</i>, Carter, Ann. Nat. Hist. (5)
+vii, p.&nbsp;87 (1881).</span>
+<span class="i0"><i>Euspongilla lacustris</i>, Vejdovsky, in Potts's
+"Fresh-Water Sponges," P. Ac. Philad. 1887, p.&nbsp;172.</span>
+<span class="i0"><i>Spongilla lacustris</i>, Potts, <i>ibid.</i>, p.
+186, pl. v, fig. 1, pl. vii, figs. 1-6.</span>
+<span class="i0"><i>Euspongilla lacustris</i>, Weltner, in Zacharias's
+Tier- und Pflanzenwelt des S�sswassers, i, p.&nbsp;211, figs. 36-38
+(1891).</span>
+<span class="i0"><i>Spongilla lacustris</i>, <i>id.</i>, Arch. Naturg.
+lxi (i), pp.&nbsp;118, 133-135 (1895).</span>
+<span class="i0"><i>Spongilla lacustris</i>, Annandale, J. Linn. Soc.,
+Zool., xxx, p.&nbsp;245 (1908).</span>
+</div>
+
+<p class="blockquote">[I have not attempted to give a detailed synonymy
+of this common species. There is no means of telling whether many of the
+earlier names given to forms or allies of <i>S. lacustris</i> are actual
+synonyms, and it would serve no useful purpose, so far as the fauna of
+India is concerned, to complicate matters by referring to obscure
+descriptions or possible descriptions of a species only represented in
+India, so far as we know, by a specialized local race, to which separate
+references are given.]</p>
+
+<p><i>Sponge</i> soft and easily compressed, very brittle when dry,
+usually consisting of a flat or rounded basal portion of no great depth
+and of long free cylindrical branches, which droop when removed from the
+water; branches occasionally absent. Colour bright green when the sponge
+is growing in a strong light, dirty flesh-colour when it is growing in
+the shade. (Even in the latter case<span class='pagenum'><a
+name="Page_70" id="Page_70">[Pg 70]</a></span> traces of the "green
+corpuscles" can be detected in the cells of the parenchyma.) Oscula
+star-shaped, of moderate size, as a rule rendered conspicuous by the
+furrows that radiate from them over the outer surface of the parenchyma
+below the external membrane; oscular collars well developed.</p>
+
+<p><i>Skeleton</i> reticulate, loose, with definite radiating and
+transverse fibres held together by a small quantity of spongin; the
+fibres slender but not extremely so.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, sharply pointed, long,
+slender. Flesh-spicules slender, covered with small spines, sharply
+pointed, nearly straight. Gemmule-spicules resembling the flesh-spicules
+but shorter and as a rule more strongly curved, sometimes bent so as to
+form semicircular figures, usually pointed somewhat abruptly; their
+spines relatively longer than those of the flesh-spicules, often curved
+backwards, especially near the ends of the spicules, at which points
+they are often longer than elsewhere.</p>
+
+<p><i>Gemmules</i> usually numerous in autumn, lying free in the sponge,
+spherical, variable in size but usually rather large, as a rule covered
+with a thick granular coat in which the spicules are arranged
+tangentially; a horizontal layer of spicules often present in the
+external membrane; the granular coat and its spicules occasionally
+deficient. No foraminal tubule; its place sometimes taken by an open,
+bowl-shaped chitinous structure the base of which is in continuity with
+the inner chitinous coat of the gemmule.</p>
+
+<p><i>S. lacustris</i> is an extremely variable species, varying in the
+size, proportions and shape of its spicules, in its external form and in
+the size and structure of the gemmule. A considerable number of
+varieties have been described from different parts of Europe and N.
+America, but some of these may represent distinct but closely-allied
+species; descriptions of most of them will be found in Potts's
+"Fresh-Water Sponges." The embryology and the earlier stages of the
+development from the egg have been described in great detail by Evans
+(Quart. J. Micr. Sci. (n. s.) xlii, p.&nbsp;363 (1899)), while the anatomy
+and physiology are discussed by most authors who have written on these
+features in the Spongillid�.</p>
+
+<p><span class="smcap">Type.</span>&mdash;It is impossible to say who
+was the first authority to use the name <i>Spongilla lacustris</i> in
+the sense in which it is used by recent authors. No type can therefore
+be <ins title="changed from 'recognzied'">recognized</ins>.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>S.
+lacustris</i> occurs all over Europe and N. America and is probably the
+commonest species in most parts of both continents. It has also been
+found in Northern Asia and may occur in the Himalayan lakes and in the
+north-west of India.</p>
+
+<p class="p2"><span class='pagenum'><a name="Page_71" id="Page_71">[Pg
+71]</a></span>1 <i>a.</i> Subspecies <b>reticulata</b>*,
+<i>Annandale</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla reticulata</i>, Annandale, Rec. Ind. Mus.
+i, p.&nbsp;387, pl. xiv, fig. 1 (1907).</span>
+<span class="i0"><i>Spongilla lacustris</i> subspecies
+<i>reticulata</i>, <i>id.</i>, P. U.S. Mus. xxxvii, p.&nbsp;401
+(1909).</span>
+</div>
+
+<p>This race differs from the typical <i>S. lacustris</i> in the
+following particulars:&mdash;</p>
+
+<p class="indent1a">(1) The branches are always compressed and
+anastomose freely when well developed (fig.&nbsp;5, p.&nbsp;<a
+href="#Page_37">37</a>);</p>
+
+<p class="indent1b">(2) the skeleton-fibres are finer;</p>
+
+<p class="indent1b">(3) the skeleton-spicules are longer;</p>
+
+<p class="indent1c">(4) the gemmule-spicules are longer and more slender
+and are never strongly bent.</p>
+
+<p>As regards the form of the skeleton- and gemmule-spicules and also
+that of the branches the subspecies <i>reticulata</i> resembles <i>S.
+alba</i> rather than <i>S. lacustris</i>, but owing to the fact that it
+agrees with <i>S. lacustris</i> in its profuse production of branches,
+in possessing green corpuscles and in its fragility, I think it should
+be associated with that species.</p>
+
+<div class="figcenter">
+<img src="images/fig_008.jpg"
+width="500" height="420"  alt="Illustration: Fig. 8"
+title="Fig. 8" />
+<p class="caption">Fig. 8.</p>
+</div>
+
+<p class="captionj">A=gemmule-spicules of <i>Spongilla lacustris</i>
+subsp. <i>reticulata</i> (from type); B=gemmule-spicules of <i>S.
+alba</i> from Calcutta: both highly magnified.</p>
+
+<p>The branches are sometimes broad (fig. 5, p.&nbsp;37), sometimes very
+slender. In the latter condition they resemble blades of grass growing
+in the water.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum; a co-type in
+the British Museum.</p>
+
+<p><span class="smcap"><span class='pagenum'><a name="Page_72"
+id="Page_72">[Pg 72]</a></span>Geographical
+Distribution.</span>&mdash;All over Eastern India and Burma; also in the
+Bombay Presidency. <i>Localities:</i>&mdash;<span
+class="smcap">Bengal</span>, Port Canning, Ganges delta; Rajshahi
+(Rampur Bhulia) on the Ganges, 150 miles N. of Calcutta
+(<i>Annandale</i>); Puri district, Orissa (<i>Annandale</i>); R. Jharai,
+Siripur, Saran district, Tirhut (<i>M. Mackenzie</i>): <span
+class="smcap">Madras Presidency</span>, Madras (town) (<i>J. R.
+Henderson</i>): <span class="smcap">Bombay Presidency</span>, Igatpuri,
+W. Ghats (<i>Annandale</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;This subspecies is usually
+found in small masses of water, especially in pools of rain-water, but
+Mr. Mackenzie found it growing luxuriantly in the Jharai at a time of
+flood in September. It is very abundant in small pools among the
+sand-dunes that skirt the greater part of the east coast of India. Here
+it grows with great rapidity during the "rains," and often becomes
+desiccated even more rapidly as soon as the rain ceases. As early in the
+autumn as October I have seen masses of the sponge attached, perfectly
+dry, to grass growing in the sand near the Sur Lake in Orissa. They
+were, of course, dead but preserved a life-like appearance. Some of them
+measured about six inches in diameter. At Port Canning the sponge grows
+during the rains on the brickwork of bridges over ditches of brackish
+water that dry up at the beginning of winter, while at Rajshahi and at
+Igatpuri I found it at the edges of small ponds, at the latter place in
+November, at the former in February. Specimens taken at Madras by Dr.
+Henderson during the rains in small ponds in the sand contained no
+gemmules, but these structures are very numerous in sponges examined in
+autumn or winter.</p>
+
+<p>Numerous larv� of <i>Sisyra indica</i> (p.&nbsp;92) were found in this
+sponge at Rajshahi. Unlike those obtained from <i>S. alba</i>, they had
+a green colour owing to the green matter sucked from the sponge in their
+stomachs. The <i>coralloides</i> phase of <i>Plumatella fruticosa</i>
+(p.&nbsp;219) was also found in <i>S. lacustris</i> subsp. <i>reticulata</i>
+at Rajshahi.</p>
+
+<p>So far as my experience goes, this subspecies has always a bright
+green colour due to the presence of "green corpuscles," even when it is
+growing in a pond heavily shaded by trees or under the arch of a small
+bridge. Probably the more intense light of India enables the corpuscles
+to flourish in situations in which in Europe they would lose their
+chlorophyll.</p>
+
+<p class="p2">2. <b>Spongilla proliferens</b>*, <i>Annandale</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla cinerea</i>, Weber (<i>nec</i> Carter),
+Zool. Ergeb. Niederl. Ost-Ind. vol. i, pp.&nbsp;35, 46 (1890).</span>
+<span class="i0"><i>Spongilla proliferens</i>, Annandale, J. Asiat. Soc.
+Bengal, 1907, p.&nbsp;15, fig. 1.</span>
+<span class="i0"><i>Spongilla proliferens</i>, <i>id.</i>, Rec. Ind.
+Mus. i, pp.&nbsp;267, 271 (1907).</span>
+</div>
+
+<p><i>Sponge</i> forming soft, shallow cushions rarely more than 10 cm.
+in diameter on the leaves of water-plants, or small irregular masses on
+their roots and stems. Colour bright green. Oscula<span
+class='pagenum'><a name="Page_73" id="Page_73">[Pg 73]</a></span>
+moderate, flat, surrounded by deep, cone-shaped collars; radiating
+furrows and canals in the parenchyma surrounding them often deep.
+External pores contained normally in single cells. The surface
+frequently covered by small rounded buds; true branches if present more
+or less flattened or conical, always short, as a rule absent.</p>
+
+<p><i>Skeleton</i> loose, feebly reticulate at the base of the sponge;
+transverse fibres slender in the upper part of the sponge, often
+scarcely recognizable at its base. Very little spongin present.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules long, smooth, sharply pointed; the
+length on an average at least 20 times the greatest breadth, often more.
+Flesh-spicules slender, gradually pointed, nearly straight, covered with
+minute straight or nearly straight spines. Gemmule-spicules very
+similar, but usually a little stouter and often blunt at the ends; their
+spines rather longer than those on the flesh-spicules, usually more
+numerous near the ends than in the middle of the spicule, slightly
+retroverted, those at the extreme tips often so arranged as to suggest a
+rudimentary rotule.</p>
+
+<div class="figcenter">
+<img src="images/fig_009.png"
+width="300" height="280"  alt="Illustration: Fig. 9.&mdash;Gemmule of
+Spongilla proliferens as seen in optical section (from Calcutta), �
+140." title="Fig. 9.&mdash;Gemmule of Spongilla proliferens as seen in
+optical section (from Calcutta), � 140." />
+<p class="caption">Fig. 9.&mdash;Gemmule of <i>Spongilla proliferens</i>
+as seen in optical section (from Calcutta), � 140.</p>
+</div>
+
+<p><i>Gemmules</i> usually numerous, lying free near the base of the
+sponge, very variable in size, spherical, surrounded by a thick granular
+layer in which the spicules, which are always very numerous, are
+arranged tangentially, their position being more near the vertical than
+the horizontal; a few horizontal spicules usually present on the
+external surface of the gemmule, which frequently has a ragged
+appearance owing to some of the tangential spicules protruding further
+than others. Foraminal tubule stout, cylindrical, usually somewhat
+contorted; its orifice irregular in outline. Sometimes more than one
+foramen present.</p>
+
+<p><span class='pagenum'><a name="Page_74" id="Page_74">[Pg
+74]</a></span><i>S. proliferens</i> can be distinguished from all forms
+of <i>S. lacustris</i> and <i>S. alba</i> by the fact that its gemmules
+possess a foraminal tubule; from <i>S. cinerea</i> it can be
+distinguished by its colour and its smooth skeleton-spicules, and from
+<i>S. travancorica</i> by its free gemmules. I have been enabled by the
+kindness of Prof. Max Weber to examine specimens from Celebes and Java
+identified by him as <i>S. cinerea</i>, Carter, and have no doubt that
+they belong to my species.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum; a co-type in
+the British Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;All over
+Eastern India and Burma; also in Cochin on the west coast; Ceylon; W.
+China; Java, Flores and Celebes. <i>Localities</i>:&mdash;<span
+class="smcap">Bengal</span>, Calcutta and neighbourhood
+(<i>Annandale</i>); Berhampore, Murshidabad district (<i>R. E.
+Lloyd</i>): <span class="smcap">Assam</span>, Mangal-dai near the Bhutan
+frontier (<i>S. W. Kemp</i>): <span class="smcap">Madras
+Presidency</span>, Madras (town) and neighbourhood (<i>J. R.
+Henderson</i>); Rambha, Ganjam district (<i>Annandale</i>); Bangalore,
+Mysore (alt. <i>ca.</i> 3000 ft.) (<i>Annandale</i>); Ernakulam and
+Trichur, Cochin (<i>G. Mathai</i>): <span class="smcap">Burma</span>,
+Rangoon (<i>Annandale</i>, <i>J. Coggin Brown</i>); Prome, Upper Burma
+(<i>J. Coggin Brown</i>); Kawkareik, Amherst district, Tenasserim
+(<i>Annandale</i>): <span class="smcap">Ceylon</span>, between
+Maradankawela and Galapita-Gala, North Central Province (<i>Willey</i>).
+Mr. J. Coggin Brown has recently brought back specimens from Yunnan.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;<i>S. proliferens</i> is
+usually found in ponds which never dry up; Prof. Max Weber found it in
+small streams in Malaysia. It is common in India on the leaves of
+<i>Vallisneria</i> and <i>Limnanthemum</i>, on the roots of <i>Pistia
+stratiotes</i> and on the stems of rushes and grass. So far as I have
+been able to discover, the life of the individual sponge is short, only
+lasting a few weeks.</p>
+
+<p>Sexual reproduction occurs seldom or never, but reproduction by means
+of buds and gemmules continues throughout the year. The former is a rare
+method of reproduction in most Spongillid� but in this species occurs
+normally and constantly, the buds being often very numerous on the
+external surface. They arise a short distance below the surface as
+thickenings in the strands of cells that accompany the radiating fibres
+of the skeleton. As they grow they push their way up the fibres, forcing
+the external membrane outwards. The membrane contracts gradually round
+their bases, cuts off communication between them and the parent sponge
+and finally sets them adrift. No hole remains when this takes place, for
+the membrane closes up both round the base of the bud and over the
+aperture whence it has emerged.</p>
+
+<p>The newly liberated bud already possesses numerous minute pores, but
+as yet no osculum; its shape exhibits considerable variation, but the
+end that was farthest from the parent-sponge before liberation is always
+more or less rounded, while the other end is flat. The size also varies
+considerably. Some of the buds float, others sink. Those that float do
+so either owing to their<span class='pagenum'><a name="Page_75"
+id="Page_75">[Pg 75]</a></span> shape, which depends on the degree of
+development they have reached before liberation, or to the fact that a
+bubble of gas is produced in their interior. The latter phenomenon only
+occurs when the sun is shining on the sponge at the moment they are set
+free, and is due to the action of the chlorophyll of the green bodies so
+abundant in certain of the parenchyma cells of this species. If the
+liberation of the bud is delayed rather longer than usual, numbers of
+flesh-spicules are produced towards the ends of the primary
+skeleton-fibres and spread out in one plane so as to have a fan-like
+outline; in such buds the form is more flattened and the distal end less
+rounded than in others, and the superficial area is relatively great, so
+that they float more readily. Those buds that sink usually fall in such
+a way that their proximal, flattened end comes in contact with the
+bottom or some suspended object, to which it adheres. Sometimes,
+however, owing to irregularity of outline in the distal end, the
+proximal end is uppermost. In this case it is the distal end that
+adheres. Whichever end is uppermost, it is in the uppermost end, or as
+it may now be called, the upper surface, that the osculum is formed.
+Water is drawn into the young sponge through the pores and, finding no
+outlet, accumulates under the external membrane, the subdermal cavity
+being at this stage even larger than it is in the adult sponge.
+Immediately after adhesion the young sponge flattens itself out. This
+process apparently presses together the water in the subdermal cavity
+and causes a large part of it to accumulate at one point, which is
+usually situated near the centre of the upper surface. A transparent
+conical projection formed of the external membrane arises at this point,
+and at the tip of the cone a white spot appears. What is the exact cause
+of this spot I have not yet been able to ascertain, but it marks the
+point at which the imprisoned water breaks through the expanded
+membrane, thus forming the first osculum. Before the aperture is formed,
+it is already possible to distinguish on the surface of the parenchyma
+numerous channels radiating from the point at which the osculum will be
+formed to the periphery of the young sponge. These channels as a rule
+persist in the adult organism and result from the fact that the inhalent
+apertures are situated at the periphery, being absent from both the
+proximal and the distal ends of the bud. In the case of floating buds
+the course of development is the same, except that the osculum, as in
+the case of development from the gemmule in other species (see Zykoff,
+Biol. Centrbl. xii, p.&nbsp;713, 1892), is usually formed before adhesion
+takes place.</p>
+
+<p>The sponge of <i>S. proliferens</i> is usually too small to afford
+shelter to other animals, and I have not found in it any of those
+commonly associated with <i>S. carteri</i> and <i>S. alba</i>.</p>
+
+<p>Owing to its small size <i>S. proliferens</i> is more easily kept
+alive in an aquarium than most species, and its production of buds can
+be studied in captivity. In captivity a curious<span class='pagenum'><a
+name="Page_76" id="Page_76">[Pg 76]</a></span> phenomenon is manifested,
+viz. the production of extra oscula, often in large numbers. This is due
+either to a feebleness in the currents of the sponge which makes it
+difficult to get rid of waste substances or to the fact that the canals
+get blocked. The effluent water collects in patches under the external
+membrane instead of making its way out of the existing oscula, and new
+oscula are formed over these patches in much the same way as the first
+osculum is formed in the bud.</p>
+
+<p class="p2">3. <b>Spongilla alba</b>*, <i>Carter</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla alba</i>, Carter, J. Bombay Asiat. Soc.
+iii, p.&nbsp;32, pl. i, fig. 4 &amp; Ann. Nat. Hist. (2) iv, p.&nbsp;83, pl.
+iii, fig. 4 (1849)</span>
+<span class="i0"><i>Spongilla alba</i>, Bowerbank, P. Zool. Soc. London,
+1863, p.&nbsp;463 pl. xxxviii, fig. 15.</span>
+<span class="i0"><i>Spongilla alba</i>, Carter, Ann. Nat. Hist. (5) vii,
+p.&nbsp;88 (1881).</span>
+<span class="i0"><i>Spongilla alba</i>, Petr, Rozp. Ceske Ak. Praze,
+<ins title="changed from 'Trida'">Tr�da</ins>, ii, pl. i, figs. 3-6
+(1899) (text in Czech).</span>
+<span class="i0"><i>Spongilla alba</i>, Annandale, Rec. Ind. Mus. i, p.
+388, pl. xiv, fig. 2 (1907).</span>
+</div>
+
+<p><i>Sponge</i> forming masses of considerable area, but never of more
+than moderate depth or thickness. Surface smooth and undulating or with
+irregular or conical projections; sponge hard but brittle; colour white
+or whitish; oscula of moderate or large size, never very conspicuous;
+radiating furrows absent or very short; external membrane adhering to
+the substance of the sponge.</p>
+
+<p><i>Skeleton</i> forming a moderately dense network of slender
+radiating and transverse fibres feebly held together; little spongin
+present; the meshes much smaller than in <i>S. lacustris</i> or <i>S.
+proliferens</i>.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, sharply pointed, slender,
+feebly curved. Gemmule-spicules (fig. 8, p.&nbsp;71) slender, cylindrical,
+blunt or abruptly pointed at the ends, feebly curved, bearing relatively
+long backwardly directed spines, which are usually more numerous at the
+ends than near the middle of the shaft. Flesh-spicules very numerous in
+the parenchyma and especially the external membrane, as a rule
+considerably more slender and more sharply pointed than the
+gemmule-spicules, covered with straight spines which are often longer at
+the middle of the shaft than at the ends.</p>
+
+<p><i>Gemmules</i> usually of large size, with a moderately thick granular
+layer; spicules never very numerous, often lying horizontally on the
+external surface of the gemmule as well as tangentially in the granular
+layer; no foraminal tubule; a foraminal cup sometimes present.</p>
+
+<p class="p2">3<i>a</i>. Var. <b>cerebellata</b>, <i>Bowerbank</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla cerebellata</i>, Bowerbank, P. Zool. Soc.
+London, 1863, p.&nbsp;465, pl. xxxviii, fig. 16.</span>
+<span class="i0"><i>Spongilla alba</i> var. <i>cerebellata</i>, Carter,
+Ann. Nat. Hist. (5) vii, p.&nbsp;88 (1881).</span>
+<span class="i0"><i>Spongilla cerebellata</i>, Weltner, Arch. Naturg.
+lxi (i), p.&nbsp;117 (1895).<span class='pagenum'><a name="Page_77"
+id="Page_77">[Pg 77]</a></span></span>
+<span class="i0"><i>Spongilla cerebellata</i>, Kirkpatrick, Ann. Nat.
+Hist. (7) xx, p.&nbsp;523 (1907).</span>
+</div>
+
+<p>This variety is distinguished from the typical form by the total
+absence of flesh-spicules. The gemmule-spicules are also more numerous
+and cross one another more regularly.</p>
+
+<p class="p2">3<i>b</i>. Var. <b>bengalensis</b>*, <i>Annandale</i>. (<a
+href="#Plate_I">Plate I</a>, figs. 1-3.)</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla lacustris</i> var. <ins title="changed
+from 'benegalensis'"><i>bengalensis</i></ins>, Annandale, J. Asiat. Soc.
+Bengal, 1906, p.&nbsp;56.</span>
+<span class="i0"><i>Spongilla alba</i> var. <i>marina</i>, <i>id.</i>,
+Rec. Ind. Mus. i, p.&nbsp;389 (1907).</span>
+</div>
+
+<p>The sponge is either devoid of branches or produces irregular,
+compressed, and often digitate processes, sometimes of considerable
+length and delicacy. Flesh-spicules are usually present throughout the
+sponge, but are sometimes absent from one part of a specimen and present
+in others. Some of the gemmules are often much smaller than the others.
+Perhaps this form should be regarded as a phase rather than a true
+variety (see p.&nbsp;18).</p>
+
+<p>All forms of <i>S. alba</i> can be distinguished from all forms of
+<i>S. lacustris</i> by the much closer network of the skeleton and by
+the consequent hardness of the sponge; also by the complete absence of
+green corpuscles.</p>
+
+<p><span class="smcap">Types.</span> The types of the species and of the
+var. <i>cerebellata</i> are in the British Museum, with fragments of the
+former in the Indian Museum; that of var. <i>bengalensis</i> is in the
+Indian Museum, with a co-type in London.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;India and
+Egypt. <i>Localities</i>:&mdash;<span class="smcap">Bombay
+Presidency</span>, island of Bombay (<i>Carter</i>); Igatpuri, W. Ghats
+(<i>Annandale</i>): <span class="smcap">Bengal</span>, Calcutta; Port
+Canning, Ganges delta (var. <i>bengalensis</i>) (<i>Annandale</i>);
+Garia, Salt Lakes, nr. Calcutta (var. <i>bengalensis</i>) (<i>B. L.
+Chaudhuri</i>); Chilka Lake, Orissa (var. <i>bengalensis</i>) (<i>Gopal
+Chunder Chatterjee</i>): <span class="smcap">Madras Presidency</span>,
+Rambha, Ganjam district (<i>Annandale</i>): <span class="smcap">Nizam's
+Territory</span>, Aurangabad (<i>Bowerbank</i>, var.
+<i>cerebellata</i>). The var. <i>cerebellata</i> has also been taken
+near Cairo.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;The typical form of the
+species is usually found growing on rocks or bricks at the edges of
+ponds, while the variety <i>bengalensis</i> abounds on grass-roots in
+pools and swamps of brackish water in the Ganges delta and has been
+found on mussel-shells (<i>Modiola jenkinsi</i>, Preston) in practically
+salt water in the Chilka Lake. Carter procured the typical form at
+Bombay on stones which were only covered for six months in the year, and
+"temporarily on floating objects." In Calcutta this form flourishes in
+the cold weather on artificial stonework in the "tanks" together with
+<i>S. carteri</i>, <i>S. fragilis</i>, <i>Ephydatia meyeni</i>, and
+<i>Trochospongilla latouchiana</i>.</p>
+
+<p>The variety <i>bengalensis</i> is best known to me as it occurs in
+certain ponds of brackish water at Port Canning on the Mutlah River,
+which connects the Salt Lakes near Calcutta with the sea.<span
+class='pagenum'><a name="Page_78" id="Page_78">[Pg 78]</a></span> It
+appears in these ponds in great luxuriance every year at the beginning
+of the cold weather and often coats the whole edge for a space of
+several hundred feet, growing in irregular masses which are more or less
+fused together on the roots and stems of a species of grass that
+flourishes in such situations. Apparently the tendency for the sponges
+to form branches is much more marked in some years than in others (see
+Pl. I, figs. 1-3). The gemmules germinate towards the end of the
+"rains," and large masses of sponge are not formed much before December.
+At this season, however, the level of the water in the ponds sinks
+considerably and many of the sponges become dry. If high winds occur,
+the dry sponges are broken up and often carried for considerable
+distances over the flat surrounding country. In January the gemmules
+floating on the surface of the ponds form a regular scum. <i>S. alba</i>
+var. <i>bengalensis</i> is the only sponge that occurs in these ponds at
+Port Canning, but <i>S. lacustris</i>, subsp. <i>reticulata</i>, is
+occasionally found with it on brickwork in the ditches that drain off
+the water from the neighbouring fields into the Mutlah estuary. The
+latter sponge, however, perishes as these ditches dry up, at an earlier
+period than that at which <i>S. alba</i> reaches its maximum
+development.</p>
+
+<p>The larv� of <i>Sisyra indica</i> are commonly found in the oscula of
+the typical form of <i>S. alba</i> as well as in those of <i>S.
+lacustris</i> subsp. <i>reticulata</i>, and <i>S. carteri</i>; but the
+compact structure of the sponge renders it a less suitable residence for
+other <i>incol�</i> than <i>S. carteri</i>.</p>
+
+<p>In the variety <i>bengalensis</i>, as it grows in the ponds at Port
+Canning, a large number of arthropods, molluscs and other small animals
+take shelter. Apart from protozoa and rotifers, which have as yet been
+little studied, the following are some of the more abundant inhabitants
+of the sponge:&mdash;The sea-anemone, <i>Sagartia schilleriana</i>
+subsp. <i>exul</i> (see p.&nbsp;140), which frequently occurs in very
+large numbers in the broader canals; the free-living nematode,
+<i>Oncholaimus indicus</i><a name="fnanchor_W" id="fnanchor_W"></a><a
+href="#footnote_W" class="fnanchor"><sup>[W]</sup></a>, which makes its
+way in and out of the oscula; molluscs belonging to several species of
+the genus <i>Corbula</i>, which conceal themselves in the canals but are
+sometimes engulfed in the growing sponge and so perish; young
+individuals of the crab <i>Varuna litterata</i>, which hide among the
+branches and ramifications of the larger sponges together with several
+small species of prawns and the schizopod <i>Macropsis orientalis</i><a
+name="fnanchor_X" id="fnanchor_X"></a><a href="#footnote_X"
+class="fnanchor"><sup>[X]</sup></a>; the <ins title="changed from
+'pecular'">peculiar</ins> amphipod <i>Quadrivisio bengalensis</i><a
+name="fnanchor_Y" id="fnanchor_Y"></a><a href="#footnote_Y"
+class="fnanchor"><sup>[Y]</sup></a>, only known from the ponds at Port
+Canning, which breeds in little communities inside the sponge; a small
+isopod<a name="fnanchor_Z" id="fnanchor_Z"></a><a href="#footnote_Z"
+class="fnanchor"><sup>[Z]</sup></a>, allied to<span class='pagenum'><a
+name="Page_79" id="Page_79">[Pg 79]</a></span> <i>Sph�roma walkeri</i>,
+Stebbing; the larva of a may-fly, and those of at least two midges
+(Chironomid�).</p>
+
+<p>The peculiarly mixed nature (marine and lacustrine) of the fauna
+associated with <i>S. alba</i> in the ponds at Port Canning is well
+illustrated by this list, and it only remains to be stated that little
+fish (<i>Gobius alcockii</i>, <i>Barbus stigma</i>, <i>Haplochilus
+melanostigma</i>, <i>H. panchax</i>, etc.) are very common and feed
+readily on injured sponges. They are apparently unable to attack a
+sponge so long as its external membrane is intact, but if this membrane
+is broken, they swarm round the sponge and devour the parenchyma
+greedily. In fresh water one of these fishes (<i>Gobius alcockii</i>,
+see p.&nbsp;94) lays its eggs in sponges.</p>
+
+<p>The chief enemy of the sponges at Port Canning is, however, not an
+animal but a plant, viz., a green filamentous alga which grows inside
+the sponge, penetrating its substance, blocking up its canals and so
+causing it to die. Similar alg� have been described as being beneficial
+to the sponges in which they grow<a name="fnanchor_AA"
+id="fnanchor_AA"></a><a href="#footnote_AA"
+class="fnanchor"><sup>[AA]</sup></a>, but my experience is that they are
+deadly enemies, for the growth of such alg� is one of the difficulties
+which must be fought in keeping sponges alive in an aquarium. The alga
+that grows in <i>S. alba</i> often gives it a dark green colour, which
+is, however, quite different from the bright green caused by the
+presence of green corpuscles. The colour of healthy specimens of the
+variety <i>bengalensis</i> is a rather dark grey, which appears to be
+due to minute inorganic particles taken into the cells of the parenchyma
+from the exceedingly muddy water in which this sponge usually grows. If
+the sponge is found in clean water, to whichever variety of the species
+it belongs, it is nearly white with a slight yellowish tinge. Even when
+the typical form is growing in close proximity to <i>S. proliferens</i>,
+as is often the case, no trace of green corpuscles is found in its
+cells.</p>
+
+<p class="p2">4. <b>Spongilla cinerea</b>*, <i>Carter</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla cinerea</i>, Carter, J. Bombay Soc. iii,
+p.&nbsp;30, pl. i, fig. 5, &amp; Ann. Nat. Hist. (2) iv, p.&nbsp;82, pl.
+iii, fig. 5 (1849).</span>
+<span class="i0"><i>Spongilla cinerea</i>, Bowerbank, P. Zool. Soc.
+London, 1863, p.&nbsp;468, pl. xxxviii, fig. 19.</span>
+<span class="i0"><i>Spongilla cinerea</i>, Carter, Ann. Nat. Hist. (5)
+vii, p.&nbsp;263 (1881).</span>
+</div>
+
+<p><i>Sponge</i> forming large, flat sheets, never more than a few
+millimetres in thickness, without a trace of branches, compact but very
+friable, of a dark greyish colour; oscula small and inconspicuous or
+moderately large, never prominent; membrane adhering closely to the
+sponge.</p>
+
+<p><i>Skeleton</i> with well-defined but slender radiating fibres, which
+contain very little spongin; transverse fibres close together but
+consisting for the most part of one or two spicules only.</p>
+
+<p><span class='pagenum'><a name="Page_80" id="Page_80">[Pg
+80]</a></span><i>Spicules.</i> Skeleton-spicules short, slender, sharply
+pointed, minutely serrated or irregular in outline, almost straight.
+Gemmule-spicules very small, rather stout, cylindrical, pointed, covered
+with relatively long and stout spines which are either straight or
+directed towards the ends of the spicule. Flesh-spicules fairly numerous
+in the external membrane but by no means abundant in the parenchyma,
+very slender, gradually pointed, covered uniformly with minute but
+distinct spines.</p>
+
+<p><i>Gemmules</i> very small, only visible to the naked eye as minute
+specks, as a rule numerous, free in the substance of the sponge, each
+provided with a slender foraminal tubule and covered with a thick
+granular coat in which the gemmule-spicules are arranged almost
+horizontally; a horizontal layer of spicules also present on the
+external surface of the gemmule; gemmule-spicules very numerous.</p>
+
+<div class="figcenter">
+<img src="images/fig_010.png"
+width="375" height="371"  alt="Illustration: Fig. 10.&mdash;Gemmules and
+fragment of the skeleton of Spongilla cinerea (from type specimen), �
+35." title="Fig. 10.&mdash;Gemmules and fragment of the skeleton of
+Spongilla cinerea (from type specimen), � 35." />
+<p class="caption">Fig. 10.&mdash;Gemmules and fragment of the skeleton
+of <i>Spongilla cinerea</i> (from type specimen), � 35.</p>
+</div>
+
+<p>This sponge is easily distinguished from its Indian allies by the
+form of its skeleton-spicules, which are, as Bowerbank expresses it,
+"subspined"; that it to say, under a high power of the microscope their
+outline appears to be very minutely serrated, although under a low power
+they seem to be quite smooth. The spicules also are smaller than those
+of <i>S. alba</i>, the only species with which <i>S. cinerea</i> is
+likely to be confused, and the gemmule has a well-developed foraminal
+tubule; the skeleton is much closer than in <i>S. proliferens</i>.</p>
+
+<p><span class="smcap">Type</span> in the British Museum; a piece in the
+Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>S.
+cinerea</i> is only known from the Bombay Presidency. Carter obtained
+the original specimens at Bombay and the only ones I have found were
+collected at Nasik, which is situated on the eastern slopes of the
+Western Ghats, about 90 miles to the north-east.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;Carter's specimens were
+growing on gravel, rocks and stones at the edge of "tanks," and were
+seldom covered for more than six months in the year. Mine were on the
+sides of a<span class='pagenum'><a name="Page_81" id="Page_81">[Pg
+81]</a></span> stone conduit built to facilitate bathing by conveying a
+part of the water of the Godaveri River under a bridge. They were
+accompanied by <i>Spongilla indica</i> and <i>Corvospongilla
+lapidosa</i> (the only other sponges I have found in running water in
+India) and in the month of November appeared to be in active growth.</p>
+
+<p class="p2">5. <b>Spongilla travancorica</b>*, <i>Annandale</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla travancorica</i>, Annandale, Rec. Ind.
+Mus. iii, p.&nbsp;101, pl. xii, fig. 1 (1909).</span>
+</div>
+
+<p><i>Sponge</i> small, encrusting, without branches, hard but brittle;
+its structure somewhat loose; colour dirty white. Dermal membrane in
+close contact with the skeleton; pores and oscula inconspicuous. Surface
+minutely hispid, smooth and rounded as a whole.</p>
+
+<p><i>Skeleton</i> consisting of moderately stout and coherent radiating
+fibres and well-defined transverse ones; a number of horizontal
+megascleres present at the base and surface, but not arranged in any
+definite order. No basal membrane.</p>
+
+<div class="figcenter">
+<img src="images/fig_011.jpg"
+width="400" height="289"  alt="Illustration: Fig. 11.&mdash;Microscleres
+of Spongilla travancorica. A=Gemmule-spicules; B=flesh-spicules (from
+type specimen), � 240." title="Fig. 11.&mdash;Microscleres of Spongilla
+travancorica. A=Gemmule-spicules; B=flesh-spicules (from type specimen),
+� 240." />
+<p class="caption">Fig. 11.&mdash;Microscleres of <i>Spongilla
+travancorica</i>. A=Gemmule-spicules; B=flesh-spicules (from type
+specimen), � 240.</p>
+</div>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, pointed at either end,
+moderately stout, straight or curved, sometimes angularly bent;
+curvature usually slight. Free microscleres abundant in the dermal
+membrane, slender, nearly straight, gradually and sharply pointed,
+profusely ornamented with short straight spines, which are much more
+numerous and longer at the middle than near the ends. Gemmule-spicules
+stouter and rather longer, cylindrical, terminating at each end in a
+sharp spine, ornamented with shorter spines, which are more numerous and
+longer at the ends than at the middle; at the ends they are sometimes
+directed backwards, without, however, being curved.</p>
+
+<p><i>Gemmules</i> firmly adherent to the support of the sponge, at the
+base of which they form a layer one gemmule thick; each provided with at
+least one foraminal tubule, which is straight and conical: two tubules,
+one at the top and one at one side, usually present. Granular layer well
+developed. Spicules arranged irregularly in this layer, as a rule being
+more nearly vertical than horizontal but pointing in all directions, not
+confined externally by a membrane; no external layer of horizontal
+spicules.</p>
+
+<p><span class='pagenum'><a name="Page_82" id="Page_82">[Pg
+82]</a></span></p>
+
+<p class="center"><i>Measurements of Spicules and Gemmules.</i></p>
+
+<table summary="measurements of spicules and gemmules 5">
+
+<tr><td class="left">Length of skeleton-spicules</td><td>0.289-0.374
+mm.</td></tr>
+
+<tr><td class="left">Greatest diameter of
+skeleton-spicules</td><td>0.012-0.016 mm.</td></tr>
+
+<tr><td class="left">Length of free microscleres</td><td>0.08-0.096
+mm.</td></tr>
+
+<tr><td class="left">Greatest diameter of free
+microscleres</td><td>0.002 mm.</td></tr>
+
+<tr><td class="left">Length of gemmule-spicules</td><td>0.1-0.116
+mm.</td></tr>
+
+<tr><td class="left">Diameter of gemmule-spicule</td><td>0.008
+mm.</td></tr>
+
+<tr><td class="left">Diameter of gemmule</td><td>0.272-0.374
+mm.</td></tr>
+</table>
+
+<p>This species is easily distinguished from its allies of the subgenus
+<i>Euspongilla</i> by its adherent gemmules with their (usually)
+multiple apertures and rough external surface.</p>
+
+<p><span class="smcap">Type</span> in the collection of the Indian
+Museum.</p>
+
+<p><span class="smcap">Habitat.</span> Backwater near Shasthancottah,
+Travancore, in slightly brackish water; on the roots of shrubs growing
+at the edge; November, 1908 (<i>Annandale</i>).</p>
+
+<p>The specimens were dead when found.</p>
+
+<p class="p2">6. <b>Spongilla hemephydatia</b>*, <i>Annandale</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla hemephydatia</i>, Annandale, Rec. Ind.
+Mus. iii, p.&nbsp;275 (1909).</span>
+</div>
+
+<div class="figcenter">
+<img src="images/fig_012.jpg"
+width="400" height="353"  alt="Illustration: Fig. 12.&mdash;Gemmule and
+spicules of Spongilla hemephydatia (from type specimen)." title="Fig.
+12.&mdash;Gemmule and spicules of Spongilla hemephydatia (from type
+specimen)." />
+<p class="caption">Fig. 12.&mdash;Gemmule and spicules of <i>Spongilla
+hemephydatia</i> (from type specimen).</p>
+</div>
+
+<p><i>Sponge</i> soft, fragile, amorphous, of a dirty yellow colour,
+with large oscula, which are not conspicuously raised above the<span
+class='pagenum'><a name="Page_83" id="Page_83">[Pg 83]</a></span>
+surface but open into very wide horizontal channels in the substance of
+the sponge. The oscular collars are fairly well developed, but the
+subepidermal space is not extensive.</p>
+
+<p><i>Skeleton</i> diffuse, consisting of very fine radiating fibres,
+which are crossed at wide and irregular intervals by still finer
+transverse ones; very little chitinoid substance present.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, slender, sharply pointed
+at both ends, nearly straight. No true flesh-spicules. Gemmule-spicules
+straight or nearly so, cylindrical, or constricted in the middle,
+obscurely pointed or blunt, clothed with short, sharp, straight spines,
+which are very numerous but not markedly longer at the two ends; these
+spicules frequently found free in the parenchyma.</p>
+
+<p><i>Gemmules</i> numerous, small, free, spherical, yellow, with a
+well-developed granular coat (in which the spicules are arranged almost
+horizontally) and external to it a fine membrane which in preserved
+specimens becomes puckered owing to unequal contraction; each gemmule
+with a single aperture provided with a straight, rather wide, but very
+delicate foraminal tubule.</p>
+
+<p class="center"><i>Measurements of Spicules and Gemmules.</i></p>
+
+<table summary="Measurements of Spicules and Gemmules 6">
+
+<tr><td class="left">Length of skeleton-spicule</td><td>0.313
+mm.</td></tr>
+
+<tr><td class="left">Breadth of skeleton-spicule</td><td>0.012
+mm.</td></tr>
+
+<tr><td class="left">Length of gemmule-spicule</td><td>0.062
+mm.</td></tr>
+
+<tr><td class="left">Breadth of gemmule-spicule</td><td>0.004
+mm.</td></tr>
+
+<tr><td class="left">Diameter of gemmule</td><td>0.313-0.365
+mm.</td></tr>
+
+</table>
+
+<p>This sponge in its general structure bears a very close resemblance
+to <i>Spongilla crateriformis</i>.</p>
+
+<p><span class="smcap">Type</span> in the collection of the Indian
+Museum.</p>
+
+<p><span class="smcap">Habitat.</span> Growing on weeds at the edge of
+the Sur Lake, Orissa, October 1908. Only one specimen was taken,
+together with many examples of <i>S. lacustris</i> subsp.
+<i>reticulata</i>, <i>S. carteri</i> and <i>S. crassissima</i>.</p>
+
+<p class="p2">7. <b>Spongilla crateriformis</b>* (<i>Potts</i>).</p>
+
+<div class="genus">
+<span class="i0"><i>Meyenia crateriforma</i>, Potts, P. Ac. Philad.
+1882, p.&nbsp;12.</span>
+<span class="i0"><i>Meyenia crateriformis, id., ibid.</i> 1887,
+p.&nbsp;228, pl. v, fig. 6, pl. x, fig. 5.</span>
+<span class="i0">? <i>Ephydatia crateriformis</i>, Hanitsch, Nature, ii,
+p.&nbsp;511 (1895).</span>
+<span class="i0"><i>Ephydatia crateriformis</i>, Weltner, Arch. Naturg.
+lxi (i), pp.&nbsp;122, 134 (1895).</span>
+<span class="i0">? <i>Ephydatia crateriformis</i>, Hanitsch, Irish
+Natural. iv, p.&nbsp;125, pl. iv, fig. 5 (1895).</span>
+<span class="i0"><i>Ephydatia indica</i>, Annandale, J. Asiat. Soc.
+Bengal, 1907, p.&nbsp;20 (figures poor).</span>
+<span class="i0"><i>Ephydatia indica, id.</i>, Rec. Ind. Mus. i, pp.
+272, 279, 388, 391 (1907).</span>
+<span class="i0"><i>Ephydatia crateriformis</i>, Scharff, European
+Animals, p.&nbsp;34 (1907).</span>
+<span class="i0"><i>Ephydatia crateriformis</i>, Annandale, P. U.S. Mus.
+xxxvii, p.&nbsp;402, fig. 1 (1909).</span>
+</div>
+
+<p><span class='pagenum'><a name="Page_84" id="Page_84">[Pg
+84]</a></span><i>Sponge</i> very fragile, forming soft irregular masses
+on the roots and stems of water-plants, between which it is sometimes
+stretched as a delicate film, or thin layers or cushions on flat
+surfaces. Oscula large, flat, circular, or of irregular shape, opening
+into broad horizontal canals, which at their distal end are superficial
+and often covered by the external membrane only. Colour white,
+yellowish, greyish, or blackish.</p>
+
+<p><i>Skeleton</i> very delicate; radiating fibres rarely consisting of
+more than two parallel spicules; transverse fibres far apart, frequently
+consisting of single spicules; very little spongin present.</p>
+
+<div class="figcenter">
+<img src="images/fig_013.jpg"
+width="400" height="291"  alt="Illustration: Fig. 13.&mdash;Spicules of
+Spongilla crateriformis." title="Fig. 13.&mdash;Spicules of Spongilla
+crateriformis." />
+<p class="caption">Fig. 13.&mdash;Spicules of <i>Spongilla
+crateriformis</i>.</p>
+</div>
+
+<p class="captionj">A. From specimen taken in July in a tank on the
+Calcutta maidan. B. From type specimen of <i>Ephydatia indica</i> taken
+in the Indian Museum tank in winter. Both figures � 240.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules feebly curved, slender, as a rule
+irregular in outline, sometimes almost smooth; the ends as a rule
+sharply pointed, often constricted off and expanded so as to resemble
+spear-heads, occasionally blunt. No true flesh-spicules.
+Gemmule-spicules often free in the parenchyma, cylindrical, slender,
+very variable in length in different sponges, straight or nearly so, as
+a rule with an irregular circle of strong straight or recurved spines at
+either end resembling a rudimentary rotule, and with shorter straight
+spines scattered on the shaft, sometimes without the rudimentary rotule,
+either truncate at the ends or terminating in a sharp spine.</p>
+
+<p><i>Gemmules</i> small, free, each surrounded by a thick granular
+layer in which the spicules stand upright or nearly so, and covered
+externally by a delicate but very distinct chitinous membrane; no<span
+class='pagenum'><a name="Page_85" id="Page_85">[Pg 85]</a></span>
+horizontal spicules; foramen situated at the base of a crater-like
+depression in the granular coat, which is sometimes raised round it so
+as to form a conspicuous rampart; a short, straight foraminal
+tubule.</p>
+
+<p>The shape of the spicules is extremely variable, and sponges in which
+they are very different occur in the same localities and even in the
+same ponds. It is possible that the differences are directly due to
+slight changes in the environment, for in one pond in Calcutta a form
+with <i>Spongilla</i>-like gemmule-spicules appears to replace the
+typical form, which is common in winter, during the hot weather and
+"rains." I have not, however, found this to be the case in other ponds.
+Perhaps <i>S. hemephydatia</i> will ultimately prove to be a variety of
+this very variable species, but its smooth and regular skeleton-spicules
+and short-spined gemmule-spicules afford a ready method of
+distinguishing it from <i>S. crateriformis</i>. The two sponges are
+easily distinguished from all others in the subgenus <i>Euspongilla</i>
+by the upright and regular arrangement of their gemmule-spicules, for
+although in <i>S. proliferens</i> and <i>S. travancorica</i> some of the
+gemmule-spicules are nearly vertical, their arrangement is always
+irregular, a large proportion of the spicules make an acute angle with
+the inner coat of the gemmule and a few as a rule lie parallel to it.
+The systematic position of <i>S. crateriformis</i> is almost exactly
+intermediate between <i>Euspongilla</i> and <i>Ephydatia</i>, to which
+genus it has hitherto been assigned. I think, however, that taking into
+consideration its close relationship to <i>S. hemephydatia</i>, it is
+best to assign it to <i>Spongilla</i>, as its rudimentary rotules never
+form distinct disks. I have examined some of Potts's original specimens
+from different American localities and can detect no constant difference
+between them and Indian specimens.</p>
+
+<p><span class="smcap">Types</span> in the United States National
+Museum; co-types in Calcutta.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;This
+sponge was originally described from North America (in which continent
+it is widely distributed) and has been recorded from the west of Ireland
+with some doubt. In India and Burma it is widely distributed. <span
+class="smcap">Bengal</span>, Calcutta and neighbourhood
+(<i>Annandale</i>); Sonarpur, Gangetic delta (<i>Annandale</i>); <span
+class="smcap">Bombay Presidency</span>, Igatpuri Lake, W. Ghats
+(altitude <i>ca.</i> 2,000 feet) (<i>Annandale</i>); <span
+class="smcap">Madras Presidency</span>, neighbourhood of Madras town
+(<i>J. R. Henderson</i>); Museum compound, Egmore (Madras town)
+(<i>Annandale</i>); near Bangalore (alt. <i>ca.</i> 3,000 ft.), Mysore
+State (Annandale); Ernakulam, Cochin (<i>G. Mathai</i>): <span
+class="smcap">Burma</span>, Kawkareik, interior of Amherst district,
+Tenasserim, and the Moulmein waterworks in the same district
+(<i>Annandale</i>).<a name="fnanchor_AB" id="fnanchor_AB"></a><a
+href="#footnote_AB" class="fnanchor"><sup>[AB]</sup></a></p>
+
+<p><span class='pagenum'><a name="Page_86" id="Page_86">[Pg
+86]</a></span><span class="smcap">Biology.</span>&mdash;<i>S.
+crateriformis</i> flourishes in Calcutta throughout the year. Here it is
+usually found adhering to the roots of water-plants, especially
+<i>Pistia</i> and <i>Limnanthemum</i>. In the case of the former it
+occurs at the surface, in that of the latter at the bottom. When growing
+near the surface or even if attached to a stone at the bottom in clear
+water, it is invariably of a pale yellowish or greyish colour. When
+growing on the roots of <i>Limnanthemum</i> in the mud of the Gangetic
+alluvium, however, it is almost black, and when growing in the reddish
+muddy waters of the tanks round Bangalore of a reddish-brown colour.
+This appears to be due entirely to the absorption of minute particles of
+inorganic matter by the cells of the parenchyma. If black sponges of the
+species are kept alive in clean water, they turn pure white in less than
+a week, apparently because these particles are eliminated. When growing
+on stones the sponge, as found in India, often conforms exactly with
+Potts's description: "a filmy grey sponge, branching off here and there
+... yet with a curious lack of continuity...."</p>
+
+<p>The wide efferent canals of this sponge afford a convenient shelter
+to small crustacea, and the isopod <i>Tach�a spongillicola</i>, Stebbing
+(see p.&nbsp;94), is found in them more abundantly than in those of any
+other sponge. This is especially the case when the sponge is growing at
+the bottom. On the surface of the sponge I have found a peculiar
+protozoon which resembles the European <i>Trichodina spongill�</i> in
+general structure but belongs, I think, to a distinct species, if not to
+a distinct genus.</p>
+
+<p class="p2 center">Subgenus B. <b>EUNAPIUS</b>, <i>J. E. Gray</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Eunapius</i>, J. E. Gray (<i>partim</i>), P. Zool.
+Soc. London, 1867, p.&nbsp;552.</span>
+<span class="i0"><i>Spongilla</i> (<i>s. str.</i>), Vejdovsky, in
+Potts's "Fresh-Water Sponges," P. Ac. Philad. 1887, p.&nbsp;172.</span>
+<span class="i0"><i>Spongilla</i> (<i>s. str.</i>), Weltner, in
+Zacharias's Tier- und Pflanzenwelt des S�sswassers, i, p.&nbsp;214
+(1891).</span>
+<span class="i0"><i>Spongilla</i> (<i>s. str.</i>), Annandale, Zool.
+Jahrb., Syst. xxvii, p.&nbsp;559 (1909).</span>
+</div>
+
+<p><span class="smcap">Type</span>, <i>Spongilla carteri</i>, Carter.</p>
+
+<p>Spongill� in which the gemmules are covered with layers of distinct
+polygonal air-spaces with chitinous walls.</p>
+
+<p>The gemmules are usually fastened together in groups, which may
+either be free in the sponge or adhere to its support as a "pavement
+layer"; sometimes, however, they are not arranged in this manner, but
+are quite independent of one another. The skeleton is usually delicate,
+sometimes very stout (<i>e.&nbsp;g.</i>, in <i>S. nitens</i>,
+Carter).</p>
+
+<p>The term <i>Eunapius</i> here used is not quite in the original
+sense, for Gray included under it Bowerbank's <i>Spongilla
+paupercula</i> which is now regarded as a form of <i>S. lacustris</i>.
+His description, nevertheless, fits the group of species here associated
+except in one particular, viz., the smoothness of the gemmule-spicules
+to which he refers, for this character, though a feature of <i>S.
+carteri</i>, is not<span class='pagenum'><a name="Page_87"
+id="Page_87">[Pg 87]</a></span> found in certain closely allied forms.
+The use of "<i>Spongilla</i>" in a double sense may be avoided by the
+adoption of Gray's name.</p>
+
+<p>The subgenus <i>Eunapius</i> is, like <i>Euspongilla</i>,
+cosmopolitan. It is not, however, nearly so prolific in species. Four
+can be recognized in India, two of which range, in slightly different
+forms, as far north as Europe, one of them also being found in North
+America, Northern Asia, and Australia.</p>
+
+<p class="p2">8. <b>Spongilla carteri</b>* <i>Carter</i>
+(<i>Bowerbank</i>, in litt.). (<a href="#Plate_II">Plate II</a>. fig.
+1.)</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla friabilis</i>?, Carter (<i>nec</i>
+Lamarck), J. Bombay Asiat. Soc. iii, p.&nbsp;31, pl. i, fig. 3 (1849),
+&amp; Ann. Nat. Hist. (2) iv, p.&nbsp;83, pl. ii. fig. 3 (1849).</span>
+<span class="i0"><i>Spongilla carteri</i>, Carter, Ann. Nat. Hist. (3)
+iii, p.&nbsp;334, pl. viii, figs. 1-7 (1859).</span>
+<span class="i0"><i>Spongilla carteri</i>, Bowerbank, P. Zool. Soc.
+London, 1863, p.&nbsp;469, pl. xxxviii, fig. 20.</span>
+<span class="i0"><i>Eunapius carteri</i>, J. E. Gray, <i>ibid.</i> 1867,
+p.&nbsp;552.</span>
+<span class="i0"><i>Spongilla carteri</i>, Carter, Ann. Nat. Hist. (5)
+vii, p.&nbsp;86 (1881).</span>
+<span class="i0"><i>Spongilla carteri</i>, <i>id.</i>, <i>ibid.</i> x,
+p.&nbsp;369 (1882).</span>
+<span class="i0"><i>Spongilla carteri</i>, Potts, P. Ac. Philad. 1887,
+p.&nbsp;194.</span>
+<span class="i0"><i>Spongilla carteri</i>, Weltner, Arch. Naturg. lxi
+(i), pp.&nbsp;117, 134 (1895).</span>
+<span class="i0"><i>Spongilla carteri</i>, Kirkpatrick, P. Zool. Soc.
+London, 1906 (i), p.&nbsp;219, pl. xv, figs. 3, 4 (? figs. 1, 2).</span>
+<span class="i0"><i>Spongilla carteri</i>, Annandale, J. Asiat. Soc.
+Bengal, 1906, p.&nbsp;188, pl. i, fig. 1.</span>
+<span class="i0"><i>Spongilla carteri</i>, Willey, Spolia Zeyl. iv, p.
+184 (1907).</span>
+<span class="i0"><i>Spongilla carteri</i>, Annandale, <i>ibid.</i> vii,
+p.&nbsp;63, pl. 1, fig. 1 (1910).</span>
+</div>
+
+<div class="figcenter">
+<img src="images/fig_014.png"
+width="400" height="282"  alt="Illustration: Fig. 14.&mdash;Gemmule of
+Spongilla carteri (from Calcutta), as seen in optical section, � 140."
+title="Fig. 14.&mdash;Gemmule of Spongilla carteri (from Calcutta), as
+seen in optical section, � 140." />
+<p class="caption">Fig. 14.&mdash;Gemmule of <i>Spongilla carteri</i>
+(from Calcutta), as seen in optical section, � 140.</p>
+</div>
+
+<p><i>Sponge</i> massive, as a rule with the surface smooth and rounded,
+occasionally bearing irregular ridges, which may even take the form of
+cockscombs; the oscula large, rounded, conspicuous but not raised above
+the surface of the sponge, leading into broad vertical<span
+class='pagenum'><a name="Page_88" id="Page_88">[Pg 88]</a></span>
+canals; the lateral canals, except in the immediate vicinity of the
+central vertical ones, not very broad; the oscular collars extending for
+a considerable distance over the oscula in living or well-preserved
+specimens, never standing out from the surface; the oscula never
+surrounded by radiating furrows. The inhalent pores surrounded
+externally by unmodified cells of the external membrane. Colour greyish,
+sometimes with a flush of green on the external surface.</p>
+
+<p>The sponge has a peculiarly strong and offensive smell.</p>
+
+<p><i>Skeleton</i> fairly compact, with well-developed radiating fibres;
+the transverse fibres splayed out at either end so that they sometimes
+resemble a pair of fans joined together by the handles (fig. 3,
+p.&nbsp;33). A moderate amount of spongin present.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, pointed, nearly straight,
+never very stout but somewhat variable in exact proportions.
+Gemmule-spicules similar but much smaller. (There are no true
+flesh-spicules, but immature skeleton-spicules may easily be mistaken
+for them.)</p>
+
+<p><i>Gemmules</i> as a rule numerous, spherical or flattened at the
+base, variable in size, each covered by a thick coat consisting of
+several layers of relatively large polygonal air-spaces. A single
+aperture surrounded by a crater-like depression in the cellular coat and
+provided with a foraminal tubule resembling an inverted bottle in shape.
+(This tubule, which does not extend beyond the surface of the cellular
+coat, is liable to be broken off in dried specimens.) The spicules
+variable in quantity, arranged irregularly among the spaces of the
+cellular coat and usually forming a sparse horizontal layer on its
+external surface. Each gemmule contained in a cage of skeleton-spicules,
+by the pressure of which it is frequently distorted.</p>
+
+<p class="p2">8<i>a.</i> Var. <b>mollis</b>*, nov.</p>
+
+<p>This variety is characterized by a paucity of skeleton-spicules. The
+sponge is therefore soft and so fragile that it usually breaks in pieces
+if lifted from the water by means of its support. Owing to the paucity
+of skeleton-spicules, which resemble those of the typical form
+individually, the radiating and transverse fibres are extremely
+delicate.</p>
+
+<p>Common in Calcutta.</p>
+
+<p class="p2">8<i>b.</i> Var. <b>cava</b>*, nov.</p>
+
+<p>This variety is characterized by the fact that the oscula open into
+broad horizontal canals, the roof of which is formed by a thin layer of
+parenchyma and skeleton or, in places, of the external membrane only.
+The skeleton is loose and fragile, and the living sponge has a peculiar
+glassy appearance. In spirit the colour is yellowish, during life it is
+greenish or white.</p>
+
+<p>Taken at Bombay; November, 1907.</p>
+
+<p class="p2"><span class='pagenum'><a name="Page_89" id="Page_89">[Pg
+89]</a></span>8<i>c.</i> Var. <b>lobosa</b>*, nov.</p>
+
+<p>The greater part of the sponge in this variety consists of a number
+of compressed but pointed vertical lobes, which arise from a relatively
+shallow, rounded base, in which the oscula occur. The dried sponge has a
+yellowish colour.</p>
+
+<p>Apparently common in Travancore.</p>
+
+<p class="center">*     *     *     *     *</p>
+
+<p>I cannot distinguish these three "varieties"<a name="fnanchor_AC"
+id="fnanchor_AC"></a><a href="#footnote_AC"
+class="fnanchor"><sup>[AC]</sup></a> from the typical form as distinct
+species; indeed, their status as varieties is a little doubtful in two
+cases out of the three. Var. <i>cava</i> appears to be a variety in the
+strict sense of the word (see p.&nbsp;18), for it was found on the
+island of Bombay, the original locality of the species, growing side by
+side with the typical form. Var. <i>lobosa</i>, however, should perhaps
+be regarded as a subspecies rather than a variety, for I have received
+specimens from two localities in the extreme south-west of India and
+have no evidence that the typical form occurs in that part of the
+country. Evidence, however, is rather scanty as regards the occurrence
+of freshwater sponges in S. India. Var. <i>mollis</i>, again, may be a
+phase directly due to environment. It is the common form in the ponds of
+certain parts (<i>e.&nbsp;g.</i> in the neighbourhood of the Maidan and
+at Alipore) of the Calcutta municipal area, but in ponds in other parts
+(<i>e.&nbsp;g.</i> about Belgatchia) of the same area, only the typical
+form is found. It is possible that the water in the former ponds may be
+deficient in silica or may possess some other peculiarity that renders
+the production of spicules difficult for <i>S. carteri</i>; but this
+seems hardly probable, for <i>S. crassissima</i>, a species with a
+rather dense siliceous skeleton, flourishes in the same ponds. I have
+noticed that in ponds in which the aquatic vegetation is luxuriant and
+such genera of plants as <i>Pistia</i> and <i>Limnanthemum</i> flourish,
+there is always a tendency for <i>S. carteri</i> to be softer than in
+ponds in which the vegetation is mostly cryptogamic, and in Calcutta
+those parts of the town in which sponges of this species produce most
+spicules are those in which a slight infiltration of brackish water into
+the ponds may be suspected; but in the interior of India, in places
+where the water is absolutely fresh, hard specimens seem to be the rule
+rather than the exception.</p>
+
+<p><i>S. carteri</i> is closely related to <i>S. nitens</i>, Carter
+(Africa, and possibly S. America), but differs from that species in its
+comparatively slender, sharp skeleton-spicules and smooth
+gemmule-spicules. It may readily be distinguished from all other Indian
+freshwater sponges by its large, deep, round oscula, but this feature is
+not so marked in var. <i>lobosa</i> as in the other forms. The typical
+form and<span class='pagenum'><a name="Page_90" id="Page_90">[Pg
+90]</a></span> var. <i>mollis</i> grow to a larger size than is recorded
+for any other species of the family. I possess a specimen of the typical
+form from the neighbourhood of Calcutta which measures 30 � 27 cm. in
+diameter and 19.5 cm. in depth, and weighs (dry) 24-3/4 oz. The base of
+this specimen, which is solid throughout, is nearly circular, and the
+general form is mound-shaped. Another large specimen from Calcutta is in
+the form of an irregular wreath, the greatest diameter of which is 34
+cm. This specimen weighs (dry) 16-1/4 oz. Both these specimens probably
+represent the growth of several years.</p>
+
+<p><span class="smcap">Types.</span>&mdash;The types of the varieties
+<i>mollis</i>, <i>cava</i> and <i>lobosa</i> are in the collection of
+the Indian Museum. I regard as the type of the species the specimen sent
+by Carter to Bowerbank and by him named <i>S. carteri</i>, although,
+owing to some confusion, Carter's description under this name appeared
+some years before Bowerbank's. This specimen is in the British Museum,
+with a fragment in the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The range
+of the species extends westwards to Hungary, southwards to Mauritius and
+eastwards to the island of Madura in the Malay Archipelago; a specimen
+from Lake Victoria Nyanza in Central Africa has been referred to it by
+Kirkpatrick (P. Zool. Soc. London, 1906 (i), p.&nbsp;219), but I doubt
+whether the identification is correct. In India <i>S. carteri</i> is by
+far the most universally distributed and usually much the commonest
+freshwater sponge; it is one of the only two species as yet found in
+Ceylon. Specimens are known from the following localities:&mdash;<span
+class="smcap">Punjab</span>, Lahore (<i>J. Stephenson</i>): <span
+class="smcap">Bombay Presidency</span>, island of Bombay (<i>Carter</i>,
+<i>Kirkpatrick</i>, <i>Annandale</i>); Igatpuri, W. Ghats (alt.
+<i>ca.</i> 2,000 ft.) (<i>Annandale</i>): <span class="smcap">United
+Provinces</span> (plains), Agra (<i>Kirkpatrick</i>); Lucknow: <span
+class="smcap">Himalayas</span>, Bhim Tal, Kumaon (alt. 4,500 ft.)
+(<i>Annandale</i>); Tribeni, Nepal (<i>Hodgart</i>): <span
+class="smcap">Bengal</span>, Calcutta and neighbourhood; Rajshahi
+(Rampur Bhulia) on the R. Ganges about 150 miles N. of Calcutta
+(<i>Annandale</i>); Berhampur, Murshidabad district (<i>R. E.
+Lloyd</i>); Pusa, Darbbhanga district (<i>Bainbrigge Fletcher</i>);
+Siripur, Saran district, Tirhut (<i>M. Mackenzie</i>); Puri and the Sur
+Lake, Orissa (<i>Annandale</i>): <span class="smcap">Madras
+Presidency</span>, near Madras town (<i>J. R. Henderson</i>); Madura
+district (<i>R. Bruce Foote</i>); Bangalore (<i>Annandale</i>) and
+Worgaum, Mysore State (2,500-3,000 ft.); Ernakulam and Trichur, Cochin
+(<i>G. Mathai</i>); Trivandrum and the neighbourhood of C. Comorin,
+Travancore (var. <i>lobosa</i>) (<i>R. S. N. Pillay</i>): <span
+class="smcap">Burma</span>, Kawkareik, interior of Amherst district,
+Tenasserim (<i>Annandale</i>); Rangoon (<i>Annandale</i>); Bhamo, Upper
+Burma (<i>J. Coggin Brown</i>): <span class="smcap">Ceylon</span>,
+Peradeniya (<i>E. E. Green</i>); outlet of the Maha Rambaikulam between
+Vavuniya and Mamadu, Northern Province (<i>Willey</i>); Horowapotanana,
+between Trincomalee and Anuradihapura, North-Central Province
+(<i>Willey</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;<i>S. carteri</i> usually
+grows in ponds and lakes; I have never seen it in running water. Mr.
+Mackenzie found it on the walls of old indigo wells in Tirhut.</p>
+
+<p>The exact form of the sponge depends to some extent on the<span
+class='pagenum'><a name="Page_91" id="Page_91">[Pg 91]</a></span> forces
+acting on it during life. At Igatpuri, for instance, I found that
+specimens attached to the stems of shrubs growing in the lake and
+constantly swayed by the wind had their surface irregularly reticulated
+with high undulating ridges, while those growing on stones at the bottom
+of a neighbouring pond were smooth and rounded.</p>
+
+<p>Sponges of this species do not shun the light.</p>
+
+<p>In Calcutta <i>S. carteri</i> flourishes during the cold weather
+(November to March). By the end of March many specimens that have
+attached themselves to delicate stems such as those of the leaves of
+<i>Limnanthemum</i>, or to the roots of <i>Pistia stratiotes</i>, have
+grown too heavy for their support and have sunk down into the mud at the
+bottom of the ponds, in which they are quickly smothered. Others fixed
+to the end of branches overhanging the water or to bricks at the edge
+have completely dried up. A large proportion, however, still remain
+under water; but even these begin to show signs of decay at this period.
+Their cells migrate to the extremities of the sponge, leaving a mass of
+gemmules in the centre, and finally perish.</p>
+
+<p>Few sponges exist in an active condition throughout the hot weather.
+The majority of those that do so exhibit a curious phenomenon. Their
+surface becomes smoothly rounded and they have a slightly pinkish
+colour; the majority of the cells of their parenchyma, if viewed under a
+high power of the microscope, can be seen to be gorged with very minute
+drops of liquid. This liquid is colourless in its natural condition, but
+if the sponge is plunged into alcohol the liquid turns of a dark brown
+colour which stains both the alcohol and the sponge almost
+instantaneously. Probably the liquid represents some kind of reserve
+food-material. Even in the hot weather a few living sponges of the
+species may be found that have not this peculiarity, but, in some ponds
+at any rate, the majority that survive assume the peculiar summer form,
+which I have also found at Lucknow.</p>
+
+<p>Reproduction takes place in <i>S. carteri</i> in three distinct ways,
+two of which may be regarded as normal, while the third is apparently
+the result of accident. If a healthy sponge is torn into small pieces
+and these pieces are kept in a bowl of water, little masses of cells
+congregate at the tips of the radiating fibres of the skeleton and
+assume a globular form. At first these cells are homogeneous, having
+clear protoplasm full of minute globules of liquid. The masses differ
+considerably in size but never exceed a few millimetres in diameter. In
+about two days differentiation commences among the cells; then spicules
+are secreted, a central cavity and an external membrane formed, and an
+aperture, the first osculum, appears in the membrane. In about ten days
+a complete young sponge is produced, but the details of development have
+not been worked out.</p>
+
+<p>The most common normal form of reproduction is by means of gemmules,
+which are produced in great numbers towards the end of the cold weather.
+If small sponges are kept alive in an aquarium even at the beginning of
+the cold weather, they begin<span class='pagenum'><a name="Page_92"
+id="Page_92">[Pg 92]</a></span> to produce gemmules almost immediately,
+but these gemmules although otherwise perfect, possess few or no
+gemmule-spicules. If the sponge becomes desiccated at the end of the
+cold weather and is protected in a sheltered place, some or all of the
+gemmules contained in the meshes of its skeleton germinate <i>in
+situ</i> as soon as the water reaches it again during the "rains." It is
+by a continuous or rather periodical growth of this kind, reassumed
+season after season, that large masses of sponge are formed. In such
+masses it is often possible to distinguish the growth of the several
+years, but as a rule the layers become more or less intimately fused
+together, for no limiting membrane separates them. A large proportion of
+the gemmules are, however, set free and either float on the surface of
+the water that remains in the ponds or are dried up and carried about by
+the wind. In these circumstances they do not germinate until the
+succeeding cold weather, even if circumstances other than temperature
+are favourable; but as soon as the cold weather commences they begin to
+produce new sponges with great energy.</p>
+
+<p>Sexual reproduction, the second normal form, takes place in <i>S.
+carteri</i> mainly if not only at the approach of a change of season,
+that is to say about March, just before the hot weather commences, and
+about November, just as the average temperature begins to sink to a
+temperate level. At these seasons healthy sponges may often be found
+full of eggs and embryos, which lie in the natural cavities of the
+sponge without protecting membrane.</p>
+
+<p>In the ponds of Calcutta a large number of animals are found
+associated in a more or less definite manner with <i>Spongilla
+carteri</i>. Only one, however, can be described with any degree of
+certainty as being in normal circumstances an enemy, namely the larva of
+<i>Sisyra indica</i>,<a name="fnanchor_AD" id="fnanchor_AD"></a><a
+href="#footnote_AD" class="fnanchor"><sup>[AD]</sup></a> and even in the
+case of this little insect it is doubtful how far its attacks are
+actually injurious to the sponge. The larva is often found in
+considerable numbers clinging to the oscula and wide efferent canals of
+<i>S. carteri</i>, its proboscis inserted into the substance of the
+sponge. If the sponge dies and the water becomes foul the larv� swim or
+crawl away. If the sponge dries up, they leave its interior (in which,
+however, they sometimes remain for some days after it has become dry)
+and pupate in a silken cocoon on its surface. Hence they emerge as
+perfect insects after about a week.</p>
+
+<p>An animal that may be an enemy of <i>S. carteri</i> is a flat-worm
+(an undescribed species of <i>Planaria</i>) common in its larger canals
+and remarkable for the small size of its pharynx. The same worm,
+however, is also found at the base of the leaves of bulrushes and in
+other like situations, and there is no evidence that it actually feeds
+on the sponge. Injured sponges are eaten by the prawn <i>Pal�mon
+lamarrei</i>, which, however, only attacks them when the dermal membrane
+is broken. A <i>Tanypus</i> larva (Chironomid<span class='pagenum'><a
+name="Page_93" id="Page_93">[Pg 93]</a></span> Diptera) that makes its
+way though the substance of the sponge may also be an enemy; it is
+commoner in decaying than in vigorous sponges.</p>
+
+<p>The presence of another Chironomid larva (<i>Chironomus</i>, sp.)
+appears to be actually beneficial. In many cases it is clear that this
+larva and the sponge grow up together, and the larva is commoner in
+vigorous than in decayed sponges. Unlike the <i>Tanypus</i> larva, it
+builds parchment-like tubes, in which it lives, on the surface of the
+sponge. The sponge, however, often grows very rapidly and the larva is
+soon in danger of being engulfed in its substance. The tube is therefore
+lengthened in a vertical direction to prevent this catastrophe and to
+maintain communication with the exterior. The process may continue until
+it is over an inch in length, the older part becoming closed up owing to
+the pressure of the growing sponge that surrounds it. Should the sponge
+die, the larva lives on in its tubes without suffering, and the ends of
+tubes containing larv� may sometimes be found projecting from the worn
+surface of dead sponges. The larva does not eat the sponge but captures
+small insects by means of a pair of legs on the first segment of its
+thorax. In so doing it thrusts the anterior part of its body out of the
+tube, to the inner surface of which it adheres by means of the pair of
+false legs at the tip of the abdomen. This insect, which is usually
+found in the variety <i>mollis</i>, appears to do good to the sponge in
+two ways&mdash;by capturing other insects that might injure it and by
+giving support to its very feeble skeleton.</p>
+
+<p>A precisely similar function, so far as the support of the sponge is
+concerned, is fulfilled by the tubular zo&oelig;cia of a phase of the
+polyzoon <i>Plumatella fruticosa</i> (see p.&nbsp;218) which in India is
+more commonly found embedded in the substance of <i>S. carteri</i> than
+in that of any other species, although in Great Britain it is generally
+found in that of <i>S. lacustris</i>, which is there the commonest
+species of freshwater sponge.</p>
+
+<p>Another animal that appears to play an active part in the
+&oelig;conomy of the sponge is a peculiar little worm (<i>Ch�togaster
+spongill�</i>) also found among the zo&oelig;cia of <i>Plumatella</i>
+and belonging to a widely distributed genus of which several species are
+found in association with pond-snails. <i>Ch�togaster spongill�</i>
+often occurs in enormous numbers in dead or dying sponges of <i>S.
+carteri</i>, apparently feeding on the decaying organic matter of the
+sponge and assisting by its movements in releasing numerous gemmules. In
+so doing it undoubtedly assists in the dissemination of the species.</p>
+
+<p>Major J. Stephenson (Rec. Ind. Mus. v, p.&nbsp;233) has recently
+found two other species of oligoch�tes inhabiting <i>S. carteri</i> var.
+<i>lobosa</i> from Travancore. Both these species, unlike <i>Ch�togaster
+spongill�</i>, belong to a genus that is vegetarian in habits. One of
+them, <i>Nais pectinata</i>, has not yet been found elsewhere, while the
+other, <i>Nais communis</i>, has a very wide distribution. The latter,
+however, occurs in the sponge in two forms&mdash;one with eyes, the
+other totally blind. The blind form (<i>N. communis</i> var.
+<i>c�ca</i>) has<span class='pagenum'><a name="Page_94" id="Page_94">[Pg
+94]</a></span> only been found in this situation, but the other (var.
+<i>punjabensis</i>) lives free as well as in association with the
+sponge, in which the blind form was the commoner of the two.</p>
+
+<p>The majority of the animals found in association with <i>S.
+carteri</i> gain shelter without evident assistance to the sponge. This
+is the case as regards the little fish (<i>Gobius alcockii</i>), one of
+the smallest of the vertebrates (length about 1/2 inch), which lays its
+eggs in the patent oscula, thus securing for them a situation peculiarly
+favourable to their development owing to the constant current of water
+that passes over them. In the absence of sponges, however, this fish
+attaches its eggs to the floating roots of the water-plant <i>Pistia
+stratiotes</i>. Numerous small crustacea<a name="fnanchor_AE"
+id="fnanchor_AE"></a><a href="#footnote_AE"
+class="fnanchor"><sup>[AE]</sup></a> also take temporary or permanent
+refuge in the cavities of <i>S. carteri</i>, the most noteworthy among
+them being the Isopod <i>Tach�a spongillicola</i><a name="fnanchor_AF"
+id="fnanchor_AF"></a><a href="#footnote_AF"
+class="fnanchor"><sup>[AF]</sup></a>, the adults of which are found in
+the canal of this and other sponges, while the young cling to the
+external surface of the carapace of <i>Pal�mon lamarrei</i> and other
+small prawns. Many worms and insects of different kinds also enter the
+canals of <i>S. carteri</i>, especially when the sponge is becoming
+desiccated; from half-dry sponges numerous beetles and flies may be
+bred, notably the moth-fly <i>Psychoda nigripennis</i><a
+name="fnanchor_AG" id="fnanchor_AG"></a><a href="#footnote_AG"
+class="fnanchor"><sup>[AG]</sup></a> of which enormous numbers sometimes
+hatch out from such sponges.</p>
+
+<p>As the sponge grows it frequently attaches itself to small molluscs
+such as the young of <i>Vivipara bengalensis</i>, which finally become
+buried in its substance and thus perish. Possibly their decaying bodies
+may afford it nourishment, but of the natural food of sponges we know
+little. <i>S. carteri</i> flourishes best and reaches its largest size
+in ponds used for domestic purposes by natives of India, and thrives in
+water thick with soap-suds. It is possible, though direct proof is
+lacking, that the sponge does good in purifying water used for washing
+the clothes, utensils, and persons of those who drink the same water, by
+absorbing decaying animal and vegetable matter from it.</p>
+
+<p>Various minute alg� are found associated with <i>S. carteri</i>, but
+of these little is yet known. The green flush sometimes seen on the
+surface of the typical form is due to the fact that the superficial
+cells of the parenchyma contain green corpuscles. These, however, are
+never very numerous and are not found in the inner parts of the sponge,
+perhaps owing to its massive form. It is noteworthy that these green
+bodies flourish in large numbers throughout the substance of sponges of
+<i>S. proliferens</i>, a species always far from massive, growing in the
+same ponds as <i>S. carteri</i>.</p>
+
+<p class="p2"><span class='pagenum'><a name="Page_95" id="Page_95">[Pg
+95]</a></span>9. <b>Spongilla fragilis</b>, <i>Leidy</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla fragilis</i>, Leidy, P. Ac. Philad. 1851,
+p.&nbsp;278.</span>
+
+<span class="i0"><i>Spongilla lordii</i>, Bowerbank, P. Zool. Soc.
+London, 1863, p.&nbsp;466, pl. xxxviii, fig. 17.</span>
+
+<span class="i0"><i>Spongilla contecta</i>, Noll, Zool. Garten*, 1870,
+p.&nbsp;173.</span>
+
+<span class="i0"><i>Spongilla ottav�nsis</i>, Dawson, Canad. Nat.* (new
+series) viii, p.&nbsp;5 (1878).</span>
+
+<span class="i0"><i>Spongilla sibirica</i>, Dybowski, Zool. Anz., Jahr.
+i, p.&nbsp;53 (1878).</span>
+
+<span class="i0"><i>Spongilla morgiana</i>, Potts, P. Ac. Philad. 1880,
+p.&nbsp;330.</span>
+
+<span class="i0"><i>Spongilla lordii</i>, Carter, Ann. Nat. Hist. (5)
+vii, p.&nbsp;89, pl. vi, fig. 13 (1881).</span>
+
+<span class="i0"><i>Spongilla sibirica</i>, Dybowski, M�m. Ac. St.
+P�tersb. (7) xxx, no. x, p.&nbsp;10, fig. 12.</span>
+
+<span class="i0"><i>Spongilla glomerata</i>, Noll, Zool. Anz., Jahr. ix,
+p.&nbsp;682 (1886).</span>
+
+<span class="i0"><i>Spongilla fragilis</i>, Vejdovsky, P. Ac. Philad.
+1887, p.&nbsp;176.</span>
+
+<span class="i0"><i>Spongilla fragilis</i>, Potts, <i>ibid.</i>
+p.&nbsp;197, pl. v, fig. 2; pl. viii, figs. 1-4.</span>
+
+<span class="i0"><i>Spongilla fragilis</i>, Weltner, Arch. Naturg. lix
+(1), p.&nbsp;266, pl. ix, figs. 18-20 (1893).</span>
+
+<span class="i0"><i>Spongilla fragilis</i>, <i>id.</i>, Arch. Naturg.
+lxi (i), p.&nbsp;117 (1895).</span>
+
+<span class="i0"><i>Spongilla fragilis</i>, <i>id.</i>, in Semon's Zool.
+Forsch. in Austral. u. d. Malay. Arch. v, part v, p.&nbsp;523.</span>
+
+<span class="i0"><i>Spongilla fragilis</i>, Annandale, P. U.S. Mus.
+xxxvii, p.&nbsp;402 (1909).</span>
+
+<span class="i0"><i>Spongilla fragilis</i>, <i>id.</i>, Annot. Zool.
+Japon. vii, part ii, p.&nbsp;106, pl. ii, fig. 1 (1909).</span>
+
+</div>
+
+<p><i>Sponge</i> flat, lichenoid, never of great thickness, devoid of
+branches, dense in texture but very friable; colour brown, green, or
+whitish; oscula numerous, small, flat, distinctly star-shaped.</p>
+
+<p><i>Skeleton</i> with well defined radiating and transverse fibres,
+which are never strong but form a fairly dense network with a small
+amount of spongin.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, sharply pointed,
+moderately stout, as a rule nearly straight. No flesh-spicules.
+Gemmule-spicules cylindrical, blunt or abruptly pointed, nearly
+straight, covered with relatively stout, straight, irregular spines,
+which are equally distributed all over the spicule.</p>
+
+<p><i>Gemmules</i> bound together in free groups of varying numbers and
+forming a flat layer at the base of the sponge; each gemmule small in
+size, surrounded by a thick cellular coat of several layers; with a
+relatively long and stout foraminal tubule, which projects outwards
+through the cellular coat at the sides of the group or at the top of the
+basal layer of gemmules, is usually curved, and is not thickened at the
+tip; more than one foraminal tubule sometimes present on a single
+gemmule; gemmule-spicules arranged horizontally or at the base of the
+cellular coat.</p>
+
+<p>The species as a species is easily distinguished from all others, its
+nearest ally being the N. American <i>S. ingloriformis</i> with sparsely
+spined skeleton-spicules which are very few in number, and gemmule
+groups in which the foraminal tubules all open downwards.</p>
+
+<p>Several varieties of <i>S. fragilis</i> have been described in Europe
+and America.</p>
+
+<p><span class='pagenum'><a name="Page_96" id="Page_96">[Pg
+96]</a></span><span class="smcap">Type.</span>&mdash;Potts refers to the
+type as being in the Academy of Natural Sciences at Philadelphia.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;All over
+Europe and N. America; also in Siberia, Australia, and S. America. The
+species is included in this work in order that its Asiatic local races
+may be fitly described.</p>
+
+<p class="p2">9 <i>a.</i> Subsp. <b>calcuttana</b>*, nov.</p>
+
+<div class="genus">
+
+<span class="i0">? <i>Spongilla decipiens</i>, Weltner (<i>partim</i>),
+Arch. Naturg. lxi (i), pp.&nbsp;117, 134 (1895).</span>
+
+<span class="i0"><i>Spongilla decipiens</i>, Annandale, Journ. As. Soc.
+Beng. 1906, p.&nbsp;57.</span>
+
+<span class="i0"><i>Spongilla fragilis</i>, <i>id.</i>, Rec. Ind. Mus.
+i, p.&nbsp;390 (1907).</span>
+
+</div>
+
+<div class="figcenter">
+<img src="images/fig_015.jpg"
+width="256" height="400"  alt="Illustration: Fig. 15.&mdash;Spongilla
+fragilis subsp. calcuttana. A=group of gemmules, � 70; B=spicules, �
+240. From type specimen." title="Fig. 15.&mdash;Spongilla fragilis
+subsp. calcuttana. A=group of gemmules, � 70; B=spicules, � 240. From
+type specimen." />
+<p class="caption">Fig. 15.&mdash;<i>Spongilla fragilis</i> subsp.
+<i>calcuttana</i>. A=group of gemmules, � 70; B=spicules, � 240. From
+type specimen.</p>
+</div>
+
+<p>This local race, which is common in Calcutta, is distinguished from
+the typical form mainly by the shape of its skeleton-spicules, most of
+which are abruptly pointed or almost rounded at<span class='pagenum'><a
+name="Page_97" id="Page_97">[Pg 97]</a></span> the tips, sometimes
+bearing a minute conical projection at each end. The gemmule-spicules,
+which are usually numerous, are slender. The foraminal tubules are
+usually long and bent, but are sometimes very short and quite straight.
+The colour is usually greyish, occasionally brown.</p>
+
+<p>I have not found this race except in Calcutta, in the ponds of which
+it grows on bricks or, very commonly, on the stems of bulrushes, often
+covering a considerable area.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p class="p2">9 <i>b.</i> Subsp. <b>decipiens</b>*, <i>Weber</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla decipiens</i>, Weber, Zool. Ergeb.
+Niederl�nd. Ost-Ind. i, p.&nbsp;40, pl. iv, figs. 1-5 (1890).</span>
+
+</div>
+
+<p>This (?) local race is distinguished by the fact that the foraminal
+tubules are invariably short and straight and thickened at the tips, and
+that gemmule-spicules do not occur on the external surface of the
+cellular coat of the gemmules.</p>
+
+<p>I include Weber's <i>Spongilla decipiens</i> in the Indian fauna on
+the authority of Weltner, who identified specimens from the Museum
+"tank," Calcutta, as belonging to this form. All, however, that I have
+examined from our "tank" belong to the subspecies <i>calcuttana</i>,
+most of the skeleton-spicules of which are much less sharp than those of
+<i>decipiens</i>. By the kindness of Prof. Max Weber I have been able to
+examine a co-type of his species, which is probably a local race
+peculiar to the Malay Archipelago.</p>
+
+<p><span class="smcap">Type</span> in the Amsterdam Museum; a co-type in
+Calcutta.</p>
+
+<p>Perhaps the Japanese form, which has spindle-shaped gemmule-spicules
+with comparatively short and regular spines, should be regarded as a
+third subspecies, and the Siberian form as a fourth.</p>
+
+<p class="p2">10. <b>Spongilla gemina</b>*, sp. nov.</p>
+
+<p><i>Sponge</i> forming small, shallow, slightly dome-shaped patches of
+a more or less circular or oval outline, minutely hispid on the surface,
+friable but moderately hard. Oscula numerous but minute and
+inconspicuous, never star-shaped. Dermal membrane adhering closely to
+the sponge. Colour grey or brown.</p>
+
+<p><i>Skeleton</i> forming a close and regular network at the base of
+the sponge, becoming rather more diffuse towards the external surface;
+the radiating and the transverse fibres both well developed, of almost
+equal diameter. Little spongin present.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules slender, smooth, sharply pointed.
+No flesh-spicules. Gemmule-spicules long, slender, cylindrical, blunt or
+bluntly pointed, somewhat irregularly covered with minute straight
+spines.</p>
+
+<p><i>Gemmules</i> small, bound together in pairs, as a rule free in the
+parenchyma but sometimes lightly attached at the base of the sponge.
+Each gemmule flattened on the surface by which it is attached to its
+twin, covered with a thin coat of polygonal air-spaces which contains
+two layers of gemmule-spicules crossing one another irregularly in a
+horizontal plane. One or two foraminal<span class='pagenum'><a
+name="Page_98" id="Page_98">[Pg 98]</a></span> tubules present on the
+surface opposite the flat one, bending towards the latter, often of
+considerable length, cylindrical and moderately stout.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p>This species is closely allied to <i>S. fragilis</i>, from which it
+may be distinguished by the curious twinned arrangement of its gemmules.
+It also differs from <i>S. fragilis</i> in having extremely small and
+inconspicuous oscula.</p>
+
+<p><i>Locality.</i> I only know this sponge from the neighbourhood of
+Bangalore, where Dr. Morris Travers and I found it in October, 1910
+growing on stones and on the leaves of branches that dipped into the
+water at the edge of a large tank.</p>
+
+<p class="p2">11. <b>Spongilla crassissima</b>*, <i>Annandale</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla crassissima</i>, Annandale, J. Asiat. Soc.
+Bengal, 1907, p.&nbsp;17, figs. 2, 3.</span>
+
+<span class="i0"><i>Spongilla crassissima</i>, <i>id.</i>, <i>ibid.</i>
+p.&nbsp;88.</span>
+
+<span class="i0"><i>Spongilla crassissima</i>, <i>id.</i>, Rec. Ind.
+Mus. i. p.&nbsp;390, pl. xiv, fig. 4 (1907).</span>
+
+</div>
+
+<p><i>Sponge</i> very hard and strong, nearly black in colour, sometimes
+with a greenish tinge, forming spherical, spindle-shaped or irregular
+masses without branches but often several inches in diameter. Oscula
+circular or star-shaped, usually surrounded by radiating furrows; pores
+normally contained in single cells. External membrane closely adherent
+to the sponge except immediately round the oscula.</p>
+
+<p><i>Skeleton</i> dense, compact and only to be broken by the exercise
+of considerable force; radiating and transverse fibres not very stout
+but firmly bound together by spongin (fig. 6, p.&nbsp;38), which
+occasionally extends between them as a delicate film; their network
+close and almost regular.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, feebly curved,
+sausage-shaped but by no means short, as a rule bearing at each end a
+minute conical projection which contains the extremity of the axial
+filament. No flesh-spicules. Gemmule-spicules closely resembling those
+of <i>S. fragilis</i> subsp. <i>calcuttana</i>, but as a rule even more
+obtuse at the ends.</p>
+
+<p><i>Gemmules</i> as in <i>S. fragilis</i> subsp. <i>calcuttana</i>; a
+basal layer of gemmules rarely formed.</p>
+
+<p class="p2">11 <i>a.</i> Var. <b>crassior</b>*, <i>Annandale</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla crassior</i>, Annandale, Rec. Ind. Mus. i,
+p.&nbsp;389, pl. xiv, fig. 3 (1907).</span>
+
+</div>
+
+<p>This variety differs from the typical form chiefly in its even
+stronger skeleton (fig. 3, p.&nbsp;33) and its stouter skeleton-spicules,
+which do not so often possess a terminal projection. The sponge is of a
+brownish colour and forms flat masses of little thickness but of
+considerable area on sticks and on the stems of water-plants.</p>
+
+<p><span class="smcap">Types.</span>&mdash;The types of both forms are
+in the Indian Museum. Co-types have been sent to London.</p>
+
+<p><span class='pagenum'><a name="Page_99" id="Page_99">[Pg
+99]</a></span><span class="smcap">Geographical
+Distribution.</span>&mdash;This sponge is only known from Bengal. The
+variety <i>crassior</i> was found at Rajshahi (Rampur Bhulia) on the
+Ganges, about 150 miles N. of Calcutta, while the typical form is fairly
+common in the "tanks" of Calcutta and very abundant in the Sur Lake near
+Puri in Orissa.</p>
+
+<div class="figcenter">
+<img src="images/fig_016.jpg"
+width="400" height="246"  alt="Illustration: Fig. 16.&mdash;Spicules of
+Spongilla crassissima var. crassior (from type specimen), � 240."
+title="Fig. 16.&mdash;Spicules of Spongilla crassissima var. crassior
+(from type specimen), � 240." />
+<p class="caption">Fig. 16.&mdash;Spicules of <i>Spongilla
+crassissima</i> var. <i>crassior</i> (from type specimen), � 240.</p>
+</div>
+
+<p><span class="smcap">Biology.</span>&mdash;<i>S. crassissima</i> is
+usually found near the surface in shallow water. Attached to the roots
+of the floating water-plant <i>Pistia stratiotes</i> it assumes a
+spherical form, while on sticks or like objects it is spindle-shaped.
+Sometimes it is found growing on the same stick or reed-stem as <i>S.
+carteri</i>, the two species being in close contact and <i>S.
+carteri</i> always overlapping <i>S. crassissima</i>. The dark colour is
+due to minute masses of blackish pigment in the cells of the parenchyma.
+The dense structure of the sponge is not favourable to the presence of
+<i>incol�</i>, but young colonies of the polyzoon <i>Plumatella
+fruticosa</i> are sometimes overgrown by it. Although they may persist
+for a time by elongating their tubular zo&oelig;cia through the
+substance of the sponge, they do not in these circumstances reach the
+same development as when they are overgrown by the much softer <i>S.
+carteri</i>.</p>
+
+<p><i>S. crassissima</i> is found during the "rains" and the cold
+weather. In Calcutta it attains its maximum size towards the end of the
+latter season. In spite of its hard and compact skeleton, the sponge
+does not persist from one cold weather to another.</p>
+
+<p>A curious phenomenon has been noticed in this species, but only in
+the case of sponges living in an aquarium, viz. the cessation during the
+heat of the day of the currents produced by its flagella.</p>
+
+<p class="p2"><span class='pagenum'><a name="Page_100" id="Page_100">[Pg
+100]</a></span>Subgenus C. <b>STRATOSPONGILLA</b>, <i>Annandale</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Stratospongilla</i>, Annandale, Zool. Jahrb., Syst.
+xxvii, p.&nbsp;561 (1909).</span>
+</div>
+
+<p><span class="smcap">Type</span>, <i>Spongilla bombayensis</i>,
+Carter.</p>
+
+<p>Spongill� in the gemmules of which the pneumatic layer is absent or
+irregularly developed, its place being sometimes taken by air-spaces
+between the stout chitinous membranes that cover the gemmule. At least
+one of these membranes is always present.</p>
+
+<p>The gemmule-spicules lie in the membrane or membranes parallel to the
+surface of the gemmule, and are often so arranged as to resemble a
+mosaic. The gemmules themselves are usually adherent to the support of
+the sponge. The chitinous membrane or membranes are often in continuity
+with a membrane that underlies the base of the sponge. The skeleton is
+usually stout, though often almost amorphous, and the skeleton-spicules
+are sometimes sausage-shaped.</p>
+
+<p>Sponges of this subgenus form crusts or sheets on solid submerged
+objects.</p>
+
+<p><i>Stratospongilla</i> is essentially a tropical subgenus, having its
+head-quarters in Central Africa and Western India. One of its species,
+however, (<i>S. sumatrana</i>*, Weber) occurs both in Africa and the
+Malay Archipelago, while another has only been found in S. America
+(<i>S. navicella</i>, Carter).</p>
+
+<p>Aberrant species occur in China (<i>S. sinensis</i>*, <i>S.
+coggini</i>*) and the Philippines (<i>S. clementis</i>*). Three species
+have been found in the Bombay Presidency and Travancore, one of which
+(<i>S. bombayensis</i>*) extends its range eastwards to Mysore and
+westwards across the Indian Ocean to Natal.</p>
+
+<p class="p2">12. <b>Spongilla indica</b>*, <i>Annandale</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla indica</i>, Annandale, Rec. Ind. Mus. ii,
+p.&nbsp;25, figs. 1, 2 (1908).</span>
+</div>
+
+<p><i>Sponge</i> forming a very thin layer, of a bright green or pale
+grey colour; surface smooth, minutely hispid; pores and oscula
+inconspicuous, the latter approached in some instances by radiating
+furrows; subdermal cavity small; texture compact, rather hard.</p>
+
+<p><i>Skeleton</i> incoherent, somewhat massive owing to the large
+number of spicules present. Spicules forming triangular meshes and
+occasionally arranged in vertical lines several spicules broad but
+without spongin.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules straight or nearly straight,
+slender, cylindrical, amphistrongylous, uniformly covered with minute,
+sharp spines; flesh-spicules slender, sharply pointed, straight or
+curved, irregularly covered with relatively long, straight sharp spines,
+abundant in the dermal membrane, scarce in the substance<span
+class='pagenum'><a name="Page_101" id="Page_101">[Pg 101]</a></span> of
+the sponge. Gemmule-spicules short, stout, sausage-shaped, covered with
+minute spines, which are sometimes absent from the extremities.</p>
+
+<p><i>Gemmules</i> spherical, somewhat variable in size, with a single
+aperture, which is provided with a trumpet-shaped foraminal tubule and
+is situated at one side of the gemmule in its natural position; the
+inner chitinous coat devoid of spicules, closely covered by an outer
+coat composed of a darkly coloured chitinoid substance in which the
+gemmule-spicules are embedded, lying parallel or almost parallel to the
+inner coat. The outer coat forms a kind of mantle by means of the skirts
+of which the gemmule is fastened to the support of the sponge. This coat
+is pierced by the foraminal tubule.  The gemmules are distinct from one
+another.</p>
+
+<div class="figcenter">
+<img src="images/fig_017.png"
+width="200" height="200"  alt="Illustration: Fig. 17.&mdash;Gemmule of
+Spongilla indica seen from the side (from type specimen), magnified."
+title="Fig. 17.&mdash;Gemmule of Spongilla indica seen from the side
+(from type specimen), magnified." />
+<p class="caption">Fig. 17.&mdash;Gemmule of <i>Spongilla indica</i>
+seen from the side (from type specimen), magnified.</p>
+</div>
+
+<table summary="average length gemmule of Spongilla">
+<tr><td class="left_a">Average length of
+skeleton-spicules</td><td>0.2046 mm.</td></tr>
+<tr><td class="left_a">Average breadth of
+skeleton-spicules</td><td>0.0172 mm.</td></tr>
+<tr><td class="left_a">Average length of
+flesh-spicules</td><td>0.053&nbsp;&nbsp; mm.</td></tr>
+<tr><td class="left_a">Average breadth of flesh-spicules</td><td>0.0053
+mm.</td></tr>
+<tr><td class="left_a">Average length of
+gemmule-spicules</td><td>0.044&nbsp;&nbsp; mm.</td></tr>
+<tr><td class="left_a">Average breadth of
+gemmule-spicules</td><td>0.0079 mm.</td></tr>
+</table>
+
+<p><i>S. indica</i> is closely allied to <i>S. sumatrana</i>*, Weber,
+which has been found both in the Malay Archipelago and in East Africa.
+It may be distinguished by its blunt, almost truncated megascleres and
+comparatively slender gemmule-spicules.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p><span class="smcap">Habitat</span>, etc.&mdash;Growing, together with
+<i>S. cinerea</i> and <i>Corvospongilla lapidosa</i>, on the stone sides
+of an artificial conduit in the R. Godaveri at Nasik on the eastern side
+of the Western Ghats in the Bombay Presidency. The water was extremely
+dirty and was used for bathing purposes. The sponge was green where<span
+class='pagenum'><a name="Page_102" id="Page_102">[Pg 102]</a></span> the
+light fell upon it, grey where it was in the shadow of the bridge under
+which the conduit ran. The only specimens I have seen were taken in
+November, 1907.</p>
+
+<p class="p2">13. <b>Spongilla bombayensis</b>*, <i>Carter</i>. (<a
+href="#Plate_II">Plate II</a>, fig. 2.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla bombayensis</i>, Carter, Ann. Nat. Hist.
+(5) x, p.&nbsp;369, pl. xvi, figs. 1-6 (1882).</span>
+
+<span class="i0"><i>Spongilla bombayensis</i>, Annandale, Zool. Jahrb.,
+Syst. xxvii, p.&nbsp;562, figs. B, C (1909).</span>
+
+</div>
+
+<p><i>Sponge</i> hard but friable, forming thin layers or cushions; its
+surface often irregular but without a trace of branches; its area never
+very great; oscula inconspicuous; external membrane adhering closely to
+the sponge; colour brownish or greyish.</p>
+
+<div class="figcenter">
+<img src="images/fig_018.png"
+width="240" height="212"  alt="Illustration: Fig. 18.&mdash;Gemmule of
+Spongilla bombayensis as seen from above (from type specimen),
+magnified." title="Fig. 18.&mdash;Gemmule of Spongilla bombayensis as
+seen from above (from type specimen), magnified." />
+<p class="caption">Fig. 18.&mdash;Gemmule of <i>Spongilla
+bombayensis</i> as seen from above (from type specimen), magnified.</p>
+</div>
+
+<p><i>Skeleton</i> almost amorphous, very dense, consisting of large
+numbers of spicules arranged irregularly; radiating fibres occasionally
+visible in sections, but almost devoid of spongin; a more or less
+definite reticulation of horizontal spicules lying immediately under the
+external membrane.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules slender, pointed, feebly curved,
+irregularly roughened or minutely spined all over the surface.
+Flesh-spicules straight, narrowly rhomboidal in outline, sharply
+pointed, slender, covered with minute, irregular, straight spines,
+scanty in the parenchyma, abundant in the external membrane.
+Gemmule-spicules sausage-shaped or bluntly pointed, variable in length
+but usually rather stout, covered with minute spines, as a rule
+distinctly curved.</p>
+
+<p><i>Gemmules</i> round or oval, firmly adherent<a name="fnanchor_AH"
+id="fnanchor_AH"></a><a href="#footnote_AH"
+class="fnanchor"><sup>[AH]</sup></a> to the base of the sponge, as a
+rule rather shallowly dome-shaped, covered by two<span
+class='pagenum'><a name="Page_103" id="Page_103">[Pg 103]</a></span>
+thick chitinous membranes, in each of which there is a dense horizontal
+layer of spicules; no granular or cellular covering; the two chitinous
+coats separated by an empty space; the aperture or apertures on the side
+of the gemmule in its natural position, provided with foraminal tubules,
+which may be either straight or curved, project through the outer
+chitinous membrane and often bend down towards the base of the gemmule.
+The spicules of the outer layer often more irregular in outline and less
+blunt than those of the inner layer.</p>
+
+<p>This sponge is allied to <i>S. indica</i>, but is distinguished among
+other characters by its sharp skeleton-spicules and by the fact that the
+gemmule is covered by two chitinous membranes instead of one.</p>
+
+<p><span class="smcap">Type</span> in the British Museum; a fragment in
+the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;S. and W.
+India and S. Africa. Carter's type was found in the island of Bombay, my
+own specimens in Igatpuri Lake in the Western Ghats. I have recently
+(October 1910) found sponges and bare gemmules attached to stones at the
+end of a tank about 10 miles from Bangalore (Mysore State) in the centre
+of the Madras Presidency. Prof. Max Weber obtained specimens in
+Natal.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;The specimens collected by
+Prof. Weber in Natal and those collected by myself in the Bombay
+Presidency were both obtained in the month of November. It is therefore
+very interesting to compare them from a biological point of view. In so
+doing, it must be remembered that while in S. Africa November is near
+the beginning of summer, in India it is at the beginning of the "cold
+weather," that is to say, both the coolest and the driest season of the
+year. The lake in which my specimens were obtained had, at the time when
+they were collected, already sunk some inches below its highest level,
+leaving bare a gently sloping bank of small stones. Adhering to the
+lower surface of these stones I found many small patches of <i>Spongilla
+bombayensis</i>, quite dry but complete so far as their harder parts
+were concerned and with the gemmules fully formed at their base. From
+the shallow water at the edge of the lake I took many similar stones
+which still remained submerged. It was evident that the sponge had been
+just as abundant on their lower surface as on that of the stones which
+were now dry; but only the gemmules remained, sometimes with a few
+skeleton-spicules adhering to them (Pl. II, fig. 2). The bulk of the
+skeleton had fallen away and the parenchyma had wholly perished. In a
+few instances a small sponge, one or two millimetres in diameter, had
+already been formed among the gemmules; but these young sponges appeared
+to belong to some other species, possibly <i>Spongilla indica</i>, which
+was also common in the lake.</p>
+
+<p>Carter's specimen of <i>S. bombayensis</i>, which was evidently in
+much the same condition as those I found still submerged a<span
+class='pagenum'><a name="Page_104" id="Page_104">[Pg 104]</a></span>
+month later, was taken in October in a disused quarry. It was surrounded
+by a mass of <i>S. carteri</i> three inches in diameter, and was
+attached to a herbaceous annual. The point on the edge of the quarry at
+which this plant grew was not reached by the water until July. It is
+therefore necessary to assume that the gemmules of <i>S. bombayensis</i>
+had been formed between July and October. Probably the larva of the
+sponge had settled down on the plant during the "rains"&mdash;which
+commence in Bombay about the beginning of June&mdash;and had grown
+rapidly. The production of gemmules may have been brought about owing to
+the sponge being choked by the more vigorous growth of <i>S.
+carteri</i>, a species which grows to a considerable size in a
+comparatively short time, while <i>S. bombayensis</i> apparently never
+reaches a thickness of more than a few millimetres.</p>
+
+<p>The manner in which the gemmules of <i>S. bombayensis</i> are
+fastened to the solid support of the sponge must be particularly useful
+in enabling them to sprout in a convenient environment as soon as the
+water reaches them. The fact that the gemmules remained fixed without
+support renders it unnecessary for the skeleton to persist as a cage
+containing them (or at any rate a proportion of them) during the period
+of rest.</p>
+
+<p>Prof. Weber's specimens of <i>S. bombayensis</i> were collected in a
+river, apparently on stones or rocks, towards the beginning of the S.
+African summer. They contain comparatively few gemmules and were
+evidently in a vigorous condition as regards vegetative growth.
+Unfortunately we know nothing of the seasonal changes which take place
+in freshwater sponges in S. Africa, but the difference between these
+changes in Europe and in India shows that they are dependent on
+environment as well as the idiosyncrasy of the species. It is very
+interesting, therefore, to see that the condition of sponges taken in S.
+Africa differs so widely from that of other individuals of the same
+species taken in India at the same season.</p>
+
+<p>In Prof. Weber's specimens I have found numerous small tubules of
+inorganic d�bris. These appear to be the work of Chironomid larv�, of
+which there are several specimens loose in the bottle containing the
+sponges. Other tubules of a very similar appearance but with a delicate
+chitinoid foundation appear to be the remains of a species of
+<i>Plumatella</i> of which they occasionally contain a statoblast.</p>
+
+<p class="p2">14. <b>Spongilla ultima</b>*, <i>Annandale</i>. (<a
+href="#Plate_II">Plate II</a>, fig. 3.)</p>
+
+<div class="genus">
+<span class="i0"><i>Spongilla ultima</i>, Annandale, Rec. Ind. Mus. v,
+p.&nbsp;31 (1910).</span>
+</div>
+
+<p><i>Sponge</i> hard and strong, forming a thin layer on solid objects,
+of a pale green colour (dry); the oscula small but rendered conspicuous
+by the deep radiating furrows that surround them; external surface of
+the sponge rough but not spiny.</p>
+
+<p><span class='pagenum'><a name="Page_105" id="Page_105">[Pg
+105]</a></span><i>Skeleton</i> forming a compact but somewhat irregular
+reticulation in which the radiating fibres are not very much more
+distinct than the transverse ones; a considerable amount of almost
+colourless spongin present.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, stout, amphioxous, as a
+rule straight or nearly straight, not infrequently inflated in the
+middle or otherwise irregular. No flesh-spicules. Gemmule-spicules
+variable in size, belonging to practically every type and exhibiting
+practically every abnormality possible in the genus, the majority being
+more or less sausage-shaped and having a roughened surface, but others
+being cruciform, spherical, subspherical, rosette-like, needle-like,
+bifid or even trifid at one extremity.</p>
+
+<div class="figcenter">
+<img src="images/fig_019.jpg"
+width="400" height="340"  alt="Illustration: Fig. 19.&mdash;Spicules of
+Spongilla ultima (from type specimen), � 120." title="Fig.
+19.&mdash;Spicules of Spongilla ultima (from type specimen), � 120." />
+<p class="caption">Fig. 19.&mdash;Spicules of <i>Spongilla ultima</i>
+(from type specimen), � 120.</p>
+</div>
+
+<p><i>Gemmules</i> adherent, spherical, large, each covered by two
+distinct layers of horizontal spicules; the outer layer intermixed with
+skeleton-spicules and often containing relatively large siliceous
+spheres, a large proportion of the spicules being irregular in shape;
+the spicules of the inner layer much more regular and as a rule
+sausage-shaped. The outer layer is contained in a chitinous membrane
+which spreads out over the base of the sponge. The foraminal tubules are
+short and straight.</p>
+
+<p>This sponge is allied to <i>S. bombayensis</i>, from which it is
+distinguished not only by the abnormal characters of its
+gemmule-spicules and the absence of flesh-spicules, but also by the form
+of its skeleton-spicules and the structure of its skeleton. I have
+examined several specimens dry and in spirit; but <i>S. ultima</i> is
+the only Indian freshwater sponge, except <i>Corvospongilla
+burmanica</i>, I have not seen in a fresh condition.</p>
+
+<p><span class="smcap">Types</span> in the Indian Museum; co-types at
+Trivandrum.</p>
+
+<p><span class="smcap">Habitat.</span> Discovered by Mr. R. Shunkara
+Narayana Pillay, of the Trivandrum Museum, in a tank near Cape Comorin,
+the southernmost point of the Indian Peninsula.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_106"
+id="Page_106">[Pg 106]</a></span>Genus 2. <b>PECTISPONGILLA</b>,
+<i>Annandale</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Pectispongilla</i>, Annandale, Rec. Ind. Mus. iii, p.
+103 (1909).</span>
+</div>
+
+<p><span class="smcap">Type</span>, <i>Pectispongilla aurea</i>,
+Annandale.</p>
+
+<p>The structure of the sponge resembling that of <i>Euspongilla</i> or
+<i>Ephydatia</i>; but the gemmule-spicules bear at either end, at one
+side only, a double vertical row of spines, so that they appear when
+viewed in profile like a couple of combs joined together by a smooth
+bar.</p>
+
+<div class="figcenter">
+<img src="images/fig_020.jpg"
+width="500" height="280"  alt="Illustration: Fig. 20.&mdash;Gemmule and
+spicules of Pectispongilla aurea (type specimen). a, Skeleton-spicules;
+b, gemmule-spicules; b', a single gemmule-spicule more highly
+magnified." title="Fig. 20.&mdash;Gemmule and spicules of Pectispongilla
+aurea (type specimen). a, Skeleton-spicules; b, gemmule-spicules; b', a
+single gemmule-spicule more highly magnified." />
+<p class="caption">Fig. 20.&mdash;Gemmule and spicules of
+<i>Pectispongilla aurea</i> (type specimen). <i>a</i>,
+Skeleton-spicules; <i>b</i>, gemmule-spicules; <i>b'</i>, a single
+gemmule-spicule more highly magnified.</p>
+</div>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The genus
+is monotypic and is only known from Travancore and Cochin in the
+south-west of the Indian Peninsula.</p>
+
+<p class="p2">15. <b>Pectispongilla aurea</b>*, <i>Annandale</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Pectispongilla aurea</i>, Annandale, <i>op.
+cit.</i>, p.&nbsp;103, pl. xii, fig. 2.</span>
+</div>
+
+<p><i>Sponge</i> forming minute, soft, cushion-like masses of a deep
+golden colour (dull yellow in spirit); the surface smooth, minutely
+hispid. One relatively large depressed osculum usually present in each
+sponge; pores inconspicuous; dermal membrane in close contact with the
+parenchyma.</p>
+
+<p><i>Skeleton</i> consisting of slender and feebly coherent radiating
+fibres as a rule two or three spicules thick, with single spicules or
+ill-defined transverse fibres running horizontally. Towards the<span
+class='pagenum'><a name="Page_107" id="Page_107">[Pg 107]</a></span>
+external surface transverse spicules are numerous, but they do not form
+any very regular structure.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, sharply pointed, straight
+or nearly so. Gemmule-spicules minute, with the stem smooth and
+cylindrical, relatively stout and much longer than the comb at either
+end; the two combs equal, with a number of minute, irregularly scattered
+spines between the two outer rows of stouter ones. No free
+microscleres.</p>
+
+<p><i>Gemmules</i> minute, spherical, with a single aperture, which is
+provided with a very short foraminal tubule; the granular coat well
+developed; the spicules arranged in a slanting position, but more nearly
+vertically than horizontally, with the combs pointing in all directions;
+no external chitinous membrane.</p>
+
+<table summary="length of spicules 15">
+
+<tr><td class="left_a">Length of skeleton-spicule</td><td
+class="left_a">0.2859 mm.</td></tr>
+
+<tr><td class="left_a">Greatest diameter of skeleton-spicule</td><td
+class="left_a">0.014 mm.</td></tr>
+
+<tr><td class="left_a">Length of gemmule-spicule</td><td
+class="left_a">0.032-0.036 mm.</td></tr>
+
+<tr><td class="left_a">Length of comb of gemmule-spicule</td><td
+class="left_a">0.008 mm.</td></tr>
+
+<tr><td class="left_a">Greatest diameter of shaft of
+gemmule-spicule</td><td class="left_a">0.004 mm.</td></tr>
+
+<tr><td class="left_a">Diameter of gemmule</td><td
+class="left_a">0.204-0.221 mm.</td></tr>
+
+</table>
+
+<p>The gemmule-spicules first appear as minute, smooth, needle-like
+bodies, which later become roughened on one side at either end and so
+finally assume the mature form. There are no bubble-cells in the
+parenchyma.</p>
+
+<p class="p2">15<i>a.</i> Var. <b>subspinosa</b>*, nov.</p>
+
+<p>This variety differs from the typical form in having its skeleton
+spicules covered with minute irregular spines or conical
+projections.</p>
+
+<p><span class="smcap">Types</span> of both the typical form and the
+variety in the Indian Museum; co-types of the typical form in the
+Trivandrum Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The same
+as that of the genus. <i>Localities</i>:&mdash;Tenmalai, at the base of
+the western slopes of the W. Ghats in Travancore (typical form)
+(<i>Annandale</i>); Ernakulam and Trichur in Cochin (var.
+<i>subspinosa</i>) (<i>G. Mathai</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;My specimens, which were
+taken in November, were growing on the roots of trees at the edge of an
+artificial pool by the roadside. They were in rather dense shade, but
+their brilliant golden colour made them conspicuous objects in spite of
+their small size. Mr. Mathai's specimens from Cochin were attached to
+water-weeds and to the husk of a cocoanut that had fallen or been thrown
+into the water.</p>
+
+<p class="p2"><span class='pagenum'><a name="Page_108" id="Page_108">[Pg
+108]</a></span>Genus 3. <b>EPHYDATIA</b>, <i>Lamouroux</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Ephydatia</i>, Lamouroux, Hist. des Polyp. corall.
+flex.* p.&nbsp;6 (<i>fide</i> Weltner) (1816).</span>
+
+<span class="i0"><i>Ephydatia</i>, J. E. Gray, P. Zool. Soc. London.
+1867, p.&nbsp;550.</span>
+
+<span class="i0"><i>Trachyspongilla</i>, Dybowsky (<i>partim</i>), Zool.
+Anz. i, p.&nbsp;53 (1874).</span>
+
+<span class="i0"><i>Meyenia</i>, Carter (<i>partim</i>), Ann. Nat. Hist.
+(5) vii, p.&nbsp;90 (1881).</span>
+
+<span class="i0"><i>Carterella</i>, Potts &amp; Mills (<i>partim</i>),
+P. Ac. Philad. 1881, p.&nbsp;150.</span>
+
+<span class="i0"><i>Ephydatia</i>, Vejdovsky, Abh. B�hm. Ges. xii,
+p.&nbsp;23 (1883).</span>
+
+<span class="i0"><i>Meyenia</i>, Potts (<i>partim</i>), <i>ibid.</i>
+1887, p.&nbsp;210.</span>
+
+<span class="i0"><i>Carterella</i>, <i>id.</i> (<i>partim</i>),
+<i>ibid.</i> 1887, p.&nbsp;260.</span>
+
+<span class="i0"><i>Ephydatia</i>, Weltner (<i>partim</i>), Arch.
+Naturg. lxi (i), p.&nbsp;121 (1895).</span>
+
+<span class="i0"><i>Ephydatia</i>, Annandale, P. U.S. Mus. xxxvii, p.
+404 (1909).</span>
+
+</div>
+
+<p><span class="smcap">Type</span>, (?) <i>Spongilla fluviatilis</i>,
+auctorum.</p>
+
+<p>This genus is separated from <i>Spongilla</i> by the structure of the
+gemmule-spicules, which bear at either end a transverse disk with
+serrated or deeply notched edges, or at any rate with edges that are
+distinctly undulated. The disks are equal and similar. True
+flesh-spicules are usually absent, but more or less perfect birotulates
+exactly similar to those associated with the gemmules are often found
+free in the parenchyma. The skeleton is never very stout and the
+skeleton-spicules are usually slender.</p>
+
+<p>As has been already stated, some authors consider <i>Ephydatia</i> as
+the type-genus of a subfamily distinguished from the subfamily of which
+<i>Spongilla</i> is the type-genus by having rotulate gemmule-spicules.
+The transition between the two genera, however, is a very easy one. Many
+species of the subgenus <i>Euspongilla</i>, the typical subgenus of
+<i>Spongilla</i> (including <i>S. lacustris</i>, the type-species of the
+genus), have the spines at the ends of the gemmule-spicules arranged in
+such a way as to suggest rudimentary rotules, while in the typical form
+of <i>S. crateriformis</i> this formation is so distinct that the
+species has hitherto been placed in the genus <i>Ephydatia</i>
+(<i>Meyenia</i>), although in some sponges that agree otherwise with the
+typical form of the species the gemmule-spicules are certainly not
+rotulate and in none do these spicules bear definite disks.</p>
+
+<p><span class="smcap">Geographical
+Distribution.</span>&mdash;<i>Ephydatia</i>, except <i>Spongilla</i>, is
+the most generally distributed genus of the Spongillid�, but in most
+countries it is not prolific in species. In Japan, however, it appears
+to predominate over <i>Spongilla</i>. Only one species is known from
+India, but another (<i>E. blembingia</i>*, Evans) has been described
+from the Malay Peninsula, while Weber found both the Indian species and
+a third (<i>E. bogorensis</i>*) in the Malay Archipelago.</p>
+
+<p class="p2">16. <b>Ephydatia meyeni</b>* (<i>Carter</i>).</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla meyeni</i>, Carter, J. Bomb. Asiat. Soc.
+iii, p.&nbsp;33, pl. i, fig. 1, &amp; Ann. Nat. Hist. (2) iv,
+p.&nbsp;84, pl. iii, fig. 1 (1849).</span>
+
+<span class="i0"><i>Spongilla meyeni</i>, Bowerbank, P. Zool. Soc.
+London, 1863, p.&nbsp;448, pl. xxxviii, fig. 4.</span>
+
+<span class="i0"><i>Spongilla meyeni</i>, Carter, Ann. Nat. Hist. (5)
+vii, p.&nbsp;93 (1881). <span class='pagenum'><a name="Page_109"
+id="Page_109">[Pg 109]</a></span></span>
+
+<span class="i0"><i>Ephydatia fluviatilis</i>, Weber, Zool. Ergeb.
+Niederl�nd. Ost-Ind. i. pp.&nbsp;32, 46 (1890).</span>
+
+<span class="i0"><i>Ephydatia m�lleri</i>, Weltner (<i>partim</i>),
+Arch. Naturg. lxi (i), p.&nbsp;125 (1895).</span>
+
+<span class="i0"><i>Ephydatia robusta</i>, Annandale, J. Asiat. Soc.
+Bengal, 1907, p.&nbsp;24, fig. 7.</span>
+
+<span class="i0"><i>Ephydatia m�lleri</i> subsp. <i>meyeni</i>,
+<i>id.</i>, Rec. Ind. Mus. ii, p.&nbsp;306 (1908).</span>
+
+</div>
+
+<p><i>Sponge</i> hard and firm but easily torn, usually of a clear
+white, sometimes tinged with green, forming irregular sheets or masses
+never of great thickness, without branches but often with stout
+subquadrate projections, the summits of which are marked with radiating
+grooves; the whole surface often irregularly nodulose and deeply pitted;
+the oscula inconspicuous; the membrane adhering closely to the
+parenchyma. <i>The parenchyma contains numerous bubble-cells</i> (see p.
+31, fig. 2).</p>
+
+<p><i>Skeleton</i> dense but by no means regular; the radiating fibres
+distinct and containing a considerable amount of spongin, at any rate in
+the outer part of the sponge; transverse fibres hardly distinguishable,
+single spicules and irregular bundles of spicules taking their
+place.</p>
+
+<div class="figcenter">
+<img src="images/fig_021.png"
+width="500" height="270"  alt="Illustration: Fig. 21.&mdash;Gemmule and
+spicules of Ephydatia meyeni (from Calcutta). a, Skeleton-spicules; b,
+gemmule-spicules." title="Fig. 21.&mdash;Gemmule and spicules of
+Ephydatia meyeni (from Calcutta). a, Skeleton-spicules; b,
+gemmule-spicules." />
+<p class="caption">Fig. 21.&mdash;Gemmule and spicules of <i>Ephydatia
+meyeni</i> (from Calcutta).<br /> <i>a</i>, Skeleton-spicules; <i>b</i>,
+gemmule-spicules.</p>
+</div>
+
+<p><i>Spicules.</i> Skeleton-spicules entirely smooth, moderately stout,
+feebly curved, sharply pointed. No flesh-spicules. Gemmule-spicules with
+the shaft as a rule moderately stout, much longer than the diameter of
+one disk, smooth or with a few stout, straight horizontal spines, which
+are frequently bifid or trifid; the disks flat, of considerable size,
+with their margins cleanly and deeply divided into a comparatively small
+number of deep, slender, triangular processes of different sizes; the
+shaft extending not at all or very little beyond the disks.</p>
+
+<p><i>Gemmules</i> spherical, usually numerous and of rather large size;
+each covered by a thick layer of minute air-spaces, among which the
+gemmule-spicules are arranged vertically, often in two or even<span
+class='pagenum'><a name="Page_110" id="Page_110">[Pg 110]</a></span>
+three concentric series; a single short foraminal tubule; the pneumatic
+coat confined externally by a delicate membrane, with small
+funnel-shaped pits over the spicules of the outer series.</p>
+
+<p>I think that the gemmules found by me in Bhim Tal and assigned to
+Potts's <i>Meyenia robusta</i> belong to this species, but some of the
+spicules are barely as long as the diameter of the disks. In any case
+Potts's description is so short that the status of his species is
+doubtful. His specimens were from N. America.</p>
+
+<p><i>E. meyeni</i> is closely related to the two commonest Holarctic
+species of the genus, <i>E. fluviatilis</i> and <i>E. m�lleri</i>, which
+have been confused by several authors including Potts. From <i>E.
+fluviatilis</i> it is distinguished by the possession of bubble-cells in
+the parenchyma, and from <i>E. m�lleri</i> by its invariably smooth
+skeleton-spicules and the relatively long shafts of its
+gemmule-spicules. The latter character is a marked feature of the
+specimens from the Malay Archipelago assigned by Prof. Max Weber to
+<i>E. fluviatilis</i>; I am indebted to his kindness for an opportunity
+of examining some of them.</p>
+
+<p><span class="smcap">Type</span> in the British Museum; a fragment in
+the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;India and
+Sumatra. <i>Localities</i>:&mdash;<span class="smcap">Bengal</span>,
+Calcutta and neighbourhood (<i>Annandale</i>); <span
+class="smcap">Madras Presidency</span>, Cape Comorin, Travancore
+(<i>Trivandrum Mus.</i>): <span class="smcap">Bombay Presidency</span>,
+Island of Bombay (<i>Carter</i>): <span class="smcap">Himalayas</span>,
+Bhim Tal, Kumaon (alt. 4,500 feet) (<i>Annandale</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;My experience agrees with
+Carter's, that this species is never found on floating objects but
+always on stones or brickwork. It grows in the Calcutta "tanks" on
+artificial stonework at the edge of the water, together with
+<i>Spongilla carteri</i>, <i>S. alba</i>, <i>S. fragilis</i> subsp.
+<i>calcuttana</i>, and <i>Trochospongilla latouchiana</i>. It flourishes
+during the cold weather and often occupies the same position in
+succeeding years. In this event the sponge usually consists of a dead
+base, which is of a dark brownish colour and contains no cells, and a
+living upper layer of a whitish colour.</p>
+
+<p>The larva of <i>Sisyra indica</i> is sometimes found in the canals,
+but the close texture of the sponge does not encourage the visits of
+other <i>incol�</i>.</p>
+
+<p class="p2 center">Genus 4. <b>DOSILIA</b>, <i>Gray</i>.</p>
+
+<div class="genus">
+<span class="i0"><i>Dosilia</i>, J. E. Gray, P. Zool. Soc. London, 1867,
+p.&nbsp;550.</span>
+</div>
+
+<p><span class="smcap">Type</span>, <i>Spongilla plumosa</i>, Carter.</p>
+
+<p>This genus is distinguished from <i>Ephydatia</i> by the nature of
+the free microscleres, the microscleres of the gemmule being <ins
+title="changed from 'milar'">similar</ins> in the two genera. The free
+microscleres consist as a rule of several or many shafts meeting
+together in several or many planes at a common centre, which is usually
+nodular. The free ends of these shafts often possess rudimentary rotul�.
+Occasionally a free microsclere may be found that is a true monaxon and
+sometimes such spicules are more or less distinctly<span
+class='pagenum'><a name="Page_111" id="Page_111">[Pg 111]</a></span>
+birotulate. The skeleton is also characteristic. It consists mainly of
+radiating fibres which bifurcate frequently in such a way that a
+bush-like structure is produced. Transverse fibres are very feebly
+developed and are invisible to the naked eye. Owing to the structure of
+the skeleton the sponge has a feathery appearance.</p>
+
+<p>Gray originally applied the name <i>Dosilia</i> to this species and
+to <i>"Spongilla" baileyi</i>, Bowerbank. It is doubtful how far his
+generic description applies to the latter, which I have not seen; but
+although the position of <i>"Spongilla" baileyi</i> need not be
+discussed here, I may say that I do not regard it as a congener of
+<i>Dosilia plumosa</i>, the free microscleres of which are of a nature
+rare but not unique in the family. With <i>Dosilia plumosa</i> we must,
+in any case, associate in one genus the two forms that have been
+described as varieties, viz., <i>palmeri</i>*, Potts from Texas and
+Mexico, and <i>brouini</i>*, Kirkpatrick from the White Nile. By the
+kindness of the authorities of the Smithsonian Institution and the
+British Museum I have been able to examine specimens of all three forms,
+in each case identified by the author of the name, and I am inclined to
+regard them as three very closely allied but distinct species. Species
+with free microscleres similar to those of these three forms but with
+heterogeneous or tubelliform gemmule-spicules will probably need the
+creation of a new genus or new genera for their reception.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The
+typical species occurs in Bombay and Madras; <i>D. palmeri</i> has
+probably an extensive range in the drier parts of Mexico and the
+neighbouring States, while <i>D. brouini</i> has only been found on the
+banks of the White Nile above Khartoum, in Tropical Africa.</p>
+
+<p class="p2">17. <b>Dosilia plumosa</b>* (<i>Carter</i>).</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla plumosa</i>, Carter, J. Bomb. Asiat. Soc.
+iii, p.&nbsp;34, pl. i, fig. 2, &amp; Ann. Nat. Hist. (2) iv,
+p.&nbsp;85, pl. iii, fig. 2 (1849).</span>
+
+<span class="i0"><i>Spongilla plumosa</i>, Bowerbank, P. Zool. Soc.
+London, 1863, p.&nbsp;449, pl. xxxviii, fig. 5.</span>
+
+<span class="i0"><i>Dosilia plumosa</i>, J. E. Gray, <i>ibid.</i> 1867,
+p.&nbsp;551.</span>
+
+<span class="i0"><i>Meyenia plumosa</i>, Carter, Ann. Nat. Hist. (5)
+vii, p.&nbsp;94, pl. v, fig. 6 (1881).</span>
+
+<span class="i0"><i>Meyenia plumosa</i>, Potts, P. Ac. Philad. 1887, p.
+233.</span>
+
+<span class="i0"><i>Ephydatia plumosa</i>, Weltner, Arch. Naturg. lxi
+(i), p.&nbsp;126 (1895).</span>
+
+<span class="i0"><i>Ephydatia plumosa</i>, Petr, Rozp. Ceske Ak. Praze,
+Tr�da ii, pl. ii, figs. 29, 30 (text in Czech) (1899).</span>
+
+</div>
+
+<p><i>Sponge</i> forming soft irregular masses which are sometimes as
+much as 14 cm. in diameter, of a pale brown or brilliant green colour;
+no branches developed but the surface covered with irregular projections
+usually of a lobe-like nature.</p>
+
+<p><i>Skeleton</i> delicate, with the branches diverging widely,
+exhibiting the characteristic structure of the genus in a marked degree,
+containing a considerable amount of chitin, which renders it resistant
+in spite of its delicacy.</p>
+
+<p><span class='pagenum'><a name="Page_112" id="Page_112">[Pg
+112]</a></span><i>Spicules.</i> Skeleton-spicules smooth, sharply
+pointed, nearly straight, moderately slender, about twenty times as long
+as their greatest transverse diameter. Flesh-spicules occasionally
+amphioxous or birotulate and with a single shaft, more frequently
+consisting of many shafts meeting in a distinct central nodule, which is
+itself smooth; the shafts irregularly spiny, usually more or less
+nodular at the tip, which often bears a distinct circle of recurved
+spines that give it a rotulate appearance. Gemmule-spicules with long,
+slender, straight shafts, which bear short, slender, straight,
+horizontal spines sparsely and irregularly scattered over their surface;
+the rotul� distinctly convex when seen in profile; their edge
+irregularly and by no means deeply notched; the shafts not extending
+beyond their surface but clearly seen from above as circular
+umbones.</p>
+
+<div class="figcenter">
+<img src="images/fig_022.jpg" width="400" height="275"
+alt="Illustration: Fig. 22.&mdash;Dosilia plumosa." title="Fig.
+22.&mdash;Dosilia plumosa." />
+<p class="caption">Fig. 22.&mdash;<i>Dosilia plumosa.</i></p>
+</div>
+
+<p class="captionj">A=microscleres, � 240; B=gemmule as seen in optical
+section from below, � 75. (From Rambha.)</p>
+
+<p><i>Gemmules.</i> Somewhat depressed, covered with a thick granular
+pneumatic coat, in which the spicules stand erect; the single aperture
+depressed. Each gemmule surrounded more or less distinctly by a circle
+or several circles of flesh-spicules.</p>
+
+<p><span class="smcap">Type</span> in the British Museum; some fragments
+in the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;Bombay
+and Madras. Carter's specimens were taken in the island of Bombay, mine
+at Rambha in the north-east of the Madras Presidency. I have been unable
+to discover this species in the neighbourhood of Calcutta, but it is
+apparently rare wherever it occurs.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;Carter writes as regards
+this species:&mdash;"This is the coarsest and most resistant of all the
+species. As yet I have only found three or four specimens of it, and
+these only in two tanks.<span class='pagenum'><a name="Page_113"
+id="Page_113">[Pg 113]</a></span> I have never seen it fixed on any
+solid body, but always floating on the surface of the water, about a
+month after the first heavy rains of the S.W. monsoon have fallen.
+Having made its appearance in that position, and having remained there
+for upwards of a month, it then sinks to the bottom. That it grows like
+the rest, adherent to the sides of the tank, must be inferred from the
+first specimen which I found (which exceeds two feet in circumference)
+having had a free and a fixed surface, the latter coloured by the red
+gravel on which it had grown. I have noticed it growing, for two
+successive years in the month of July, on the surface of the water of
+one of the two tanks in which I have found it, and would account for its
+temporary appearance in that position, in the following way, viz., that
+soon after the first rains have fallen, and the tanks have become
+filled, all the sponges in them appear to undergo a partial state of
+putrescency, during which gas is generated in them, and accumulates in
+globules in their structure, through which it must burst, or tear them
+from their attachments and force them to the surface of the water. Since
+then the coarse structure of <i>plumosa</i> would appear to offer
+greater resistance to the escape of this air, than that of any of the
+other species, it is probable that this is the reason of my having
+hitherto only found it in the position mentioned."</p>
+
+<p>It seems to me more probable that the sponges are actually broken
+away from their supports by the violence of the rain and retain air
+mechanically in their cavities. The only specimens of <i>D. plumosa</i>
+that I have seen alive were attached very loosely to their support. In
+writing of the "coarse structure" of this species, Carter evidently
+alludes to the wide interspaces between the component branches of the
+skeleton.</p>
+
+<p>My specimens were attached to the stem of a water-lily growing in a
+pool of slightly brackish water and were of a brilliant green colour. I
+mistook them at first for specimens of <i>S. lacustris</i> subsp.
+<i>reticulata</i> in which the branches had not developed normally. They
+were taken in March and were full of gemmules. The pool in which they
+were growing had already begun to dry up.</p>
+
+<p class="p2 center">Genus 5. <b>TROCHOSPONGILLA</b>,
+<i>Vejdovsky</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Trochospongilla</i>, Vejdovsky, Abh. K. B�hm. Ges.
+Wiss. xii, p.&nbsp;31 (1883).</span>
+
+<span class="i0"><i>Trochospongilla</i>, Wierzejski, Arch. Slaves de
+Biologie, i, p.&nbsp;44 (1886).</span>
+
+<span class="i0"><i>Trochospongilla</i>, Vejdovsky, P. Ac. Philad. 1887,
+p.&nbsp;176.</span>
+
+<span class="i0"><i>Meyenia</i>, Potts (<i>partim</i>), <i>ibid.</i> p.
+210.</span>
+
+<span class="i0"><i>Tubella</i>, <i>id.</i> (<i>partim</i>),
+<i>ibid.</i>, p.&nbsp;248.</span>
+
+<span class="i0"><i>Meyenia</i>, Carter (<i>partim</i>), Ann. Nat. Hist.
+(5) vii, p.&nbsp;90 (1881).</span>
+
+<span class="i0"><i>Trochospongilla</i>, Weltner, in Zacharias's Tier-
+und Pflanzenwelt, i, p.&nbsp;215 (1891).</span>
+
+<span class="i0"><i>Trochospongilla</i>, <i>id.</i>, Arch. Naturg. lxi
+(i), p.&nbsp;120 (1895).</span>
+
+<span class="i0"><i>Tubella</i>, <i>id.</i> (<i>partim</i>),
+<i>ibid.</i> p.&nbsp;128.</span>
+
+</div>
+
+<p><span class="smcap">Type</span>, <i>Spongilla erinaceus</i>,
+Ehrenberg.</p>
+
+<p><span class='pagenum'><a name="Page_114" id="Page_114">[Pg
+114]</a></span>The characteristic feature of this genus is that the
+rotul� of the gemmule-spicules, which are homogeneous, have smooth
+instead of serrated edges. Their stem is always short and they are
+usually embedded in a granular pneumatic coat. The sponge is small in
+most of the species as yet known; in some species microscleres without
+rotul� are associated with the gemmules.</p>
+
+<div class="figcenter">
+<img src="images/fig_023.jpg"
+width="500" height="177"  alt="Illustration: Fig.
+23.&mdash;A=skeleton-spicule of Trochospongilla latouchiana;
+A'=gemmule-spicule of the same species; B=gemmule of T. phillottiana as
+seen in optical section from above; B'=skeleton-spicule of same species:
+A, A', B' � 240; B � 75. All specimens from Calcutta." title="Fig.
+23.&mdash;A=skeleton-spicule of Trochospongilla latouchiana;
+A'=gemmule-spicule of the same species; B=gemmule of T. phillottiana as
+seen in optical section from above; B'=skeleton-spicule of same species:
+A, A', B' � 240; B � 75. All specimens from Calcutta." />
+<p class="caption">Fig. 23.&mdash;A=skeleton-spicule of
+<i>Trochospongilla latouchiana</i>; A'=gemmule-spicule of the same
+species; B=gemmule of <i>T. phillottiana</i> as seen in optical section
+from above; B'=skeleton-spicule of same species: A, A', B' � 240; B �
+75. All specimens from Calcutta.</p>
+</div>
+
+<p>I think it best to include in this genus, as the original diagnosis
+would suggest, all those species in which all the gemmule-spicules are
+definitely birotulate and have smooth edges to their disks, confining
+the name <i>Tubella</i> to those in which the upper rotula is reduced to
+a mere knob. Even in those species in which the two disks are normally
+equal, individual spicules may be found in which the equality is only
+approximate, while, on the other hand, it is by no means uncommon for
+individual spicules in such species as <i>"Tubella" pennsylvanica</i>,
+which is here included in <i>Trochospongilla</i>, to have the two disks
+nearly equal, although normally the upper one is much smaller than the
+lower. There is very rarely any difficulty, however, in seeing at a
+glance whether the edge of the disk is smooth or serrated, the only
+species in which this difficulty would arise being, so far as I am
+aware, the Australian <i>Ephydatia capewelli</i>* (Haswell), the disks
+of which are undulated and nodulose rather than serrated.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The genus
+includes so large a proportion of small, inconspicuous species that its
+distribution is probably known but imperfectly. It would seem to have
+its headquarters in N. America but also occurs in Europe and Asia. In
+India three species have been found, one of which (<i>T.
+pennsylvanica</i>) has an extraordinarily wide and apparently
+discontinuous range, being common in N. America, and having been found
+in the west of Ireland, the Inner Hebrides, and near the west coast of
+S. India. The other two Indian species are apparently of not uncommon
+occurrence in eastern India and Burma.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_115"
+id="Page_115">[Pg 115]</a></span><i>Key to the Indian Species of</i>
+Trochospongilla.</p>
+
+<table summary="Key to Indian Species of Trochospongilla">
+
+<tr><td class="left_a">I.</td><td class="left_a">Rotules of the
+gemmule-spicules equal or nearly so.</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Skeleton-spicules
+smooth, usually pointed</td><td class="right"><i>latouchiana</i>,
+p.&nbsp;<a href="#Page_115">115</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Skeleton-spicules
+spiny, blunt</td><td class="right"><i>phillottiana</i>, p.&nbsp;<a
+href="#Page_117">117</a>.</td></tr>
+
+<tr><td class="left_a">II.</td><td class="left_a">Upper rotule of the
+gemmule-spicules distinctly smaller than the lower.</td></tr>
+
+<tr><td></td><td class="left_a">Skeleton-spicules spiny, pointed</td><td
+class="right"><i>pennsylvanica</i>, p.&nbsp;<a
+href="#Page_118">118</a>.</td></tr>
+
+</table>
+
+<p class="p2">18. <b>Trochospongilla latouchiana</b>*,
+<i>Annandale</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Trochospongilla latouchiana</i>, Annandale, J.
+Asiat. Soc. Bengal, 1907, p.&nbsp;21, fig. 5.</span>
+
+<span class="i0"><i>Trochospongilla latouchiana</i>, <i>id.</i>, Rec.
+Ind. Mus. ii, p.&nbsp;157 (1908).</span>
+
+<span class="i0"><i>Trochospongilla leidyi</i>, <i>id.</i> (<i>nec</i>
+Bowerbank), <i>ibid.</i> iii, p.&nbsp;103 (1909).</span>
+
+</div>
+
+<div class="figcenter">
+<img src="images/fig_024.jpg"
+width="317" height="400"  alt="Illustration: Fig.
+24.&mdash;Trochospongilla latouchiana." title="Fig.
+24.&mdash;Trochospongilla latouchiana." />
+<p class="caption">Fig. 24.&mdash;<i>Trochospongilla
+latouchiana.</i></p>
+</div>
+
+<p class="captionj">Vertical section of part of skeleton with gemmules
+<i>in situ</i>, � 30; also a single gemmule, � 70. (From Calcutta).</p>
+
+<p><i>Sponge</i> forming cushion-shaped masses rarely more than a few
+centimetres in diameter or thickness and of a brown or yellow colour,
+hard but rather brittle; surface evenly rounded, minutely hispid; oscula
+inconspicuous, small, circular, depressed, very few in number; external
+membrane adhering closely to the parenchyma;<span class='pagenum'><a
+name="Page_116" id="Page_116">[Pg 116]</a></span> a chitinous membrane
+at the base of the sponge. Larger sponges divided into several layers by
+similar membranes.</p>
+
+<p><i>Skeleton</i> dense, forming a close reticulation; radiating fibres
+slender but quite distinct, running up right through the sponge, crossed
+at frequent intervals by single spicules or groups of spicules.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, about twenty times as long
+as the greatest transverse diameter, as a rule sharply pointed; smooth
+amphistrongyli, which are often inflated in the middle, sometimes mixed
+with them but never in large numbers. No flesh-spicules.
+Gemmule-spicules with the rotul� circular or slightly asymmetrical, flat
+or nearly flat, marked with a distinct double circle as seen from above,
+sometimes not quite equal; the shaft not projecting beyond them; the
+diameter of the rotule 4-1/2 to 5 times that of the shaft, which is
+about 2-2/3 times as long as broad.</p>
+
+<p><i>Gemmules</i> small (0.2 � 0.18 mm.), as a rule very numerous and
+scattered throughout the sponge, flask-shaped, clothed when mature with
+a thin microcell coat in which the birotulates are arranged with
+overlapping rotul�, their outer rotul� level with the surface; foraminal
+aperture circular, situated on an eminence.</p>
+
+<p class="p2 center"><i>Average Measurements.</i></p>
+
+<table summary="average measurements 18">
+
+<tr><td class="left">Diameter of gemmule</td><td class="right">0.2 �
+0.18&nbsp;&nbsp;mm.</td></tr>
+
+<tr><td class="left">Length of skeleton-spicule</td><td
+class="right">0.28&nbsp;&nbsp;mm.</td></tr>
+
+<tr><td class="left">Length of birotulate-spicule</td><td
+class="right">0.175 mm.</td></tr>
+
+<tr><td class="left">Diameter of rotula</td><td
+class="right">0.02&nbsp;&nbsp;mm.</td></tr>
+
+</table>
+
+<p><i>T. latouchiana</i> is closely related to <i>T. leidyi</i>
+(Bowerbank) from N. America, but is distinguished by its much more
+slender skeleton-spicules, by the fact that the gemmules are not
+enclosed in cages of megascleres or confined to the base of the sponge,
+and by differences in the structure of the skeleton.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;Lower
+Bengal and Lower Burma. <i>Localities</i>:&mdash;<span
+class="smcap">Bengal</span>, Calcutta and neighbourhood
+(<i>Annandale</i>): <span class="smcap">Burma</span>, Kawkareik, Amherst
+district, Tenasserim (<i>Annandale</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;This species, which is
+common in the Museum tank, Calcutta, is apparently one of those that can
+grow at any time of year, provided that it is well covered with water.
+Like <i>T. leidyi</i> it is capable of producing fresh layers of living
+sponge on the top of old ones, from which they are separated by a
+chitinous membrane. These layers are not, however, necessarily produced
+in different seasons, for it is often clear from the nature of the
+object to which the sponge is attached that they must all have been
+produced in a short space of time. What appears to happen in most cases
+is this:&mdash;A young sponge grows on a brick, the stem of a reed or
+some other object at or near the edge<span class='pagenum'><a
+name="Page_117" id="Page_117">[Pg 117]</a></span> of a pond, the water
+in which commences to dry up. As the sponge becomes desiccated its cells
+perish. Its gemmules are, however, retained in the close-meshed
+skeleton, which persists without change of form. A heavy shower of rain
+then falls, and the water rises again over the dried sponge. The
+gemmules germinate immediately and their contents spread out over the
+old skeleton, secrete a chitinous membrane and begin to build up a new
+sponge. The process may be repeated several times at the change of the
+seasons or even during the hot weather, or after a "break in the rains."
+If, however, the dried sponge remains exposed to wind and rain for more
+than a few months, it begins to disintegrate and its gemmules are
+carried away to other places. Owing to their thin pneumatic coat and
+relatively heavy spicules they are not very buoyant. Even in the most
+favourable circumstances the sponge of <i>T. latouchiana</i> never forms
+sheets of great area. In spite of its rapid growth it is frequently
+overgrown by <i>Spongilla carteri</i>.</p>
+
+<p class="p2">19. <b>Trochospongilla phillottiana</b>*,
+<i>Annandale</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Trochospongilla phillottiana</i>, Annandale, J.
+Asiat. Soc. Bengal, 1907, p.&nbsp;22, fig. 6.</span>
+
+<span class="i0"><i>Trochospongilla phillottiana</i>, <i>id.</i>, Rec.
+Ind. Mus. i, p.&nbsp;269 (1907).</span>
+
+<span class="i0"><i>Trochospongilla phillottiana</i>, <i>id.</i>,
+<i>ibid.</i> ii, p.&nbsp;157 (1908).</span>
+
+</div>
+
+<p><i>Sponge</i> hard but friable, forming sheets or patches often of
+great extent but never more than about 5 mm. thick; the surface minutely
+hispid, flat; colour pale yellow, the golden-yellow gemmules shining
+through the sponge in a very conspicuous manner; oscula inconspicuous;
+external membrane adherent; no basal chitinous membrane.</p>
+
+<p><i>Skeleton</i> dense but by no means strong; the reticulation close
+but produced mainly by single spicules, which form triangular meshes;
+radiating fibres never very distinct, only persisting for a short
+distance in a vertical direction; each gemmule enclosed in an open,
+irregular cage of skeleton-spicules.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules short, slender, blunt, more or
+less regularly and strongly spiny, straight or feebly curved. No
+flesh-spicules. Gemmule-spicules with the rotul� circular, very wide as
+compared with the shaft, concave on the surface, with the shaft
+projecting as an umbo on the surface; the lower rotula often a little
+<ins title="changed from 'large'">larger</ins> than the upper.</p>
+
+<p><i>Gemmules</i> numerous, situated at the base of the sponge in
+irregular, one-layered patches, small (0.32 � 0.264 mm.), of a brilliant
+golden colour, distinctly wider than high, with a single aperture
+situated on an eminence on the apex, each clothed (when mature) with a
+pneumatic coat that contains relatively large but irregular air-spaces
+among which the spicules stand with the rotul� overlapping alternately,
+a funnel-shaped pit in the coat descending from the surface to the upper
+rotula of each of them; the surface of the gemmule covered with
+irregular projections.</p>
+
+<p><span class='pagenum'><a name="Page_118" id="Page_118">[Pg
+118]</a></span></p>
+
+<table summary ="measurements 19">
+
+<tr><td class="left">Diameter of gemmule</td><td class="right">0.32 �
+0.264 mm.</td></tr>
+
+<tr><td class="left">Length of skeleton-spicule</td><td
+class="right">0.177 mm.</td></tr>
+
+<tr><td class="left">Length of gemmule-spicule</td><td
+class="right">0.015 mm.</td></tr>
+
+<tr><td class="left">Diameter of rotule</td><td class="right">0.022
+mm.</td></tr>
+
+</table>
+
+<p>This species appears to be related to <i>T. pennsylvanica</i>, from
+which it differs mainly in the form of its gemmule-spicules and the
+structure of its gemmule. My original description was based on specimens
+in which the gemmule-spicules were not quite mature.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;Lower
+Bengal and Lower Burma. <i>Localities</i>:&mdash;<span
+class="smcap">Bengal</span>, Calcutta (<i>Annandale</i>): <span
+class="smcap">Burma</span>, jungle pool near Kawkareik, Amherst
+district, Tenasserim (<i>Annandale</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;This species covers a brick
+wall at the edge of the Museum tank in Calcutta every year during the
+"rains." In the cold weather the wall is left dry, but it is usually
+submerged to a depth of several feet before the middle of July. It is
+then rapidly covered by a thin layer of the sponge, which dies down as
+soon as the water begins to sink when the "rains" are over. For some
+months the gemmules adhere to the wall on account of the cage of
+spicules in which each of them is enclosed, but long before the water
+rises again the cages disintegrate and the gemmules are set free. Many
+of them fall or are carried by the wind into the water, on the surface
+of which, owing to their thick pneumatic coat, they float buoyantly.
+Others are lodged in cavities in the wall. On the water the force of
+gravity attracts them to one another and to the edge of the pond, and as
+the water rises they are carried against the wall and germinate. In
+thick jungle at the base of the Dawna Hills near Kawkareik<a
+name="fnanchor_AI" id="fnanchor_AI"></a><a href="#footnote_AI"
+class="fnanchor"><sup>[AI]</sup></a> in the interior of Tenasserim, I
+found the leaves of shrubs which grew round a small pool, covered with
+little dry patches of the sponge, which had evidently grown upon them
+when the bushes were submerged. This was in March, during an unusually
+severe drought.</p>
+
+<p class="p2">20. <b>Trochospongilla pennsylvanica</b>*
+(<i>Potts</i>).</p>
+
+<div class="genus">
+
+<span><i>Tubella pennsylvanica</i>, Potts, P. Ac. Philad. 1882, p.
+14.</span>
+
+<span class="i0"><i>Tubella pennsylvanica</i>, <i>id.</i>, <i>ibid.</i>
+1887, p.&nbsp;251, pl. vi, fig. 2, pl. xii, figs. 1-3.</span>
+
+<span class="i0"><i>Tubella pennsylvanica</i>, Mackay, Trans. Roy. Soc.
+Canada, 1889, Sec. iv, p.&nbsp;95.</span>
+
+<span class="i0"><i>Tubella pennsylvanica</i>, Hanitsch, Nature, li, p.
+511 (1895).</span>
+
+<span class="i0"><i>Tubella pennsylvanica</i>, Weltner, Arch. Naturg.
+lxi (i), p.&nbsp;128 (1895).</span>
+
+<span class="i0"><i>Tubella pennsylvanica</i>, Hanitsch, Irish Natural.
+iv, p.&nbsp;129 (1895).</span>
+
+<span class="i0"><i>Tubella pennsylvanica</i>, Annandale, J. Linn. Soc.,
+Zool., xxx, p.&nbsp;248 (1908).</span>
+
+<span class="i0"><i>Tubella pennsylvanica</i>, <i>id.</i>, Rec. Ind.
+Mus. iii, p.&nbsp;102 (1909).</span>
+
+<span class="i0"><i>Tubella</i> <ins title="changed from
+'pennsylvania'"><i>pennsylvanica</i></ins>, <i>id.</i>, P. U.S. Mus.
+xxxvii, p.&nbsp;403, fig. 2 (1909).</span>
+
+</div>
+
+<p><span class='pagenum'><a name="Page_119" id="Page_119">[Pg
+119]</a></span><i>Sponge</i> soft, fragile, forming small cushion-shaped
+masses, grey or green; oscula few in number, often raised on sloping
+eminences surrounded by radiating furrows below the external membrane;
+external membrane adhering to the parenchyma.</p>
+
+<p><i>Skeleton</i> close, almost structureless. "Surface of mature
+specimens often found covered with parallel skeleton spicules, not yet
+arranged to form cell-like interspaces" (<i>Potts</i>).</p>
+
+<p><i>Spicules.</i> Skeleton-spicules slender, cylindrical, almost
+straight, sharp or blunt, minutely, uniformly or almost uniformly
+spined; spines sometimes absent at the tips. No flesh-spicules.
+Gemmule-spicules with the lower rotula invariably larger than the upper;
+both rotul� flat or somewhat sinuous in profile, usually circular but
+sometimes asymmetrical or subquadrate in outline, varying considerably
+in size.</p>
+
+<p><i>Gemmules</i> small, numerous or altogether absent, covered with a
+granular pneumatic coat of variable thickness; the rotul� of the
+gemmule-spicules overlapping and sometimes projecting out of the
+granular coat.</p>
+
+<p>The measurements of the spicules and gemmules of an Indian specimen
+and of one from Lehigh Gap, Pennsylvania, are given for
+comparison:&mdash;</p>
+
+<table summary="measurements 20">
+
+<tr><td></td><th>Travancore.</th><th>Pennsylvania.</th></tr>
+
+<tr><td class="left">Length of skeleton-spicules</td><td
+class="left">0.189-0.242 mm.</td><td class="left">0.16-0.21
+mm.</td></tr>
+
+<tr><td></td><td class="left">(average 0.205 mm.)</td><td
+class="left">(average 0.195 mm.)</td></tr>
+
+<tr><td class="left">Breadth of skeleton-spicules</td><td
+class="left">0.0084-0.0155 mm.</td><td class="left">0.0084 mm.</td></tr>
+
+<tr><td class="left">Length of birotulate</td><td class="left">0.0126
+mm</td><td class="left">0.0099 mm.</td></tr>
+
+<tr><td class="left">Diameter of upper rotula</td><td
+class="left">0.0084 mm.</td><td class="left">0.0084 mm.</td></tr>
+
+<tr><td class="left">Diameter of lower rotula</td><td
+class="left">0.0169 mm.</td><td class="left">0.0168 mm.</td></tr>
+
+<tr><td class="left">Diameter of gemmule</td><td
+class="left">0.243-0.348 mm.</td><td class="left">0.174-0.435
+mm.</td></tr>
+
+</table>
+
+<p>The spicules of the Travancore specimen are, therefore, a trifle
+larger than those of the American one, but the proportions are closely
+similar.</p>
+
+<p>The difference between the gemmule-spicules of this species and those
+of such a form as <i>T. phillottiana</i> is merely one of degree and can
+hardly be regarded as a sufficient justification for placing the two
+species in different genera. If, as I have proposed, we confine the
+generic name <i>Tubella</i> to those species in which the
+gemmule-spicules are really like "little trumpets," the arrangement is a
+much more natural one, for these species have much in common apart from
+the gemmule-spicules. <i>T. pennsylvanica</i> does not appear to be very
+closely related to any other known species except <i>T.
+phillottiana</i>.</p>
+
+<p><span class="smcap">Type</span> in the U.S. National Museum, from
+which specimens that appear to be co-types have been sent to the Indian
+Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;Very wide
+and apparently discontinuous:&mdash;N. America (widely distributed),
+Ireland (<i>Hanitsch</i>), Hebrides of Scotland (<i>Annandale</i>),
+Travancore, S. India (<i>Annandale</i>). The only Indian locality whence
+I have obtained specimens is Shasthancottah Lake near Quilon in
+Travancore.</p>
+
+<p><span class='pagenum'><a name="Page_120" id="Page_120">[Pg
+120]</a></span><span class="smcap">Biology.</span>&mdash;In
+Shasthancottah Lake <i>T. pennsylvanica</i> is found on the roots of
+water-plants that are matted together to form floating islands. It
+appears to avoid light and can only be obtained from roots that have
+been pulled out from under the islands. In Scotland I found it on the
+lower surface of stones near the edge of Loch Baa, Isle of Mull. In such
+circumstances the sponge is of a greyish colour, but specimens of the
+<ins title="changed from 'variely'">variety</ins> <i>minima</i> taken by
+Potts on rocks and boulders in Bear Lake, Pennsylvania, were of a bright
+green.</p>
+
+<p>Sponges taken in Travancore in November were full of gemmules; in my
+Scottish specimens (taken in October) I can find no traces of these
+bodies, but embryos are numerous.</p>
+
+<p class="p2 center">Genus 6. <b>TUBELLA</b>, <i>Carter</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Tubella</i>, Carter, Ann. Nat. Hist. (5) vii,
+p.&nbsp;96 (1881).</span>
+
+<span class="i0"><i>Tubella</i>, Potts (<i>partim</i>), P. Ac. Philad.
+1887, p.&nbsp;248.</span>
+
+<span class="i0"><i>Tubella</i>, Weltner (<i>partim</i>), Arch. Naturg.
+lxi (i), p.&nbsp;128 (1895).</span>
+
+</div>
+
+<p><span class="smcap">Type</span>, <i>Spongilla paulula</i>,
+Bowerbank.</p>
+
+<p>This genus is distinguished from <i>Ephydatia</i> and
+<i>Trochospongilla</i> by the fact that the two ends of the
+gemmule-spicules are unlike not only in size but also in form. It
+sometimes happens that this unlikeness is not so marked in some spicules
+as in others, but in some if not in all the upper end of the shaft (that
+is to say the end furthest removed from the inner coat of the gemmule in
+the natural position) is reduced to a rounded knob, while the lower end
+expands into a flat transverse disk with a smooth or denticulated edge.
+The spicule thus resembles a little trumpet resting on its mouth. The
+shaft of the spicule is generally slender and of considerable length.
+The skeleton of the sponge is as a rule distinctly reticulate and often
+hard; the skeleton-spicules are either slender or stout and sometimes
+change considerably in proportions and outline as they approach the
+gemmules.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The genus
+is widely distributed in the tropics of both Hemispheres, its
+headquarters apparently being in S. America; but it is nowhere rich in
+species. Only two are known from the Oriental Region, namely <i>T.
+vesparium</i>* from Borneo, and <i>T. vesparioides</i>* from Burma.</p>
+
+<p class="p2">21. <b>Tubella vesparioides</b>*, <i>Annandale</i>. (<a
+href="#Plate_II">Plate II</a>, fig. 4.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Tubella vesparioides</i>, Annandale, Rec. Ind. Mus.
+ii, p.&nbsp;157 (1908).</span>
+
+</div>
+
+<p><i>Sponge</i> forming rather thick sheets of considerable size, hard
+but brittle, almost black in colour; oscula inconspicuous; external
+membrane supported on a reticulate horizontal skeleton.</p>
+
+<p><i>Skeleton.</i> The surface covered with a network of stout
+spicule-fibres, the interstices of which are more or less deeply sunk,
+with sharp fibres projecting vertically upwards at the nodes; the whole
+mass pervaded by a similar network, which is composed of a considerable
+number of spicules lying parallel to one another,<span
+class='pagenum'><a name="Page_121" id="Page_121">[Pg 121]</a></span>
+overlapping at the ends and bound together by a profuse secretion of
+spongin.</p>
+
+<div class="figcenter">
+<img src="images/fig_025.jpg" width="195" height="375"
+alt="Illustration: Fig. 25.&mdash;Spicules of Tubella vesparioides (from
+type specimen). � 240." title="Fig. 25.&mdash;Spicules of Tubella
+vesparioides (from type specimen). � 240." />
+<p class="caption">Fig. 25.&mdash;Spicules of <i>Tubella
+vesparioides</i> (from type specimen). � 240.</p>
+</div>
+
+<p><i>Spicules.</i> Skeleton-spicules slender, smooth, amphioxous, bent
+in a wide arc or, not infrequently, at an angle. No true flesh-spicules.
+Gemmule-spicules terminating above in a rounded, knob-like structure and
+below in a relatively broad, flat rotula, which is very deeply and
+irregularly indented round the edge when mature, the spicules at an
+earlier stage of development having the form of a sharp pin with a round
+head; shaft of adult spicules projecting slightly below the rotula,
+long, slender, generally armed with a few stout conical spines, which
+stand out at right angles to it.</p>
+
+<p><i>Gemmules</i> numerous throughout the sponge, spherical, provided
+with a short, straight foraminal tubule, surrounded by one row of
+spicules, which are embedded in a rather thin granular coat.</p>
+
+<table summary="measurements 21">
+
+<tr><td class="left">Average length of skeleton-spicule</td><td
+class="left">0.316&nbsp;&nbsp;&nbsp;mm.</td></tr>
+
+<tr><td class="left">Average breadth of skeleton-spicule</td><td
+class="left">0.0135 mm.</td></tr>
+
+<tr><td class="left">Average length of gemmule-spicule</td><td
+class="left">0.046&nbsp;&nbsp;&nbsp;mm.</td></tr>
+
+<tr><td class="left">Average diameter of rotula</td><td
+class="left">0.0162 mm.</td></tr>
+
+<tr><td class="left">Average diameter of gemmule</td><td
+class="left">0.446&nbsp;&nbsp;&nbsp;mm.</td></tr>
+
+</table>
+
+<p>This sponge is closely related to <i>Tubella vesparium</i> (v.
+Martens) from Borneo, from which it may be distinguished by its smooth
+skeleton-spicules and the deeply indented disk of its
+gemmule-spicules.<span class='pagenum'><a name="Page_122"
+id="Page_122">[Pg 122]</a></span> The skeleton-fibres are also rather
+less stout. By the kindness of Dr. Weltner, I have been able to compare
+types of the two species.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p><span class="smcap">Habitat.</span>&mdash;Taken at the edge of the
+Kanghyi ("great pond") at Mudon near Moulmein in the Amherst district of
+Tenasserim. The specimens were obtained in March in a dry state and had
+grown on logs and branches which had evidently been submerged earlier in
+the year. The name <i>vesparium</i> given to the allied species on
+account of its resemblance to a wasps' nest applies with almost equal
+force to this Burmese form.</p>
+
+<p class="p2 center">Genus 7. <b>CORVOSPONGILLA</b>, nov.</p>
+
+<p><span class="smcap">Type</span><a name="fnanchor_AJ"
+id="fnanchor_AJ"></a><a href="#footnote_AJ"
+class="fnanchor"><sup>[AJ]</sup></a>, <i>Spongilla loricata</i>,
+Weltner.</p>
+
+<p>Spongillid� in which the gemmule-spicules are without a trace of
+rotul� and the flesh-spicules have slender cylindrical shafts that bear
+at or near either end a circle of strong recurved spines. The
+gemmule-spicules are usually stout and sausage-shaped, and the gemmules
+resemble those of <i>Stratospongilla</i> in structure. The skeleton is
+strong and the skeleton-spicules stout, both resembling those of the
+"genus" <i>Potamolepis</i>, Marshall.</p>
+
+<p>As in all other genera of Spongillid� the structure of the skeleton
+is somewhat variable, the spicule-fibres of which it is composed being
+much more distinct in some species than in others. The skeleton-spicules
+are often very numerous and in some cases the skeleton is so compact and
+rigid that the sponge may be described as stony. The flesh-spicules
+closely resemble the gemmule-spicules of some species of
+<i>Ephydatia</i> and <i>Heteromeyenia</i>.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The
+species of this genus are probably confined to Africa (whence at least
+four are known) and the Oriental Region. One has been recorded from
+Burma and another from the Bombay Presidency.</p>
+
+<p class="p2 center"><i>Key to the Indian Species of</i> Corvospongilla.</p>
+
+<table summary="Key to Indian Species of Corvospongilla">
+
+<tr><td class="left_a">I.</td><td class="left_a">Gemmule with two layers
+of gemmule-spicules; those of the inner layer not markedly smaller than
+those of the outer.</td><td class="right_a"><i>burmanica</i>, p.&nbsp;<a
+href="#Page_123">123</a>.</td></tr>
+
+<tr><td class="left_a">II.</td><td class="left_a">Gemmule with two
+layers of gemmule-spicules, the outer of which contains spicules of much
+greater size than the inner.</td><td class="right_a"><i>lapidosa</i>,
+p.&nbsp;<a href="#Page_124">124</a>.</td></tr>
+
+</table>
+
+<p class="p2"><span class='pagenum'><a name="Page_123" id="Page_123">[Pg
+123]</a></span>22. <b>Corvospongilla burmanica</b>*
+(<i>Kirkpatrick</i>). (<a href="#Plate_II">Plate II</a>, fig. 5.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla loricata</i> var. <i>burmanica</i>,
+Kirkpatrick, Rec. Ind. Mus. ii, p.&nbsp;97, pl. ix (1908).</span>
+
+</div>
+
+<p><i>Sponge</i> forming a shallow sheet, hard, not very strong, of a
+pale brownish colour; the surface irregularly spiny; the oscula small
+but conspicuous, circular, raised on little turret-like eminences; the
+external membrane adhering closely to the sponge.</p>
+
+<p><i>Skeleton</i> dense but by no means regular; the network composed
+largely of single spines; thick radiating fibres distinguishable in the
+upper part of the sponge.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules smooth, not very stout,
+amphistrongylous, occasionally a little swollen at the ends, often with
+one or more fusiform swellings, measuring on an average about 0.27 �
+0.0195 mm. Flesh-spicules with distinct rotules, the recurved spines
+numbering 4 to 6, measuring about 1/7 the length of the spicules; the
+shaft by no means strongly curved; their length from 0.03-0.045 mm.
+Gemmule-spicules amphioxous, as a rule distinctly curved, sometimes
+swollen at the ends, covered regularly but somewhat sparsely with fine
+spines, not measuring more than 0.49 � 0.078 mm.</p>
+
+<p><i>Gemmules</i> strongly adherent, arranged in small groups, either
+single or double; when single spherical, when double oval; each gemmule
+or pair of gemmules covered by two layers of gemmule-spicules bound
+together in chitinous substance; the inner layer on the inner coat of
+the gemmule, the outer one separated from it by a space and in contact
+with the outer cage of skeleton-spicules; the size of the
+gemmule-spicules variable in both layers; external to the outer layer a
+dense cage of skeleton-spicules; foraminal tubule short,
+cylindrical.</p>
+
+<p>This sponge is closely related to <i>S. loricata</i>, Weltner, of
+which Kirkpatrick regards it as a variety. "The main difference," he
+writes, "between the typical African form and the Burmese variety
+consists in the former having much larger microstrongyles (83 � 15.7 �
+[0.83 � 0.157 mm.]) with larger and coarser spines;... Judging from
+Prof. Weltner's sections of gemmules, these bodies lack the definite
+outer shell of smooth macrostrongyles [blunt skeleton-spicules], though
+this may not improbably be due to the breaking down and removal of this
+layer. A further difference consists in the presence, in the African
+specimen, of slender, finely spined strongyles [amphistrongyli], these
+being absent in the Burmese form, though perhaps this fact is not of
+much importance."</p>
+
+<p><span class="smcap">Type</span> in the British Museum; a piece in the
+Indian Museum.</p>
+
+<p><span class="smcap">Habitat.</span>&mdash;Myitkyo, head of the
+Pegu-Sittang canal, Lower Burma (<i>E. W. Oates</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;The sponge had grown over a
+sheet of the polyzoon <i>Hislopia lacustris</i>, Carter (see p.&nbsp;204),
+remains of which can be detected on its lower surface.</p>
+
+<p><span class='pagenum'><a name="Page_124" id="Page_124">[Pg
+124]</a></span>"Mr. E. W. Oates, who collected and presented the sponge,
+writes that the specimen was found encrusting the vertical and
+horizontal surfaces of the bottom beam of a lock gate, where it covered
+an area of six square feet. The beam had been tarred several times
+before the sponge was discovered. The portion of the gate on which the
+sponge was growing was submerged from November to May for eight hours a
+day at spring tides, but was entirely dry during the six days of neap
+tides. From May to October it was constantly submerged. The sponge was
+found in April. Although the canal is subject to the tides, the water at
+the lock is always fresh. The colour of the sponge during life was the
+same as in its present condition."</p>
+
+<p class="p2">23. <b>Corvospongilla lapidosa</b>*
+(<i>Annandale</i>).</p>
+
+<div class="genus">
+
+<span class="i0"><i>Spongilla lapidosa</i> Annandale, Rec. Ind. Mus. ii,
+pp.&nbsp;25, 26, figs. 3, 4, 5 (1908).</span>
+
+</div>
+
+<p>The <i>sponge</i> forms a thin but extremely hard and resistant crust
+the surface of which is either level, slightly concave, or distinctly
+corrugated; occasional groups of spicules project from it, but their
+arrangement is neither so regular nor so close as is the case in <i>C.
+burmanica</i>. The dermal membrane adheres closely to the sponge. The
+oscula are small; some of them are raised above the general surface but
+not on regular turret-shaped eminences. The colour is grey or black.
+There is a thick chitinous membrane at the base of the sponge.</p>
+
+<div class="figcenter">
+<img src="images/fig_026.png" width="500" height="193"
+alt="Illustration: Fig. 26.&mdash;Spicules of Corvospongilla lapidosa
+(from type specimen), � 240." title="Fig. 26.&mdash;Spicules of
+Corvospongilla lapidosa (from type specimen), � 240." />
+<p class="caption">Fig. 26.&mdash;Spicules of <i>Corvospongilla
+lapidosa</i> (from type specimen), � 240.</p>
+</div>
+
+<p>The <i>skeleton</i> is extremely dense owing to the large number of
+spicules it contains, but almost structureless; broad vertical groups of
+spicules occur but lack spongin and only traverse a small part of the
+thickness of the sponge; their position is irregular. The firmness of
+the skeleton is due almost entirely to the interlocking of individual
+spicules. At the base of the sponge the direction of a large proportion
+of the spicules is horizontal or nearly horizontal, the number arranged
+vertically being much greater in the upper part.</p>
+
+<p><span class='pagenum'><a name="Page_125" id="Page_125">[Pg
+125]</a></span><i>Spicules.</i> The skeleton-spicules are sausage-shaped
+and often a little swollen at the ends or constricted in the middle. A
+large proportion are twisted or bent in various ways, and a few bear
+irregular projections or swellings. The majority, however, are quite
+smooth. Among them a few more or less slender, smooth amphioxi occur,
+but these are probably immature spicules. The length and curvature of
+the amphistrongyli varies considerably, but the average <ins
+title="changed from 'measurments'">measurements</ins> are about 0.28 �
+0.024 mm. The flesh-spicules also vary greatly in length and in the
+degree to which their shafts are curved. At first sight it seems to be
+possible to separate them into two categories, one in which the shaft is
+about 0.159 mm. long, and another in which it is only 0.05 mm. or even
+less; and groups of birotulates of approximately the same length often
+occur in the interstices of the skeleton. Spicules of all intermediate
+lengths can, however, be found. The average diameter of the shaft is
+0.0026 mm. and of the rotula 0.0106 mm., and the rotula consists of from
+6 to 8 spines. The gemmule-spicules vary greatly in size, the longest
+measuring about 0.08 � 0.014 and the smallest about 0.034 � 0.007 or
+even less. There appears to be in their case an even more distinct
+separation as regards size than there is in that of the flesh-spicules;
+but here again intermediate forms occur. They are all stout, more or
+less blunt, and more or less regularly covered with very short spines;
+most of them are distinctly curved, but some are quite straight.</p>
+
+<p><i>Gemmules.</i> The gemmules are firmly adherent to the support of
+the sponge, at the base of which they are congregated in groups of four
+or more. They vary considerably in size and shape, many of them being
+asymmetrical and some elongate and sausage-shaped. The latter consist of
+single gemmules and not of a pair in one case. Extreme forms measure
+0.38 � 0.29 and 0.55 � 0.25. Each gemmule is covered with a thick
+chitinous membrane in close contact with its wall and surrounding it
+completely. This membrane is full of spicules arranged as in a mosaic;
+most or all of them belong to the smaller type, and as a rule they are
+fairly uniform in size. Separated from this layer by a considerable
+interval is another layer of spicules embedded in a chitinous membrane
+which is in continuity with the basal membrane of the sponge. The
+spicules in this membrane mostly belong to the larger type and are very
+variable in size; mingled with them are often a certain number of
+birotulate flesh-spicules. The membrane is in close contact with a dense
+cage of skeleton-spicules arranged parallel to it and bound together by
+chitinous substance. The walls of this cage, when they are in contact
+with those of the cages of other gemmules, are coterminous with them.
+There is a single depressed aperture in the gemmules, as a rule situated
+on one of the longer sides.</p>
+
+<p>This sponge is distinguished from <i>C. burmanica</i> not only by
+differences in external form, in the proportions of the spicules and the
+structure of the skeleton, but also by the peculiar nature of the
+armature of the gemmule. The fact that birotulate spicules<span
+class='pagenum'><a name="Page_126" id="Page_126">[Pg 126]</a></span> are
+often found in close association with them, is particularly
+noteworthy.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;This
+sponge has only been found in the Western Ghats of the Bombay
+Presidency. <i>Localities</i>:&mdash;Igatpuri Lake and the R. Godaveri
+at Nasik.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;There is a remarkable
+difference in external form between the specimens taken in Igatpuri and
+those from Nasik, and this difference is apparently due directly to
+environment. In the lake, the waters of which are free from mud, the
+sponges were growing on the lower surface of stones near the edge. They
+formed small crusts not more than about 5 cm. (2 inches) in diameter and
+of a pale greyish colour. Their surface was flat or undulated gently,
+except round the oscula where it was raised into sharply conical
+eminences with furrowed sides. The specimens from Nasik, which is about
+30 miles from Igatpuri, were attached, together with specimens of
+<i>Spongilla cinerea</i> and <i>S. indica</i>, to the sides of a stone
+conduit full of very muddy running water. They were black in colour,
+formed broad sheets and were markedly corrugated on the surface. Their
+oscula were not raised on conical eminences and were altogether most
+inconspicuous. The skeleton was also harder than that of sponges from
+the lake.</p>
+
+<p>In the lake <i>C. lapidosa</i> was accompanied by the gemmules of
+<i>Spongilla bombayensis</i>, but it is interesting that whereas the
+latter sponge was entirely in a resting condition, the former was in
+full vegetative vigour, a fact which proves, if proof were necessary,
+that the similar conditions of environment do not invariably have the
+same effect on different species of Spongillid�.</p>
+
+<p class="footnote">
+<a name="footnote_W" id="footnote_W"></a>
+<a href="#fnanchor_W">[W]</a>
+O. von Linstow, Rec. Ind. Mus. i, p.&nbsp;45 (1907).</p>
+
+<p class="footnote">
+<a name="footnote_X" id="footnote_X"></a>
+<a href="#fnanchor_X">[X]</a>
+W. M. Tattersall, <i>ibid.</i>, ii, p.&nbsp;236 (1908).</p>
+
+<p class="footnote">
+<a name="footnote_Y" id="footnote_Y"></a>
+<a href="#fnanchor_Y">[Y]</a>
+T. R. R. Stebbing, <i>ibid.</i>, i, p.&nbsp;160 (1907); and N. Annandale,
+<i>ibid.</i>, ii, p.&nbsp;107 (1908).</p>
+
+<p class="footnote">
+<a name="footnote_Z" id="footnote_Z"></a>
+<a href="#fnanchor_Z">[Z]</a>
+Mr. Stebbing has been kind enough to examine specimens of this isopod,
+which he will shortly describe in the Records of the Indian Museum.
+<i>S. walkeri</i>, its nearest ally, was originally described from the
+Gulf of Manaar, where it was taken in a tow-net gathering (see Stebbing
+in Herdman's Report on the Ceylon Pearl Fisheries, pt. iv, p.&nbsp;31
+(1905)).</p>
+
+<p class="footnote">
+<a name="footnote_AA" id="footnote_AA"></a>
+<a href="#fnanchor_AA">[AA]</a>
+See M. and A. Weber in M. Weber's Zool. Ergeb. Niederl. Ost-Ind. vol. i,
+p.&nbsp;48, pl. v (1890).</p>
+
+<p class="footnote">
+<a name="footnote_AB" id="footnote_AB"></a>
+<a href="#fnanchor_AB">[AB]</a>
+Mr. C. A. Paiva, Assistant in the Indian Museum, has lately (March 31st,
+1911) obtained specimens of <i>S. crateriformis</i> in a small pond of
+fresh water on Ross Island in the Andaman group. The existence of this
+widely distributed species on an oceanic island is noteworthy.</p>
+
+<p class="footnote">
+<a name="footnote_AC" id="footnote_AC"></a>
+<a href="#fnanchor_AC">[AC]</a>
+The only complete European specimen of the species I have seen differs
+considerably in outward form from any Indian variety, consisting of a
+flat basal area from which short, cylindrical turret-like branches
+arise. This specimen is from Lake Balaton in Hungary and was sent me by
+Prof. von Daday de Dees of Buda-Pesth.</p>
+
+<p class="footnote">
+<a name="footnote_AD" id="footnote_AD"></a>
+<a href="#fnanchor_AD">[AD]</a>
+Needham. Rec. Ind. Mus. iii, p.&nbsp;206 (1909).</p>
+
+<p class="footnote">
+<a name="footnote_AE" id="footnote_AE"></a>
+<a href="#fnanchor_AE">[AE]</a>
+According to the late Rai Bahadur R. B. Sanyal, freshwater sponges are
+called in Bengali "shrimps' nests." From his description it is evident
+that he refers mainly to <i>S. carteri</i> (see Hours with Nature, p.
+46; Calcutta 1896).</p>
+
+<p class="footnote">
+<a name="footnote_AF" id="footnote_AF"></a>
+<a href="#fnanchor_AF">[AF]</a>
+Stebbing, J. Linn. Soc. xxx, p.&nbsp;40; Annandale, Rec. Ind. Mus. i, p.
+279.</p>
+
+<p class="footnote">
+<a name="footnote_AG" id="footnote_AG"></a>
+<a href="#fnanchor_AG">[AG]</a>
+Brunetti, Rec. Ind. Mus. ii, p.&nbsp;376 (1908).</p>
+
+<p class="footnote">
+<a name="footnote_AH" id="footnote_AH"></a>
+<a href="#fnanchor_AH">[AH]</a>
+The outer covering by means of which the gemmule is fixed is not formed
+until the other structures are complete. In young sponges, therefore,
+free gemmules may often be found.</p>
+
+<p class="footnote">
+<a name="footnote_AI" id="footnote_AI"></a>
+<a href="#fnanchor_AI">[AI]</a>
+This locality is often referred to in zoological literature as
+Kawkare<i>et</i> or Kawkari<i>t</i>, or even K<i>o</i>kari<i>t</i>.</p>
+
+<p class="footnote">
+<a name="footnote_AJ" id="footnote_AJ"></a>
+<a href="#fnanchor_AJ">[AJ]</a>
+Potts's <i>Spongilla nov�-terr�</i> from Newfoundland and N. America
+cannot belong to this genus although it has similar flesh-spicules, for,
+as Weltner has pointed out (<i>op. cit. supra</i> p.&nbsp;126), the
+gemmule-spicules are abortive rotul�. This is shown very clearly in the
+figure published by Petr (Rozp. Ceske Ak. Praze, <ins title="changed
+from 'Tr�da'">Tr�da</ins>, ii, pl. ii, figs. 27, 28, 1899), who assigns
+the species to <i>Heteromeyenia</i>. Weltner places it in
+<i>Ephydatia</i>, and it seems to be a connecting link between the two
+genera. It has been suggested that it is a hybrid (Traxler, Termes.
+Fuzetek, xxi, p.&nbsp;314, 1898).</p>
+
+<p class="p4 center ls">APPENDIX TO PART I.</p>
+
+<p class="center"><span class="smcap">Form of Uncertain
+Position.</span></p>
+
+<p class="center">(<a href="#Plate_I">Plate I</a>, fig. 4.)</p>
+
+<p>On more than one occasion I have found in my aquarium in Calcutta
+small sponges of a peculiar type which I am unable to refer with
+certainty to any of the species described above. Fig. 4, pl. I,
+represents one of these sponges. They are never more than about a
+quarter of an inch in diameter and never possess more than one osculum.
+They are cushion-shaped, colourless and soft. The skeleton-spicules are
+smooth, sharply pointed, moderately slender and relatively large. They
+are arranged in definite vertical groups, which project through the
+dermal membrane, and in irregular transverse formation. Small spherical
+gemmules are present but have only a thin chitinous covering without
+spicules or foramen.</p>
+
+<p>These sponges probably represent an abnormal form of some well-known
+species, possibly of <i>Spongilla carteri</i>. I have seen nothing like
+them in natural conditions.</p>
+
+<p><span class='pagenum'><a name="Page_127" id="Page_127">[Pg
+127]</a></span></p>
+
+<h3 class="p4">PART II.<br />
+
+FRESHWATER POLYPS<br />
+
+(HYDRIDA).</h3>
+
+<p><span class='pagenum'><a name="Page_128" id="Page_128">[Pg
+128]</a></span><br /><span class='pagenum'><a name="Page_129"
+id="Page_129">[Pg 129]</a></span></p>
+
+<h3 class="p4">INTRODUCTION TO PART II.</h3>
+
+<p class="p2 center">I.</p>
+
+<p class="center"><span class="smcap">The Phylum C&oelig;lenterata and
+the Class Hydrozoa.</span></p>
+
+<p>The second of the great groups or phyla into which the metazoa are
+divided is the C&oelig;lenterata, in which are included most of the
+animals commonly known as zoophytes, and also the corals, sea-anemones
+and jelly-fish. These animals are distinguished from the sponges on the
+one hand and from the worms, molluscs, arthropods, vertebrates, etc., on
+the other by possessing a central cavity (the c&oelig;lenteron or
+"hollow inside") the walls of which are the walls of the body and
+consist of <i>two</i> layers of cells separated by a structureless, or
+apparently structureless, jelly. This cavity has as a main function that
+of a digestive cavity.</p>
+
+<p>An ideally simple c&oelig;lenterate would not differ much in general
+appearance from an olynthus (p.&nbsp;27), but it would have no pores in the
+body-wall and its upper orifice would probably be surrounded by
+prolongations of the body-wall in the form of tentacles. There would be
+no collar-cells, and the cells of the body generally would have a much
+more fixed and definite position and more regular functions than those
+of any sponge. The most characteristic of them would be the so-called
+cnidoblasts. Each of these cells contains a capsule<a name="fnanchor_AK"
+id="fnanchor_AK"></a><a href="#footnote_AK"
+class="fnanchor"><sup>[AK]</sup></a> from which a long thread-like body
+can be suddenly uncoiled and shot out.</p>
+
+<p>The simplest in structure of the c&oelig;lenterates are those that
+constitute the class Hydrozoa. In this class the primitive central
+cavity is not divided up by muscular partitions and there is no folding
+in of the anterior part of the body to form an &oelig;sophagus or
+stomatod�um such as is found in the sea-anemones and coral<span
+class='pagenum'><a name="Page_130" id="Page_130">[Pg 130]</a></span>
+polyps. In many species and genera the life-history is complex,
+illustrating what is called the alternation of generations. That is to
+say, only alternate generations attain sexual maturity, those that do so
+being produced as buds from a sexless generation, which itself arises
+from the fertilized eggs of a previous sexual generation. The sexual
+forms as a rule differ considerably in structure from the sexless ones;
+many medus� are the sexual individuals in a life-cycle in which those of
+the sexless generation are sedentary.</p>
+
+<p>An excellent general account of the c&oelig;lenterates will be found
+in the Cambridge Natural History, vol. i (by Prof. Hickson).</p>
+
+<p class="p2 center"><span class="smcap">STRUCTURE OF HYDRA.</span></p>
+
+<p><i>Hydra</i>, the freshwater polyp, is one of the simplest of the
+Hydrozoa both as regards structure and as regards life-history. Indeed,
+it differs little as regards structure from the ideally simple
+c&oelig;lenterate sketched in a former paragraph, while its descent is
+direct from one polyp to another, every generation laying its own eggs<a
+name="fnanchor_AL" id="fnanchor_AL"></a><a href="#footnote_AL"
+class="fnanchor"><sup>[AL]</sup></a>. The animal may be described as
+consisting of the following parts:&mdash;(1) an upright (or potentially
+upright) column or body, (2) a circle of contractile tentacles at the
+upper extremity of the column, (3) an oral disk or peristome surrounding
+the mouth and surrounded by the tentacles, and (4) a basal or aboral
+disk at the opposite extremity. The whole animal is soft and naked. The
+column, when the animal is at rest, is almost cylindrical in some forms
+but in others has the basal part distinctly narrower than the upper
+part. It is highly contractile and when contracted sometimes assumes an
+annulate appearance; but as a rule the external surface is smooth.</p>
+
+<p>The tentacles vary in number, but are never very numerous. They are
+disposed in a single circle round the oral disk and are hollow, each
+containing a prolongation of the central cavity of the column. Like the
+column but to an even greater degree they are contractile, and in some
+forms they are capable of great elongation. They cannot seize any object
+between them, but are able to move in all directions.</p>
+
+<p>The disk that surrounds the mouth, which is a circular aperture, is
+narrow and can to some extent assume the form of a conical proboscis,
+although this feature is never so marked as it is in some hydroids. The
+basal disk is even narrower and is not splayed out round the edges.</p>
+
+<div class="figcenter">
+<span class='pagenum'><a name="Page_131" id="Page_131">[Pg
+131]</a></span>
+<img src="images/fig_027.jpg" width="298" height="500"
+alt="Illustration: Fig. 27.&mdash;Nettle-cells of Hydra." title="Fig.
+27.&mdash;Nettle-cells of Hydra." />
+<p class="caption">Fig. 27.&mdash;Nettle-cells of <i>Hydra</i>.</p>
+</div>
+
+<p class="captionj">A=capsules from nettle-cells of a single specimen of
+the summer phase of <i>H. vulgaris</i> from Calcutta, � 480: figures
+marked with a dash represent capsules with barbed threads. B=a capsule
+with the thread discharged, from the same specimen, � 480. C=capsule
+with barbed thread, from a specimen of <i>H. oligactis</i> from Lahore.
+D=undischarged nettle-cell of <i>H. vulgaris</i> from Europe (after
+Nussbaum, highly magnified). E=discharged capsule of the same (after the
+same author). <i>a</i>=cnidoblast; <i>b</i>=capsule; <i>c</i>=thread;
+<i>d</i>=cnidocil. Only the base of the thread is shown in E.</p>
+
+<p>A section through the body-wall shows it to consist of the three
+typical layers of the c&oelig;lenterates, viz., (i) an outer cellular
+layer of comparatively small cells, the ectoderm; (ii) an
+intermediate,<span class='pagenum'><a name="Page_132" id="Page_132">[Pg
+132]</a></span> structureless or apparently structureless layer, the
+mesogl&oelig;a or "central jelly"; and (iii) an internal layer or
+endoderm consisting of relatively large cells. The cells of the ectoderm
+are not homogeneous. Some of them possess at their base narrow and
+highly contractile prolongations that exercise the functions of muscles.
+Others are gland-cells and secrete mucus; others have round their
+margins delicate ramifying prolongations and act as nerve-cells.
+Sense-cells, each of which bears on its external surface a minute
+projecting bristle, are found in connection with the nerve-cells, and
+also nettle-cells of more than one type.</p>
+
+<p>The mesogl&oelig;a is very thin.</p>
+
+<p>The endoderm consists mainly of comparatively large cells with
+polygonal bases which can be seen from the external surface of the
+column in colourless individuals. Their inner surface is am&oelig;boid
+and in certain conditions bears one or more vibratile cilia or
+protoplasmic lashes. Nettle-cells are occasionally found in the
+endoderm, but apparently do not originate in this layer.</p>
+
+<p>The walls of the tentacles do not differ in general structure from
+those of the column, but the cells of the endoderm are smaller and the
+nematocysts of the ectoderm more numerous, and there are other minor
+differences.</p>
+
+<p>A more detailed account of the anatomy of <i>Hydra</i> will be found
+in any biological text-book, for instance in Parker's Elementary
+Biology; but it is necessary here to say something more as regards the
+nettle-cells, which are of great biological and systematic
+importance.</p>
+
+<p>A nettle-cell of the most perfect type and the structures necessary
+to it consist of the following parts:&mdash;</p>
+
+<p class="indent1a">(1) A true cell (the cnidoblast), which
+contains&mdash;</p>
+
+<p class="indent1b">(2) a delicate capsule full of liquid;</p>
+
+<p class="indent1b">(3) a long thread coiled up in the capsule;
+and</p>
+
+<p class="indent1c">(4) a cnidocil or sensory bristle, which
+projects from the external surface of the cnidoblast.</p>
+
+<p>A nerve-cell is associated with each cnidoblast.</p>
+
+<p>In <i>Hydra</i> the nettle-cells are of two distinct types, in one of
+which the thread is barbed at the base, whereas in the other it is
+simple. Both types have often two or more varieties and intermediate
+forms occur, but generally speaking the capsules with simple threads are
+much smaller than those with barbed ones. The arrangement of the
+nettle-cells is not the same in all species of <i>Hydra</i>, but as a
+rule they are much more numerous in the tentacles than elsewhere on the
+body, each large cell being surrounded by several small ones. The latter
+are always much more numerous than the former.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_133"
+id="Page_133">[Pg 133]</a></span><span class="smcap">Capture and
+Ingestion of Prey: Digestion.</span></p>
+
+<p>The usual food of <i>Hydra</i> consists of small insect larv�, worms,
+and crustacea, but the eggs of fish are also devoured. The method in
+which prey is captured and ingested has been much disputed, but the
+following facts appear to be well established.</p>
+
+<p>If a small animal comes in contact with the tentacles of the polyp,
+it instantly becomes paralysed. If it adheres to the tentacle, it
+perishes; but if, as is often the case, it does not do so, it soon
+recovers the power of movement. Animals which do not adhere are
+generally those (such as ostracod crustacea) which have a hard
+integument without weak spots. Nematocysts of both kinds shoot out their
+threads against prey with considerable violence, the discharge being
+effected, apparently in response to a chemical stimulus, by the sudden
+uncoiling of the thread and its eversion from the capsule. Apparently
+the two kinds of threads have different functions to perform, for
+whereas there is no doubt that the barbed threads penetrate the more
+tender parts of the body against which they are hurled, there is
+evidence that the simple threads do not do so but wrap themselves round
+the more slender parts. Nussbaum (Arch. mikr. Anat. xxix, pl. xx, fig.
+108) figures the tail of a <i>Cyclops</i> attacked by <i>Hydra
+vulgaris</i> and shows several simple threads wrapped round the hairs
+and a single barbed thread that has penetrated the integument. Sometimes
+the cyst adheres to the thread and remains attached to its cnidoblast
+and to the polyp, but sometimes the thread breaks loose. Owing to the
+large mass of threads that sometimes congregate at the weaker spots in
+the external covering of an animal attacked (<i>e.&nbsp;g.</i>, at the
+little sensory pits in the integument of the dorsal surface of certain
+water-mites) it is often difficult to trace out the whole length of any
+one thread, and as a thread still attached to its capsule is frequently
+buried in the body of the prey, right up to the barbs, while another
+thread that has broken loose from its capsule appears immediately behind
+the fixed one, it seems as though the barbs, which naturally point
+towards the capsule, had become reversed. This appearance, however, is
+deceptive. The barbs are probably connected with the discharge of the
+thread and do not function at all in the same way as those on a spear-
+or arrow-head, never penetrating the object against which the projectile
+is hurled. Indeed, their position as regards the thread resembles that
+of the feathers on the shaft of an arrow rather than that of the barb of
+the head.</p>
+
+<p>Adhesion between the tentacles and the prey is effected partly by the
+gummy secretion of the glands of the ectoderm, which is perhaps
+poisonous as well as adhesive, and partly by the threads. Once the prey
+is fast and has ceased to struggle, it is brought to the mouth, which
+opens wide to receive it, by the contraction and the contortions of the
+tentacles, the column, and the peristome. At the same time a mass of
+transparent mucus from the gastral cavity envelops it and assists in
+dragging it in. There is some<span class='pagenum'><a name="Page_134"
+id="Page_134">[Pg 134]</a></span> dispute as to the part played by the
+tentacles in conveying food into the mouth. My own observations lead me
+to think that, at any rate so far as <i>H. vulgaris</i> is concerned,
+they do not push it in, but sometimes in their contortions they even
+enter the cavity accidentally.</p>
+
+<p>When the food has once been engulfed some digestive fluid is
+apparently poured out upon it. In <i>H. vulgaris</i> it is retained in
+the upper part of the cavity and the soluble parts are here dissolved
+out, the insoluble parts such as the chitin of insect larv� or crustacea
+being ejected from the mouth. Digestion is, however, to a considerable
+extent intracellular, for the cells of the endoderm have the power of
+thrusting out from their surface lobular masses of their cell-substance
+in which minute nutritive particles are enveloped and dissolved. The
+movements of the cilia which can also be thrust out from and retracted
+into these cells, keep the food in the gastral cavity in motion and
+probably turn it round so as to expose all parts in turn to digestive
+action. Complete digestion, at any rate in the Calcutta form, takes
+several days to accomplish, and after the process is finished a
+flocculent mass of colourless excreta is emitted from the mouth.</p>
+
+<p class="p2 center"><span class="smcap">Colour.</span></p>
+
+<p>In <i>Hydra viridis</i>, a species that has not yet been found in
+India, the green colour is due to the presence in the cells of green
+corpuscles which closely resemble those of the cells of certain
+freshwater sponges. They represent a stage in the life-cycle of
+<i>Chlorella vulgaris</i>, Beyerinck<a name="fnanchor_AM"
+id="fnanchor_AM"></a><a href="#footnote_AM"
+class="fnanchor"><sup>[AM]</sup></a>, an alga which has been cultivated
+independently.</p>
+
+<p>In other species of the genus colour is largely dependent on food,
+although minute corpuscles of a <i>dark</i> green shade are sometimes
+found in the cells of <i>H. oligactis</i>. In the Calcutta phase of
+<i>H. vulgaris</i> colour is due entirely to amorphous particles
+situated mainly in the cells of the endoderm. If the polyp is starved or
+exposed to a high temperature, these particles disappear and it becomes
+practically colourless. They probably form, therefore, some kind of
+food-reserve, and it is noteworthy that a polyp kept in the unnatural
+conditions that prevail in a small aquarium invariably becomes pale, and
+that its excreta are not white and flocculent but contain dark granules
+apparently identical with those found in the cells of coloured
+individuals (p.&nbsp;154).</p>
+
+<p>Berninger<a name="fnanchor_AN" id="fnanchor_AN"></a><a
+href="#footnote_AN" class="fnanchor"><sup>[AN]</sup></a> has just
+published observations on the effect of long-continued starvation on
+<i>Hydra</i> carried out in Germany. He finds that the tentacles, mouth,
+and central jelly disappear, and that a closed "bladder" consisting of
+two cellular layers remains; but, to judge from his figures, the colour
+does not disappear in these circumstances.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_135"
+id="Page_135">[Pg 135]</a></span><span class="smcap">Behaviour.</span></p>
+
+<p><i>Hydra viridis</i> is a more sluggish animal than the other species
+of its genus and does not possess the same power of elongating its
+column and tentacles. It is, nevertheless, obliged to feed more
+frequently. Wagner (Quart. J. Micr. Sci. xlviii, p.&nbsp;586, 1905) found it
+impossible to use this species in his physiological experiments because
+it died of starvation more rapidly than other forms. This fact is
+interesting in view of the theory that the green corpuscles in the cells
+of <i>H. viridis</i> elaborate nutritive substances for its benefit.
+<i>H. vulgaris</i>, at any rate in Calcutta, does not ordinarily capture
+prey more often than about once in three days.</p>
+
+<p>All <i>Hydr�</i> (except possibly the problematical <i>H. rubra</i>
+of Roux, p.&nbsp;160) spend the greater part of their time attached by
+the basal disk to some solid object, but, especially in early life,
+<i>H. vulgaris</i> is often found floating free in the water, and all
+the species possess powers of progression. They do not, however, all
+move in the same way. <i>H. viridis</i> progresses by "looping" like a
+geometrid caterpillar. During each forward movement the column is arched
+downwards so that the peristome is in contact with the surface along
+which the animal is moving. The basal disk is then detached and the
+column is twisted round until the basal disk again comes in contact with
+the surface at a point some distance in advance of its previous point of
+attachment. The man&oelig;uvre is then repeated. <i>H. vulgaris</i>,
+when about to move, bends down its column so that it lies almost prone,
+stretches out its tentacles, which adhere near the tips to the surface
+(p.&nbsp;153), detaches its basal disk, and then contracts the
+tentacles. The column is dragged forward, still lying almost prone, the
+basal disk is bent downwards and again attached, and the whole movement
+is repeated. Probably <i>H. oligactis</i> moves in the same way.</p>
+
+<p>When <i>H. viridis</i> is at rest the tentacles and column, according
+to Wagner, exhibit rhythmical contractions in which those of the buds
+act in sympathy with those of the parent. In <i>H. vulgaris</i> no such
+movements have been observed. This species, however, when it is waiting
+for prey (p.&nbsp;154) changes the direction of its tentacles about once in
+half an hour.</p>
+
+<p>All species of <i>Hydra</i> react to chemical and physical stimuli by
+contraction and by movements of the column and tentacles, but if the
+stimuli are constantly repeated, they lose the power to some extent. All
+species are attracted by light and move towards the point whence it
+reaches them. <i>H. vulgaris</i>, however, at any rate in India, is more
+strongly repelled by heat. Consequently, if it is placed in a glass
+vessel of water, on one side of which the sun is shining directly, it
+moves away from the source of the light<a name="fnanchor_AO"
+id="fnanchor_AO"></a><a href="#footnote_AO"
+class="fnanchor"><sup>[AO]</sup></a>. But if the vessel be
+protected<span class='pagenum'><a name="Page_136" id="Page_136">[Pg
+136]</a></span> from the direct rays of the sun and only a subdued light
+falls on one side of it, the polyp moves towards that side. No species
+of the genus is able to move in a straight line. Wilson (Amer. Natural.
+xxv, p.&nbsp;426, 1891) and Wagner (<i>op. cit. supra</i>) have published
+charts showing the elaborately erratic course pursued by a polyp in
+moving from one point to another and the effect of light as regards its
+movements.</p>
+
+<p>If an individual of <i>H. vulgaris</i> that contains half digested
+food in its gastral cavity is violently removed from its natural
+surroundings and placed in a glass of water, the column and tentacles
+contract strongly for a few minutes. The body then becomes greatly
+elongated and the tentacles moderately so; the tentacles writhe in all
+directions (their tips being sometimes thrust into the mouth), and the
+food is ejected.</p>
+
+<p class="p2 center"><span class="smcap">Reproduction.</span></p>
+
+<p>Reproduction takes place in <i>Hydra</i> (i) by means of buds, (ii)
+by means of eggs, and (iii) occasionally by fission.</p>
+
+<p class="p2 center">(a) <i>Sexual Reproduction.</i></p>
+
+<p>The sexual organs consist of ovaries (female) and spermaries (male).
+Sometimes the two kinds of organs are borne by the same individual
+either simultaneously or in succession, but some individuals or races
+appear to be exclusively of one sex. There is much evidence that in
+unfavourable conditions the larger proportion of individuals develop
+only male organs.</p>
+
+<p>In temperate climates most forms of <i>Hydra</i> breed at the
+approach of winter, but starvation undoubtedly induces a precocious
+sexual activity, and the same is probably the case as regards other
+unfavourable conditions such as lack of oxygen in the water and either
+too high or too low a temperature.</p>
+
+<p>Downing states that in N. America (Chicago) <i>H. vulgaris</i> breeds
+in spring and sometimes as late as December; in Calcutta it has only
+been found breeding in February and March. Except during the
+breeding-season sexual organs are absent; they do not appear in the same
+position on the column in all species.</p>
+
+<p>The spermaries take the form of small mound-shaped projections on the
+surface of the column. Each consists of a mass of sperm-mother cells, in
+which the spermatozoa originate in large numbers. The spermatozoa
+resemble those of other animals, each possessing a head, which is shaped
+like an acorn, and a long vibratile tail by means of which it moves
+through the water. In the cells of the spermary the spermatozoa are
+closely packed together, with their heads pointing outwards towards the
+summit of the mound through which they finally make their way into the
+water. The aperture is formed by their own movements. Downing (Zool.
+Jahrb. (Anat.) xxi, p.&nbsp;379, 1905) and other authors have studied the
+origin of the spermatozoa in great detail.</p>
+
+<p><span class='pagenum'><a name="Page_137" id="Page_137">[Pg
+137]</a></span></p>
+
+<div class="figcenter">
+<img src="images/fig_028.png"
+width="600" height="247"  alt="Illustration: Fig. 28.&mdash;Eggs of
+Hydra (magnified)." title="Fig. 28.&mdash;Eggs of Hydra (magnified)." />
+<p class="caption">Fig. 28.&mdash;Eggs of <i>Hydra</i> (magnified).</p>
+</div>
+
+<p class="captionj">A=egg of <i>H. vulgaris</i> (after Chun). B=vertical
+section through egg of <i>H. oligactis</i>, form A (after Brauer).
+C=vertical section through egg of <i>H. oligactis</i>, form B (after
+Brauer).</p>
+
+<p>The ovaries consist of rounded masses of cells lying at the base of
+the ectoderm. One of these cells, the future egg, grows more rapidly
+than the others, some or all of which it finally absorbs by means of
+lobose pseudopodia extruded from its margin. It then makes its way by
+am&oelig;boid movements between the cells of the ectoderm until it
+reaches the surface. In <i>H. vulgaris</i> (Mem. Asiat. Soc. Beng. i, p.
+350, 1906) the egg is first visible with the aid of a lens as a minute
+star-shaped body of an intense white colour lying at the base of the
+ectoderm cells. It increases in size rapidly, gradually draws in its
+pseudopodia (the rays of the star) and makes its way through the
+ectoderm to the exterior. The process occupies not more than two hours.
+The issuing ovum does not destroy the ectoderm cells as it passes out,
+but squeezes them together round the aperture it makes. Owing to the
+pressure it exerts upon them, they become much elongated and form a cup,
+in which the embryo rests on the surface of the parent. By the time that
+the egg has become globular, organic connection has ceased to exist. The
+embryo is held in position partly by means of the cup of elongated
+ectoderm cells and partly by a delicate film of mucus secreted by the
+parent. The most recent account of the oogenesis ("ovogenesis") is by
+Downing (Zool. Jahrb. (Anat.) xxvii, p.&nbsp;295, 1909).</p>
+
+<p class="p2 center">(b) <i>Budding.</i></p>
+
+<p>The buds of <i>Hydra</i> arise as hollow outgrowths from the wall of
+the column, probably in a definite order and position in each species.
+The tentacles are formed on the buds much as the buds themselves arise
+on the column. There is much dispute as to the order in which these
+structures appear on the bud, and Haacke (Jenaische Zeitschr. Naturwiss.
+xiv, p.&nbsp;133, 1880) has proposed to distinguish two species, <i>H.
+trembleyi</i> and <i>H. r&oelig;selii</i>, in accordance with the manner
+in which the phenomenon is manifested.<span class='pagenum'><a
+name="Page_138" id="Page_138">[Pg 138]</a></span> It seems probable,
+however, that the number of tentacles that are developed in the first
+instance is due, at any rate to some extent, to circumstances, for in
+the summer brood of <i>H. vulgaris</i> in Calcutta five usually appear
+simultaneously, while in the winter brood of the same form four as a
+rule do so. Sometimes buds remain attached to their parents sufficiently
+long to develop buds themselves, so that temporary colonies of some
+complexity arise, but I have not known this to occur in the case of
+Indian individuals.</p>
+
+<p class="p2 center">(c) <i>Fission.</i></p>
+
+<p>Reproduction by fission occurs naturally but not habitually in all
+species of <i>Hydra</i>. It may take place either by a horizontal or by
+a vertical division of the column. In the latter case it may be either
+equal or unequal. If equal, it usually commences by an elongation in one
+direction of the circumoral disk, which assumes a narrowly oval form;
+the tentacles increase in number, and a notch appears at either side of
+the disk and finally separates the column into two equal halves, each of
+which is a complete polyp. The division sometimes commences at the base
+of the column, but this is very rare. Transverse fission can be induced
+artificially and is said to occur sometimes in natural conditions. It
+commences by a constriction of the column which finally separates the
+animal into two parts, the lower of which develops tentacles and a
+mouth, while the upper part develops a basal disk. Unequal vertical
+division occurs when the column is divided vertically in such a way that
+the two resulting polyps are unequal in size. It is apparently not
+accompanied by any great increase in the number of the tentacles, but
+probably starts by one of the tentacles becoming forked and finally
+splitting down the middle.</p>
+
+<p>The question of the regeneration of lost parts in <i>Hydra</i> cannot
+well be separated from that of reproduction by fission. Over a hundred
+and fifty years ago Trembley found that if a polyp were cut into several
+pieces, each piece produced those structures necessary to render it a
+perfect polyp. He also believed that he had induced a polyp that had
+been turned inside out to adapt itself to circumstances and to reverse
+the functions and structure of the two cellular layers of its body. In
+this, however, he was probably mistaken, for there can be little doubt
+that his polyp turned right side out while not under his immediate
+observation. Many investigators have repeated some of his other
+experiments with success in Europe, but the Calcutta <i>Hydra</i> is too
+delicate an animal to survive vivisection and invariably dies if
+lacerated. It appears that, even in favourable circumstances, for a
+fresh polyp to be formed by artificial fission it is necessary for the
+piece to contain cells of both cell-layers.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_139"
+id="Page_139">[Pg 139]</a></span><span class="smcap">Development of the
+Egg.</span></p>
+
+<p>The egg of <i>Hydra</i> is said to be fertilized as it lies at the
+base of the ectoderm, through which the fertilizing spermatozoon bores
+its way. As soon as the egg has emerged from the cells of its parent it
+begins to split up in such a manner as to form a hollow mass of
+comparatively large equal cells. Smaller cells are separated off from
+these and soon fill the central cavity. Before segmentation begins a
+delicate film of mucus is secreted over the egg, and within this film
+the larger cells secrete first a thick chitinous or horny egg-shell and
+within it a delicate membrane. Development in some cases is delayed for
+a considerable period, but sooner or later, by repeated division of the
+cells, an oval hollow embryo is formed and escapes into the water by the
+disintegration of the egg-shell and the subsequent rupture of the inner
+membrane. Tentacles soon sprout out from one end of the embryo's body
+and a mouth is formed; the column becomes more slender and attaches
+itself by the aboral pole to some solid object.</p>
+
+<p class="p2 center"><span class="smcap">Enemies.</span></p>
+
+<p><i>Hydra</i> seems to have few natural enemies. Martin (Q. J. Micr.
+Sci. London, lii, p.&nbsp;261, 1908) has, however, described how the
+minute worm <i>Microstoma lineare</i> attacks <i>Hydra "rubra"</i> in
+Scottish lochs, while the larva of a midge devours <i>H. vulgaris</i> in
+considerable numbers in Calcutta tanks (p.&nbsp;156).</p>
+
+<p class="p2 center"><span class="smcap">C&oelig;lenterates of Brackish
+Water.</span></p>
+
+<p>Marine c&oelig;lenterates of different orders not infrequently make
+their way or are carried by the tide up the estuaries of rivers into
+brackish water, and several species have been found living in isolated
+lagoons and pools of which the water was distinctly salt or brackish.
+Among the most remarkable instances of such isolation is the occurrence
+in Lake Qurun in the Fay�m of Egypt of <i>Cordylophora lacustris</i> and
+of the peculiar little hydroid recently described by Mr. C. L. Boulenger
+as <i>M&oelig;risia lyonsi</i> (Q. J. Micr. Sci. London, lii, p.&nbsp;357,
+pls. xxii, xxiii, 1908). In the delta of the Ganges there are numerous
+ponds which have at one time been connected with estuaries or creeks of
+brackish water and have become isolated either naturally or by the hand
+of man without the marine element in their fauna by any means
+disappearing (p.&nbsp;14). The following species have been found in such
+ponds:&mdash;</p>
+
+<p class="center">(<i>a</i>) <i>Hydrozoa.</i></p>
+
+<p>(1) <i>Bimeria vestita</i>, Wright (1859).</p>
+
+<div class="genus">
+<span class="i0">Hincks, Hist. Brit. Hydr. Zooph. p.&nbsp;103, pl. xv,
+fig. 2 (1868); Annandale, Rec. Ind. Mus. i, p.&nbsp;141, fig. 3
+(1907).</span>
+</div>
+
+<p>This is a European species which has also been found off<span
+class='pagenum'><a name="Page_140" id="Page_140">[Pg 140]</a></span> S.
+America. It occurs not uncommonly in the creeks that penetrate into the
+Ganges delta and has been found in pools of brackish water at Port
+Canning. The Indian form is perhaps sufficiently distinct to be regarded
+as a subspecies. The medusoid generation is suppressed in this
+genus.</p>
+
+<p class="p2">(2) <i>Syncoryne filamentata</i>, Annandale (1907).</p>
+
+<div class="genus">
+<span class="i0">Annandale, Rec. Ind. Mus. i, p.&nbsp;139, figs. 1, 2
+(1907).</span>
+</div>
+
+<p>Both hydroid and medus� were found in a small pool of brackish water
+at Port Canning. The specific name refers to the fact that the ends of
+the rhizomes from which the polyps arise are frequently free and
+elongate, for the young polyp at the tip apparently takes some time to
+assume its adult form.</p>
+
+<p class="p2">(3) <i>Irene ceylonensis</i>, Browne (1905).</p>
+
+<div class="genus">
+<span class="i0">Browne, in Herdman's Report on the Pearl Fisheries of
+Ceylon, iv, p.&nbsp;140, pl. iii, figs. 9-11 (1905); Annandale, Rec. Ind.
+Mus. i, p.&nbsp;142, fig. 4 (1907).</span>
+</div>
+
+<p>The medusa was originally taken off the coast of Ceylon, while the
+hydroid was discovered in ponds of brackish water at Port Canning. It is
+almost microscopic in size.</p>
+
+<p>The first two of these species belong to the order Gymnoblastea
+(Anthomedus�) and the third to the Calyptoblastea (Leptomedus�).</p>
+
+<p class="p2 center">(b) <i>Actinozoa.</i></p>
+
+<p>(4) <i>Sagartia schilleriana</i>, Stoliczka (1869).</p>
+
+<div class="genus">
+
+<span class="i0"><i>S. schilleriana</i>, Stoliczka, Journ. As. Soc.
+Beng. (2) xxxviii, p.&nbsp;28, pls. x, xi (1869); <i>Metridium
+schillerianum</i>, Annandale, Rec. Ind. Mus. i, p.&nbsp;47, pl. iii
+(1907).</span>
+
+</div>
+
+<p>This sea-anemone, which has only been found in the delta of the
+Ganges, offers a most remarkable instance of what appears to be rapid
+adaptation of a species to its environment. The typical form, which was
+described in 1869 by Stoliczka from specimens taken in tidal creeks and
+estuaries in the Gangetic area and in the ponds at Port Canning, is
+found attached to solid objects by its basal disk. The race (subsp.
+<i>exul</i>), however, that is now found in the same ponds has become
+elongate in form and has adopted a burrowing habit, apparently owing to
+the fact that the bottom of the ponds in which it lives is soft and
+muddy.</p>
+
+<p>In addition to these four species a minute hydroid belonging to the
+order Gymnoblastea and now being described by Mr. J. Ritchie has been
+taken in the ponds at Port Canning. It is a very aberrant form.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_141"
+id="Page_141">[Pg 141]</a></span><span class="smcap">Freshwater
+C&oelig;lenterates other than Hydra.</span></p>
+
+<p><i>Hydra</i> is the only genus of c&oelig;lenterates as yet found in
+fresh water in India, but several others have been discovered in other
+countries. They are:&mdash;</p>
+
+<p>(1) <i>Cordylophora lacustris</i>, Allman (1843).</p>
+
+<div class="genus">
+<span class="i0">Hincks, Hist. Brit. Hydr. Zooph. p.&nbsp;16, pl. iii,
+fig. 2 (1868).</span>
+</div>
+
+<p>This is a branching hydroid that does not produce free medus�. It
+forms bushy masses somewhat resembling those formed by a luxuriant
+growth of <i>Plumatella fruticosa</i> (pl. iii, fig. 1) in general
+appearance. <i>C. lacustris</i> is abundant in canals, rivers, and
+estuaries in many parts of Europe and has recently been found in the
+isolated salt lake Birket-el-Qurun in the Fay�m of Egypt.</p>
+
+<p>(2) <i>Cordylophora whiteleggei</i>, v. Lendenfeld (1887).</p>
+
+<div class="genus">
+<span class="i0">Zool. Jahrb. ii, p.&nbsp;97 (1887).</span>
+</div>
+
+<p>A species or race of much feebler growth; as yet imperfectly known
+and only recorded from fresh water in Australia.</p>
+
+<p><i>Cordylophora</i> is a normal genus of the class Hydrozoa and the
+order Gymnoblastea; the next four genera are certainly Hydrozoa, but
+their affinities are very doubtful.</p>
+
+<p> (3) <i>Microhydra ryderi</i>, Potts (1885).</p>
+
+<div class="genus">
+<span class="i0">Potts, Q. J. Micr. Sci. London, l, p.&nbsp;623, pls.
+xxxv, xxxvi; Browne, <i>ibid.</i> p.&nbsp;635, pl. xxxvii (1906).</span>
+</div>
+
+<p>This animal, which has been found in N. America and in Germany,
+possesses both an asexual hydroid and a sexual medusoid generation. The
+former reproduces its species by direct budding as well as by giving
+rise, also by a form of budding, to medus� that become sexually mature.
+The hydroid has no tentacles.</p>
+
+<p>(4) <i>Limnocodium sowerbii</i>, Lankester (1880).</p>
+
+<div class="genus">
+<span class="i0">Lankester, Q. J. Micr. Sci. London, xx, p.&nbsp;351, pls.
+xxx, xxxi (1880); Fowler, <i>ibid.</i> xxx, p.&nbsp;507, pl. xxxii
+(1890).</span>
+</div>
+
+<p>There is some doubt as to the different stages in the life-cycle of
+this species. The medusa has been found in tanks in hot-houses in
+England, France and Germany, and a minute hydroid closely resembling
+that of <i>Microhydra ryderi</i> has been associated with it
+provisionally.</p>
+
+<p>(5) <i>Limnocodium kawaii</i>, Oka (1907).</p>
+
+<div class="genus">
+<span class="i0">Oka, Annot. Zool. Japon. vi, p.&nbsp;219, pl. viii
+(1907).</span>
+</div>
+
+<p>Only the medusa, which was taken in the R. Yang-tze-kiang,
+is as yet known.</p>
+
+<p><span class='pagenum'><a name="Page_142" id="Page_142">[Pg
+142]</a></span>(6) <i>Limnocnida tanganyik�</i>, Bohm (1889).</p>
+
+<div class="genus">
+<span class="i0">R. T. G�nther, Ann. Nat. Hist. (6) xi, p.&nbsp;269, pls.
+xiii, xiv (1893).</span>
+</div>
+
+<p>Only the medusa, which is found in Lake Tanganyika, Lake Victoria
+Nyanza and the R. Niger, has been found and it is doubtful whether a
+hydroid generation exists.</p>
+
+<p>(7) <i>Polypodium hydriforme</i>, Ussow (1885).</p>
+
+<div class="genus">
+<span class="i0">Morph. Jahrb. xii, p.&nbsp;137 (1887).</span>
+</div>
+
+<p>Two stages in this peculiar hydroid, which is found in the R. Volga,
+are known, (<i>a</i>) a spiral ribbon-like form parasitic on the eggs of
+the sterlet (<i>Acipenser ruthenus</i>), and (<i>b</i>) a small
+<i>Hydra</i>-like form with both filamentous and club-shaped tentacles.
+The life-history has not yet been worked out<a name="fnanchor_AP"
+id="fnanchor_AP"></a><a href="#footnote_AP"
+class="fnanchor"><sup>[AP]</sup></a>.</p>
+
+<p class="footnote">
+<a name="footnote_AK" id="footnote_AK"></a>
+<a href="#fnanchor_AK">[AK]</a>
+Similar capsules are found in the tissues of certain worms and molluscs,
+but there is the strongest evidence that these animals, which habitually
+devour c&oelig;lenterates, are able to swallow the capsules uninjured
+and to use them as weapons of defence (see Martin, Q. J. Micro. Sci.
+London, lii, p.&nbsp;261, 1908, and Grosvenor, Proc. Roy. Soc. London,
+lxxii, p.&nbsp;462, 1903). The "trichocysts" of certain protozoa bear a
+certain resemblance to the nettle-cells of c&oelig;lenterates and
+probably have similar functions.</p>
+
+<p class="footnote">
+<a name="footnote_AL" id="footnote_AL"></a>
+<a href="#fnanchor_AL">[AL]</a>
+The statement is not strictly accurate as regards the Calcutta phase of
+<i>H. vulgaris</i>, for the summer brood apparently does not lay eggs
+but reproduces its species by means of buds only. This state of affairs,
+however, is probably an abnormality directly due to environment.</p>
+
+<p class="footnote">
+<a name="footnote_AM" id="footnote_AM"></a>
+<a href="#fnanchor_AM">[AM]</a>
+Bot. Zeitung, xlviii (1890): see p.&nbsp;49, <i>antea</i>.</p>
+
+<p class="footnote">
+<a name="footnote_AN" id="footnote_AN"></a>
+<a href="#fnanchor_AN">[AN]</a>
+Zool. Anz. xxxvi, pp.&nbsp;271-279, figs., Oct. 1910.</p>
+
+<p class="footnote">
+<a name="footnote_AO" id="footnote_AO"></a>
+<a href="#fnanchor_AO">[AO]</a>
+Mr. F. H. Gravely tells me that this is also the case as regards <i>H.
+viridis</i> in England, at any rate if freshly captured specimens are
+placed overnight in a bottle in a window in such a position that the
+early morning sunlight falls upon one side of the bottle.</p>
+
+<p class="footnote">
+<a name="footnote_AP" id="footnote_AP"></a>
+<a href="#fnanchor_AP">[AP]</a>
+Since this was written, Lippen has described a third stage in the
+life-history of <i>Polypodium</i> (Zool. Anz. Leipzig, xxxvii, Nr. 5, p.
+97 (1911)).</p>
+
+<p class="p2 center">II.</p>
+
+<p class="center"><span class="smcap">History of the Study of
+Hydra.</span></p>
+
+<p>Hydra was discovered by Leeuwenhoek at the beginning of the
+eighteenth century and had attracted the attention of several skilful
+and accurate observers before that century was half accomplished. Among
+them the chief was Trembley, whose "M�moires pour servir � l'histoire
+d'un genre de Polype d'eau douce"* was published at Paris 1744, and is
+remarkable not only for the extent and accuracy of the observations it
+enshrines but also for the beauty of its plates. Baker in his work
+entitled "An attempt towards a natural history of the Polyp"* (London,
+1743) and R�sel von Rosenhof in the third part of his
+"Insecten-Belustigung" (Nurenberg, 1755) also made important
+contributions to the study of the physiology and structure of
+<i>Hydra</i> about the same period. Linn� invented the name
+<i>Hydra</i>, and in his "Fauna Sueica" and in the various editions of
+his "Systema Natur�" described several forms in a manner that permits
+some of them to be recognized; but Linn� did not distinguish between the
+true <i>Hydra</i> and other soft sessile C&oelig;lenterates, and it is
+to Pallas ("Elenchus Zoophytorum," 1766) that the credit properly
+belongs of reducing the genus to order. It is a tribute to his insight
+that three of the four species he described are still accepted as "good"
+by practically all students of the C&oelig;lenterates, while the fourth
+was a form that he had not himself seen.</p>
+
+<p>In the nineteenth century the freshwater polyp became a favourite
+object of biological observation and was watched and examined by a host
+of observers, among the more noteworthy of whom were Kleinenberg,
+Nussbaum, and Brauer, who has since the beginning of the present century
+made an important contribution to the taxonomy of the genus.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_143"
+id="Page_143">[Pg 143]</a></span><span class="smcap">Bibliography of
+Hydra.</span></p>
+
+<p><i>Hydra</i> has been examined by thousands of students in biological
+laboratories all over the civilized world, and the literature upon it is
+hardly surpassed in magnitude by that on any other genus but
+<i>Homo</i>. The following is a list of a few of the more important
+general memoirs and of the papers that refer directly to Asiatic
+material. A systematic bibliography is given by Bedot in his "Mat�riaux
+pour servir a l'Histoire des Hydro�des," Rev. Suisse Zool. xviii, fasc.
+2 (1910).</p>
+
+<table summary="bibliography II">
+
+<tr><td></td><th class="normal">(a) <i>General.</i></th></tr>
+
+<tr><td class="left_a">1743.</td><td><span class="smcap">Baker</span>,
+"An attempt towards a natural history of the Polyp"* (London).</td></tr>
+
+<tr><td class="left_a">1744.</td><td><span
+class="smcap">Trembley</span>, "M�moires pour servir � l'histoire d'un
+genre de polypes d'eau douce"* (Paris).</td></tr>
+
+<tr><td class="left_a">1755.</td><td><span class="smcap">R�sel Von
+Rosenhof</span>, "Insecten-Belustigung: iii, Hist. Polyporum."</td></tr>
+
+<tr><td class="left_a">1766.</td><td><span class="smcap">Pallas</span>,
+"Elenchus Zoophytorum."</td></tr>
+
+<tr><td class="left_a">1844.</td><td><span class="smcap">Laurent</span>,
+"Rech. sur l'Hydre et l'Eponge d'eau douce" ("Voy. de la Bonite,
+Zoophytologie").</td></tr>
+
+<tr><td class="left_a">1847.</td><td><span
+class="smcap">Johnston</span>, "A History of the British Zoophytes" (2nd
+edition).</td></tr>
+
+<tr><td class="left_a">1868.</td><td><span class="smcap">Hincks</span>,
+"History of British Hydroid Zoophytes."</td></tr>
+
+<tr><td class="left_a">1872.</td><td><span
+class="smcap">Kleinenberg</span>, "Hydra. Eine Anatomisch
+Entwicklungsgeschichtliche Untersuchung."</td></tr>
+
+<tr><td class="left_a">1882.</td><td><span class="smcap">Jickeli</span>,
+"Der Bau der Hydroidpolypen," Morph. Jahrb. viii, p.&nbsp;373.</td></tr>
+
+<tr><td class="left_a">1887.</td><td><span
+class="smcap">Nussbaum</span>, "Ueber die Theilbarkeit der lebendigen
+Materie. II. Mittheilung. Beitr�ge zur Naturgeschichte des Genus Hydra,"
+Arch. mikr. Anat. Bonn, xxix, p.&nbsp;265.</td></tr>
+
+<tr><td class="left_a">1891.</td><td><span class="smcap">Brauer</span>,
+"�ber die Entwicklung von Hydra," Zeitschr. wiss. Zool. Leipzig, lii, p.
+169.</td></tr>
+
+<tr><td class="left_a">1892.</td><td><span class="smcap">Chun</span>,
+"C&oelig;lenterata (Hohlthiere)," in Bronn's Thier-Reichs II
+(2).</td></tr>
+
+<tr><td class="left_a">1905.</td><td><span class="smcap">Downing</span>,
+"The spermatogenesis of Hydra," Zool. Jahrb. (Anat.) xxi, p.
+379.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span class="smcap">Brauer</span>,
+"Die Benennung und Unterscheidung der Hydra-Arten," Zool. Ann. xxxiii,
+p.&nbsp;790.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Frischholz</span>, "Biologie und Systematik im Genus
+Hydra," Braun's Annal. Zool. (W�rzburg) iii, p.&nbsp;105.</td></tr>
+
+<tr><td class="left_a">1910.</td><td><span
+class="smcap">Berninger</span>, "�ber Einwirkung des Hungers auf Hydra,"
+Zool. Anz. xxxvi, p.&nbsp;271.</td></tr>
+
+<tr><td></td><th class="normal">(b) <i>Asiatic References.</i></th></tr>
+
+<tr><td class="left_a">1894.</td><td><span class="smcap">Richard</span>,
+"Sur quelques Animaux inf�rieurs des eaux douces du Tonkin
+(Protozoaires, Rotif�res, Entomostrac�s)," M�m. Soc. zool. France, vii,
+p.&nbsp;237.</td></tr>
+
+<tr><td class="left_a">1904.</td><td><span class="smcap">Von
+Daday</span>, "Mikroskopische S�sswasserthiere aus Turkestan," Zool.
+Jahrb. (Syst.) xix, p.&nbsp;469.</td></tr>
+
+<tr><td class="left_a">1906.</td><td><span
+class="smcap">Annandale</span>, "Notes on the Freshwater Fauna of India.
+No. IV. <i>Hydra orientalis</i> and its bionomical relations with other
+Invertebrates," J. Asiat. Soc. Bengal (new series), ii, p.&nbsp;109.<span
+class='pagenum'><a name="Page_144" id="Page_144">[Pg
+144]</a></span></td></tr>
+
+<tr><td class="left_a">1906.</td><td><span
+class="smcap">Annandale</span>, "The Common <i>Hydra</i> of Bengal: its
+Systematic Position and Life History," Mem. As. Soc. Bengal, i, p.
+339.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "Notes on the Freshwater Fauna of India.
+No. X. <i>Hydra orientalis</i> during the Rains," J. Asiat. Soc. Bengal
+(new series), iii, p.&nbsp;27.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "Notes on the Freshwater Fauna of India.
+No. XI. Preliminary Note on the occurrence of a Medusa (<i>Irene
+ceylonensis</i>, Browne) in a brackish pool in the Ganges Delta and on
+the Hydroid Stage of the species," J. Asiat. Soc. Bengal (new series),
+iii, p.&nbsp;79.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span class="smcap">Willey</span>,
+"Freshwater Sponge and Hydra in Ceylon," Spolia Zeylan. Colombo, iv, p.
+184.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span
+class="smcap">Annandale</span>, "Observations on specimens of
+<i>Hydra</i> from Tibet, with notes on the distribution of the genus in
+Asia," Rec. Ind. Mus. ii, p.&nbsp;311.</td></tr>
+
+<tr><td class="left_a">1910.</td><td><span class="smcap">Powell</span>,
+"Lessons in Practical Biology for Indian Students" (Bombay).</td></tr>
+
+<tr><td class="left_a">1910.</td><td><span class="smcap">Lloyd</span>,
+"An Introduction to Biology for Students in India" (London).</td></tr>
+
+</table>
+
+<p><span class='pagenum'><a name="Page_145" id="Page_145">[Pg
+145]</a></span></p>
+
+<h3 class="p4">GLOSSARY OF TECHNICAL TERMS USED IN PART II.</h3>
+
+<table summary="Technical Terms Part II" cellpadding="5">
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Aboral</i>
+(or <i>basal disk</i>)</span></td><td class="left_a">The disk by means
+of which a free polyp attaches itself to external objects.</td></tr>
+
+<tr><td class="left_a"><i>Cnidoblast</i></td><td class="left_a">The
+living cell of the nematocyst or nettle-cell (<i>q. v.</i>).</td></tr>
+
+<tr><td class="left_a"><i>Cnidocil</i></td><td class="left_a">A minute
+bristle that projects on the surface in connection with a nettle-cell
+(<i>q. v.</i>).</td></tr>
+
+<tr><td class="left_a"><i>Column</i></td><td class="left_a">The upright
+or potentially upright part of a polyp (<i>q. v.</i>).</td></tr>
+
+<tr><td class="left_a"><i>Ectoderm</i></td><td class="left_a">The
+external cell-layer of the body-wall.</td></tr>
+
+<tr><td class="left_a"><i>Endoderm</i></td><td class="left_a">The
+internal cell-layer of the body-wall.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Green
+(chlorophyll) corpuscles</i></span></td><td class="left_a">Minute green
+bodies contained in cells of polyps or other animals and representing a
+stage in the life-history of an alga (<i>Chlorella</i>).</td></tr>
+
+<tr><td class="left_a"><i>Mesogl&oelig;a</i></td><td class="left_a">The
+intermediate, gelatinous layer of the body-wall.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Nettle-cell
+(nematocyst)</i></span></td><td class="left_a">A cell capsule full of
+liquid in which an eversible thread is coiled up.</td></tr>
+
+<tr><td class="left_a"><i>Oral disk</i></td><td class="left_a">The
+eminence that surrounds the mouth and is surrounded by
+tentacles.</td></tr>
+
+<tr><td class="left_a"><i>Peristome</i></td><td class="left_a">See "oral
+disk."</td></tr>
+
+<tr><td class="left_a"><i>Polyp</i></td><td class="left_a">An individual
+c&oelig;lenterate of simple structure that is fixed temporarily or
+permanently by one end of a more or less cylindrical body and possesses
+a mouth at the other end.</td></tr>
+
+<tr><td class="left_a"><i>Tentacles</i></td><td
+class="left_a">Filamentous outgrowths (in <i>Hydra</i> hollow) of the
+body-wall round the mouth.</td></tr>
+
+</table>
+
+<p><span class='pagenum'><a name="Page_146" id="Page_146">[Pg
+146]</a></span></p>
+
+<h3 class="p4">LIST OF THE INDIAN HYDRIDA.</h3>
+
+<hr class="c33" /> <p class="p2 center">Class HYDROZOA.</p>
+
+<p class="center">Order <b>ELEUTHEROBLASTEA</b>.</p>
+
+<p class="center larger">Family HYDRID�.</p>
+
+<p class="center">Genus <span class="smcap">Hydra</span>, <i>Linn�</i>
+(1746).</p>
+
+<p class="indent5a">24. <i>H. vulgaris</i>, Pallas (1766).</p>
+
+<p class="indent5c">25. <i>H. oligactis</i>, Pallas (1766).</p>
+
+<p class="p4 center"><span class='pagenum'><a name="Page_147"
+id="Page_147">[Pg 147]</a></span> Order <b>ELEUTHEROBLASTEA</b>.</p>
+
+<p>Naked hydrozoa which reproduce their kind by means of buds or eggs,
+or by fission, without exhibiting the phenomena of alternation of
+generations.</p>
+
+<p class="p2 center larger">Family HYDRID�.</p>
+
+<div class="genus">
+
+<span class="i0"><span class="smcap">Hydraid�</span>, Johnston, Hist.
+Brit. Zooph. (ed. 2) i, p.&nbsp;120 (1847).</span>
+
+<span class="i0"><span class="smcap">Hydrid�</span>, Hincks, Hist. Brit.
+Hydroid. Zooph. p.&nbsp;309 (1868).</span>
+
+</div>
+
+<p>Small Eleutheroblastea in which the mouth is surrounded by
+hollow tentacles. Permanent colonies are not formed, but reproduction
+by budding commonly takes place.</p>
+
+<p class="p2 center">Genus <b>HYDRA</b>, <i>Linn�</i>.</p>
+
+<p><span class="smcap">Type</span>, <i>Hydra viridis</i>, Linn�.</p>
+
+<p>Freshwater polyps which produce eggs with hard chitinous
+shells. Although habitually anchored by the end of the body
+furthest from the mouth to extraneous objects, they possess considerable
+powers of locomotion. They are extremely contractile
+and change greatly from time to time in both form and size.</p>
+
+<p>Only three well-established species of the genus, which is
+universally distributed and occurs only in fresh or brackish<a
+name="fnanchor_AQ" id="fnanchor_AQ"></a><a href="#footnote_AQ"
+class="fnanchor"><sup>[AQ]</sup></a> water, can be recognized, namely,
+<i>H. viridis</i>, Linn� (=<i>H. viridissima</i>, Pallas), <i>H.
+vulgaris</i>, Pallas (=<i>H. grisea</i>, Linn�), and <i>H.
+oligactis</i>, Pallas (=<i>H. fusca</i>, Linn�). The two latter occur in
+India, but <i>H. viridis</i> does not appear to have been found as yet
+anywhere in the Oriental Region, although it is common all over Europe
+and N. America and also in Japan. The distribution of <i>H. vulgaris</i>
+is probably cosmopolitan, but there is some evidence that <i>H.
+oligactis</i> avoids tropical districts, although, under the name
+<i>Hydra fusca</i>, it has been doubtfully recorded as occurring in
+Tonquin<a name="fnanchor_AR" id="fnanchor_AR"></a><a href="#footnote_AR"
+class="fnanchor"><sup>[AR]</sup></a>.</p>
+
+<p>The three species may be distinguished from one another by
+the following key:&mdash;</p>
+
+<table summary="Key to Hydra Linn�">
+
+<tr><td class="left_a">[I.</td><td class="left_a">Colour leaf-green; the
+cells contain green (chlorophyll) corpuscles of definite form.</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Tentacles
+comparatively stout, habitually shorter than the column, which is
+cylindrical. Egg-shell without spines, ornamented with a reticulate
+pattern</td><td class="right"><i>viridis</i>.]</td></tr>
+
+<tr><td class="left_a">II.</td><td class="left_a">Colour never
+leaf-green; no chlorophyll corpuscles present in the cells.<span
+class='pagenum'><a name="Page_148" id="Page_148">[Pg
+148]</a></span></td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Tentacles capable of
+great elongation but when the animal is at rest never very much longer
+than the column, which is cylindrical when the gastral cavity is empty.
+Largest nettle-cells almost as broad as long. Egg-shell bearing long
+spines most of which are divided at the tips</td><td
+class="right"><i>vulgaris</i>, p.&nbsp;<a
+href="#Page_148">148</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Tentacles, even when
+the animal is at rest, much longer than the column, the basal part of
+which, even when the gastral cavity is empty, is constricted. Largest
+nettle-cells considerably longer than broad.  Egg-shell smooth or
+bearing short, simple spines</td><td class="right"><i>oligactis</i>,
+p.&nbsp; <a href="#Page_158">158</a>.</td></tr>
+
+</table>
+
+<p class="p2">24. <b>Hydra vulgaris</b>, <i>Pallas</i>.</p>
+
+<div class="genus">
+
+<span class="i0">Polypes de la seconde esp�ce, Trembley, M�m. pour
+servir � l'histoire d'un genre de polypes d'eau douce*, pl. i, figs. 2,
+5; pl. vi, figs. 2, 8; pl. viii, figs. 1-7; pl. xi, figs. 11-13
+(1744).</span>
+
+<span class="i0">R�sel von Rosenhof, Insecten-Belustigung, iii, Hist.
+Polyporum, pls. lxxvi, lxxvii, lxxix-lxxxiii (1755).</span>
+
+<span class="i0">? <i>Hydra polypus</i>, Linn�, Fauna Suecica,
+p.&nbsp;542 (1761).</span>
+
+<span class="i0"><i>Hydra vulgaris</i>, Pallas, Elenchus Zoophytorum, p.
+30 (1766).</span>
+
+<span class="i0">? <i>Hydra attenuata</i>, <i>id</i>., <i>ibid</i>. p.
+32.</span>
+
+<span class="i0"><i>Hydra grisea</i>, Linn� (Gmelin), Systema Natur�
+(ed. 13), p.&nbsp;3870 (1782).</span>
+
+<span class="i0"><i>Hydra pallens</i>, <i>id</i>., <i>ibid</i>. p.
+3871.</span>
+
+<span class="i0"><i>Hydra vulgaris</i>, Ehrenberg, Abhandl. Akad. Wiss.
+Berlin, 1836, p.&nbsp;134, taf. ii.</span>
+
+<span class="i0"><i>Hydra brunnea</i>, Templeton, London's Mag. Nat.
+Hist. ix, p.&nbsp;417 (1836).</span>
+
+<span class="i0"><i>Hydra vulgaris</i>, Laurent, Rech. sur l'Hydre at
+l'�ponge d'eau douce (Voy. de la Bonite, Zoophytologie), p.&nbsp;11, pl.
+i, pl. ii, figs. 2, 2'' (1844).</span>
+
+<span class="i0"><i>Hydra vulgaris</i>, Johnston, Hist. British
+Zoophytes (ed. 2), i, p.&nbsp;122, pl. xxix, fig. 2 (1847).</span>
+
+<span class="i0"><i>Hydra vulgaris</i>, Hincks, Hist. British Hydroid
+Zoophytes, i, p.&nbsp;314, fig. 41 (1868).</span>
+
+<span class="i0"><i>Hydra aurantiaca</i>, Kleinenberg, Hydra,
+p.&nbsp;70, pl. i, fig. 1, pl. iii, fig. 10 (1872).</span>
+
+<span class="i0"><i>Hydra trembleyi</i>, Haacke, Zool. Anz. Leipzig, ii,
+p.&nbsp;622 (1879).</span>
+
+<span class="i0"><i>Hydra grisea</i>, Jickeli, Morph. Jahrb. viii, p.
+391, pl. xviii, fig. 2 (1883).</span>
+
+<span class="i0"><i>Hydra grisea</i>, Nussbaum, Arch. mikr. Anat. Bonn,
+xxix, p.&nbsp;272, pl. xiii, pl. xiv, figs. 33, 37, 47 (1887).</span>
+
+<span class="i0">? <i>Hydra hexactinella</i>, v. Lendenfeld, Zool.
+Jahrb. Jena, ii, p.&nbsp;96, pl. vi, figs. 13, 14 (1887).</span>
+
+<span class="i0">? <i>Hydra hexactinella</i>, <i>id</i>., Proc. Linn.
+Soc. N. S. Wales, x, p.&nbsp;678, p. xlviii, figs. 1-4 (1887).</span>
+
+<span class="i0"><i>Hydra grisea</i>, Brauer, Zeit. wiss. Zool. Leipzig,
+lii, p.&nbsp;169 (1891).</span>
+
+<span class="i0"><i>Hydra grisea</i>, Chun, in Br�nn's Thier-Reichs, ii
+(2), pl. ii, figs. 2<i>b</i>, 2<i>c</i>, 5 (1892).</span>
+
+<span class="i0"><i>Hydra grisea</i>, Downing, Zool. Jahrb. (Anat.)
+Jena, xxi, p.&nbsp;381 (1905).</span>
+
+<span class="i0"><i>Hydra orientalis</i>, Annandale, J. Asiat. Soc.
+Bengal, (new series) i, 1905, p.&nbsp;72.</span>
+
+<span><i>Hydra orientalis</i>, <i>id.</i>, <i>ibid.</i> (new series) ii,
+1906, p.&nbsp;109.<span class='pagenum'><a name="Page_149"
+id="Page_149">[Pg 149]</a></span></span>
+
+<span class="i0"><i>Hydra orientalis</i>, <i>id.</i>, Mem. Asiat. Soc.
+Bengal, i, p.&nbsp;340 (1906).</span>
+
+<span class="i0">? <i>Hydra orientalis</i>, Willey, Spol. Zeylan.
+Colombo, iv, p.&nbsp;185 (1907).</span>
+
+<span class="i0"><i>Hydra grisea</i>, Weltner, Arch. Naturg. Berlin,
+lxxiii, i, p.&nbsp;475 (1907).</span>
+
+<span class="i0"><i>Hydra vulgaris</i>, Brauer, Zool. Anz. xxxiii, p.
+792, fig. 1 (1908).</span>
+
+<span class="i0"><i>Hydra orientalis</i>, Annandale, Rec. Ind. Mus. ii,
+p.&nbsp;312 (1908).</span>
+
+<span class="i0"><i>Hydra grisea</i>, Frischholz, Braun's Zool. Annal.
+(W�rzburg), iii, pp.&nbsp;107, 134, &amp;c. , figs. 1 and 10-17
+(1909).</span>
+
+<span class="i0"><i>Hydra grisea</i>, <i>id.</i>, Biol. Centralbl.
+Berlin, xxix, p.&nbsp;184 (1909).</span>
+
+<span class="i0"><i>Hydra vulgaris</i>, Brauer, Die S�sswasserfauna
+Deutschlands, xix, p.&nbsp;192, figs. 336-338 (1909).</span>
+
+<span class="i0"><i>Hydra pentactinella</i>, Powell, Lessons in
+Practical Biology for Indian Students, p.&nbsp;24 (Bombay, 1910).</span>
+
+</div>
+
+<p class="p2 center">Phase <i>orientalis</i>*, Annandale.</p>
+
+<p><i>Colour</i> variable; in summer usually pale, in winter either deep
+orange, dull brown, or dark green. The cells do not contain spherical or
+oval coloured bodies.</p>
+
+<div class="figcenter">
+<img src="images/fig_029.jpg"
+width="400" height="346"  alt="Illustration: Fig. 29.&mdash;Hydra
+vulgaris, from Calcutta (phase orientalis)" title="Fig. 29.&mdash;Hydra
+vulgaris, from Calcutta (phase orientalis)" />
+<p class="caption">Fig. 29.&mdash;<i>Hydra vulgaris</i>, from Calcutta
+(phase <i>orientalis</i>).</p>
+</div>
+
+<p class="captionj">A=winter brood; B=summer brood, the same individual
+in an expanded and a contracted condition. B is more highly magnified
+than A.</p>
+
+<p><i>Column</i> slender and capable of great elongation, normally
+almost cylindrical, but when containing food often shaped like a
+wine-glass. The surface is thickly set with nettle-cells the cnidocils
+of which give it an almost hirsute appearance under the<span
+class='pagenum'><a name="Page_150" id="Page_150">[Pg 150]</a></span>
+microscope. When extended to the utmost the column is sometimes nearly
+30 mm. (1-1/5 inches) long, but more commonly it is about half that
+length or even shorter.</p>
+
+<p><i>Tentacles</i> usually 4-6, occasionally 8. They are always slender
+except when they are contracted, then becoming swollen at the base and
+slightly globular at the tip. If the animal is at rest they are not very
+much longer than the body, but if it is hungry or about to move from one
+place to another they are capable of very great extension, often
+becoming like a string of minute beads (the groups of nettle-cells)
+strung on an invisible wire.</p>
+
+<p><i>Nettle-cells.</i> The capsules with barbed threads (fig. 27, p.
+131) are very variable in size, but they are invariably broad in
+proportion to their length and as a rule nearly spherical. In a
+<i>Hydra</i> taken in Calcutta during the winter the largest capsules
+measured (unexploded) 0.0189 mm. in breadth and 0.019 in length, but in
+summer they are smaller (about 0.012 mm. in breadth). Smaller capsules
+with barbed threads always occur. The barbed threads are very long and
+slender. At their base they bear a circle of stout and prominent spines,
+usually 4 in number; above these there are a number of very small
+spines, but the small spines are usually obscure. Malformed corpuscles
+are common. The capsules with unbarbed threads are very nearly as broad
+at the distal as at the proximal end; they are broadly oval with rounded
+ends.</p>
+
+<p><i>Reproductive organs.</i> The reproductive organs are confined to
+the upper part of the body. In India eggs (fig. 28, p.&nbsp;137) are
+seldom produced. They sometimes appear, however, at the beginning of the
+hot weather. In form they are spherical, and their shell bears
+relatively long spines, which are expanded, flattened and more or less
+divided at the tip. The part of the egg that is in contact with the
+parent-polyp is bare. Spermaries are produced more readily than ovaries;
+they are mammillate in form and number from 4 to 24. Ovaries and
+spermaries have not been found on the same individual.</p>
+
+<p><i>Buds</i> are confined to a narrow zone nearer the base than the
+apex of the column. Rarely more than 2 are produced at a time, and I
+have never seen an attached bud budding. In winter 5 tentacles are as a
+rule produced simultaneously, and in summer 4. In the former case a
+fifth often makes its appearance before the bud is liberated.</p>
+
+<p>In Calcutta two broods can be distinguished, a cold-weather brood,
+which is larger, stouter, and more deeply coloured, produces buds more
+freely, has larger nematocysts, and as a rule possesses 6 tentacles; and
+a hot-weather brood, which is smaller, more slender and paler, produces
+buds very sparingly, has smaller nematocysts, and as a rule possesses
+only 4 or 5 tentacles. Only the cold-weather form is known to become
+sexually mature. There is evidence, however, that in those parts of
+India which enjoy a more uniform tropical climate than Lower Bengal,
+polyps found at all times of year resemble those found in the hot
+weather in Calcutta, and sometimes produce spermatozoa or eggs.</p>
+
+<p><span class='pagenum'><a name="Page_151" id="Page_151">[Pg
+151]</a></span>I have recently had an opportunity of comparing specimens
+of the Calcutta hot-weather form with well-preserved examples of <i>H.
+vulgaris</i>, Pallas (=<i>H. grisea</i>, Linn.), from England. They
+differ from these polyps in very much the same way as, but to a greater
+degree than they do from the winter phase of their own race, and I have
+therefore no doubt that <i>H. orientalis</i> is merely a tropical phase
+of Pallas's species. My description is based on Indian specimens, which
+seem to differ, so far as anatomy is concerned, from European ones in
+the following points:&mdash;</p>
+
+<p class="indent1a">(1) The sexes are invariably distinct;</p>
+<p class="indent1c">(2) the nematocysts are invariably smaller.</p>
+
+<p>I have seen in Burma an abnormal individual with no tentacles. <ins
+title="changed from 'It'">Its</ins> buds, however, possessed these
+organs.</p>
+
+<p><span class="smcap">Type.</span> None of the older types of
+<i>Hydra</i> are now in existence. That of <i>H. orientalis</i> is,
+however, in the collection of the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>H.
+vulgaris</i> is common in Europe and N. America and is probably found
+all over tropical Asia. The following are Indian and Ceylon
+localities:&mdash;<span class="smcap">Bengal</span>, Calcutta and
+neighbourhood (<i>Annandale</i>, <i>Lloyd</i>); Adra, Manbhum district
+(<i>Paiva</i>), Rampur Bhulia on the R. Ganges (<i>Annandale</i>);
+Chakradharpur, Chota Nagpur (<i>Annandale</i>); Pusa, Bihar
+(<i>Annandale</i>); Puri, Orissa (<i>Annandale</i>): <span
+class="smcap">Madras</span>, sea-beach near Madras town
+(<i>Henderson</i>): <span class="smcap">Bombay</span>, island of Bombay
+(<i>Powell</i>): <span class="smcap">Burma</span>, Mandalay, Upper
+Burma, and Moulmein, N. Tenasserim (<i>Annandale</i>): <span
+class="smcap">Ceylon</span>, Colombo and Peradeniya (<i>Willey</i>,
+<i>Green</i>). Dr. A. D. Imms tells me that he has obtained specimens
+that probably belong to this species in the Jumna at Allahabad.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;In India <i>H. vulgaris</i>
+is usually found, so far as my experience goes, in stagnant water. In
+Calcutta it is most abundant in ponds containing plenty of aquatic
+vegetation, and seems to be especially partial to the plant
+<i>Limnanthemum</i>, which has floating leaves attached to thin stalks
+that spring up from the bottom, and to <i>Lemna</i> (duckweed). Dr.
+Henderson, however, found specimens in a pool of rain-water on the
+sea-shore near Madras.</p>
+
+<p>There is evidence that each of the two broods which occur in Lower
+Bengal represents at least one generation; probably it represents more
+than one, for tentacles are rarely if ever produced after the animal has
+obtained its full size, and never (or only owing to accident) decrease
+in number after they have once appeared. The winter form is found
+chiefly near the surface of the water, especially on the roots of
+duckweed and on the lower surface of the leaves of <i>Limnanthemum</i>;
+but the summer form affects deeper water in shady places, and as a rule
+attaches itself to wholly submerged plants. The latter form is to be met
+with between March and October, the cold-weather form between October
+and March, both being sometimes found together at the periods of
+transition. In the unnatural environment of an aquarium, however,
+individuals of the winter form lose their colour and become attenuated,
+in these features resembling the<span class='pagenum'><a name="Page_152"
+id="Page_152">[Pg 152]</a></span> summer form, even in the cooler
+months. Buds produced in these conditions rarely have more than five
+tentacles or themselves produce buds freely after liberation.</p>
+
+<p>The buds appear in a fixed order and position, at any rate on
+individuals examined in winter; in specimens of the summer form the
+position is fixed, but the order is irregular. Each quadrant of the
+column has apparently the power of producing, in a definite zone nearer
+the aboral pole than the mouth, a single bud; but the buds of the
+different quadrants are not produced simultaneously. If we imagine that
+the quadrants face north, south, east, and west, and that the first bud
+is produced in the north quadrant, the second will be produced in the
+east quadrant, the third in the south, and the fourth in the west. It is
+doubtful whether more than four buds are produced in the lifetime of an
+individual, and apparently attached buds never bud in this race. The
+second bud usually appears before the first is liberated, and this is
+also the case occasionally as regards the third, but it is exceptional
+for four buds to be present at one time. About three weeks usually
+elapse between the date at which the bud first appears as a minute
+conical projection on the surface of the parent and that at which it
+liberates itself. This it does by bending down, fixing itself to some
+solid object by means of the tips of its tentacles, the gland-cells of
+which secrete a gummy fluid, and then tearing itself free.</p>
+
+<p>Although it is rare for more than two buds to be produced
+simultaneously, budding is apparently a more usual form of reproduction
+than sexual reproduction. Individuals that bear eggs have not yet been
+found in India in natural conditions, although males with functional
+spermaries are not uncommon at the approach of the hot weather. The few
+eggs that I have seen were produced in my aquarium towards the end of
+the cold weather. Starvation, lack of oxygen, and too high a temperature
+(perhaps also lack of light) appear to stimulate the growth of the male
+organs in ordinary cases, but perhaps they induce the development of
+ovaries in the case of individuals that are unusually well
+nourished.</p>
+
+<p>The spines that cover the egg retain d�bris of various kinds upon its
+surface, so that it becomes more or less completely concealed by a
+covering of fragments of dead leaves and the like even before it is
+separated from the polyp. Its separation is brought about by its falling
+off the column of the parent. Nothing is known of its subsequent fate,
+but probably it lies dormant in the mud through the hot weather. Eggs
+are sometimes produced that have no shells. This is probably due to the
+fact that they have not been fertilized.</p>
+
+<p>Reproduction by fission occurs rarely in the Indian <i>Hydra</i>, but
+both equal and unequal vertical fission have been observed. In the case
+of equal fission the circumoral area lengthens in a horizontal
+direction, and as many extra tentacles as those the polyp already
+possesses make their appearance. The mouth then becomes constricted in
+the middle and notches corresponding to its constriction appear at
+either side of the upper part of the column. Finally the<span
+class='pagenum'><a name="Page_153" id="Page_153">[Pg 153]</a></span>
+whole animal divides into two equal halves in a vertical direction. I
+have only seen one instance of what appeared to be unequal vertical
+fission&mdash;that of a polyp consisting of two individuals still joined
+together by the basal disk, but one about half the size of the other.
+Each had three well-developed tentacles, and in addition a minute fourth
+tentacle. This was situated on the side opposed to that of the other
+individual which bore a similar tentacle. Transverse fission has not
+been observed. The Indian <i>Hydra</i> is a very delicate animal as
+compared with such a form as <i>H. viridis</i>, and all attempts to
+produce artificial fission without killing the polyp have as yet
+failed.</p>
+
+<p>Young individuals are often, and adults occasionally, found floating
+free in the water, either with the mouth uppermost and the tentacles
+extended so as to cover as large an area as possible or with the aboral
+pole at the surface. In the former case they float in mid-water, being
+of nearly the same specific gravity as the water, and are carried about
+by any movement set up in it. In the latter case, however, the base of
+the column is actually attached to some small object such as the cast
+skin of a water-flea or to a minute drop of mucus originally given out
+by the polyp's own mouth; the tentacles either hang downwards or are
+spread out round the mouth, and the animal is carried about by wind or
+other agencies acting on the surface.</p>
+
+<p>In addition to this passive method of progression the polyp can crawl
+with considerable rapidity. In doing so it bends its column down to the
+object along which it is about to move in such a way that it lies almost
+parallel to the surface, the basal disk, however, being still attached.
+The tentacles are then extended and attach themselves near the tips to
+the surface a considerable distance away. Attachment is effected by the
+secretion of minute drops of adhesive substance from gland-cells. The
+basal disk is liberated and the tentacles contract, dragging the column,
+which still lies prone, along as they do so. The basal disk again
+affixes itself, the tentacles wrench themselves free, the surface of
+their cells being often drawn out in the process into pseudopodia-like
+projections, which of course are not true pseudopodia<a
+name="fnanchor_AS" id="fnanchor_AS"></a><a href="#footnote_AS"
+class="fnanchor"><sup>[AS]</sup></a> but merely projections produced by
+the mechanical strain. The whole action is then repeated. The polyp can
+also pull itself across a space such as that between two stems or leaves
+by stretching out one of its tentacles, fixing the tip to the object it
+desires to reach, pulling itself free from its former point of
+attachment, and dragging itself across by contracting the fixed
+tentacle. The basal disk is then turned round and fixed to the new
+support.</p>
+
+<p>The Indian polyp, like all its congeners, is attracted by light, but
+it is more strongly repelled by heat. Probably it never moves in a
+straight line, but if direct sunlight falls on one side<span
+class='pagenum'><a name="Page_154" id="Page_154">[Pg 154]</a></span> of
+a glass aquarium, the polyps move away from that side in a much less
+erratic course than is usually the case. If conditions are favourable,
+they often remain in one spot for weeks at a time, their buds
+congregating round them as they are set free. In a natural environment
+it seems that regular migrations take place in accordance with changes
+in temperature, for whereas in cool weather many individuals are found
+adhering to the lower surface of the floating leaves of
+<i>Limnanthemum</i>, few are found in this position immediately after a
+rise in the thermometer. If the rise is only a small one, they merely
+crawl down the stems to the end of which the leaves are attached, but as
+soon as the hot weather begins in earnest, the few that survive make
+their way to the deepest and most shady part of the pond. In captivity
+the polyps seek the bottom of any vessel in which they are contained, if
+sunlight falls on the surface of the water.</p>
+
+<p>The chief function of the tentacles is that of capturing prey. The
+Indian polyp feeds as a rule in the early morning, before the day has
+become hot. In an aquarium at any rate, the tentacles are never more
+than moderately extended during the night. If the polyp is hungry, they
+are extended to their greatest length in the early morning, and if prey
+is not captured, they sometimes remain in this condition throughout the
+day. In these circumstances they hang down or stand up in the water
+closely parallel to one another, and often curved in the middle as if a
+current were directed against them. Prey that comes in contact with one
+of them has little chance of escape, for nematocysts from all the
+tentacles can be readily discharged against it. Approximately once in
+half an hour the direction of the tentacles is changed, but I have been
+unable to observe any regular rhythmical movements of the tentacles or
+any correlation between those of a parent polyp and the buds still
+attached to it.</p>
+
+<p>The prey consists chiefly of the young larv� of midges (Chironomid�)
+and may-flies, but small copepod and phyllopod crustacea are also
+captured.</p>
+
+<p>As soon as the prey adheres firmly to the tentacles and has become
+paralysed it is brought to the mouth by their contracting strongly and
+is involved in a mass of colourless mucus extruded from the digestive
+cavity. Partly by the contraction of muscle-fibres in the body-wall and
+partly by movements of the mouth itself assisted by the mucus, which
+apparently remains attached to the walls of the cavity, the food is
+brought into the mouth. If it is at all bulky, it remains in the upper
+part of the cavity, the gland-cells pouring out a digestive fluid upon
+it and so dissolving out soluble substances. A large share of the
+substances thus prepared falls down to the bottom of the cavity and are
+there digested by the endoderm cells. The insoluble parts of the food
+are, however, ejected from the mouth without ever reaching the base of
+the cavity.</p>
+
+<p>The colour of the polyp appears to be due mainly to the results of
+digestion. Brown or orange individuals recently captured in<span
+class='pagenum'><a name="Page_155" id="Page_155">[Pg 155]</a></span> a
+pond and kept in favourable conditions take three or four days to digest
+their food, and the excreta ejected from the mouth then take the form of
+a white flocculent mass. If, however, the same individuals are kept for
+long in a glass aquarium, they lose their colour, even though they feed
+readily. Digestion is then a much more rapid process, and the excreta
+contain minute, irregular, coloured granules, which appear to be
+identical with those contained in the endoderm cells of individuals that
+have recently digested a meal fully. Starved individuals are always
+nearly colourless. It seems, therefore, that in this species colour is
+due directly to the products of digestion, and that digestion does not
+take place so fully in unfavourable conditions or at a high temperature
+as it does in more healthy circumstances. The dark green colour of some
+polyps is, however, less easily explained. I have noticed that all the
+individuals which have produced eggs in my aquarium have been of this
+colour, which they have retained in spite of captivity; whereas
+individuals that produced spermatozoa often lost their colour completely
+before doing so, sometimes becoming of a milky white owing to the
+accumulation of minute drops of liquid in their endoderm cells. Even in
+green individuals there is never any trace in the cells of coloured
+bodies of a definite form.</p>
+
+<p>The Indian polyp, unlike European representatives of its species, is
+a very delicate little animal. In captivity at any rate, three
+circumstances are most inimical to its life: firstly, a sudden rise in
+the temperature, which may either kill the polyp directly or cause it to
+hasten its decease by becoming sexually mature; secondly, the lack of a
+free current of air on the surface of the aquarium; and thirdly, the
+growth of a bacterium, which forms a scum on the top of the water and
+clogs up the interstices between the leaves and stems of the
+water-plants, soon killing them. If adult polyps are kept even in a
+shallow opaque vessel which is shut up in a room with closed shutters
+they generally die in a single night; indeed, they rarely survive for
+more than a few days unless the vessel is placed in such a position that
+air is moving almost continuously over its surface. The bacterium to
+which I allude often almost seals up the aquarium, especially in March
+and April, in which months its growth is very rapid. Strands of slime
+produced by it surround the polyp and even enter its mouth. In this
+event the polyp retracts its tentacles until they become mere
+prominences on its disk, and shrinks greatly in size. The colouring
+matter in its body becomes broken up into irregular patches owing to
+degeneracy of the endoderm cells, and it dies within a few hours.</p>
+
+<p><i>Hydra</i> in Calcutta is often devoured by the larva of a small
+midge (<i>Chironomus fasciatipennis</i>, Kieffer) common in the tanks
+from November to February. In the early stages of its larval life this
+insect wanders free among communities of protozoa (<i>Vorticella</i>,
+<i>Epistylis</i>, &amp;c. ) and rotifers on which it feeds, but as
+maturity approaches begins to build for itself a temporary shelter of
+one<span class='pagenum'><a name="Page_156" id="Page_156">[Pg
+156]</a></span> of two kinds, either a delicate silken tunnel the base
+of which is formed by some smooth natural surface, or a regular tube the
+base of which is fixed by a stalk situated near the middle of its length
+to some solid object, while the whole surface is covered with little
+projections. The nature of the covering appears to depend partly on that
+of the food-supply and partly on whether the larva is about to change
+its skin.</p>
+
+<p>I had frequently noticed that tunnels brought from the tank on the
+under surface of <i>Limnanthemum</i> leaves had a <i>Hydra</i> fixed to
+them. This occurred in about a third of the occupied shelters examined.
+The <i>Hydra</i> was always in a contracted condition and often more or
+less mutilated. By keeping a larva together with a free polyp in a glass
+of clean water, I have been able to observe the manner in which the
+polyp is captured and entangled. The larva settles down near the base of
+its column and commences to spin a tunnel. When this is partially
+completed, it passes a thread round the polyp's body to which it gives a
+sharp bite. This causes the polyp to bend down its tentacles, which the
+larva entangles with threads of silk, doing so by means of rapid,
+darting movements; for the nettle-cells would prove fatal should they be
+shot out against its body, which is soft. Its head is probably too
+thickly coated with chitin to excite their discharge. Indeed, small
+larv� of this very species form no inconsiderable part of the food of
+the polyp, and, so far as my observations go, a larva is always attacked
+in the body and swallowed in a doubled-up position.</p>
+
+<p>When the <i>Hydra</i> has been firmly built into the wall of the
+shelters and its tentacles fastened down by their bases on the roof, the
+larva proceeds, sometimes after an interval of some hours, to eat the
+body, which it does very rapidly, leaving the tentacles attached to its
+shelter. The meal only lasts for a few minutes; after it the larva
+enjoys several hours' repose, protected by remains of its victim, which
+retain a kind of vitality for some time. During this period it remains
+still, except for certain undulatory movements of the posterior part of
+the body which probably aid in respiration. Then it leaves the shelter
+and goes in search of further prey. Its food, even when living in a
+tunnel, does not consist entirely of <i>Hydra</i>. I have watched a
+larva building its shelter near a number of rotifers, some of which it
+devoured and some of which it plastered on to its tunnel.</p>
+
+<p>The tubular shelters occasionally found are very much stouter
+structures than the tunnels, but are apparently made fundamentally of
+the same materials; and structures intermediate between them and the
+tunnels are sometimes produced. The larva as a rule fastens to them
+branches detached from living colonies of Vorticellid protozoa such as
+<i>Epistylis</i><a name="fnanchor_AT" id="fnanchor_AT"></a><a
+href="#footnote_AT" class="fnanchor"><sup>[AT]</sup></a>.</p>
+
+<p>Of animals living in more or less intimate relations with the<span
+class='pagenum'><a name="Page_157" id="Page_157">[Pg 157]</a></span>
+polyp, I have found two very distinct species of protozoa, neither of
+which is identical with either of the two commonly found in association
+with <i>Hydra</i> in Europe, <i>Trichodina pediculus</i> and <i>Kerona
+polyporum</i>. On two occasions, one in January and the other at the
+beginning of February, I have seen a minute colourless flagellate on the
+tentacles of the Calcutta polyp. On the first occasion the tentacles
+were completely covered with this protozoon, so that they appeared at
+first sight as though encased in flagellated epithelium. The minute
+organism was colourless, transparent, considerably larger than the
+spermatozoa of <i>Hydra</i>, slightly constricted in the middle and
+rounded at each end. It bore a long flagellum at the end furthest from
+its point of attachment, the method of which I could not ascertain. When
+separated from the polyp little groups clung together in rosettes and
+gyrated in the water. On the other occasion only a few individuals were
+observed. Possibly this flagellate was a parasite rather than a
+commensal, as the individual on which it swarmed was unusually emaciated
+and colourless, and bore neither gonads nor buds. The larger stinging
+cells were completely covered by groups of the organism, and possibly
+this may have interfered with the discharge of stinging threads.</p>
+
+<p>The other protozoon was <i>Vorticella monilata</i>, Tatem, which has
+been found, not in association with <i>Hydra</i>, in Europe and S.
+America. In Calcutta I have only seen it attached to the column of the
+polyp, but probably it would also be found, if carefully looked for,
+attached to water-weeds.</p>
+
+<p>Especially in the four-rayed stage, the polyp not infrequently
+attaches itself to shells of <i>Vivipara</i>, and, more rarely, to those
+of other molluscs. It is doubtful whether this temporary association
+between <i>Hydra</i> and the mollusc is of any importance to the latter.
+Even when the polyp settles on its body and not on its shell (as is
+sometimes the case) the <i>Vivipara</i> appears to suffer no
+inconvenience, and makes no attempt to get rid of its burden. It is
+possible, on the other hand, that the <i>Hydra</i> may protect it by
+devouring would-be parasites; but of this there is no evidence<a
+name="fnanchor_AU" id="fnanchor_AU"></a><a href="#footnote_AU"
+class="fnanchor"><sup>[AU]</sup></a>.</p>
+
+<p>The association, however, is undoubtedly useful to <i>Hydra</i>. The
+mud on the shells of <i>Vivipara</i> taken on floating objects
+shows<span class='pagenum'><a name="Page_158" id="Page_158">[Pg
+158]</a></span> that in cool weather the snail comes up from the bottom
+to the surface, and it probably goes in the opposite direction in hot
+weather. Moreover, the common Calcutta species (<i>V. bengalensis</i>)
+feeds very largely, if not exclusively, on minute green alg�. It
+therefore naturally moves towards spots where smaller forms of animal
+and vegetable life abound and conditions are favourable for the polyp.
+The polyp's means of progression are limited, and the use of a beast of
+burden is most advantageous to it, for it can detach itself when it
+arrives at a favourable habitat. If specimens are kept in water which is
+allowed to become foul, a very large proportion of them will attach
+themselves to any snails confined with them. Under natural conditions
+they would thus in all probability be rapidly conveyed to a more
+suitable environment. In the tanks it is far commoner to find young
+four-rayed polyps on <i>Vivipara</i> than individuals with five or six
+rays; but the adults of the species are far less prone to change their
+position than are the young.</p>
+
+<p>The Calcutta <i>Hydra</i>, especially in spring, exhibits a distinct
+tendency to frequent the neighbourhood of sponges and polyzoa, such as
+<i>Spongilla carteri</i> and the denser forms of <i>Plumatella</i>.
+Possibly this is owing to the shade these organisms provide.</p>
+
+<p class="p2">25. <b>Hydra oligactis</b>, <i>Pallas</i>.</p>
+
+<div class="genus">
+
+<span class="i0">Polypes de la troisi�me esp�ce, Trembley, M�m. hist.
+Polypes,* pl. i, figs. 3, 4, 6; pl. ii, figs. 1-4; pl. iii, fig. 11; pl.
+v, figs. 1-4; pl. vi, figs. 3-7, 9, 10; pl. viii, figs. 8, 11; pl. ix
+(1744).</span>
+
+<span class="i0">R�sel von Rosenhof, Insekt.-Belustigung, iii, Hist.
+Polyp., pls. lxxxiv-lxxxvi (1755).</span>
+
+<span class="i0"><i>Hydra socialis</i>, Linn�, Fauna Sueica, p.&nbsp;542
+(1761).</span>
+
+<span class="i0"><i>Hydra oligactis</i>, Pallas, Elench. Zooph. p.&nbsp;29
+(1766).</span>
+
+<span class="i0">? <i>Hydra attenuata</i>, <i>id.</i>, <i>ibid.</i> p.
+32.</span>
+
+<span class="i0"><i>Hydra fusca</i>, Linn�, Syst. Nat. (ed. 13),
+p.&nbsp;3870 (1782).</span>
+
+<span class="i0"><i>Hydra oligactis</i>, Johnston, Brit. Zooph. i, p.
+124, fig. 27 (p.&nbsp;120) (1847).</span>
+
+<span class="i0"><i>Hydra oligactis</i>, Hincks, Hist. Brit. Hydr.
+Zooph. i, p.&nbsp;315, fig. 42 (1868).</span>
+
+<span class="i0"><i>Hydra roeselii</i>, Haacke, Jena Zeitschr.
+Naturwiss. xiv, p.&nbsp;135 (1880).</span>
+
+<span class="i0">? <i>Hydra rh�tica</i>, Asper, Zool. Anz. 1880,
+p.&nbsp;204, figs. 1-3.</span>
+
+<span class="i0"><i>Hydra vulgaris</i>, Jickeli (<i>nec</i> Pallas),
+Morph. Jahrb. viii, p.&nbsp;391, pl. xviii, fig. 3 (1882).</span>
+
+<span class="i0"><i>Hydra fusca</i>, Nussbaum, Arch. mikr. Anat. Bonn,
+xxix, p.&nbsp;273, pl. xiv, figs. 34-36, pl. xv, figs. 48-51, &amp;c.
+(1887).</span>
+
+<span class="i0"><i>Hydra fusca</i>, Brauer, Zeit. wiss. Zool. Leipzig,
+lii, p.&nbsp;177, pl. xi, figs. 2, 5, 6; pl. xii, fig. 6 (1891).</span>
+
+<span class="i0"><i>Hydra</i> sp. ? <i>id.</i>, <i>ibid.</i> pl. xi,
+figs. 3, 3a, 4, 7, 8; pl. xii, figs. 1, 2, 5-13.</span>
+
+<span class="i0"><i>Hydra fusca</i>, Chun in Br�nn's Thier-Reichs, ii
+(2), pl. ii, figs. 2(<i>a</i>), 4, 6 (1892).</span>
+
+<span class="i0"><i>Hydra mon&oelig;cia</i>, Downing, Science* (5) xii,
+p.&nbsp;228.</span>
+
+<span class="i0"><i>Hydra fusca</i>, <i>id.</i>, Zool. Jahrb. (Anat.)
+xxi, p.&nbsp;382 (1905).</span>
+
+<span class="i0"><i>Hydra di&oelig;cia</i>, <i>id.</i>, <i>ibid.</i> pl.
+xxiii, figs. 6, 7, &amp;c. </span>
+
+<span class="i0"><i>Hydra fusca</i>, Hertwig, Biol. Centralbl. xxvi, p.
+489 (1906).</span>
+
+<span class="i0"><i>Hydra oligactis</i>, Brauer, Zool. Anz. xxxiii, p.
+792, fig. 2 (1908).<span class='pagenum'><a name="Page_159"
+id="Page_159">[Pg 159]</a></span></span>
+
+<span class="i0"><i>Hydra polypus</i>, <i>id.</i>, <i>ibid.</i></span>
+
+<span class="i0"><i>Hydra fusca</i>, Frischholz, Ann. Zool. (W�rzburg), iii, p.&nbsp;114,
+figs. 2-9 (1909).</span>
+
+<span class="i0"><i>Hydra oligactis</i>, Brauer, S�sswasserfauna
+Deutschl. xix, p.&nbsp;193, figs. 339-341 (1909).</span>
+
+<span class="i0"><i>Hydra polypus</i>, <i>id.</i>, <i>ibid.</i> figs.
+342-344.</span>
+
+</div>
+
+<p>This species differs from <i>H. vulgaris</i> in the following
+characters:&mdash;</p>
+
+<p class="blockquote_b">(1) Even when the gastral cavity is empty, the
+basal part of the column is distinctly more slender than the upper
+part;<br />
+
+(2) even when the animal is at rest, the tentacles are much longer than
+the column;<br />
+
+(3) the nettle-cells of both types are usually smaller and more uniform
+in size than in the other species; those with barbed threads (fig. 27,
+p.&nbsp;131) are always flask-shaped and somewhat narrower in proportion
+to their length, while those with simple threads are pointed or almost
+pointed at their distal end;<br />
+
+(4) the stinging threads of the more complex form are comparatively
+stout and short;<br />
+
+(5) there are comparatively few nettle-cells in the column;<br />
+
+(6) the egg-shell is nearly smooth or covered more or less completely
+with short, simple spines (fig. 28, p.&nbsp;137).</p>
+
+<p><i>H. oligactis</i> is usually a more vigorous form than <i>H.
+vulgaris</i> and, in spite of its name, has often a considerable number
+of tentacles. The few Indian specimens examined have, however, been
+small and have not had more than six tentacles. I have not seen an
+Indian specimen with more than two buds, but European specimens
+sometimes produce a great many, and as the daughter buds do not always
+separate from the parent until they have themselves produced buds,
+temporary colonies of some complexity arise; Chun figures a specimen
+with nineteen daughter and granddaughter buds<a name="fnanchor_AV"
+id="fnanchor_AV"></a><a href="#footnote_AV"
+class="fnanchor"><sup>[AV]</sup></a>.</p>
+
+<p>In Europe and N. America there appear to be two races or phases of
+the species. To avoid ambiguity they may be called form A and form B and
+described as follows:&mdash;</p>
+
+<p class="blockquote_b">Form A is of vigorous growth. It is as a rule
+di&oelig;cious, and its reproductive organs may be borne practically at
+any level on the surface of the column. Its eggs are spherical and as a
+rule covered almost uniformly with spines.</p>
+
+<p class="blockquote_b"><span class='pagenum'><a name="Page_160"
+id="Page_160">[Pg 160]</a></span>Form B is smaller and has smaller and
+more variable nettle-cells. Its reproductive organs are borne only on
+the distal third or at the base of its column and it is often
+mon&oelig;cious. The lower surface of its egg is flattened, adherent,
+and devoid of spines.</p>
+
+<p>The larger form (A) was originally named <i>Hydra mon&oelig;cia</i>
+by Downing, who in 1904 expressed a wish to substitute for the specific
+name, which had been given through inadvertence, the more appropriate
+one <i>di&oelig;cia</i>. As, however, it appears to be the commoner of
+the two in northern Europe, we may regard it as probably being the one
+named <i>Hydra oligactis</i> by Pallas and therefore may accept it as
+the <i>forma typica</i> of that species. According to Brauer (1908) the
+smaller form is Linn�'s <i>Hydra polypus</i>; but the original
+description of the "species" hardly bears out this view. As reproductive
+organs have not yet been found in Indian specimens, it is impossible to
+say to which of the two forms they belong.</p>
+
+<p>A red form of <i>H. oligactis</i> occurs in Tibet in the lake
+Rham-tso, at an altitude of about 15,000 feet and has been reported from
+various small lakes in mountainous parts of Europe. It is probably the
+form called <i>Hydra rh�tica</i> by Asper, but his figures are lacking
+in detail and appear to have been drawn from specimens in a state of
+partial contraction. <i>H. rubra</i>, Lewes (Ann. Mag. Nat. Hist. (3) v,
+p.&nbsp;71, 1860), may also be identical with this form. Roux, indeed,
+states that <i>H. rubra</i> is only found living unattached at
+considerable depths (Ann. Biol. lacustre ii, p.&nbsp;266, 1907); but
+this statement does not accord with the fact that Lewes's specimens were
+found in ponds on Wimbledon Common.</p>
+
+<p><span class="smcap">Type</span> not in existence.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>H.
+oligactis</i> is widely distributed in Europe and N. America, but in
+India has only been found in and near the city of Lahore in the
+Punjab.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;This species was found by
+Major J. Stephenson, I.M.S., in the basin of a fountain at Lahore and in
+an ornamental canal in the Shalimar Gardens on the outskirts of the same
+city. Nothing is known as regards its habits in this country. In N.
+America, according to Downing, form B breeds in September and October
+and form A from October to December. The eggs of form B remain attached
+to the parent until the two cellular layers are formed and then drop
+off, whereas those of form A are fixed by the parent to some extraneous
+object, its column contracting until they are in a favourable position
+for attachment.</p>
+
+<p>The colour of Indian examples of <i>H. oligactis</i> apparently
+resembles that of the Calcutta winter brood of <i>H. vulgaris</i> so far
+as visual effect is concerned, but I have noticed in specimens from
+Lahore and the neighbourhood that very minute spherical bodies of a dark
+green colour are present in the endoderm cells.</p>
+
+<p class="footnote">
+<a name="footnote_AQ" id="footnote_AQ"></a>
+<a href="#fnanchor_AQ">[AQ]</a>
+A small form of <i>H. viridis</i> (var. <i>bakeri</i>, Marshall) is
+found in brackish water in England.</p>
+
+<p class="footnote">
+<a name="footnote_AR" id="footnote_AR"></a>
+<a href="#fnanchor_AR">[AR]</a>
+Richard, M�m. Soc. zool. France, vii, p.&nbsp;237 (1894).</p>
+
+<p class="footnote">
+<a name="footnote_AS" id="footnote_AS"></a>
+<a href="#fnanchor_AS">[AS]</a>
+See Zykoff, Biol. Centralbl. xviii, p.&nbsp;272 (1898), and Annandale,
+Rec. Ind. Mus. i, p.&nbsp;67 (1907).</p>
+
+<p class="footnote">
+<a name="footnote_AT" id="footnote_AT"></a>
+<a href="#fnanchor_AT">[AT]</a>
+Further particulars regarding the life-history of this larva will be
+found on pp.&nbsp;114 and 115, J. Asiat. Soc. Bengal, ii (n. s.) 1906.</p>
+
+<p class="footnote">
+<a name="footnote_AU" id="footnote_AU"></a>
+<a href="#fnanchor_AU">[AU]</a>
+In the Calcutta tanks operculate molluscs such as <i>Vivipara</i> are
+certainly more free from visible attack than non-operculate species.
+This is the case for instance, as regards the common aquatic glowworm
+(<i>Luciola</i> sp.), which destroys large numbers of individuals of
+<i>Limnophysa</i>, <i>Limn�us</i>, &amp;c.  If it has been starved for
+several days in an aquarium it will attack an operculate form, but
+rarely with success. Similarly <i>Ch�togaster bengalensis</i> attaches
+itself exclusively to non-operculate forms. In the one case the polyp
+could do very little against an adversary with so stout an integument as
+the insect, while, in the other, it is doubtful whether the worm does
+any harm to its host. The polyp would afford very little protection
+against the snail's vertebrate enemies or against what appears to be its
+chief foe, namely, drought. As the water sinks in the tank
+non-operculate species migrate to the deeper parts, but <i>Vivipara</i>
+and <i>Ampullaria</i> close their shells, remain where they are, and so
+often perish, being left high and dry, exposed to the heat of the
+sun.</p>
+
+<p class="footnote">
+<a name="footnote_AV" id="footnote_AV"></a>
+<a href="#fnanchor_AV">[AV]</a>
+Pallas writes as regards this "pulcherrime vegetantem varietatem" with
+his usual critical insight, "Vix tamen peculiaris speciei nomine
+salutanda videtur." It is probably the <i>Hydra socialis</i> of
+Linn�.</p>
+
+<p><span class='pagenum'><a name="Page_161" id="Page_161">[Pg
+161]</a></span></p>
+
+<h3 class="p4">PART III.<br />
+
+FRESHWATER POLYZOA<br />
+
+(CTENOSTOMATA &amp; PHYLACTOL�MATA).</h3>
+
+<p><span class='pagenum'><a name="Page_162" id="Page_162">[Pg
+162]</a></span><br /><span class='pagenum'><a name="Page_163"
+id="Page_163">[Pg 163]</a></span></p>
+
+<h3 class="p4">INTRODUCTION TO PART III.</h3>
+
+<p class="p2 center">I.</p>
+
+<p class="center"><span class="smcap">Status and Structure of the
+Polyzoa.</span></p>
+
+<p>The Polyzoa constitute a class in the third great division of the
+animal kingdom, the so-called Triploblastea. In this division are
+included also the worms, molluscs, insects, crustacea, spiders,
+vertebrates, etc.; for heterogeneous as its elements appear, all these
+animals may be considered to have essential features in common, in
+particular a body consisting primarily of three cellular layers. Most of
+them also possess a body cavity distinct from the alimentary canal. Some
+authors regard the position of the polyzoa as near that of the higher
+worms, but the group is an isolated one.</p>
+
+<p>In considering the anatomy of simple forms of animal life such as the
+sponges it is necessary to pay attention mainly to individual cells, but
+in discussing more complicated forms our notice is first attracted to
+tissues and organs, for the cells of which these tissues and organs are
+composed have each a definite position, a definite structure, and a
+definite function. The most characteristic feature of the polyzoa,
+considered from this point of view, is the fact that most of their
+organs fall into one of two categories and are connected either with
+what is called the "zo&oelig;cium" or with what is known as the
+"polypide." The zo&oelig;cium is a cage in which the polypide is
+enclosed, but it is a living cage, differing from the shell of a snail
+or the tubes in which many worms encase themselves in being part of the
+animal itself. The polypide consists mainly of the organs connected
+directly and indirectly with nutrition and of part of the muscular
+system; its name is derived from the fact that it bears a superficial
+resemblance to a polyp such as <i>Hydra</i>.</p>
+
+<p>The shape and structure of the zo&oelig;cium differs greatly in
+different groups of polyzoa. In its simplest form it is merely a
+cylindrical tube of living matter which secretes an outer horny or
+gelatinous covering. It is open at the end furthest from its base, at
+which it is attached either to another zo&oelig;cium or to some kind of
+supporting structure. Certain parts of the polypide can always be
+extruded from the aperture, which is known technically as the "orifice,"
+or withdrawn through it into the zo&oelig;cium.<span class='pagenum'><a
+name="Page_164" id="Page_164">[Pg 164]</a></span> When the polypide is
+retracted it draws in with it a portion of the zo&oelig;cium. The dead
+outer layer or ectocyst lines part of the portion thus invaginated and
+forms the walls of a cavity within the orifice. The base of this cavity
+consists in many forms of a transverse partition pierced in the middle
+by a circular hole and known as the "diaphragm." The diaphragm, however,
+does not constitute the limit of the invaginated portion of the
+zo&oelig;cium, for the living inner wall or endocyst is dragged in still
+further and forms a sheath round the retracted tentacles. When the
+tentacles are protruded they emerge through the hole in the diaphragm,
+carrying with them their sheath of endocyst. The invagination above the
+diaphragm, consisting of both endocyst and ectocyst, is then
+everted.</p>
+
+<p>The tentacles are a characteristic feature of the polypide. Together
+with the base to which they are attached they are known as the
+"lophophore"; they surround the mouth, usually in a circle. They differ
+widely from the tentacles of <i>Hydra</i> in both structure and
+function, although they too serve as organs for the capture of prey;
+they are not highly contractile and are not provided with nettle-cells
+but are covered with cilia, which are in constant motion. When extruded
+they form a conspicuous calix-like crown to the zo&oelig;cium, but in
+the retracted condition they are closely pressed together and lie
+parallel to one another. They are capable individually of motion in all
+directions but, although they usually move in concert, they cannot as a
+rule seize objects between them.</p>
+
+<p>The mouth is a hole situated in the midst of the tentacles. It leads
+directly into a funnel-shaped &oelig;sophagus, the upper part of which
+is lined with cilia and is sometimes distinguished as the "pharynx,"
+while the lower part, the &oelig;sophagus proper, is a thin-walled tube
+that connects the pharynx with the stomach, which it enters on the
+dorsal side. The stomach is a bulky organ that differs markedly in form
+and structure in different groups of polyzoa. It is lined internally
+with glandular cells and the inner wall is sometimes thrown into folds
+or "rug�." The part with which the &oelig;sophagus communicates is known
+as the "cardiac" portion, while the part whence the intestine originates
+is called the "pylorus" or "pyloric" portion. The intestine commences on
+the ventral side opposite the entrance of the &oelig;sophagus and nearly
+on a level with it, the bulk of the stomach depending between the two
+tubes. This part of the stomach is often produced into a blind tube, the
+fundus or c�cum. The alimentary canal may therefore be described as
+distinctly <b>Y</b>-shaped. The proximal part of the intestine is in
+some forms lined with cilia, and the tube as a whole is usually divided
+into two parts&mdash;the intestine proper, which is nearest the stomach,
+and the rectum, which opens by the anus not far from the mouth.</p>
+
+<p>The nervous system consists of a central ganglion or brain, which is
+situated at the base of the tentacles on the side nearest the anus and
+gives out radiating nerves in all directions. Close<span
+class='pagenum'><a name="Page_165" id="Page_165">[Pg 165]</a></span> to
+the brain and providing a communication between the cavity of the
+zo&oelig;cium and the cavity in which the tentacles are contained (or,
+in the case of an expanded polyp, the external world) is a ciliated tube
+known as the "intertentacular organ." Apparently it acts as a passage
+through which the genital products are expelled; but contradictory
+statements have been made regarding it, and perhaps it is present only
+at certain seasons or in certain conditions of the polypide.</p>
+
+<div class="figcenter">
+<img src="images/fig_030.png"
+width="275" height="374"  alt="Illustration: Fig. 30.&mdash;Vertical
+section through a polypide of Alcyonidium with the polypide retracted
+(after Prouho)." title="Fig. 30.&mdash;Vertical section through a
+polypide of Alcyonidium with the polypide retracted (after Prouho)." />
+<p class="caption">Fig. 30.&mdash;Vertical section through a polypide of
+<i>Alcyonidium</i> with the polypide retracted (after Prouho).</p>
+</div>
+
+<p class="captionj">A=orifice; B=contracted collar; C=diaphragm;
+D=parieto-vaginal muscles; E=tentacles; F=pharynx; G=&oelig;sophagus;
+H=stomach; J=intestine; K=rectum; L=intertentacular organ; M=retractor
+muscle; N=testes; O=ovary; P=funiculus; Q=parietal muscles; R=ectocyst;
+S=endocyst.</p>
+
+<p>The muscular system is often of a complicated nature, but three sets
+of muscles may be distinguished as being of peculiar importance, viz.,
+(i) the retractor muscles, which are fixed to the<span
+class='pagenum'><a name="Page_166" id="Page_166">[Pg 166]</a></span>
+base of the lophophore at one end and to the base of the zo&oelig;cium
+at the other, and by contracting pull the former back into the
+zo&oelig;cium; (ii) the parieto-vaginal muscles, which connect the upper
+part of the invaginated portion of the zo&oelig;cium with the main wall
+thereof; and (iii) the parietal muscles, which run round the inner wall
+of the zo&oelig;cium and compress the zo&oelig;cium as a whole. The
+parietal muscles are not developed in the Phylactol�mata, the most
+highly specialized group of freshwater polyzoa.</p>
+
+<p>The cavity between the polypide and the zo&oelig;cium contains a
+reticulate tissue of cells known as the "funicular" tissue, and this
+tissue is usually concentrated to form a hollow strand or strands
+("funiculi") that connect the outer wall of the alimentary canal with
+the endocyst.</p>
+
+<p>This rapid sketch of the general anatomy of a simple polyzoon will be
+the best understood by comparing it with fig. 30, which represents, in a
+somewhat diagrammatic fashion, a vertical section through a single
+zo&oelig;cium and polypide of the order Ctenostomata, to which some of
+the freshwater species belong. The polypide is represented in a
+retracted condition in which the <b>Y</b>-shaped <ins title="changed
+from 'dispsition'">disposition</ins> of the alimentary canal is somewhat
+obscured.</p>
+
+<p>In the great majority of cases the polyzoa form permanent colonies or
+polyparia, each of which consists of a number of individual zo&oelig;cia
+and polypides connected together by threads of living tissue. These
+colonies are formed by budding, not by independent individuals becoming
+associated together. In a few cases compound colonies are formed owing
+to the fact that separate simple colonies congregate and secrete a
+common investment; but in these cases there is no organic connection
+between the constituent colonies. It is only in the small subclass
+Entoprocta, the polypides and zo&oelig;cia of which are not nearly so
+distinct from one another as they are in other polyzoa (the Ectoprocta),
+that mature solitary individuals occur.</p>
+
+<p>As representatives of both subclasses of polyzoa and of more than one
+order of Ectoprocta occur in fresh water, I have prefaced my description
+of the Indian species with a synopsis of the more conspicuous characters
+of the different groups (pp.&nbsp;183-186).</p>
+
+<p class="p2 center"><span class="smcap">Capture and Digestion of Food:
+Elimination of Waste Products.</span></p>
+
+<p>The food of all polyzoa consists of minute living organisms, but its
+exact nature has been little studied as regards individual species and
+genera. In <i>Victorella bengalensis</i> it consists largely of diatoms,
+while the species of <i>Hislopia</i> and <i>Arachnoidea</i> possess an
+alimentary canal modified for the purpose of retaining flagellate
+organisms until they become encysted. Similar organisms form a large
+part of the food of the phylactol�mata.</p>
+
+<p>Although the tentacles may be correctly described as organs used in
+capturing prey, they do not themselves seize it but waft<span
+class='pagenum'><a name="Page_167" id="Page_167">[Pg 167]</a></span> it
+by means of the currents set up by their cilia to the mouth, into which
+it is swept by the currents produced by the cilia lining the pharynx.
+The tentacles are also able in some species to interlace themselves in
+order to prevent the escape of prey. Apparently they have the power of
+rejecting unsuitable food, for they may often be observed to bend
+backwards and forwards and thrust particles that have approached them
+away, and if the water contains anything of a noxious nature in solution
+the lophophore is immediately retracted, unless it has been completely
+paralysed. In the phylactol�mata the peculiar organ known as the
+epistome is capable of closing the mouth completely, and probably acts
+as an additional safeguard in preventing the ingestion of anything of an
+injurious nature.</p>
+
+<p>In many genera and larger groups the food commonly passes down the
+pharynx into the stomach without interruption, although it is probable
+that in all species the &oelig;sophagus can be closed off from the
+stomach by a valve at its base. In some forms, however, a "gizzard" is
+interposed between the &oelig;sophagus and the stomach. This gizzard has
+not the same function in all cases, for whereas in some forms
+(<i>e.&nbsp;g.</i>, in <i>Bowerbankia</i>) it is lined with horny
+projections and is a powerful crushing organ, in others
+(<i>e.&nbsp;g.</i>, in <i>Hislopia</i> or <i>Victorella</i>) it acts as
+an antechamber in which food can be preserved without being crushed
+until it is required for digestion, or rough indigestible particles can
+be retained which would injure the delicate walls of the stomach.</p>
+
+<p>Digestion takes place mainly in the stomach, the walls of which are
+of a glandular nature. The excreta are formed into oval masses in the
+rectum and are extruded from the anus in this condition.</p>
+
+<p>Although the gross non-nutritious parts of the food are passed <i>per
+anum</i>, the waste products of the vital processes are not eliminated
+so easily, and a remarkable process known as the formation of brown
+bodies frequently takes place. This process cannot be described more
+clearly and succinctly than by quoting Dr. Harmer's description of it
+from pp.&nbsp;471 and 472 of vol. ii. of the Cambridge Natural History, a
+volume to which I have been much indebted in the preparation of this
+introduction. The description is based very largely on Dr. Harmer's own
+observations<a name="fnanchor_AW" id="fnanchor_AW"></a><a
+href="#footnote_AW" class="fnanchor"><sup>[AW]</sup></a>.</p>
+
+<p>"The tentacles, alimentary canal, and nervous system break down, and
+the tentacles cease to be capable of being protruded. The degenerating
+organs become compacted into a rounded mass, known from its colour as
+the 'brown body.' This structure may readily be seen in a large
+proportion of the zo&oelig;cia of transparent species. In active parts
+of the colony of the body-wall next develops an internal bud-like
+structure, which rapidly acquires the form of a new polypide. This takes
+the place originally occupied by the<span class='pagenum'><a
+name="Page_168" id="Page_168">[Pg 168]</a></span> old polypide, while
+the latter may either remain in the zo&oelig;cium in the permanent form
+of a 'brown body,' or pass to the exterior. In <i>Flustra</i> the young
+polypide-bud becomes connected with the 'brown body' by a funiculus. The
+apex of the blind pouch or 'c�cum' of the young stomach is guided by
+this strand to the 'brown body,' which it partially surrounds. The
+'brown body' then breaks up, and its fragments pass into the cavity of
+the stomach, from which they reach the exterior by means of the
+anus."</p>
+
+<p>Brown bodies are rarely if ever found in the phylactol�mata, in which
+the life of the colony is always short; but they are not uncommon in
+<i>Hislopia</i> and <i>Victorella</i>, although in the case of the
+former they may easily escape notice on account of the fact that they
+are much paler in colour than is usually the case. When they are found
+in a ctenostome the collar-like membrane characteristic of the suborder
+is extruded from the orifice (which then disappears) and remains as a
+conspicuous external addition to the zo&oelig;cium, the ectocyst of
+which, at any rate in <i>Bowerbankia</i> and <i>Victorella</i>,
+sometimes becomes thickened and dark in colour.</p>
+
+<p>It is noteworthy that the colouring matter of the brown bodies is
+practically the only colouring matter found in the polypides of most
+polyzoa. Young polypides are practically colourless in almost all
+cases.</p>
+
+<p class="p2 center"><span class="smcap">Reproduction:
+Budding.</span></p>
+
+<p>Polyzoa reproduce their species in three ways&mdash;(i) by means of
+eggs, (ii) by budding, and (iii) by means of bodies developed asexually
+and capable of lying dormant in unfavourable conditions without losing
+their vitality.</p>
+
+<p>Most, if not all species are hermaphrodite, eggs and spermatozoa
+being produced either simultaneously or in succession by each
+individual, or by certain individuals in each zoarium. The reproductive
+organs are borne on the inner surface of the endocyst, as a rule in a
+definite position, and often in connection with the funiculus or
+funiculi. It is doubtful to what extent eggs are habitually fertilized
+by spermatozoa of the individual that has borne them, but in some cases
+this is practically impossible and spermatozoa from other individuals
+must be introduced into the zo&oelig;cium.</p>
+
+<p>Budding as a rule does not result in the formation of independent
+organisms, but is rather comparable to the proliferation that has become
+the normal method of growth in sponges, except of course that
+individuality is much more marked in the component parts of a polyzoon
+colony than it is in a sponge. In the genera described in this volume
+budding takes place by the outgrowth of a part of the body-wall and the
+formation therein of a new polypide, but the order in which the buds
+appear and their arrangement in reference to the parent zo&oelig;cium is
+different in the<span class='pagenum'><a name="Page_169"
+id="Page_169">[Pg 169]</a></span> different groups. In the freshwater
+ctenostomes three buds are typically produced from each zo&oelig;cium,
+one at the anterior end and one at either side, the two latter being
+exactly opposite one another. The parent zo&oelig;cium in this formation
+arises from another zo&oelig;cium situated immediately behind it, so
+that each zo&oelig;cium, except at the extremities of the zoarium, is
+connected with four other zo&oelig;cia, the five together forming a
+cross. The two lateral buds are, however, frequently suppressed, or only
+one of them is developed, and a linear series of zo&oelig;cia with
+occasional lateral branches is formed instead of a series of crosses. In
+the phylactol�mata, on the other hand, the linear method of budding is
+the typical one, but granddaughter-buds are produced long before the
+daughter-buds are mature, so that the zo&oelig;cia are frequently
+pressed together, and lateral buds are produced irregularly. In
+<i>Victorella</i> additional adventitious buds are produced freely near
+the tip of the zo&oelig;cium.</p>
+
+<p>Reproduction by spontaneous fission sometimes occurs, especially in
+the Lophopin�, but the process differs from that which takes place when
+a <i>Hydra</i> divides into two, for there is no division of individual
+zo&oelig;cia or polypides but merely one of the whole zoarium.</p>
+
+<p>The production of reproductive bodies analogous to the gemmules of
+sponges appears to be confined in the polyzoa to the species that
+inhabit fresh or brackish water, nor does it occur in all of these.</p>
+
+<p>All the phylactol�mata produce, within their zo&oelig;cia, the bodies
+known as statoblasts. These bodies consist essentially of masses of
+cells containing abundant food-material and enclosed in a capsule with
+thick horny walls. In many cases the capsule is surrounded by a
+"swim-ring" composed of a mass of horny-walled chambers filled with air,
+which renders the statoblast extremely light and enables it to float on
+the surface of the water; while in some genera the margin of the
+swim-ring bears peculiar hooked processes, the function of which is
+obscure. The whole structure first becomes visible as a mass of cells
+(the origin of all of which is not the same) formed in connection with
+the funiculus, and the statoblast may be regarded as an internal bud.
+Its origin and development in different genera has been studied by
+several authors, notably by Oka<a name="fnanchor_AX"
+id="fnanchor_AX"></a><a href="#footnote_AX"
+class="fnanchor"><sup>[AX]</sup></a> in <i>Pectinatella</i>, and by
+Braem<a name="fnanchor_AY" id="fnanchor_AY"></a><a href="#footnote_AY"
+class="fnanchor"><sup>[AY]</sup></a> in <i>Cristatella</i>.</p>
+
+<p>The external form of the statoblasts is very important in the
+classification of the phylactol�mata, to which these structures are
+confined. In all the genera that occur in India they are flattened and
+have an oval, circular, or approximately oval outline.</p>
+
+<p>In temperate climates statoblasts are produced in great<span
+class='pagenum'><a name="Page_170" id="Page_170">[Pg 170]</a></span>
+profusion at the approach of winter, but in India they occur, in most
+species, in greatest numbers at the approach of the hot weather.</p>
+
+<div class="figcenter">
+<img src="images/fig_031.png"
+width="450" height="298"  alt="Illustration: Fig. 31.&mdash;Part of the
+zoarium of Victorella bengalensis entirely transformed into resting
+buds, � 25. (From an aquarium in Calcutta.)" title="Fig. 31.&mdash;Part
+of the zoarium of Victorella bengalensis entirely transformed into
+resting buds, � 25. (From an aquarium in Calcutta.)" />
+<p class="caption">Fig. 31.&mdash;Part of the zoarium of <i>Victorella
+bengalensis</i> entirely transformed into resting buds, � 25. (From an
+aquarium in Calcutta.)</p>
+</div>
+
+<p>In the family Paludicellid� (ctenostomata) external buds which
+resemble the statoblasts in many respects are produced at the approach
+of unfavourable climatic conditions, but no such buds are known in the
+family Hislopiid�, the zoaria of which appear to be practically
+perennial. The buds consist of masses of cells formed at the points at
+which ordinary buds would naturally be produced, but packed with
+food-material and protected like statoblasts by a thick horny coat. It
+seems also that old zo&oelig;cia and polypides are sometimes transformed
+into buds of the kind (fig. 31), and it is possible that there is some
+connection between the formation of brown bodies and their production.
+Like the statoblasts of the phylactol�mata the resting buds of the
+Paludicellid� are produced in Europe at the approach of winter, and in
+India at that of the hot weather.</p>
+
+<p class="p2 center"><span class="smcap">Development.</span></p>
+
+<p class="center">(a) <i>From the Egg.</i></p>
+
+<p>Some polyzoa are oviparous, while in others a larva is formed within
+the zo&oelig;cium and does not escape until it has attained some
+complexity of structure. Both the ctenostomatous genera that are found
+in fresh water in India are oviparous, but whereas in <i>Victorella</i>
+the egg is small and appears to be extruded soon after its
+fertilization, in <i>Hislopia</i> it remains in the zo&oelig;cium for a
+considerable time, increases to a relatively large size, and in some
+unknown manner accumulates a considerable amount of food-material before
+escaping. Unfortunately the development is unknown in both genera.</p>
+
+<p>In the phylactol�mata the life-history is much better known, having
+been studied by several authors, notably by Allman, by Kraepelin, and by
+Braem (1908). The egg is contained in a thin<span class='pagenum'><a
+name="Page_171" id="Page_171">[Pg 171]</a></span> membrane, and while
+still enclosed in the zo&oelig;cium, forms by regular division a hollow
+sphere composed of similar cells. This sphere then assumes an ovoid
+form, becomes covered with cilia externally, and breaks its way through
+the egg-membrane into the cavity of the zo&oelig;cium. Inside the
+embryo, by a process analogous to budding, a polypide or a pair of
+polypides is formed. Meanwhile the embryo has become distinctly
+pear-shaped, the polypide or polypides being situated at its narrow end,
+in which a pore makes its appearance. The walls are hollow in the region
+occupied by the polypide, the cavity contained in them being bridged by
+slender threads of tissue. The larva thus composed makes its way out of
+the zo&oelig;cium, according to Kraepelin through the orifice of a
+degenerate bud formed for its reception, and swims about for a short
+time by means of the cilia with which it is covered. Its broad end then
+affixes itself to some solid object, the polypide is everted through the
+pore at the narrow end and the whole of that part of the larva which
+formerly enclosed it is turned completely inside out. A zoarium with its
+included polypides is finally produced from the young polypide by the
+rapid development of buds.</p>
+
+<p class="p2 center">(b) <i>From the Statoblast and Resting
+Buds.</i></p>
+
+<p>There is little information available as regards the development of
+the young polyzoon in the resting buds of the freshwater ctenostomes. In
+<i>Paludicella</i> and <i>Pottsiella</i> the capsule of the bud splits
+longitudinally into two valves and the polypide emerges between them;
+but in <i>Victorella bengalensis</i> one of the projections on the
+margin of the bud appears to be transformed directly into the tip of a
+new zo&oelig;cium and the capsule is gradually absorbed.</p>
+
+<p>Contradictory statements have been made as regards several important
+points in the development of the statoblast and it is probable that
+considerable differences exist in different species. The following facts
+appear to be of general application. The cellular contents of the
+capsule consist mainly of a mass of cells packed with food-material in a
+granular form, the whole enclosed in a delicate membrane formed of flat
+cells. When conditions become favourable for development a cavity
+appears near one end of the mass and the cells that form its walls
+assume a columnar form in vertical section. The cavity increases rapidly
+in size, and, as it does so, a young polypide is budded off from its
+walls. Another bud may then appear in a similar fashion, and the
+zo&oelig;cium of the first bud assumes its characteristic features. The
+capsule then splits longitudinally into two disk-like valves and the
+young polypide, in some cases already possessing a daughter bud, emerges
+in its zo&oelig;cium, adheres by its base to some external object and
+produces a new polyparium by budding. The two valves of the statoblast
+often remain attached to the zoarium that has emerged from between them
+until it attains considerable dimensions (see <a href="#Plate_IV">Plate
+IV</a>, fig. 3 <i>a</i>).</p>
+
+<p><span class='pagenum'><a name="Page_172" id="Page_172">[Pg
+172]</a></span>What conditions favour development is a question that
+cannot yet be answered in a satisfactory manner. Statoblasts can lie
+dormant for months and even for years without losing their power of
+germinating, and it is known that in Europe they germinate more readily
+after being subjected to a low temperature. In tropical India this is,
+of course, an impossible condition, but perhaps an abnormally high
+temperature has the same effect. At any rate it is an established fact
+that whereas the gemmules of most species germinate in Europe in spring,
+in Bengal they germinate either at the beginning of the "rains" or at
+that of our mild Indian winter.</p>
+
+<p class="p2 center "><span class="smcap">Movements.</span></p>
+
+<div class="figcenter">
+<img src="images/fig_032.png"
+width="300" height="219"  alt="Illustration: Fig. 32.&mdash;Zoarium of
+Lophopodella carteri moving along the stem of a water plant, � 4. (From
+Igatpuri Lake.)" title="Fig. 32.&mdash;Zoarium of Lophopodella carteri
+moving along the stem of a water plant, � 4. (From Igatpuri Lake.)" />
+<p class="caption">Fig. 32.&mdash;Zoarium of <i>Lophopodella carteri</i>
+moving along the stem of a water plant, � 4. (From Igatpuri Lake.)</p>
+</div>
+
+<p>In the vast majority of the polyzoa, marine as well as freshwater,
+movement is practically confined to the polypide, the external walls of
+the zo&oelig;cium being rigid, the zo&oelig;cia being closely linked
+together and the whole zoarium permanently fixed to some extraneous
+object. In a few freshwater species belonging to the genera
+<i>Cristatella</i>, <i>Lophopus</i>, <i>Lophopodella</i> and
+<i>Pectinatella</i>, the whole zoarium has the power of progression.
+This power is best developed in <i>Cristatella</i>, which glides along
+with considerable rapidity on a highly specialized "sole" provided with
+abundant mucus and representing all that remains of the ectocyst. It is
+by no means clear how the zoaria of the other genera move from one place
+to another, for the base is not modified, so far as can be seen, for the
+purpose, and the motion is extremely slow. It is probable, however, that
+progression is effected by alternate expansions and contractions of the
+base, and in <i>Lophopodella</i> (fig. 32), which moves rather less
+slowly than its allies, the anterior part of the base is raised at times
+from the surface along which it is moving. The whole zoarium can be
+released in this way and occasionally drops through the water, and is
+perhaps carried by currents from one place to another in so doing.</p>
+
+<p><span class='pagenum'><a name="Page_173" id="Page_173">[Pg
+173]</a></span>So far as the polypides are concerned, the most important
+movements are those which enable the lophophore and the adjacent parts
+to be extruded from and withdrawn into the zo&oelig;cium. The latter
+movement is executed by means of the retractor muscles, which by
+contracting drag the extruded parts back towards the posterior end of
+the endocyst, but it is not by any means certain how the extrusion of
+the lophophore is brought about. In most ctenostomes the action of the
+parietal muscles doubtless assists in squeezing it out when the
+retractor and parieto-vaginal muscles relax, but Oka states that
+protrusion can be effected in the phylactol�mata even after the
+zo&oelig;cium has been cut open. Possibly some hydrostatic action takes
+place, however, and allowance must always be made for the natural
+resilience of the inverted portion of the ectocyst.</p>
+
+<p>Even when the polypide is retracted, muscular action does not cease,
+for frequent movements, in some cases apparently rhythmical, of the
+alimentary canal may be observed, and in <i>Hislopia</i> contraction of
+the gizzard takes place at irregular intervals.</p>
+
+<p>When the lophophore is expanded, the tentacles in favourable
+circumstances remain almost still, except for the movements of their
+cilia; but if a particle of matter too large for the mouth to swallow or
+otherwise unsuitable is brought by the currents of the cilia towards it,
+individual tentacles can be bent down to wave it away and similar
+movements are often observed without apparent cause.</p>
+
+<p>In the cheilostomes certain individuals of each zoarium are often
+profoundly modified in shape and function and exhibit almost constant
+rhythmical or convulsive movements, some ("avicularia") being shaped
+like a bird's beak and snapping together, others ("vibracula") being
+more or less thread-like and having a waving motion.</p>
+
+<p class="p2 center"><span class="smcap">Distribution of the Freshwater
+Polyzoa.</span></p>
+
+<p>Fifteen genera of freshwater Polyzoa are now recognized, one
+entoproctous and fourteen ectoproctous; five of the latter are
+ctenostomatous and nine phylactol�matous. Of the fourteen ectoproctous
+genera seven are known to occur in India, viz., <i>Victorella</i>,
+<i>Hislopia</i>, <i>Fredericella</i>, <i>Plumatella</i>,
+<i>Stolella</i>, <i>Lophopodella</i>, and <i>Pectinatella</i>. Except
+<i>Stolella</i>, which is only known from northern India, these genera
+have an extremely wide geographical range; <i>Victorella</i> occurs in
+Europe, India, Africa, and Australia; <i>Hislopia</i> in India,
+Indo-China, China, and Siberia; <i>Fredericella</i> in Europe, N.
+America, Africa, India, and Australia; <i>Plumatella</i> in all
+geographical regions; <i>Lophopodella</i> in E. and S. Africa, India,
+and Japan; <i>Pectinatella</i> in Europe, N. America, Japan, and
+India.</p>
+
+<p>Two genera, <i>Paludicella</i> and <i>Lophopus</i>, have been stated
+on insufficient grounds to occur in India. The former is known<span
+class='pagenum'><a name="Page_174" id="Page_174">[Pg 174]</a></span>
+from Europe and N. America, and is said to have been found in Australia,
+while the latter is common in Europe and N. America and also occurs in
+Brazil.</p>
+
+<p>Of the genera that have not been found in this country the most
+remarkable are <i>Urnatella</i> and <i>Cristatella</i>. The former is
+the only representative in fresh water of the Entoprocta and has only
+been found in N. America. Each individual is borne upon a segmented
+stalk the segments of which are enclosed in strong horny coverings and
+are believed to act as resting buds. <i>Cristatella</i>, which is common
+in Europe and N. America, is a phylactol�matous genus of highly
+specialized structure. It possesses a creeping "sole" or organ of
+progression at the base of the zoarium.</p>
+
+<p>The other phylactol�matous genera that do not occur in India appear
+to be of limited distribution, for <i>Australella</i> is only known from
+N. S. Wales, and <i>Stephanella</i> from Japan. The ctenostomatous
+<i>Arachnoidea</i> has only been reported from Lake Tanganyika, and
+<i>Pottsiella</i> only from a single locality in N. America.</p>
+
+<p>As regards the exotic distribution of the Indian species little need
+be said. The majority of the <i>Plumatell�</i> are identical with
+European species, while the only species of <i>Fredericella</i> that has
+been discovered is closely allied to the European one. The Indian
+species of <i>Lophopodella</i> occurs also in E. Africa and Japan, while
+that of <i>Pectinatella</i> is apparently confined to India, Burma and
+Ceylon, but is closely allied to a Japanese form.</p>
+
+<p class="p2 center"><span class="smcap">Polyzoa of Brackish
+Water.</span></p>
+
+<p>With the exception of <i>Victorella</i>, which occurs more commonly
+in brackish than in fresh water and has been found in the sea, the
+genera that occur in fresh water are confined or practically confined to
+that medium; but certain marine ctenostomes and cheilostomes not
+uncommonly make their way, both in Europe and in India, into brackish
+water, and in the delta of the Ganges an entoproctous genus also does
+so. The ctenostomatous genera that are found occasionally in brackish
+water belong to two divisions of the suborder, the Vesicularina and the
+Alcyonellea. To the former division belongs <i>Bowerbankia</i>, a form
+of which (<i>B. caudata</i> subsp. <i>bengalensis</i>, p.&nbsp;187) is
+often found in the Ganges delta with <i>Victorella bengalensis</i>. No
+species of Alcyonellea has, however, as yet been found in Indian
+brackish waters. The two Indian cheilostomes of brackish water belong to
+a genus (<i>Membranipora</i>) also found in similar situations in
+Europe. One of them (<i>M. lacroixii</i><a name="fnanchor_AZ"
+id="fnanchor_AZ"></a><a href="#footnote_AZ"
+class="fnanchor"><sup>[AZ]</sup></a>) is, indeed, identical with a
+European form<span class='pagenum'><a name="Page_175" id="Page_175">[Pg
+175]</a></span> that occurs in England both in the sea and in ditches of
+brackish water. I have found it in the Cochin backwaters, in ponds of
+brackish water at the south end of the Chilka Lake (Ganjam, Madras), on
+the shore at Puri in Orissa, and in the Mutlah River at Port Canning.
+The second species (<i>M. bengalensis</i>, Stoliczka) is peculiar to the
+delta of the Ganges<a name="fnanchor_BA" id="fnanchor_BA"></a><a
+href="#footnote_BA" class="fnanchor"><sup>[BA]</sup></a> and has not as
+yet been found in the open sea. The two species are easily recognized
+from one another, for whereas the lip of <i>M. bengalensis</i> (fig. 33)
+bears a pair of long forked spines, there are no such structures on that
+of <i>M. lacroixii</i>, the dorsal surface of which is remarkably
+transparent. <i>M. lacroixii</i> forms a flat zoarium, the only part
+visible to the naked eye being often the beaded margin of the
+zo&oelig;cia, which appears as a delicate reticulation on bricks, logs
+of wood, the stems of rushes and of hydroids, etc.; but the zoarium of
+<i>M. bengalensis</i> is as a rule distinctly foliaceous and has a
+peculiar silvery lustre.</p>
+
+<div class="figcenter">
+<img src="images/fig_033.jpg"
+width="500" height="187"  alt="Illustration: Fig. 33.&mdash;Outline of
+four zo&oelig;cia of Membranipora bengalensis, Stoliczka (from type
+specimen, after Thornely). In the left upper zo&oelig;cium the lip is
+shown open." title="Fig. 33.&mdash;Outline of four zo&oelig;cia of
+Membranipora bengalensis, Stoliczka (from type specimen, after
+Thornely). In the left upper zo&oelig;cium the lip is shown open." />
+<p class="caption">Fig. 33.&mdash;Outline of four zo&oelig;cia of
+<i>Membranipora bengalensis</i>, Stoliczka (from type specimen, after
+Thornely). In the left upper zo&oelig;cium the lip is shown open.</p>
+</div>
+
+<p><i>Loxosomatoides</i><a name="fnanchor_BB" id="fnanchor_BB"></a><a
+href="#footnote_BB" class="fnanchor"><sup>[BB]</sup></a> (fig. 34), the
+Indian entoproctous genus found in brackish water, has not as yet been
+obtained from the open sea, but has recently been introduced, apparently
+from a tidal creek, into isolated ponds of brackish water at Port
+Canning. It is easily recognized by the chitinous shield attached to the
+ventral (posterior) surface.</p>
+
+<p><span class='pagenum'><a name="Page_176" id="Page_176">[Pg
+176]</a></span></p>
+
+<div class="figcenter">
+<img src="images/fig_034.jpg"
+width="341" height="600"  alt="Illustration: Fig.
+34.&mdash;Loxosomatoides colonialis, Annandale." title="Fig.
+34.&mdash;Loxosomatoides colonialis, Annandale." />
+<p class="caption">Fig. 34.&mdash;<i>Loxosomatoides colonialis</i>,
+Annandale.</p>
+</div>
+
+<p class="captionj">A and B, a single individual of form A, as seen (A)
+in lateral, and (B) in ventral view; C, outline of a similar individual
+with the tentacles retracted, as seen from in front (dorsal view); D,
+ventral view of an individual and bud of form B. All the figures are
+from the type specimens and are multiplied by about 70.</p>
+
+<p class="footnote">
+<a name="footnote_AW" id="footnote_AW"></a>
+<a href="#fnanchor_AW">[AW]</a>
+Q. J. Micr. Sci. xxxiii, p.&nbsp;123 (1892).</p>
+
+<p class="footnote">
+<a name="footnote_AX" id="footnote_AX"></a>
+<a href="#fnanchor_AX">[AX]</a>
+Journ. Coll. Sci. Tokyo, iv, p.&nbsp;124 (1891).</p>
+
+<p class="footnote">
+<a name="footnote_AY" id="footnote_AY"></a>
+<a href="#fnanchor_AY">[AY]</a>
+Bibliotheca Zoologica, ii, pt. 6, p.&nbsp;17 (1890).</p>
+
+<p class="footnote">
+<a name="footnote_AZ" id="footnote_AZ"></a>
+<a href="#fnanchor_AZ">[AZ]</a>
+There is some doubt as to the proper name of this species, which may not
+be the one originally described as <i>Membranipora lacroixii</i> by
+Andouin. I follow Busk and Hincks in my identification (see Cat. Polyzoa
+Brit. Mus. ii, p.&nbsp;60, and Hist. Brit. Polyzoa, p.&nbsp;129).
+Levinsen calls it <i>M. hippopus</i>, sp. nov. (see Morphological and
+Systematic Studies on the Cheilostomatous Bryozoa, p.&nbsp;144;
+Copenhagen, 1909).</p>
+
+<p class="footnote">
+<a name="footnote_BA" id="footnote_BA"></a>
+<a href="#fnanchor_BA">[BA]</a>
+Miss Thornely (Rec. Ind. Mus. i, p.&nbsp;186, 1907) records it from
+Mergui, but this is an error due to an almost illegible label. The
+specimens she examined were the types of the species from Port Canning.
+Since this was written I have obtained specimens from
+Bombay&mdash;<i>April</i>, 1911.</p>
+
+<p class="footnote">
+<a name="footnote_BB" id="footnote_BB"></a>
+<a href="#fnanchor_BB">[BB]</a>
+Annandale, Rec. Ind. Mus. ii, p.&nbsp;14 (1908).</p>
+
+<p class="p2 center">II.<span class='pagenum'><a name="Page_177"
+id="Page_177">[Pg 177]</a></span></p>
+
+<p class="center"><span class="smcap">History of the Study of the
+Freshwater Polyzoa.</span></p>
+
+<p>The naturalists of the eighteenth century were acquainted with more
+than one species of freshwater polyzoon, but they did not distinguish
+these species from the hydroids. Trembley discovered <i>Cristatella</i>,
+which he called "Polype � Panache," in 1741, and Linn� described a
+species of <i>Plumatella</i> under the name <i>Tubipora repens</i> in
+1758, while ten years later Pallas gave a much fuller description (under
+the name <i>Tubularia fungosa</i>) of the form now known as
+<i>Plumatella fungosa</i> or <i>P. repens</i> var. <i>fungosa</i>.
+Although Trembley, Baker, and other early writers on the fauna of fresh
+water published valuable biological notes, the first really important
+work of a comprehensive nature was that of Dumortier and van Beneden,
+published in 1848. All previous memoirs were, however, superseded by
+Allman's Monograph of the Fresh-Water Polyzoa, which was issued in 1857,
+and this memoir remains in certain respects the most satisfactory that
+has yet been produced. In 1885 Jullien published a revision of the
+phylactol�mata and freshwater ctenostomes which is unfortunately
+vitiated by some curious lapses in observation, but it is to Jullien
+that the recognition of the proper position of <i>Hislopia</i> is due.
+The next comprehensive monograph was that of Kraepelin, which appeared
+in two parts (1887 and 1892) in the Abhandlungen des Naturwiss. Vereins
+of Hamburg. In its detailed information and carefully executed
+histological plates this work is superior to any that preceded it or has
+since appeared, but the system of classification adopted is perhaps less
+liable to criticism than that followed by Braem in his "Untersuchungen,"
+published in the Bibliotheca Zoologica in 1888.</p>
+
+<p>During the second half of the nineteenth century and the first decade
+of the twentieth several authors wrote important works on the embryology
+and anatomy of the phylactol�mata, notably Kraepelin, Braem, and Oka;
+but as yet the ctenostomes of fresh water have received comparatively
+little attention from anything but a systematic point of view.</p>
+
+<p>From all points of view both the phylactol�mata and the ctenostomes
+of Asia have been generally neglected, except in the case of the
+Japanese phylactol�mata, which have been studied by Oka. Although Carter
+made some important discoveries as regards the Indian forms, he did not
+devote to them the same attention as he did to the sponges. In the case
+of the only new genus he described he introduced a serious error into
+the study of the two groups by placing <i>Hislopia</i> among the
+cheilostomes, instead of in its true position as the type genus of a
+highly specialized family of ctenostomes.</p>
+
+<p>For fuller details as to the history of the study of the freshwater
+Polyzoa the student may refer to Allman's and to Kraepelin's monographs.
+An excellent summary is given by Harmer in his<span class='pagenum'><a
+name="Page_178" id="Page_178">[Pg 178]</a></span> chapter on the
+freshwater Polyzoa in vol. ii. of the Cambridge Natural History; and
+Loppens has recently (1908) published in the Annales de Biologie
+lacustre a concise survey of the systematic work that has recently been
+undertaken. Unfortunately he perpetuates Carter's error as regards the
+position of <i>Hislopia</i>.</p>
+
+<p class="p2 center"><span class="smcap">Bibliography of the Freshwater
+Polyzoa.</span></p>
+
+<p>A very full bibliography of the freshwater Polyzoa will be found in
+pt. i. of Kraepelin's "Die Deutschen S�sswasserbryozoen" (1887), while
+Loppens, in his survey of the known species (Ann. Biol. lacustre, ii,
+1908), gives some recent references. The following list contains the
+titles of some of the more important works of reference, of memoirs on
+special points such as reproduction and of papers that have a special
+reference to Asiatic species. Only the last section is in any way
+complete.</p>
+
+<table summary="References Part III">
+
+<tr><td></td><th class="normal">(a) <i>Works of Reference.</i></th></tr>
+
+<tr><td class="left_a">1847.</td><td><span class="smcap">Van
+Beneden</span>, "Recherches sur les Bryozoaires fluviatiles de
+Belgique," M�m. Ac. Roy. Belgique, xxi.</td></tr>
+
+<tr><td class="left_a">1850.</td><td><span
+class="smcap">Dumortier</span> and <span class="smcap">Van
+Beneden</span>, "Histoire Naturelle des Polypes compos�s d'eau douce,"
+2^e partie, M�m. Ac. Roy. Bruxelles, xvi (compl�ment).</td></tr>
+
+<tr><td class="left_a">1856.</td><td><span class="smcap">Allman</span>,
+"A Monograph of the Fresh-Water Polyzoa" (London).</td></tr>
+
+<tr><td class="left_a"><span
+style="white-space:nowrap;">1866-1868.</span></td><td><span
+class="smcap">Hyatt</span>, "Observations on Polyzoa, suborder
+Phylactol�mata," Comm. Essex Inst. iv, p.&nbsp;197, v,
+p.&nbsp;97.</td></tr>
+
+<tr><td class="left_a">1880.</td><td><span class="smcap">Hincks</span>,
+"A History of the British Marine Polyzoa."</td></tr>
+
+<tr><td class="left_a">1885.</td><td><span class="smcap">Jullien</span>,
+"Monographie des Bryozoaires d'eau douce," Bull. Soc. zool. France, x,
+p.&nbsp;91.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;">1887 &amp;
+1892.</span></td><td><span class="smcap">Kraepelin</span>, "Die
+deutschen S�sswasserbryozoen," Abhandl. Nat. Vereins Hamburg, x &amp;
+xii.</td></tr>
+
+<tr><td class="left_a">1890.</td><td><span class="smcap">Braem</span>,
+"Untersuchungen des Bryozoen des s�ssen Wassers," Bibl. Zool. ii, Heft 6
+(Cassel).</td></tr>
+
+<tr><td class="left_a">1896.</td><td><span class="smcap">Harmer</span>,
+Cambridge Natural History, ii, Polyzoa, chap. xviii.</td></tr>
+
+<tr><td class="left_a">1899.</td><td><span
+class="smcap">Korschelt</span> and <span class="smcap">Heider</span>,
+"Embryology of Invertebrates," vol. ii, chap. xvi. (English edition by
+Bernard and Woodward, 1899.)</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span class="smcap">Loppens</span>,
+"Les Bryozoaires d'eau douce," Ann. Biol. lacustre, iii. p.
+141.</td></tr>
+
+<tr><td></td><th class="normal"><p class="p2 center">(b) <i>Special
+Works on Embryology, etc.</i></p></th></tr>
+
+<tr><td class="left_a">1875.</td><td><span class="smcap">Nitsche</span>,
+"Beitr�ge zur Kenntniss der Bryozoen," Zeitschr. f. wiss. Zool. xxv
+(supplement), p.&nbsp;343.</td></tr>
+
+<tr><td class="left_a">1880.</td><td><span
+class="smcap">Reinhard</span>, "Zur Kenntniss der S�sswasser-Bryozoen,"
+Zool. Anz. iii, p.&nbsp;208.</td></tr>
+
+<tr><td class="left_a">1888.</td><td><span class="smcap">Braem</span>,
+"Untersuchungen �ber die Bryozoen des s�ssen Wassers," Zool. Anz. xi,
+pp.&nbsp;503, 533.</td></tr>
+
+<tr><td class="left_a">1891.</td><td><span class="smcap">Oka</span>,
+"Observations on Freshwater Polyzoa," J. Coll. Sci. Tokyo, iv, p.
+89.</td></tr>
+
+<tr><td class="left_a">1906.</td><td><span class="smcap">Wilcox</span>,
+"Locomotion in young colonies of <i>Pectinatella magnifica</i>," Biol.
+Bull. Wood's <ins title="changed from 'Holl'">Hole</ins>, ii.<span
+class='pagenum'><a name="Page_179" id="Page_179">[Pg
+179]</a></span></td></tr>
+
+<tr><td class="left_a">1908.</td><td><span class="smcap">Braem</span>,
+"Die geschlechtliche Entwickelung von Fredericella sultana nebst
+Beobachtungen �ber die weitere Lebensgeschichte der Kolonien," Bibl.
+Zool. xx, Heft 52.</td></tr>
+
+<tr><td></td><th class="normal"><p class="p2 center">(c) <i>Papers that
+refer specifically to Asiatic species.</i></p></th></tr>
+
+<tr><td class="left_a">1851.</td><td><span class="smcap">Leidy</span>
+described <i>Plumatella diffusa</i> in Proc. Ac. Philad. v, p.&nbsp;261
+(<ins title="changed from 1852">1851</ins>).</td></tr>
+
+<tr><td class="left_a">1858.</td><td><span class="smcap">Carter</span>,
+"Description of a Lacustrine Bryozoon allied to <i>Flustra</i>," Ann.
+Nat. Hist. (3) i, p.&nbsp;169.</td></tr>
+
+<tr><td class="left_a">1859.</td><td><span class="smcap">Carter</span>,
+"On the Identify in Structure and Composition of the so-called Seed-like
+Body of <i>Spongilla</i> with the Winter-egg of the Bryozoa: and the
+presence of Starch-granules in each," Ann. Nat. Hist. (3) iii,
+p.&nbsp;331. (Statoblast of <i>Lophopodella</i> described and
+figured.)</td></tr>
+
+<tr><td class="left_a">1862.</td><td><span
+class="smcap">Mitchell</span>, "Freshwater Polyzoa," Q. J. Micr. Sci.
+(new series) ii, p.&nbsp;61. ("<i>Lophopus</i>" recorded from
+Madras.)</td></tr>
+
+<tr><td class="left_a">1866.</td><td><span class="smcap">Hyatt</span>,
+"Observations on Polyzoa, suborder Phylactol�mata," Comm. Essex Inst.
+iv, p.&nbsp;197. ("<i>Pectinatella carteri</i>" named.)</td></tr>
+
+<tr><td class="left_a">1869.</td><td><span
+class="smcap">Stoliczka</span>, "On the Anatomy of <i>Sagartia
+schilleriana</i> and <i>Membranipora bengalensis</i>, a new coral and a
+bryozoon living in brackish water at Port Canning," J. As. Soc. Bengal,
+xxxviii, ii, p.&nbsp;28.</td></tr>
+
+<tr><td class="left_a">1880.</td><td><span class="smcap">Jullien</span>,
+"Description d'un nouveau genre de Bryozoaire Cheilostomien des eaux
+douces de la Chine et du Cambodge et de deux esp�ces nouvelles," Bull.
+Soc. zool. France, v, p.&nbsp;77. ("<i>Norodonia</i>"
+described.)</td></tr>
+
+<tr><td class="left_a">1885.</td><td><span class="smcap">Jullien</span>,
+"Monographie des Bryozoaires d'eau douce," Bull. Soc. zool. France, x,
+p.&nbsp;91. (<i>Hislopia</i> assigned to the ctenostomes.)</td></tr>
+
+<tr><td class="left_a">1887.</td><td><span
+class="smcap">Kraepelin</span>, "Die deutschen S�sswasserbryozoen," Abh.
+Ver. Hamburg, x. (<i>Plumatella philippinensis.</i>)</td></tr>
+
+<tr><td class="left_a">1891.</td><td><span class="smcap">Oka</span>,
+"Observations on Freshwater Polyzoa," J. Coll. Sci. Tokyo, iv, p.
+89.</td></tr>
+
+<tr><td class="left_a">1898.</td><td><span
+class="smcap">Meissner</span>, "Die Moosthiere Ost-Afrikas," in Mobius's
+Deutsch-Ost-Afrika, iv. (<i>Lophopodella carteri</i> recorded from E.
+Africa.)</td></tr>
+
+<tr><td class="left_a">1901.</td><td><span
+class="smcap">Korotneff</span>, "Faunistische Studien am Baikalsee,"
+Biol. Centrbl. xxi, p.&nbsp;305. ("<i>Echinella</i>" described.)</td></tr>
+
+<tr><td class="left_a">1904-1906.</td><td><span
+class="smcap">Rousselet</span>, "On a new Freshwater Polyzoon from
+Rhodesia, <i>Lophopodella thomasi</i>, gen. et sp. nov.", J. Quekett
+Club (2) ix, p.&nbsp;45. (Genus <i>Lophopodella</i> described.)</td></tr>
+
+<tr><td class="left_a">1906.</td><td><span
+class="smcap">Annandale</span>, "Notes on the Freshwater Fauna of India.
+No. II. The Affinities of <i>Hislopia</i>," J. As. Soc. Bengal (new
+series) ii, p.&nbsp;59.</td></tr>
+
+<tr><td class="left_a">1906.</td><td><span
+class="smcap">Kraepelin</span>, "Eine S�sswasser-bryozo�
+(<i>Plumatella</i>) aus Java," Mitth. Mus. Hamburg, xxiii, p.
+143.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "Notes on the Freshwater Fauna of India.
+No. XII. The Polyzoa occurring in Indian Fresh and Brackish Pools," J.
+As. Soc. Bengal (new series) iii, p.&nbsp;83.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "Statoblasts from the surface of a
+Himalayan Pond," Rec. Ind. Mus. i, p.&nbsp;177.<span class='pagenum'><a
+name="Page_180" id="Page_180">[Pg 180]</a></span></td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "The Fauna of Brackish Ponds at Port
+Canning, Lower Bengal: I.&mdash;Introduction and Preliminary Account of
+the Fauna," Rec. Ind. Mus. i, p.&nbsp;35.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "The Fauna of Brackish Ponds at Port
+Canning, Lower Bengal: VI.&mdash;Observations on the Polyzoa, with
+further notes on the Ponds," Rec. Ind. Mus. i, p.&nbsp;197.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Annandale</span>, "Further Note on a Polyzoon from the
+Himalayas," Rec. Ind. Mus. i, p.&nbsp;145.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span
+class="smcap">Rousselet</span>, "Zoological Results of the Third
+Tanganyika Expedition, conducted by Dr. W. A. Cunnington,
+1904-1905.&mdash;Report on the Polyzoa," P. Z. Soc. London, i,
+p.&nbsp;250. (<i>Plumatella tanganyik�.</i>)</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span class="smcap">Oka</span>,
+"Eine dritte Art von <i>Pectinatella</i> (<i>P. davenporti</i>, n.
+sp.)," Zool. Anz. xxxi, p.&nbsp;716.</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span class="smcap">Apstein</span>,
+"Das Plancton im Colombo-See auf Ceylon," Zool. Jahrb. (Syst.) xxv, p.
+201. (<i>Plumatella</i> recorded.)</td></tr>
+
+<tr><td class="left_a">1907.</td><td><span class="smcap">Walton</span>,
+"Notes on <i>Hislopia lacustris</i>, Carter," Rec. Ind. Mus. i, p.
+177.</td></tr>
+
+<tr><td class="left_a">1907-1908.</td><td><span
+class="smcap">Oka</span>, "Zur Kenntnis der S�sswasser-Bryozoenfauna von
+Japan," Annot. Zool. Japon, vi, p.&nbsp;117.</td></tr>
+
+<tr><td class="left_a">1907-1908.</td><td><span
+class="smcap">Oka</span>, "Ueber eine neue Gattung von
+S�sserwasserbryozoen," Annot. Zool. Japon, vi, p.&nbsp;277.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span
+class="smcap">Annandale</span>, "The Fauna of Brackish Ponds at Port
+Canning, Lower Bengal: VII.&mdash;Further Observations on the Polyzoa
+with the description of a new genus of Entoprocta," Rec. Ind. Mus. ii,
+p.&nbsp;11.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span
+class="smcap">Annandale</span>, "Corrections as to the Identity of
+Indian Phylactol�mata," Rec. Ind. Mus. ii, p.&nbsp;110.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span
+class="smcap">Annandale</span>, "Three Indian Phylactol�mata," Rec. Ind.
+Mus. ii, p.&nbsp;169.</td></tr>
+
+<tr><td class="left_a">1908.</td><td><span
+class="smcap">Kirkpatrick</span>, "Description of a new variety of
+<i>Spongilla loricata</i>, Weltner," Rec. Ind. Mus. ii, p.&nbsp;97.
+(<i>Hislopia</i> recorded from Burma.)</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "Preliminary Note on a new genus of
+Phylactol�matous Polyzoa," Rec. Ind. Mus. iii, p.&nbsp;279.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span
+class="smcap">Annandale</span>, "A new species of <i>Fredericella</i>
+from Indian Lakes," Rec. Ind. Mus. iii. p.&nbsp;373.</td></tr>
+
+<tr><td class="left_a">1909.</td><td><span class="smcap">Walton</span>,
+"Large Colonies of <i>Hislopia lacustris</i>," Rec. Ind. Mus. iii, p.
+295.</td></tr>
+
+<tr><td class="left_a">1910.</td><td><span
+class="smcap">Annandale</span>, "Materials for a Revision of the
+Phylactol�matous Polyzoa of India," Rec. Ind. Mus. v,
+p.&nbsp;37.</td></tr>
+
+<tr><td class="left_a">1911.</td><td><span class="smcap">West</span> and
+<span class="smcap">Annandale</span>, "Descriptions of Three Species of
+Alg� associated with Indian Freshwater Polyzoa," J. As. Soc. Bengal
+(<i>ined.</i>).</td></tr>
+
+</table>
+
+<p><span class='pagenum'><a name="Page_181" id="Page_181">[Pg
+181]</a></span></p>
+
+<h3 class="p4">GLOSSARY OF TECHNICAL TERMS USED<br />
+IN PART III.</h3>
+
+<table summary="Glossary Part III">
+
+<tr><td class="left_a"><i>Brown body</i></td><td>A body formed in a
+zo&oelig;cium by the degeneration of a polypide as a preparation for its
+regeneration.</td></tr>
+
+<tr><td class="left_a"><span style="white-space:nowrap;"><i>Cardiac
+portion</i> (of the stomach).</span></td><td>That part which
+communicates with the &oelig;sophagus.</td></tr>
+
+<tr><td class="left_a"><i>Collar</i></td><td>A longitudinally pleated
+circular membrane capable of being thrust out of the orifice in advance
+of the lophophore and of closing together inside the zo&oelig;cium above
+the tentacles when they are retracted.</td></tr>
+
+<tr><td class="left_a"><i>Dorsal surface</i></td><td>(<i>Of
+zo&oelig;cium</i> or <i>polypide</i>) the surface nearest the mouth;
+(<i>of statoblast</i>) the surface furthest from that by which the
+statoblast is attached to the funiculus during development.</td></tr>
+
+<tr><td class="left_a"><i>Ectocyst</i></td><td>The outer, structureless
+layer of the zo&oelig;cium.</td></tr>
+
+<tr><td class="left_a"><i>Emarginate</i> (of a
+zo&oelig;cium)</td><td>Having a thin or defective triangular area in the
+ectocyst at the tip.</td></tr>
+
+<tr><td class="left_a"><i>Endocyst</i></td><td>The inner, living
+(cellular) layer of the zo&oelig;cium.</td></tr>
+
+<tr><td class="left_a"><i>Epistome</i></td><td>A leaf-like ciliated
+organ that projects upwards and forwards over the mouth between it and
+the anus.</td></tr>
+
+<tr><td class="left_a"><i>Funiculus</i></td><td>A strand of tissue
+joining the alimentary canal to the endocyst.</td></tr>
+
+<tr><td class="left_a"><i>Furrowed</i> (of a
+zo&oelig;cium)</td><td>Having a thin or defective longitudinal linear
+streak in the ectocyst on the dorsal surface.</td></tr>
+
+<tr><td class="left_a"><i>Gizzard</i></td><td>A chamber of the
+alimentary canal situated at the cardiac end of the stomach and provided
+internally with a structureless lining.</td></tr>
+
+<tr><td class="left_a"><i>Intertentacular organ</i></td><td>A ciliated
+tube running between the cavity of the zo&oelig;cium and the external
+base of the lophophore.</td></tr>
+
+<tr><td class="left_a"><i>Keeled</i> (of a zo&oelig;cium)</td><td>Having
+a longitudinal ridge on the dorsal surface.</td></tr>
+
+<tr><td class="left_a"><i>Lophophore</i></td><td>The tentacles with the
+base to which they are attached.<span class='pagenum'><a name="Page_182"
+id="Page_182">[Pg 182]</a></span></td></tr>
+
+<tr><td class="left_a"><i>Marginal processes</i> (of
+statoblast).</td><td>Chitinous hooked processes on the margin of the
+swim-ring (<i>q. v.</i>).</td></tr>
+
+<tr><td class="left_a"><i>&OElig;sophagus</i></td><td>That part of the
+alimentary canal which joins the mouth to the stomach.</td></tr>
+
+<tr><td class="left_a"><i>Orifice</i></td><td>The aperture through which
+the lophophore can be protruded from or retracted into the
+zo&oelig;cium.</td></tr>
+
+<tr><td class="left_a"><i>Parietal muscles</i></td><td>Transverse
+muscles running round the inner wall of the zo&oelig;cium.</td></tr>
+
+<tr><td class="left_a"><i>Parieto-vaginal muscles</i></td><td>Muscles
+that surround the orifice, running between the folds of the
+zo&oelig;cium in an oblique direction.</td></tr>
+
+<tr><td class="left_a"><i>Polyparium</i></td><td>The whole body of
+zo&oelig;cia and polypides which are in organic connection.</td></tr>
+
+<tr><td class="left_a"><i>Polypide</i></td><td>The tentacular crown,
+alimentary canal, and retractor muscles of a
+polyzoon-individual.</td></tr>
+
+<tr><td class="left_a"><i>Pyloric portion</i> (of the
+stomach).</td><td>That part which communicates with the
+intestine.</td></tr>
+
+<tr><td class="left_a"><i>Resting bud</i></td><td>An external bud
+provided with food-material in its cells, with a horny external coat and
+capable of lying dormant in unfavourable conditions.</td></tr>
+
+<tr><td class="left_a"><i>Retractor muscles</i></td><td>The muscles by
+the action of which the lophophore can be pulled back into the
+zo&oelig;cium.</td></tr>
+
+<tr><td class="left_a"><i>Statoblast</i></td><td>An internal bud arising
+from the funiculus, containing food-material in its cells, covered with
+a horny coat and capable of lying dormant in unfavourable
+conditions.</td></tr>
+
+<tr><td class="left_a"><i>Swim-ring</i></td><td>A ring of polygonal
+air-spaces surrounding the statoblast.</td></tr>
+
+<tr><td class="left_a"><i>Ventral surface</i></td><td>(<i>Of
+zo&oelig;cium</i> or <i>polypide</i>) the surface nearest the anus;
+(<i>of statoblast</i>) the surface by which the statoblast is attached
+to the funiculus during development.</td></tr>
+
+<tr><td class="left_a"><i>Zoarium</i></td><td>The whole body of
+zo&oelig;cia which are in organic connection.</td></tr>
+
+<tr><td class="left_a"><i>Zo&oelig;cium</i></td><td>Those parts of the
+polyzoon-individual which constitute a case or "house" for the
+polypide.</td></tr>
+
+</table>
+
+<p><span class='pagenum'><a name="Page_183" id="Page_183">[Pg
+183]</a></span></p>
+
+<h3 class="p4">SYNOPSIS</h3>
+<h5>OF THE</h5>
+<h3>CLASSIFICATION OF THE POLYZOA.</h3>
+
+<p class="p2 center">I.</p>
+
+<p class="center"><span class="smcap">Synopsis of the Subclasses,
+Orders, and Suborders.</span></p>
+
+<p class="center larger">Class POLYZOA.</p>
+
+<p>Small c&oelig;lomate animals, each individual of which consists of a
+polyp-like organism or polypide enclosed in a "house" or zo&oelig;cium
+composed partly of living tissues. The mouth is surrounded by a circle
+of ciliated tentacles that can be retracted within the zo&oelig;cium;
+the alimentary canal, which is suspended in the zo&oelig;cium, is <span
+style="white-space:nowrap;"><b>Y</b>-shaped</span> and consists of three
+parts, the &oelig;sophagus, the stomach, and the intestine.</p>
+
+<p class="p2 center">Subclass <b>ENTOPROCTA</b>.</p>
+
+<p>The anus as well as the mouth is enclosed in the circle of tentacles
+and the zo&oelig;cium is not very distinctly separated from the
+polypide. Some forms are solitary or form temporary colonies by
+budding.</p>
+
+<p>Most Entoprocta are marine, but a freshwater genus (<i>Urnatella</i>)
+occurs in N. America, while the Indian genus <i>Loxosomatoides</i> (fig.
+34, p.&nbsp;176) is only known from brackish water.</p>
+
+<p class="p2 center">Subclass <b>ECTOPROCTA</b>.</p>
+
+<p>The anus is outside the circle of tentacles and the zo&oelig;cium can
+always be distinguished from the polypide. All species form by budding
+permanent communities the individuals in which remain connected together
+by living tissue.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_184"
+id="Page_184">[Pg 184]</a></span>Order I. <b>GYMNOL�MATA.</b></p>
+
+<p>Ectoproctous polyzoa the polypides of which have no epistome; the
+zo&oelig;cia are in nearly all cases distinctly separated from one
+another by transverse perforated plates.</p>
+
+<p>Most of the Gymnol�mata are marine, but species belonging to two of
+the three suborders into which they are divided often stray into
+brackish water, while a few genera that belong to one of these two
+suborders are practically confined to fresh water. The three suborders
+are distinguished as follows:&mdash;</p>
+
+<p class="p2 center">Suborder A. <i>CHEILOSTOMATA.</i></p>
+
+<p>The zo&oelig;cia are provided with a "lip" or lid hinged to the
+posterior margin of the orifice (see fig. 33, p.&nbsp;175). This lid
+closes automatically outside the zo&oelig;cium or in a special chamber
+on the external surface (the "peristome") when the polypide retracts and
+is pushed open by the tentacles as they expand. The majority of the
+zo&oelig;cia in each zoarium are more or less distinctly flattened, but
+some of them are often modified to form "vibracula" and
+"avicularia."</p>
+
+<p>The Cheilostomata are essentially a marine group, but some species
+are found in estuaries and even in pools and ditches of brackish water
+(fig. 33).</p>
+
+<p class="p2 center">Suborder B. <i>CTENOSTOMATA.</i></p>
+
+<p>The zo&oelig;cia are provided with a collar-like membrane which is
+pleated vertically and closes together above the polypide inside the
+zo&oelig;cium when the former is retracted; it is thrust out of the
+zo&oelig;cium and expands into a ring-shaped form just before the
+tentacles are extruded. The zo&oelig;cia are usually more or less
+tubular, but in some genera and species are flattened.</p>
+
+<p>The majority of the Ctenostomata are marine, but some genera are
+found in estuaries, while those of one section of the suborder live
+almost exclusively in fresh water.</p>
+
+<p class="p2 center">Suborder C. <i>CYCLOSTOMATA.</i></p>
+
+<p>The zo&oelig;cia are provided neither with a lip nor with a
+collar-like membrane. They are tubular and usually have circular
+orifices.</p>
+
+<p>The Cyclostomata are exclusively marine.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_185"
+id="Page_185">[Pg 185]</a></span>Order II. <b>PHYLACTOL�MATA.</b></p>
+
+<p>Ectoproctous polyzoa the polypides of which have a leaf-shaped organ
+called an epistome projecting upwards and forwards within the circle of
+tentacles and between the mouth and the anus. The zo&oelig;cia are not
+distinct from one another, but in dendritic forms the zoarium is divided
+irregularly by chitinous partitions.</p>
+
+<p>The Phylactol�mata are, without exception, freshwater species.</p>
+
+<p class="p2 center">II.</p>
+
+<p class="center"><span class="smcap">Synopsis of the Leading Characters
+of the Divisions of the Suborder Ctenostomata.</span></p>
+
+<p class="p2 center">Suborder B. <i>CTENOSTOMATA.</i></p>
+
+<p>The suborder has been subdivided in various ways by different
+authors. The system here adopted is essentially the same as that
+proposed in a recent paper by Waters (Journ. Linn. Soc. London, Zool.
+xxi, p.&nbsp;231, 1910), but I have thought it necessary to add a fourth
+division to the three adopted by that author, namely, the Alcyonellea,
+Stolonifera, and Vesicularina. This new division includes all the
+freshwater genera and may be known as the Paludicellina. In none of
+these divisions are the tentacles webbed at the base.</p>
+
+<p>The four divisions may be recognized from the following synopsis of
+their characteristic features:&mdash;</p>
+
+<p class="p2 center">Division I. ALCYONELLEA.</p>
+
+<p>The zo&oelig;cia arise directly from one another in a fleshy or
+gelatinous mass. The polypide has no gizzard. The species are
+essentially marine, but a few are found in brackish water in
+estuaries.</p>
+
+<p class="p2 center">Division II. STOLONIFERA.</p>
+
+<p>The zo&oelig;cia arise from expansions in a delicate creeping rhizome
+or root-like structure, the order in which they are connected together
+being more or less irregular. As a rule (perhaps always) there is no
+gizzard. The species are marine.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_186"
+id="Page_186">[Pg 186]</a></span>Division III. VESICULARINA.</p>
+
+<p>The zo&oelig;cia grow directly from a tubular stem which is usually
+free and vertical, their arrangement being alternate, spiral or
+irregular. There is a stout gizzard which bears internal chitinous
+projections and is tightly compressed when the polypide is retracted.
+The species are essentially marine, but a few are found in brackish
+water.</p>
+
+<p class="p2 center">Division IV. PALUDICELLINA, nov.</p>
+
+<p>The zo&oelig;cia are arranged in a regular cruciform manner and arise
+either directly one from another or with the intervention of tubular
+processes. If the polypide has a gizzard it does not bear internal
+chitinous projections. Most of the species are confined to fresh water,
+but a few are found in brackish water or even in the sea.</p>
+
+<p>Although all true freshwater Ctenostomes belong to the fourth of
+these divisions, species of a genus (<i>Bowerbankia</i>) included in the
+third are so frequently found in brackish water and in association with
+one belonging to the fourth, and are so easily confounded with the
+latter, that I think it necessary to include a brief description of the
+said genus and of the form that represents it in ponds of brackish water
+in India.</p>
+
+<p><span class='pagenum'><a name="Page_187" id="Page_187">[Pg
+187]</a></span></p>
+
+<h3 class="p4">SYSTEMATIC LIST OF THE INDIAN<br />
+FRESHWATER POLYZOA.</h3>
+
+<p class="blockquote">[The types have been examined in the case of all
+species, etc., whose names are marked thus, *.]</p>
+
+<p class="p2 center">Order I. <b>GYMNOL�MATA.</b></p>
+
+<p class="center">Suborder I. <i>CTENOSTOMATA.</i></p>
+
+<p class="center">[Division III. <b>Vesicularina.</b>]</p>
+
+<p>[Genus <span class="smcap">Bowerbankia</span>, Farre (1837).]</p>
+
+<p class="indent5_a">&nbsp;</p>
+<p class="indent5aa">[<i>B. caudata</i> subsp. <i>bengalensis</i>*,
+Annandale (1907). </p>
+
+<p class="indent5_c">&nbsp;</p>
+<p class="indent5cc">&nbsp;&nbsp;(Brackish water).]</p>
+
+<p class="p2 center">Division IV. <b>Paludicellina</b>, nov.</p>
+
+<p class="center">Family I. PALUDICELLID�.</p>
+
+<p>Genus 1. <span class="smcap">Paludicella</span>, Gervais (1836).</p>
+
+<p class="indent5_a">&nbsp;</p>
+<p class="indent5aa">? <i>Paludicella</i> sp. (<i>fide</i> Carter).</p>
+
+<p>Genus 2. <span class="smcap">Victorella</span>, Kent (1870).</p>
+
+<p class="indent5_a">26.</p>
+<p class="indent5aa"><i>V. bengalensis</i>*, Annandale (1907).</p>
+
+<p class="p2 center">Family II. HISLOPIID�.</p>
+
+<p>Genus <span class="smcap">Hislopia</span>, Carter (1858).</p>
+
+<p class="indent5_a">27.</p>
+<p class="indent5aa"><i>H. lacustris</i>, Carter (1858).</p>
+
+<p class="indent5_c">27 <i>a</i>.</p>
+<p class="indent5cc"><i>H. lacustris</i> subsp. <i>moniliformis</i>*,
+nov.</p>
+
+<p><span class='pagenum'><a name="Page_188" id="Page_188">[Pg
+188]</a></span></p>
+<p class="p2 center">Order II. <b>PHYLACTOL�MATA.</b></p>
+
+<p class="center">Division I. <b>Plumatellina.</b></p>
+
+<p class="center">Family 1. FREDERICELLID�.</p>
+
+<p>Genus <span class="smcap">Fredericella</span>, Gervais (1836).</p>
+
+<p class="indent5_a">28.</p>
+<p class="indent5aa"><i>F. indica</i>*, Annandale (1909).</p>
+
+<p class="p2 center">Family 2. PLUMATELLID�.</p>
+
+<p class="center">Subfamily A. <span class="ls
+smcap">Plumatellin�.</span></p>
+
+<p>Genus 1. <span class="smcap">Plumatella</span>, Lamarck (1816).</p>
+
+<p class="indent5_a">29.</p>
+<p class="indent5aa"><i>P. fruticosa</i>, Allman (1844).</p>
+
+<p class="indent5_b">30.</p>
+<p class="indent5bb"><i>P. emarginata</i>, Allman (1844).</p>
+
+<p class="indent5_b">31.</p>
+<p class="indent5bb"><i>P. javanica</i>*, Kraepelin (1905).</p>
+
+<p class="indent5_b">32.</p>
+<p class="indent5bb"><i>P. diffusa</i>, Leidy (1851).</p>
+
+<p class="indent5_b">33.</p>
+<p class="indent5bb"><i>P. allmani</i>, Hancock (1850).</p>
+
+<p class="indent5_b">34.</p>
+<p class="indent5bb"><i>P. tanganyik�</i>*, Rousselet (1907).</p>
+
+<p class="indent5_c">35.</p>
+<p class="indent5cc"><i>P. punctata</i>, Hancock (1850).</p>
+
+<p>Genus 2. <span class="smcap">Stolella</span>, Annandale (1909).</p>
+
+<p class="indent5_a">36.</p>
+<p class="indent5aa"><i>S. indica</i>*, Annandale (1909).</p>
+
+<p class="p2 center">Subfamily B. <span class="ls
+smcap">Lophopin�</span>.</p>
+
+<p>Genus 1. <span class="smcap">Lophopodella</span>, Rousselet
+(1904).</p>
+
+<p class="indent5_a">37.</p>
+<p class="indent5aa"><i>L. carteri</i>* (Hyatt) (1865).</p>
+
+<p class="indent5_c">37 <i>a</i>.</p>
+<p class="indent5cc"><i>L. carteri</i> var. <i>himalayana</i>*
+(Annandale) (1907).</p>
+
+<p>Genus 2. <span class="smcap">Pectinatella</span>, Leidy (1851).</p>
+
+<p class="indent5_a">38.</p>
+<p class="indent5aa"><i>P. burmanica</i>*, Annandale (1908).</p>
+
+<p class="p4 center"><span class='pagenum'><a name="Page_189"
+id="Page_189">[Pg 189]</a></span>Order <b>CTENOSTOMATA.</b></p>
+
+<p class="center">[Division VESICULARINA.</p>
+
+<p class="center larger">Family VESICULARID�.</p>
+
+<div class="genus">
+<span class="i0"><span class="smcap">Vesicularid�</span>, Hincks, Brit.
+Marine Polyzoa, p.&nbsp;512 (1880).</span>
+</div>
+
+<p>Zo&oelig;cia constricted at the base, deciduous, attached to a stem
+that is either recumbent or vertical.</p>
+
+<p class="p2 center">Genus <b>BOWERBANKIA</b>, <i>Farre</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Bowerbankia</i>, Farre, Phil. Trans. Roy. Soc.
+cxxvii, p.&nbsp;391 (1837).</span>
+
+<span class="i0"><i>Bowerbankia</i>, Hincks, <i>op. cit.</i> p.
+518.</span>
+
+</div>
+
+<p><i>Zoarium</i> vertical or recumbent. <i>Zo&oelig;cia</i> ovate or
+almost cylindrical, arranged on the stem singly, in clusters or in a
+subspiral line. <i>Polypide</i> with 8 or 10 tentacles.</p>
+
+<p class="p2"><b>Bowerbankia caudata</b>, <i>Hincks</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Bowerbankia caudata</i>, Hincks, <i>op. cit.</i> p.
+521, pl. lxxv, figs. 7, 8.</span>
+
+</div>
+
+<p>This species is easily distinguished from all others by the fact that
+mature zo&oelig;cia have always the appearance of being fixed to the
+sides of a creeping, adherent stem and are produced, below the point at
+which they are thus fixed, into a pointed "tail."</p>
+
+<p class="p2">Subsp. <b>bengalensis</b>, <i>Annandale</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Bowerbankia caudata</i>, Thornely, Rec. Ind. Mus. i,
+p.&nbsp;196 (1907).</span>
+
+<span class="i0"><i>Bowerbankia caudata</i>, Annandale, <i>ibid.</i> p.
+203.</span>
+
+<span class="i0"><i>Bowerbankia caudata</i> race <i>bengalensis</i>,
+<i>id.</i>, <i>ibid.</i> ii. p.&nbsp;13 (1908).</span>
+
+</div>
+
+<p>The Indian race is only distinguished from the typical form by its
+greater luxuriance of growth and by the fact that the "tail" of the
+zo&oelig;cia is often of relatively great length, sometimes equaling or
+exceeding the rest of the zo&oelig;cium. The stem, which is divided at
+irregular intervals by partitions, often crosses and recrosses its own
+course and even anastomoses, and a fur-like structure is formed in which
+the zo&oelig;cia representing the hairs become much elongated; but
+upright branches are never formed. The zoarium has a greenish or greyish
+tinge.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>B.
+caudata</i> subsp. <i>bengalensis</i> is common in brackish water in the
+Ganges delta, where it often occurs in close association with
+<i>Victorella bengalensis</i>, and also at the south end of the Chilka
+Lake in the north-east of the Madras Presidency. Although it has not yet
+been found elsewhere, it probably occurs all round the Indian
+coasts.]</p>
+
+<p class="p2 center">Division PALUDICELLINA, nov.<span
+class='pagenum'><a name="Page_190" id="Page_190">[Pg 190]</a></span></p>
+
+<p>This division consists of two very distinct families, the species of
+which are easily distinguished at a glance by the fact that in one (the
+Paludicellid�) the zo&oelig;cia are tubular, while in the other (the
+Hislopiid�) they are broad and flattened. The anatomical and
+physiological differences between the two families are important, and
+they are associated together mainly on account of the method of budding
+by means of which their zoaria are produced.</p>
+
+<div class="figcenter">
+<img src="images/fig_035.jpg"
+width="350" height="344"  alt="Illustration: Fig. 35.&mdash;Single
+zo&oelig;cia of Victorella and Hislopia (magnified)." title="Fig.
+35.&mdash;Single zo&oelig;cia of Victorella and Hislopia (magnified)."
+/>
+<p class="caption">Fig. 35.&mdash;Single zo&oelig;cia of
+<i>Victorella</i> and <i>Hislopia</i> (magnified).</p>
+</div>
+
+<p class="captionj">A, zo&oelig;cium of <i>Victorella pavida</i>, Kent,
+with the polypide retracted (after Kraepelin).<br />
+
+B, zo&oelig;cium of <i>Hislopia lacustris</i>, Carter (typical form from
+the United Provinces), with the collar completely and the tentacles
+partly protruded.<br />
+
+A=collar; B=orifice; C=tentacles; D=pharynx; E=&oelig;sophagus proper;
+F=gizzard; G=stomach; G'=cardiac portion of stomach; H=intestine;
+J=rectum; K=anus; L=young egg; M=green cysts in gizzard; N=testes;
+O=ovary; O'=funiculus.<br />
+
+The muscles are omitted except in fig. B.</p>
+
+<p class="p4 center larger">Family PALUDICELLID�.<span class='pagenum'><a
+name="Page_191" id="Page_191">[Pg 191]</a></span></p>
+
+<div class="genus">
+
+<span class="i0"><span class="smcap">Paludicellid�</span>, Allman, Mon.
+Fresh-Water Polyzoa, p.&nbsp;113 (1857).</span>
+
+<span class="i0"><span class="smcap">Homodi�tid�</span>, Kent, Q. J.
+Micr. Sci. x, p.&nbsp;35 (1870).</span>
+
+<span class="i0"><span class="smcap">Victorellid�</span>, Hincks, Brit.
+Marine Polyzoa, p.&nbsp;558 (1880).</span>
+
+<span class="i0"><span class="smcap">Paludicellid�es</span>, Jullien,
+Bull. Soc. zool. France, x, p.&nbsp;174 (1885).</span>
+
+<span class="i0"><span class="smcap">Paludicellides</span>, Loppens,
+Ann. Biol. lacustre, iii, p.&nbsp;170 (1908).</span>
+
+<span class="i0"><span class="smcap">Victorellides</span>, <i>id.</i>,
+<i>ibid.</i> p.&nbsp;171.</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoarium is recumbent or erect, and is formed
+typically either of zo&oelig;cia arising directly in cruciform formation
+from one another, or of zo&oelig;cia joined together in similar
+formation with the intervention of tubules arising from their own bases.
+Complications often arise, however, either on account of the suppression
+of the lateral buds of a zo&oelig;cium, so that the formation becomes
+linear instead of cruciform, or by the production in an irregular manner
+of additional tubules and buds from the upper part of the zo&oelig;cia.
+A confused and tangled zoarium may thus be formed, the true nature of
+which can only be recognized by the examination of its terminal
+parts.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia are tubular and have a terminal
+or subterminal orifice, which is angulate or subangulate as seen from
+above. Owing to this fact, to the stiff nature of the external ectocyst,
+to the action of circular muscles that surround the tentacular sheath,
+and to the cylindrical form of the soft inverted part, the orifice, as
+seen from above, appears to form four flaps or valves, thus <img
+src="images/i199.png" style="vertical-align:middle" width="50"
+height="42"  alt="Illustration: Valve design" title="Valve design"
+/>.</p>
+
+<p><i>Polypide.</i> The alimentary canal is elongate and slender as a
+whole, the &oelig;sophagus (including the pharynx) being of considerable
+length. In <i>Paludicella</i> and <i>Pottsiella</i> the &oelig;sophagus
+opens directly into the cardiac limb of the stomach, which is distinctly
+constricted at its base; but in <i>Victorella</i> the base of the
+&oelig;sophagus is constricted off from the remainder to form an
+elongate oval sac the walls of which are lined with a delicate
+structureless membrane. <i>Victorella</i> may therefore be said to
+possess a gizzard, but the structure that must be so designated has not
+the function (that of crushing food) commonly associated with the name,
+acting merely as a chamber for the retention of solid particles. In this
+genus the cardiac limb of the stomach is produced and vertical but not
+constricted at the base. The tentacles in most species number 8, but in
+<i>Paludicella</i> there are 16.</p>
+
+<p><i>Resting buds.</i> The peculiar structures known in Europe as
+"hibernacula" are only found in this family. The name hibernacula,
+however, is inappropriate to the only known Indian species<span
+class='pagenum'><a name="Page_192" id="Page_192">[Pg 192]</a></span> as
+they are formed in this country at the approach of summer instead of, as
+in Europe and N. America, at that of winter. It is best, therefore, to
+call them "resting buds." They consist of masses of cells congregated at
+the base of the zo&oelig;cia, gorged with food material and covered with
+a resistant horny covering.</p>
+
+<p>The family Paludicellid� consists of three genera which may be
+distinguished as follows:&mdash;</p>
+
+<table summary="Family Paludicellid�">
+
+<tr><td class="left_a">I.</td><td class="left_a">Orifice terminal; main
+axis of the zo&oelig;cium vertical; zo&oelig;cia separated from one
+another by tubules.</td></tr>
+
+<tr><td class="right_a">[A.</td><td class="left_a">Base of the
+zo&oelig;cia not swollen; no adventitious buds</td><td
+class="left_b"><span class="smcap">Pottsiella.</span>]</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Base of the
+zo&oelig;cium swollen; adventitious buds produced near the tip</td><td
+class="left_b"><span class="smcap">Victorella</span>,&nbsp;p.&nbsp;<a
+href="#Page_194">194</a>.</td></tr>
+
+<tr><td class="left_a">II.</td><td class="left_a">Orifice subterminal,
+distinctly on the dorsal surface; main axis of the zo&oelig;cium
+horizontal (the zoarium being viewed from the dorsal surface); buds not
+produced at the tip of the zo&oelig;cia</td><td class="left_b"><span
+class="smcap">Paludicella</span>,&nbsp;p.&nbsp;<a
+href="#Page_192">192</a>.</td></tr>
+
+</table>
+
+<p>Of these three genera, <i>Pottsiella</i> has not yet been found in
+India and is only known to occur in N. America. It consists of one
+species, <i>P. erecta</i> (Potts) from the neighbourhood of Philadelphia
+in the United States.</p>
+
+<p><i>Victorella</i> includes four species, <i>V. pavida</i> known from
+England and Germany and said to occur in Australia, <i>V. m�lleri</i>
+from Germany (distinguished by possessing parietal muscles at the tip of
+the zo&oelig;cia), <i>V. symbiotica</i> from African lakes and <i>V.
+bengalensis</i> from India. These species are closely related.</p>
+
+<p><i>Paludicella</i> is stated by Carter to have been found in Bombay,
+but probably what he really found was the young stage of <i>V.
+bengalensis</i>. A single species is known in Europe and N. America,
+namely <i>P. ehrenbergi</i>, van Beneden (=<i>Alcyonella articulata</i>,
+Ehrenberg).</p>
+
+<p>I have examined specimens of all the species of this family as yet
+known.</p>
+
+<p class="p2 center">Genus 1. <b>PALUDICELLA</b>, <i>Gervais</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Paludicella</i>, Gervais, Compt. Rend. iii,
+p.&nbsp;797 (1836).</span>
+
+<span class="i0"><i>Paludicella</i>, Allman, Mon. Fresh-Water Polyzoa,
+p.&nbsp;113 (1857).</span>
+
+<span class="i0">? <i>Paludicella</i>, Carter, Ann. Nat. Hist. (3) iii,
+p.&nbsp;333 (1859).</span>
+
+<span class="i0"><i>Paludicella</i>, Jullien, Bull. Soc. zool. France,
+x, p.&nbsp;174 (1885).</span>
+
+<span class="i0"><i>Paludicella</i>, Kraepelin, Deutsch.
+S�sswasserbryozoen, i, p.&nbsp;96 (1887).</span>
+
+<span class="i0"><i>Paludicella</i>, Loppens, Ann. Biol. lacustre, iv,
+p.&nbsp;14 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The nature of the zoarium in this genus is well
+expressed by Ehrenberg's specific name "<i>articulata</i>," although the
+name was given under a false impression. The zo&oelig;cia arise directly
+from one another in linear series with occasional side-branches. The
+side-branches are, however, often suppressed. The zoarium as a whole is
+either recumbent and adherent or at least partly vertical.</p>
+
+<p><span class='pagenum'><a name="Page_193" id="Page_193">[Pg
+193]</a></span><i>Zo&oelig;cia.</i> Although the zo&oelig;cia are
+distinctly tubular as a whole, two longitudinal axes may be
+distinguished in each, for the tip is bent upwards in a slanting
+direction, bearing the orifice at its extremity. The main axis is,
+however, at right angles to the dorso-ventral axis, and the dorsal
+surface, owing to the position of the aperture, can always be readily
+distinguished from the ventral, even when the position of the
+zo&oelig;cium is vertical. Each zo&oelig;cium tapers towards the
+posterior extremity. Parietal muscles are always present.</p>
+
+<div class="figcenter">
+<img src="images/fig_036.png"
+width="400" height="386"  alt="Illustration: Fig. 36.&mdash;Structure of
+Paludicella ehrenbergi (A and B after Allman)." title="Fig.
+36.&mdash;Structure of Paludicella ehrenbergi (A and B after Allman)."
+/>
+<p class="caption">Fig. 36.&mdash;Structure of <i>Paludicella
+ehrenbergi</i> (A and B after Allman).</p>
+</div>
+
+<p class="captionj">A=a single zo&oelig;cium with the polypide
+retracted. B=the base of the lophophore as seen from above with the
+tentacles removed. C=the orifice of a polypide with the collar expanded
+and the tentacles partly retracted. <i>a</i>=tentacles; <i>c</i>=collar;
+<i>d</i>=mouth; <i>e</i>=&oelig;sophagus; <i>f</i>=stomach;
+<i>g</i>=intestine; <i>k</i>=parieto-vaginal muscles; <i>p</i>=parietal
+muscles; <i>o</i>=cardiac part of the stomach; <i>r</i>=retractor
+muscle; <i>s</i>=funiculus.</p>
+
+<p><i>Polypide.</i> The most striking features of the polypide are the
+absence of any trace of a gizzard and the highly specialized form
+assumed by the cardiac part of the stomach. There are two funiculi, both
+connecting the pyloric part of the stomach with the endocyst. The ovary
+develops at the end of the upper, the testis at that of the lower
+funiculus.</p>
+
+<p><i>Resting buds.</i> The resting buds are spindle-shaped.</p>
+
+<p>Kraepelin recognized two species in the genus mainly by their method
+of growth and the number of tentacles. In his <i>P. m�lleri</i> the
+zoarium is always recumbent and the polypide has 8 tentacles, whereas in
+<i>P. articulata</i> or <i>ehrenbergi</i> the tentacles number 16 and
+upright branches are usually developed. It is probable,<span
+class='pagenum'><a name="Page_194" id="Page_194">[Pg 194]</a></span>
+however, that the former species should be assigned to
+<i>Victorella</i>, for it is often difficult to distinguish
+<i>Paludicella</i> from young specimens of <i>Victorella</i> unless the
+latter bear adventitious terminal buds. The gizzard of <i>Victorella</i>
+can be detected in well-preserved material even under a fairly low power
+of the microscope, and I have examined specimens of what I believe to be
+the adult of <i>m�lleri</i> which certainly belong to that genus.</p>
+
+<p>It is always difficult to see the collar of <i>Paludicella</i>,
+because of its transparency and because of the fact that its pleats are
+apparently not strengthened by chitinous rods as is usually the case.
+Allman neither mentions it in his description of the genus nor shows it
+in his figures, and Loppens denies its existence, but it is figured by
+Kraepelin and can always be detected in well-preserved specimens, if
+they are examined carefully. If the collar were actually absent, its
+absence would separate <i>Paludicella</i> not only from
+<i>Victorella</i> and <i>Pottsiella</i>, but also from all other
+ctenostomes. In any case, <i>Victorella</i> is distinguished from
+<i>Paludicella</i> and <i>Pottsiella</i> by anatomical peculiarities
+(<i>e.&nbsp;g.</i>, the possession of a gizzard and the absence of a
+second funiculus) that may ultimately be considered sufficiently great
+to justify its recognition as the type and only genus of a separate
+family or subfamily.</p>
+
+<p>The description of <i>Paludicella</i> is included here on account of
+Carter's identification of the specimens he found at Bombay; but its
+occurrence in India is very doubtful.</p>
+
+<p class="p2 center">Genus 2. <b>VICTORELLA</b>, <i>Kent</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Victorella</i>, Kent, Q. J. Micr. Sci. x, p.&nbsp;34
+(1870).</span>
+
+<span class="i0"><i>Victorella</i>, Hincks, Brit. Marine Polyzoa,
+p.&nbsp;559 (1880).</span>
+
+<span class="i0"><i>Victorella</i>, Kraepelin, Deutsch.
+S�sswasserbryozoen, i, p.&nbsp;93 (1887).</span>
+
+</div>
+
+<p><span class="smcap">Type</span>, <i>Victorella pavida</i>, Kent.</p>
+
+<p><i>Zoarium.</i> The zoarium consists primarily of a number of erect
+or semi-erect tubular zo&oelig;cia joined together at the base in a
+cruciform manner by slender tubules, but complications are introduced by
+the fact that adventitious buds and tubules are produced, often in large
+numbers, round the terminal region of the zo&oelig;cia, and that these
+buds are often separated from their parent zo&oelig;cium by a tubule of
+considerable length, and take root among other zo&oelig;cia at a
+distance from their point of origin. A tangled mass may thus be formed
+in which it is difficult to recognize the regular arrangement of the
+zo&oelig;cia that can be readily detached at the growing points of the
+zoarium.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia when young closely resemble
+those of <i>Paludicella</i>, but as they grow the terminal upturned part
+increases rapidly, while the horizontal basal part remains almost
+stationary and finally appears as a mere swelling at the base of an
+almost vertical tube, in which by far the greater part, if not the
+whole, of the polypide is contained. Round the terminal part of
+this<span class='pagenum'><a name="Page_195" id="Page_195">[Pg
+195]</a></span> tube adventitious buds and tubules are arranged more or
+less regularly. There are no parietal muscles.</p>
+
+<p><i>Polypide.</i> The polypide has 8 slender tentacles, which are
+thickly covered with short hairs. The basal part of the &oelig;sophagus
+forms a thin-walled sac (the "gizzard") constricted off from the upper
+portion and bearing internally a thin structureless membrane. Circular
+muscles exist in its wall but are not strongly developed on its upper
+part. There is a single funiculus, which connects the posterior end of
+the stomach with the base of the zo&oelig;cium. The ovaries and testes
+are borne on the endocyst, not in connection with the funiculus.</p>
+
+<p><i>Resting buds.</i> The resting buds are flattened or resemble young
+zo&oelig;cia in external form.</p>
+
+<p><i>Victorella</i>, although found in fresh water, occurs more
+commonly in brackish water and is known to exist in the littoral zone of
+the sea.</p>
+
+<p class="p2">26. <b>Victorella bengalensis</b>, <i>Annandale</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Victorella pavida</i>, Annandale (<i>nec</i> Kent),
+Rec. Ind. Mus. i, p.&nbsp;200, figs. 1-4 (1907).</span>
+
+<span class="i0"><i>Victorella bengalensis</i>, <i>id.</i>, <i>ibid.</i>
+ii, p.&nbsp;12, fig. 1 (1908).</span>
+
+</div>
+
+<p><i>Zoarium.</i> <i>The mature zoarium resembles a thick fur</i>, the
+hairs of which are represented by elongate, erect, slender tubules (the
+zo&oelig;cia), the arrangement of the whole being very complicated and
+irregular. The base of the zoarium often consists of an irregular
+membrane formed of matted tubules, which are sometimes agglutinated
+together by a gummy secretion. The zoarium as a whole has a faint
+yellowish tinge.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia when young are practically
+recumbent, each being of an ovoid form and having a stout, distinctly
+quadrate orificial tubule projecting upwards and slightly forwards near
+the anterior margin of the dorsal surface. At this stage a single
+tubule, often of great relative length, is often given off near the
+orifice, bearing a bud at its free extremity. As the zo&oelig;cium grows
+the tubular part becomes much elongated as compared with the basal part
+and assumes a vertical position. Its quadrate form sometimes persists
+but more often disappears, so that it becomes almost circular in
+cross-section throughout its length. Buds are produced near the tip in
+considerable profusion. As a rule, if they appear at this stage, the
+tubule connecting them with the parent zo&oelig;cium is short or
+obsolete; sometimes they are produced only on one side of the
+zo&oelig;cium, sometimes on two. The buds themselves produce
+granddaughter and great-granddaughter buds, often connected together by
+short tubules, while still small and imperfectly developed. The swelling
+at the base of the zo&oelig;cium, when the latter is fully formed, is
+small.</p>
+
+<p><i>Polypide.</i> The polypide has the features characteristic of the
+genus. The base of the gizzard is surrounded by a strong circular
+muscle.</p>
+
+<p><span class='pagenum'><a name="Page_196" id="Page_196">[Pg
+196]</a></span></p>
+
+<div class="figcenter">
+<img src="images/fig_037.png"
+width="251" height="375"  alt="Illustration: Fig. 37.&mdash;Victorella
+bengalensis (type specimens)." title="Fig. 37.&mdash;Victorella
+bengalensis (type specimens)." />
+<p class="caption">Fig. 37.&mdash;<i>Victorella bengalensis</i> (type
+specimens).</p>
+</div>
+
+<p class="captionj">A=single zo&oelig;cium without adventitious buds but
+with a young resting bud (<i>b</i>), � 70 (dorsal view); B=lateral view
+of a smaller zo&oelig;cium without buds, � 70; C=upper part of a
+zo&oelig;cium with a single adventitious bud, � 70; D=outline of the
+upper part of a zo&oelig;cium with adventitious buds of several
+generations, � 35; E=remains of a zo&oelig;cium with two resting buds
+(<i>b</i>) attached. All the specimens figured are from Port Canning
+and, except D, are represented as they appear when stained with borax
+carmine and mounted in canada balsam.</p>
+
+<p> <span class='pagenum'><a name="Page_197" id="Page_197">[Pg
+197]</a></span><i>Resting buds.</i> The resting buds (fig. 31,
+p.&nbsp;170) are somewhat variable in shape but are always flat with
+irregular cylindrical or subcylindrical projections round the margin, on
+which the horny coat is thinner than it is on the upper surface. This
+surface is either smooth or longitudinally ridged.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p>This species differs from the European <i>V. pavida</i> in very much
+the same way as, but to a greater extent than, the Indian race of
+<i>Bowerbankia caudata</i> does from the typical English one (see p.
+189). The growth of the zoarium is much more luxuriant, and the form of
+the resting buds is different.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>V.
+bengalensis</i> is abundant in pools of brackish water in the Ganges
+delta and in the Salt Lakes near Calcutta; it also occurs in ponds of
+fresh water near the latter. I have received specimens from Madras from
+Dr. J. R. Henderson, and it is probable that the form from Bombay
+referred by Carter to <i>Paludicella</i> belonged to this species.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;In the Ganges delta <i>V.
+bengalensis</i> is usually found coating the roots and stems of a
+species of grass that grows in and near brackish water, and on sticks
+that have fallen into the water. It also spreads over the surface of
+bricks, and I have found a specimen on a living shell of the common
+mollusc <i>Melania tuberculata</i>. Dr. Henderson obtained specimens at
+Madras from the surface of a freshwater shrimp, <i>Pal�mon
+malcolmsonii</i>. In the ponds at Port Canning the zoaria grow side by
+side with, and even entangled with those of <i>Bowerbankia caudata</i>
+subsp. <i>bengalensis</i>, to the zo&oelig;cia of which their
+zo&oelig;cia bear a very strong external resemblance so far as their
+distal extremity is concerned. This resemblance, however, disappears in
+the case of zo&oelig;cia that bear terminal buds, for no such buds are
+borne by <i>B. caudata</i>; and the yellowish tint of the zoaria of
+<i>V. bengalensis</i> is characteristic. Zoaria of the entoproct
+<i>Loxosomatoides colonialis</i> and colonies of the hydroid <i>Irene
+ceylonensis</i> are also found entangled with the zoaria of <i>V.
+bengalensis</i>, the zo&oelig;cia of which are often covered with
+various species of Vorticellid protozoa and small rotifers. The growth
+of <i>V. bengalensis</i> is more vigorous than that of the other polyzoa
+found with it, and patches of <i>B. caudata</i> are frequently
+surrounded by large areas of <i>V. bengalensis</i>.</p>
+
+<p>The food of <i>V. bengalensis</i> consists largely of diatoms, the
+siliceous shells of which often form the greater part of its excreta.
+Minute particles of silt are sometimes retained in the gizzard, being
+apparently swallowed by accident.</p>
+
+<p>There are still many points to be elucidated as regards the
+production and development of the resting buds in <i>V. bengalensis</i>,
+but two facts are now quite clear as regards them: firstly, that these
+buds are produced at the approach of the hot weather and germinate in
+November or December; and secondly, that the whole zoarium may be
+transformed at the former season into a layer of resting buds closely
+pressed together but sometimes exhibiting in their arrangement the
+typical cruciform formation. Resting buds may often be found in vigorous
+colonies as late as<span class='pagenum'><a name="Page_198"
+id="Page_198">[Pg 198]</a></span> the beginning of December; these buds
+have not been recently formed but have persisted since the previous
+spring and have not yet germinated. Sometimes only one or two buds are
+formed at the base of an existing zo&oelig;cium (fig. 37 <i>a</i>), but
+apparently it is possible not only for a zo&oelig;cium to be transformed
+into a resting bud but for it to produce four other buds round its base
+before undergoing the change. Young polypides are formed inside the buds
+and a single zo&oelig;cium sprouts out of each, as a rule by the growth
+of one of the basal projections, when conditions are favourable.</p>
+
+<p>Polypides of <i>V. bengalensis</i> are often transformed into brown
+bodies. When this occurs the orifice closes together, with the collar
+expanded outside the zo&oelig;cium. I have occasionally noticed that the
+ectocyst of such zo&oelig;cia was distinctly thicker and darker in
+colour than that of normal zo&oelig;cia.</p>
+
+<p>Eggs and spermatozoa are produced in great numbers, as a rule
+simultaneously in the same zo&oelig;cia, but individuals kept in
+captivity often produce spermatozoa only. The eggs are small and are set
+free as eggs. Nothing is known as regards their development.</p>
+
+<p>Polypides are as a rule found in an active condition only in the cold
+weather, but I have on one occasion seen them in this condition in
+August, in a small zoarium attached to a shell of <i>Melania
+tuberculata</i> taken in a canal of brackish water near Calcutta.</p>
+
+<p><span class='pagenum'><a name="Page_199" id="Page_199">[Pg
+199]</a></span></p>
+
+<p class="p2 center larger">Family HISLOPIID�.</p>
+
+<div class="genus">
+
+<span class="i0"><span class="smcap">Hislopid�es</span>, Jullien, Bull.
+Soc. zool. France, x, p.&nbsp;180 (1885).</span>
+
+<span class="i0"><span class="smcap">Hislopiid�</span>, Annandale, Rec.
+Ind. Mus. i, p.&nbsp;200 (1907).</span>
+
+</div>
+
+<p><i>Zoarium</i> recumbent, often forming an almost uniform layer on
+solid subjects.</p>
+
+<p><i>Zo&oelig;cia</i> flattened, adherent; the orifice dorsal, either
+surrounded by a chitinous rim or situated at the tip of an erect
+chitinous tubule; no parietal muscles.</p>
+
+<p><i>Polypide</i> with an ample gizzard which possesses a uniform
+chitinous lining and does not close together when the polypide is
+retracted.</p>
+
+<p><i>Resting bud</i>, not produced.</p>
+
+<p>Only two genera can be recognized in this family, <i>Arachnoidea</i>,
+Moore, from Central Africa, and <i>Hislopia</i>, Carter, which is widely
+distributed in Eastern Asia. The former genus possesses an upright
+orificial tubule and has zo&oelig;cia separated by basal tubules. Its
+anatomy is imperfectly known, but it certainly possesses a gizzard of
+similar structure to that of <i>Hislopia</i>, between which and
+<i>Victorella</i> its zo&oelig;cium is intermediate in form.</p>
+
+<p class="p2 center">Genus <b>HISLOPIA</b>, <i>Carter</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Hislopia</i>, Carter, Ann. Nat. Hist. (3) i,
+p.&nbsp;169 (1858).</span>
+
+<span class="i0"><i>Hislopia</i>, Stolickza, J. As. Soc. Bengal, xxxviii
+(2), p.&nbsp;61 (1869).</span>
+
+<span class="i0"><i>Norodonia</i>, Jullien, Bull. Soc. zool. France, v,
+p.&nbsp;77 (1880).</span>
+
+<span class="i0"><i>Hislopia</i>, <i>id.</i>, <i>ibid.</i> x,
+p.&nbsp;183 (1885).</span>
+
+<span class="i0"><i>Norodonia</i>, <i>id.</i>, <i>ibid.</i> p.
+180.</span>
+
+<span class="i0"><i>Echinella</i>, Korotneff, Biol. Centrbl. xxi,
+p.&nbsp;311 (1901).</span>
+
+<span class="i0"><i>Hislopia</i>, Annandale, J. As. Soc. Bengal (new
+series) ii, p.&nbsp;59 (1906).</span>
+
+<span class="i0"><i>Hislopia</i>, Loppens, Ann. Biol. lacustre, iii, p.
+175 (1908).</span>
+
+</div>
+
+<p><span class="smcap">Type</span>, <i>Hislopia lacustris</i>,
+Carter.</p>
+
+<p><i>Zoarium.</i> The zoarium consists primarily of a main axis running
+in a straight line, with lateral branches that point forwards and
+outwards. Further proliferation, however, often compacts the structure
+into an almost uniform flat area.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia (fig. 35 B, p.&nbsp;190) are
+flat and have the orifice surrounded by a chitinous rim but not much
+raised above the dorsal surface. They arise directly one from
+another.</p>
+
+<p><i>Polypide.</i> The polypide possesses from 12 to 20 tentacles. Its
+funiculus is rudimentary or absent. Neither the ovaries nor the testes
+have any fixed position on the lateral walls of the zo&oelig;cium to
+which they are confined.</p>
+
+<p>The position of this genus has been misunderstood by several
+zoologists. Carter originally described <i>Hislopia</i> as a cheilostome
+allied to <i>Flustra</i>; in 1880 Jullien perpetuated the error in<span
+class='pagenum'><a name="Page_200" id="Page_200">[Pg 200]</a></span>
+describing his <i>Norodonia</i>, which was founded on dried specimens of
+Carter's genus; while Loppens in 1908 still regarded the two "genera" as
+distinct and placed them both among the cheilostomes. In 1885, however,
+Jullien retracted his statement that <i>Norodonia</i> was a cheilostome
+and placed it, together with <i>Hislopia</i>, in a family of which he
+recognized the latter as the eponymic genus. Carter's mistake arose from
+the fact that he had only examined preserved specimens, in which the
+thickened rim of the orifice is strongly reminiscent of the "peristome"
+of certain cheilostomes, while the posterior of the four folds into
+which the tentacle sheath naturally falls (as in all ctenostomes,
+<i>cf.</i> the diagram on p.&nbsp;191) is in certain conditions rather
+larger than the other three and suggests the "lip" characteristic of the
+cheilostomes. If living specimens are examined, however, it is seen at
+once that the posterior fold, like the two lateral folds and the
+anterior one, changes its form and size from time to time and has no
+real resemblance to a "lip."</p>
+
+<p>That there is a remarkable, if superficial, resemblance both as
+regards the form of the zo&oelig;cium and as regards the method of
+growth between <i>Hislopia</i> and certain cheilostomes cannot be
+denied, but the structure of the orifice and indeed of the whole
+organism is that of a ctenostome and the resemblance must be regarded as
+an instance of convergence rather than of genetic relationship.</p>
+
+<p>The most striking feature of the polypide of <i>Hislopia</i> is its
+gizzard (fig. 38, p.&nbsp;201) which is perhaps unique (except for that
+of <i>Arachnoidea</i>) both in structure and function. In structure its
+peculiarities reside mainly in three particulars: (i), it is not
+constricted off directly from the thin-walled &oelig;sophageal tube, but
+possesses at its upper extremity a thick-walled tubular portion which
+can be entirely closed from the &oelig;sophagus at its upper end but
+always remains in communication with the spherical part of the gizzard;
+(ii), this spherical part of the gizzard is uniformly lined with a thick
+chitinous or horny layer which in optical section has the appearance of
+a pair of ridges; and (iii), there is a ring of long and very powerful
+cilia round the passage from the gizzard to the stomach. The cardiac
+limb of the stomach, which is large and heart-shaped, is obsolete. The
+wall of the spherical part of the gizzard consists of two layers of
+cells, an outer muscular layer consisting of powerful circular muscles
+and an inner glandular layer, which secretes the chitinous lining. The
+inner walls of the tubular part consist of non-ciliated columnar cells,
+and when the polypide is retracted it lies almost at right angles to the
+main axis of the zo&oelig;cium.</p>
+
+<p>The spherical part of the gizzard invariably contains a number of
+green cells, which lie free in the liquid it holds and are kept in
+motion by the cilia at its lower aperture. The majority of these cells
+can be seen with the aid of a high power of the microscope to consist of
+a hard spherical coat or cyst containing green protoplasm in which a
+spherical mass of denser substance (the nucleus) and a number of minute
+transparent granules can<span class='pagenum'><a name="Page_201"
+id="Page_201">[Pg 201]</a></span> sometimes be detected. The external
+surface of many of the cysts is covered with similar granules, but some
+are quite clean.</p>
+
+<p>There can be no doubt that these cysts represent a stage in the
+life-history of some minute unicellular plant or animal. Indeed,
+although it has not yet been found possible to work out this
+life-history in detail, I have been able to obtain much evidence that
+they are the resting stage of a flagellate organism allied to
+<i>Euglena</i> which is swallowed by the polyzoon and becomes encysted
+in its gizzard, extruding in so doing from its external surface a large
+proportion of the food-material that it has stored up within itself in
+the form of transparent granules. It may also be stated that some of the
+organisms die and disintegrate on being received into the gizzard,
+instead of encysting themselves.</p>
+
+<p>So long as the gizzard retains its spherical form the green cells and
+its other contents are prevented from entering the stomach by the
+movements of the cilia that surround its lower aperture, but every now
+and then, at irregular intervals, the muscles that form its outer wall
+contract. The chitinous lining although resilient and not inflexible is
+too stiff to prevent the lumen of the gizzard being obliterated, but the
+action of the muscles changes its contents from a spherical to an ovoid
+form and in so doing presses a considerable part of them down into the
+stomach, through the ring of the cilia.</p>
+
+<div class="figcenter">
+<img src="images/fig_038.png"
+width="440" height="354"  alt="Illustration: Fig. 38.&mdash;Optical
+section of gizzard of Hislopia lacustris, with contained green cysts, �
+240." title="Fig. 38.&mdash;Optical section of gizzard of Hislopia
+lacustris, with contained green cysts, � 240." />
+<p class="caption">Fig. 38.&mdash;Optical section of gizzard of
+<i>Hislopia lacustris</i>, with contained green cysts, � 240.</p>
+</div>
+
+<p>The contraction of the gizzard is momentary, and on its re-expansion
+some of the green cysts that have entered the stomach are often
+regurgitated into it. Some, however, remain in the stomach,<span
+class='pagenum'><a name="Page_202" id="Page_202">[Pg 202]</a></span> in
+which they are turned round and round by the action of the cilia at both
+apertures. They are apparently able to retain their form for some hours
+in these circumstances but finally disintegrate and disappear, being
+doubtless digested by the juices poured out upon them by the glandular
+lining of the stomach. In polypides kept under observation in clean
+tap-water all the cysts finally disappear, and the f�ces assume a green
+colour. In preserved specimens apparently unaltered cysts are sometimes
+found in the rectum, but this is exceptional: I have observed nothing of
+the kind in living polypides. Cysts often remain for several days
+unaltered in the gizzard.</p>
+
+<p>Imperfect as these observations are, they throw considerable light on
+the functions of the gizzard in <i>Hislopia</i>. Primarily it appears to
+act as a food-reservoir in which the green cysts and other minute
+organisms can be kept until they are required for digestion. When in the
+gizzard certain organisms surrender a large proportion of the
+food-material stored up for their own uses, and this food-material
+doubtless aids in nourishing the polyzoon. Although the cysts in the
+gizzard are frequently accompanied by diatoms, the latter are not
+invariably present. The cysts, moreover, are to be found in the
+zo&oelig;cia of polypides that have formed brown bodies, often being
+actually enclosed in the substance of the brown body. The gizzards of
+the specimens of <i>Arachnoidea</i> I have examined contain cysts that
+resemble those found in the same position in <i>Hislopia</i>.</p>
+
+<p><i>Hislopia</i> is widely distributed in the southern part of the
+Oriental Region, and, if I am right in regarding <i>Echinella</i>,
+Korotneff as a synonym, extends its range northwards to Lake Baikal. It
+appears to be a highly specialized form but is perhaps related, through
+<i>Arachnoidea</i>, to <i>Victorella</i>.</p>
+
+<p class="p2">27. <b>Hislopia lacustris</b>, <i>Carter</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Hislopia lacustris</i>, Carter, Ann. Nat. Hist. (3)
+i, p.&nbsp;170, pl. vii, figs. 1-3 (1858).</span>
+
+<span class="i0"><i>Norodonia cambodgiensis</i>, Jullien, Bull. Soc.
+zool. France, v, p.&nbsp;77, figs. 1-3 (1880).</span>
+
+<span class="i0"><i>Norodonia sinensis</i>, <i>id.</i>, <i>ibid.</i> p.
+78, figs. 1-3.</span>
+
+<span class="i0"><i>Norodonia cambodgiensis</i>, <i>id.</i>,
+<i>ibid.</i> x, p.&nbsp;181, figs. 244, 245 (1885).</span>
+
+<span class="i0"><i>Norodonia sinensis</i>, <i>id.</i>, <i>ibid.</i> p.
+182, figs. 246, 247.</span>
+
+<span class="i0"><i>Hislopia lacustris</i>, Annandale, J. As. Soc.
+Bengal (new series) iii, p.&nbsp;85 (1907).</span>
+
+<span class="i0"><i>Hislopia lacustris</i>, Walton, Rec. Ind. Mus. i, p.
+177 (1907).</span>
+
+<span class="i0"><i>Hislopia lacustris</i>, Kirkpatrick, <i>ibid.</i>
+ii, p.&nbsp;98 (1908).</span>
+
+<span class="i0"><i>Hislopia lacustris</i>, Walton, <i>ibid.</i> iii, p.
+295 (1909).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoarium forms a flat, more or less solid layer
+and is closely adherent to foreign objects. As a rule it covers a
+considerable area, with radiating branches at the edges; but when
+growing on slender twigs or the stems of water-plants it forms<span
+class='pagenum'><a name="Page_203" id="Page_203">[Pg 203]</a></span>
+narrow, closely compressed masses. One zo&oelig;cium, however, never
+grows over another.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia are variable in shape. In
+zoaria which have space for free expansion they are as a rule
+irregularly oval, the posterior extremity being often narrower than the
+anterior; but small triangular zo&oelig;cia and others that are almost
+square may often be found. When growing on a support of limited area the
+zo&oelig;cia are smaller and as a rule more elongate. The orifice is
+situated on a slight eminence nearer the anterior than the posterior
+margin of the dorsal surface. It is surrounded by a strong chitinous
+rim, which is usually square or subquadrate but not infrequently
+circular or subcircular. Sometimes a prominent spine is borne at each
+corner of the rim, but these spines are often vestigial or absent; they
+are rarely as long as the transverse diameter of the orifice. The
+zo&oelig;cium is usually surrounded by a chitinous margin, and outside
+this margin there is often a greater or less extent of adherent
+membrane. In some zo&oelig;cia the margin is obsolete or obsolescent.
+The dorsal surface is of a glassy transparency but by no means soft.</p>
+
+<div class="figcenter">
+<img src="images/fig_039.png"
+width="475" height="394"  alt="Illustration: Fig. 39.&mdash;Hislopia
+lacustris." title="Fig. 39.&mdash;Hislopia lacustris." />
+<p class="caption">Fig. 39.&mdash;<i>Hislopia lacustris.</i></p>
+</div>
+
+<p class="captionj">A=part of a zoarium of the subspecies
+<i>moniliformis</i> (type specimen, from Calcutta), � 15; A=green cysts
+in gizzard; E=eggs.<br /> B=outline of part of a zoarium of the typical
+form of the species from the United Provinces, showing variation in the
+form of the zo&oelig;cia and of the orifice, � 15.</p>
+
+<p><i>Polypide.</i> The polypide has from 12 to 20 tentacles, 16 being a
+common number.</p>
+
+<p><span class="smcap">Type</span> probably not in existence. It is not
+in the British Museum and Prof. Dendy, who has been kind enough to
+examine the specimens from Carter's collection now in his possession,
+tells me that there are none of <i>Hislopia</i> among them.</p>
+
+<p class="p2">27 <i>a.</i> Subsp. <b>moniliformis</b>, nov.<span
+class='pagenum'><a name="Page_204" id="Page_204">[Pg 204]</a></span></p>
+
+<div class="genus">
+
+<span class="i0"><i>Hislopia lacustris</i>, Annandale, J. As. Soc.
+Bengal (new series) ii, p.&nbsp;59, fig. 1 (1906).</span>
+
+</div>
+
+<p>In this race, which is common in Calcutta, the zo&oelig;cia are
+almost circular but truncate or concave anteriorly and posteriorly. They
+form linear series with few lateral branches. I have found specimens
+occasionally on the shell of <i>Vivipara bengalensis</i>, but they are
+much more common on the leaves of <i>Vallisneria spiralis</i>.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p>The exact status of the forms described by Jullien as <i>Norodonia
+cambodgiensis</i> and <i>N. sinensis</i> is doubtful, but I see no
+reason to regard them as specifically distinct from <i>H. lacustris</i>,
+Carter, of which they may be provisionally regarded as varieties. The
+variety <i>cambodgiensis</i> is very like my subspecies
+<i>moniliformis</i> but has the zo&oelig;cia constricted posteriorly,
+while var. <i>sinensis</i>, although the types were found on
+<i>Anodonta</i> shells on which there was plenty of room for growth,
+resemble the confined phase of <i>H. lacustris</i> so far as the form of
+their zo&oelig;cia and of the orifice is concerned.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The
+typical form is common in northern India and occurs also in Lower Burma;
+the subspecies <i>moniliformis</i> appears to be confined to Lower
+Bengal, while the varieties <i>cambodgiensis</i> and <i>sinensis</i>
+both occur in China, the former having been found also in Cambodia and
+Siam. Indian and Burmese localities are:&mdash;<span
+class="smcap">Bengal</span>, Calcutta (subsp. <i>moniliformis</i>);
+Berhampur, Murshidabad district (<i>J. Robertson Milne</i>): <span
+class="smcap">Central Provinces</span>, Nagpur (<i>Carter</i>): <span
+class="smcap">United Provinces</span>, Bulandshahr (<i>H. J.
+Walton</i>): <span class="smcap">Burma</span>, Pegu-Sittang Canal
+(<i>Kirkpatrick</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;Regarding the typical form
+of the species Major Walton writes (Rec. Ind. Mus. iii, p.
+296):&mdash;"In volume i (page 177) of the Records of the Indian Museum,
+I described the two forms of colonies of <i>Hislopia</i> that I had
+found in the United Provinces (Bulandshahr). Of these, one was a more or
+less linear arrangement of the zo&oelig;cia on leaves and twigs, and the
+other, and more common, form was an encrusting sheath on the outer
+surface of the shells of <i>Paludina</i>. During the present 'rains'
+(July 1908) I have found many examples of what may be considered a much
+exaggerated extension of the latter form. These colonies have been on
+bricks, tiles, and other submerged objects. The largest colony that I
+have seen so far was on a tile; one side of the tile was exposed above
+the mud of the bottom of the tank, and its area measured about 120
+square inches; the entire surface was almost completely covered by a
+continuous growth of <i>Hislopia</i>. Another large colony was on a
+piece of bark which measured 7 inches by 3 inches; both sides were
+practically everywhere covered by <i>Hislopia</i>."</p>
+
+<p>Major Walton also notes that in the United Provinces the growth of
+<i>Hislopia</i> is at its maximum during "rains," and that at that time
+of year almost every adult <i>Paludina</i> in a certain<span
+class='pagenum'><a name="Page_205" id="Page_205">[Pg 205]</a></span>
+tank at Bulandshahr had its shell covered with the zo&oelig;cia. The
+Calcutta race flourishes all the year round but never forms large or
+closely compacted zoaria, those on shells of <i>Vivipara</i> exactly
+resembling those on leaves of <i>Vallisneria</i>.</p>
+
+<p>In Calcutta both eggs and spermatozoa are produced at all times of
+the year simultaneously in the same zo&oelig;cia, but the eggs in one
+zo&oelig;cium often vary greatly in size. When mature they reach
+relatively considerable dimensions and contain a large amount of food
+material; but they are set free from the zo&oelig;cium as eggs. They lie
+loose in the zo&oelig;cium at a comparatively small size and grow in
+this position. Nothing is known as regards the development of
+<i>Hislopia</i>.</p>
+
+<p>Both forms of the species appear to be confined to water that is free
+from all traces of contamination with brine.</p>
+
+<p class="p4 center larger">Order <b>PHYLACTOL�MATA.</b><span
+class='pagenum'><a name="Page_206" id="Page_206">[Pg 206]</a></span></p>
+
+<p>The polypide in this order possesses a leaf-like ciliated organ (the
+epistome) which arises within the lophophore between the mouth and the
+anus and projects upwards and forwards over the mouth, which it can be
+used to close. The zo&oelig;cia are never distinct from one another, but
+in dendritic forms such as <i>Plumatella</i> the zoarium is divided at
+irregular intervals by chitinous partitions. The lophophore in most
+genera is horseshoe-shaped instead of circular, the part opposite the
+anus being deeply indented. There are no parietal muscles. The orifice
+of the zo&oelig;cium is always circular, and there is no trace of any
+structure corresponding to the collar of the ctenostomes. The tentacles
+are always webbed at the base.</p>
+
+<p>All the phylactol�mata produce the peculiar reproductive bodies known
+as statoblasts.</p>
+
+<p>The phylactol�mata, which are probably descended from ctenostomatous
+ancestors, are confined to fresh or slightly brackish water. Most of the
+genera have a wide geographical distribution, but (with the exception of
+a few statoblasts of almost recent date) only one fossil form
+(<i>Plumatellites</i>, Fric. from the chalk of Bohemia) has been
+referred to the order, and that with some doubt.</p>
+
+<p>It is convenient to recognize two main divisions of the
+phylactol�mata, but these divisions hardly merit the distinction of
+being regarded as suborders. They may be called Cristatellina and
+Plumatellina and distinguished as follows:&mdash;</p>
+
+<p>Division I, <span class="smcap">Plumatellina</span>,
+nov.&mdash;Ectocyst well developed; zoaria without a special organ of
+progression; polypides contained in tubes.</p>
+
+<p>Division II, <span class="smcap">Cristatellina</span>,
+nov.&mdash;Ectocyst absent except at the base of the zoarium which is
+modified to form a creeping "sole"; polypides embedded in a common
+syn&oelig;cium of reticulate structure.</p>
+
+<p>The Cristatellina consist of a single genus and probably of a single
+species (<i>Cristatella mucedo</i>, Cuvier), which is widely distributed
+in Europe and N. America, but has not been found in the Oriental Region.
+Eight genera of Plumatellina are known, and five (possibly six) of these
+genera occur in India.</p>
+
+<p class="p2 center">Division PLUMATELLINA, nov.</p>
+
+<p>The structure of the species included in this division is very
+uniform as regards the internal organs (see fig. 40 opposite and fig. 47
+<i>a</i>, p.&nbsp;236). The alimentary canal is simpler than that of the
+Paludicellid�. A short &oelig;sophagus leads directly into the
+stomach,<span class='pagenum'><a name="Page_207" id="Page_207">[Pg
+207]</a></span> the cardiac portion of which is produced as a vertical
+limb almost cylindrical in form and not constricted at the base. This
+limb is as a rule of greater length than the &oelig;sophagus. The
+pyloric part of the stomach is elongated and narrow, and the intestine
+short, straight, and of ovoid form. There are no cilia at the pyloric
+opening. A single funiculus joins the posterior end of the stomach to
+the wall of the zo&oelig;cium, bearing the statoblasts. Sexual organs
+are often absent.</p>
+
+<div class="figcenter">
+<img src="images/fig_040.jpg"
+width="324" height="400"  alt="Illustration: Fig. 40.&mdash;Structure of
+the Plumatellina (after Allman)." title="Fig. 40.&mdash;Structure of the
+Plumatellina (after Allman)." />
+<p class="caption">Fig. 40.&mdash;Structure of the Plumatellina (after
+Allman).</p>
+</div>
+
+<p class="captionj">A=a zo&oelig;cium of <i>Fredericella</i> with the
+polypide extruded. B=the lophophore of <i>Lophopus</i> (tentacles
+removed) as seen obliquely from the right side. C=larva of
+<i>Plumatella</i> as seen in optical section. <i>a</i>=tentacles;
+<i>b</i>=velum; <i>c</i>=epistome; <i>d</i>=mouth;
+<i>e</i>=&oelig;sophagus; <i>f</i>=stomach; <i>g</i>=intestine;
+<i>h</i>=anus; <i>j</i>=retractor muscle; <i>k</i>=parieto-vaginal
+muscles; <i>l</i>=funiculus.</p>
+
+<p>Two families may be recognized as constituting the division,
+<i>viz.</i>, (<i>a</i>) the Fredericellid�, which have a circular or
+oval lophophore and simple statoblast without a swim-ring, and
+(<i>b</i>) the Plumatellid�, in which the lophophore is shaped like a
+horseshoe and some or all of the statoblasts are provided with a ring of
+air-spaces.</p>
+
+<p class="p2 center larger">Family 1. FREDERICELLID�.<span
+class='pagenum'><a name="Page_208" id="Page_208">[Pg 208]</a></span></p>
+
+<div class="genus">
+
+<span class="i0"><span class="smcap">Fredericellid�</span>, Kraepelin,
+Deutsch. S�sswasserbryozoen, i, p.&nbsp;168 (1887).</span>
+
+</div>
+
+<p><i>Zoaria</i> dendritic; <i>zo&oelig;cia</i> distinctly tubular, with
+the ectocyst well developed; <i>statoblasts</i> of one kind only, each
+surrounded by a chitinous ring devoid of air-spaces; <i>polypides</i>
+with the lophophore circular or oval when expanded.</p>
+
+<p>The Fredericellid� consist of a single genus (<i>Fredericella</i>)
+which includes several closely-allied forms and has a wide geographical
+distribution.</p>
+
+<p class="p2 center">Genus <b>FREDERICELLA</b>, <i>Gervais</i>
+(1838).</p>
+
+<div class="genus">
+
+<span class="i0"><i>Fredericella</i>, Allman, Mon. Fresh-Water Polyzoa,
+p.&nbsp;110 (1857).</span>
+
+<span class="i0"><i>Plumatella</i>, ("arr�t de d�veloppement") Jullien,
+Bull. Soc. zool. France, x, p.&nbsp;121 (1885).</span>
+
+<span class="i0"><i>Fredericella</i>, Kraepelin, Deutsch.
+S�sswasserbryozoen, i, p.&nbsp;99 (1887).</span>
+
+<span class="i0"><i>Fredericella</i>, Goddard, Proc. Linn. Soc. N. S.
+Wales, xxxiv, p.&nbsp;489 (1909).</span>
+
+</div>
+
+<p>This genus has the characters of the family. Its status has been much
+disputed, some authors regarding the shape of the lophophore as of great
+morphological importance, while Jullien believed that
+<i>Fredericella</i> was merely an abnormal or monstrous form of
+<i>Plumatella</i>. The latter belief was doubtless due to the fact that
+the zoaria of the two genera bear a very close external resemblance to
+one another and are sometimes found entangled together. The importance
+of the shape of the lophophore may, however, easily be exaggerated, for,
+as both Jullien and Goddard have pointed out, it assumes an emarginate
+form when retracted.</p>
+
+<p>The best known species is the European and N. American <i>F.
+sultana</i> (Blumenbach), of which several varieties or phases have been
+described as distinct. This form is stated to occur also in S. Africa.
+<i>F. australiensis</i>, Goddard<a name="fnanchor_BC"
+id="fnanchor_BC"></a><a href="#footnote_BC"
+class="fnanchor"><sup>[BC]</sup></a> from N. S. Wales is said to differ
+from this species in having an oval instead of a circular lophophore and
+in other small anatomical characters; but it is doubtful how far these
+characters are valid, for the lophophore appears to be capable of
+changing its shape to some slight extent and has been stated by Jullien
+to be habitually oval in specimens from France. <i>F. cunningtoni</i>,
+Rousselet<a name="fnanchor_BD" id="fnanchor_BD"></a><a
+href="#footnote_BD" class="fnanchor"><sup>[BD]</sup></a> from Lake
+Tanganyika has stout zo&oelig;cia encrusted with relatively large
+sand-grains.</p>
+
+<p>The zoaria of <i>Fredericella</i> are usually found attached to solid
+objects in shallow water, but a form described as <i>F. duplessisi</i>,
+Ford has been found at a depth of 40 fathoms embedded in mud at the
+bottom of the Lake of Geneva. <i>F. cunningtoni</i> was dredged from
+depths of about 10 and about 25 fathoms.</p>
+
+<p>The statoblasts of this genus do not float and often germinate in the
+parent zo&oelig;cium after its polypides have died. They are produced in
+smaller numbers than is usually the case in other genera of the order.
+The polypides sometimes undergo a process of regeneration, but without
+the formation of brown bodies.</p>
+
+<p><span class='pagenum'><a name="Page_209" id="Page_209">[Pg
+209]</a></span></p>
+
+<div class="figcenter">
+<img src="images/fig_041.png"
+width="331" height="475"  alt="Illustration: Fig. 41.&mdash;Fredericella
+indica." title="Fig. 41.&mdash;Fredericella indica." />
+<p class="caption">Fig. 41.&mdash;<i>Fredericella indica.</i></p>
+</div>
+
+<p class="captionj">A=statoblast, � 120. B=outline of expanded
+lophophore and adjacent parts, � 75; a=anus, r=rectum. C=outline of
+zoarium on leaf of water-plant, � 3.</p>
+
+<p class="center"><b>(A and B are from specimens from Igatpuri, C from
+specimen from Shasthancottah).</b></p>
+
+<p class="p2">28. <b>Fredericella indica</b>, <i>Annandale</i>.<span
+class='pagenum'><a name="Page_210" id="Page_210">[Pg 210]</a></span></p>
+
+<div class="genus">
+
+<span class="i0"><i>Fredericella indica</i>, Annandale, Rec. Ind. Mus.
+iii, p.&nbsp;373, fig. (1909).</span>
+
+<span class="i0"><i>Fredericella indica</i>, <i>id.</i>, <i>ibid.</i> v,
+p.&nbsp;39 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoarium is of delicate appearance and branches
+sparingly. It is often entirely recumbent but sometimes produces short,
+lax branches that consist of two or three zo&oelig;cia only.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia are very slender and almost
+cylindrical; they are slightly emarginate and furrowed, the keel in
+which the furrow runs being sometimes prominent. The external surface is
+minutely roughened and apparently soft, for small grains of sand and
+other d�bris cling to it, but never thickly. The ectocyst is practically
+colourless but not transparent.</p>
+
+<p><i>Statoblasts.</i> The statoblasts are variable in size and form but
+most commonly have a regular broad oval outline; sometimes they are
+kidney-shaped. The dorsal surface is covered with minute star-shaped
+prominences, which sometimes cover it almost uniformly and are sometimes
+more numerous in the centre than towards the periphery. The ventral
+surface is smooth.</p>
+
+<p><i>Polypide.</i> The lophophore bears about 20-25 tentacles, which
+are very slender and of moderate length; the velum at their base is
+narrow; as a rule the lophophore is accurately circular.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p>The most definite character in which this species differs from <i>F.
+sultana</i> and <i>F. australiensis</i> is the ornamentation of one
+surface of the statoblast, both surfaces of which are smooth in the two
+latter species. From <i>F. cunningtoni</i>, the statoblasts of which are
+unknown, it differs in having almost cylindrical instead of depressed
+zo&oelig;cia and in not having the zo&oelig;cia densely covered with
+sand-grains.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;Western
+India (the Malabar Zone): Igatpuri Lake, W. Ghats (alt. ca. 2,000 feet),
+Bombay Presidency, and Shasthancottah Lake near Quilon, Travancore.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;In both the lakes in which
+the species has yet been found it was collected in November. The
+specimens obtained in Travancore were found to be undergoing a process
+of regeneration due at least partly to the fact that most of the
+polypides had perished and that statoblasts were germinating in the old
+zo&oelig;cia. Specimens from the Bombay Presidency, which were obtained
+a little later in the month, were in a more vigorous condition, although
+even they contained many young polypides that were not yet fully formed.
+It seems, therefore, not improbable that <i>F. indica</i> dies down at
+the beginning of the hot weather and is regenerated by the germination
+of its statoblasts at the beginning of the cold weather.</p>
+
+<p>At Shasthancottah zoaria were found entangled with zoaria of a
+delicate form of <i>Plumatella fruticosa</i> to which they bore a very
+close external resemblance.</p>
+
+<p class="p4 center larger">Family 2. PLUMATELLID�.<span
+class='pagenum'><a name="Page_211" id="Page_211">[Pg 211]</a></span></p>
+
+<div class="genus">
+
+<span class="i0"><span class="smcap">Plumatellid�</span>, Allman (<i>partim</i>), Mon.
+Fresh-Water Polyzoa, pp.&nbsp;76, 81 (1857).</span>
+
+</div>
+
+<p>Phylactol�mata which have horseshoe-shaped lophophores and a
+well-developed ectocyst not specialized to form an organ of progression.
+Some or all of the statoblasts are provided with a "swim-ring"
+consisting of symmetrically disposed, polygonal chitinous chambers
+containing air.</p>
+
+<p>It is convenient to divide the Plumatellid� as thus defined into
+subfamilies (the Plumatellin� and the Lophopin�), which may be defined
+as follows:&mdash;</p>
+
+<p class="p2 center">Subfamily A. PLUMATELLIN�.</p>
+
+<p>Zoarium dendritic or linear, firmly fixed to extraneous objects;
+zo&oelig;cia tubular, not fused together to form a gelatinous mass.</p>
+
+<p class="p2 center">Subfamily B. LOPHOPIN�.</p>
+
+<p>Zoarium forming a gelatinous mass in which the tubular nature of the
+zo&oelig;cia almost disappears, capable to a limited extent of
+progression along a smooth surface.</p>
+
+<p>Both these subfamilies are represented in the Indian fauna, the
+Plumatellin� by two of the three genera known to exist, and the
+Lophopin� by two (or possibly three) of the four that have been
+described. The following key includes all the known genera, but the
+names of those that have not been recorded from India are enclosed in
+square brackets.</p>
+
+<p class="p2 center"><i>Key to the Genera of</i> Plumatellid�.</p>
+
+<table summary="Key to Genera Plumatellidae">
+
+<tr><td class="left_a">I.</td><td class="left_a">Statoblasts without
+marginal processes.</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Zo&oelig;cia
+cylindrical, not embedded in a gelatinous investment
+(Plumatellin�).</td></tr>
+
+<tr><td></td><td class="left_a"><i>a</i>. Zo&oelig;cia arising directly
+from one another; no stolon; free statoblast oval</td><td
+class="right"><span class="smcap">Plumatella</span>, p.&nbsp;<a
+href="#Page_212">212</a>.</td></tr>
+
+<tr><td></td><td class="left_a"><i>a'</i>. Zo&oelig;cia arising singly
+or in groups from an adherent stolon; free statoblasts oval.</td><td
+class="right"><span class="smcap">Stolella</span>, p.&nbsp;<a
+href="#Page_229">229</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Zo&oelig;cia
+cylindrical, embedded in a structureless gelatinous
+investment.</td></tr>
+
+<tr><td></td><td class="left_a">Zo&oelig;cia arising from a ramifying
+stolon; statoblasts circular</td><td class="right">[<span
+class="smcap">Stephanella.</span>]</td></tr>
+
+<tr><td class="right_a">C.</td><td class="left_a">Polypides embedded in
+a hyaline syn&oelig;cium that conceals the cylindrical form of the
+zo&oelig;cia (Lophopin�).<span class='pagenum'><a name="Page_212"
+id="Page_212">[Pg 212]</a></span></td></tr>
+
+<tr><td></td><td class="left_a"><i>c</i>. Polypides upright, their base
+far removed from that of the zoarium when they are expanded</td><td
+class="right"><span class="smcap">Lophopus</span>, p.&nbsp;<a
+href="#Page_231">231</a>.</td></tr>
+
+<tr><td></td><td class="left_a"><i>c</i>'. Polypides recumbent for the
+greater part of their length at the base of the zoarium</td><td
+class="right">[<span class="smcap">Australella</span><a
+name="fnanchor_BE" id="fnanchor_BE"></a><a href="#footnote_BE"
+class="fnanchor"><sup>[BE]</sup></a>.]</td></tr>
+
+<tr><td class="left_a">II.</td><td class="left_a">Statoblasts armed
+(normally) with hooked processes (Lophopin�).</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Processes confined to
+the extremities of the statoblast; zoaria remaining separate throughout
+life</td><td class="right"><span
+class="smcap">Lophopodella</span>, p.&nbsp;<a
+href="#Page_231">231</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Processes entirely
+surrounding the statoblast; many zoaria embedded in a common gelatinous
+investment so as to form large compound colonies</td><td
+class="right"><span class="smcap">Pectinatella</span>, p.&nbsp;<a
+href="#Page_235">235</a>.</td></tr>
+
+</table>
+
+<p class="p2 center">Subfamily A. PLUMATELLIN�.</p>
+
+<p>Of the two Indian genera of this subfamily, one (<i>Plumatella</i>)
+is almost universally distributed, while the other (<i>Stolella</i>) has
+only been found in the valley of the Ganges. The third genus of the
+subfamily (<i>Stephanella</i>) is only known from Japan.</p>
+
+<p>It should be noted that zoaria of different species and genera of
+this subfamily are often found in close proximity to one another and to
+zoaria of <i>Fredericella</i>, and that the branches of the different
+species are sometimes entangled together in such a way that they appear,
+unless carefully separated, to belong to the same zoarium.</p>
+
+<p class="p2 center">Genus 1. <b>PLUMATELLA</b>, <i>Lamarck</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Plumatella</i>, Lamarck, Animaux sans Vert. (ed.
+1re) ii, p.&nbsp;106 (1816).</span>
+
+<span class="i0"><i>Alcyonella</i>, <i>id</i>., <i>ibid</i>.
+p.&nbsp;100.</span>
+
+<span class="i0"><i>Plumatella</i>, Allman, Mon. Fresh-Water Polyzoa,
+p.&nbsp;92 (1857).</span>
+
+<span class="i0"><i>Alcyonella</i>, <i>id</i>., <i>ibid</i>.
+p.&nbsp;86.</span>
+
+<span class="i0"><i>Plumatella</i>, Hyatt, Comm. Essex Inst. iv,
+p.&nbsp;207, pl. viii (1866).</span>
+
+<span class="i0"><i>Plumatella</i>, Jullien (<i>partim</i>), Bull. Soc.
+zool. France, x, p.&nbsp;100 (1885).</span>
+
+<span class="i0"><i>Hyalinella</i>, <i>id</i>., <i>ibid</i>.
+p.&nbsp;133.</span>
+
+<span class="i0"><i>Plumatella</i>, Kraepelin, Deutsch. S�sswass.
+Bryozoen, i, p.&nbsp;104 (1887).</span>
+
+<span class="i0"><i>Plumatella</i>, Braem, Unter. �. Bryozoen des s�ssen
+Wassers, p.&nbsp;2 (Bibliotheca Zoologica, ii, 1890).</span>
+
+</div>
+
+<p><i>Zoarium</i> dendritic, recumbent, erect, or partly recumbent and
+partly erect.</p>
+
+<p><i>Zo&oelig;cia</i> tubular, not confined in a gelatinous <ins
+title="changed from 'sy&oelig;cium'">syn&oelig;cium</ins>; the ectocyst
+usually horny.</p>
+
+<p><i>Statoblasts</i> often of two kinds, free and stationary, the
+latter without air-cells and as a rule adherent by one surface, the
+former provided with a well-developed ring of air-cells but without
+marginal processes, oval in form, never more than about 0.6 mm. in
+length.</p>
+
+<p><i>Polypide</i> with less than 65 tentacles.</p>
+
+<p><span class='pagenum'><a name="Page_213" id="Page_213">[Pg
+213]</a></span></p>
+
+<div class="figcenter">
+<img src="images/fig_042.jpg"
+width="446" height="500"  alt="Illustration: Fig. 42.&mdash;Outlines of
+free statoblasts of Plumatella (enlarged)." title="Fig.
+42.&mdash;Outlines of free statoblasts of Plumatella (enlarged)." />
+<p class="caption">Fig. 42.&mdash;Outlines of free statoblasts of
+<i>Plumatella</i> (enlarged).</p>
+</div>
+
+<p class="captionj">A, of <i>P. fruticosa</i> (Calcutta); B, of <i>P.
+emarginata</i> (Calcutta); C, of <i>P. javanica</i> (Travancore); D, of
+<i>P. diffusa</i> (Sikhim); E, of <i>P. allmani</i> (Bhim Tal); F, of
+<i>P. diffusa</i> (Rajshahi, Bengal); G, G', of <i>P. punctata</i>
+(Calcutta); H, of <i>P. diffusa</i> (Sikhim), statoblast further
+enlarged: <span class="smcap">A</span>=outline of capsule; <span
+class="smcap">B</span>=limit of swim-ring on ventral surface; <span
+class="smcap">C</span>=limit of swim-ring on dorsal surface. [The dark
+area represents the capsule of the statoblast.]</p>
+
+<p>Certain forms of this genus are liable to become compacted together
+in such a way as to constitute solid masses consisting of elongate
+vertical zo&oelig;cia closely parallel to one another and sometimes
+agglutinated by means of a gummy substance. These forms were given by
+Lamarck in 1816 the name <i>Alcyonella</i>, and there has been much
+dispute as to whether they represent a distinct genus, distinct species,
+or merely varieties or phases of more typical forms. It appears to be
+the case that all species which produce vertical branches are liable to
+have these branches closely packed together and the individual
+zo&oelig;cia of which they are composed more or less greatly elongated.
+It is in this way that the form known to Allman as <i>Alcyonella
+benedeni</i> is produced from the typical <i>Plumatella emarginata</i>.
+Other forms go further and secrete a gummy substance that glues the
+upright zo&oelig;cia<span class='pagenum'><a name="Page_214"
+id="Page_214">[Pg 214]</a></span> together and forces them to elongate
+themselves without branching. In these conditions the zo&oelig;cia
+become polygonal in cross-section. It is probable that such forms
+(<i>e.&nbsp;g.</i>, <i>Plumatella fungosa</i> (Pallas)) should rank as
+distinct species, for the gummy secretion is present in great profusion
+even in young zoaria in which the zo&oelig;cia have not yet assumed a
+vertical position. No such form, however, has as yet been found in
+India, and in any case it is impossible to regard <i>Alcyonella</i> as a
+distinct genus.</p>
+
+<p class="p2 center"><i>Key to the Indian Species of</i> Plumatella.</p>
+
+<table summary="Key to Indian Species of Plumatella">
+
+<tr><td class="left_a">I.</td><td class="left_a">Ectocyst more or less
+stiff, capable of transverse wrinkling only near the tips of the
+zo&oelig;cia, never contractile or greatly swollen; zo&oelig;cia
+rounded<a name="fnanchor_BF" id="fnanchor_BF"></a><a href="#footnote_BF"
+class="fnanchor"><sup>[BF]</sup></a> at the tip when the polypide is
+retracted. Free statoblasts elongate; the free portion of their
+swim-ring distinctly narrower at the sides than at the ends.</td></tr>
+
+<tr><td class="right_a">A.</td><td class="left_a">Ectocyst by no means
+rigid, of a uniform pale colour; zo&oelig;cia never emarginate or
+furrowed, straight, curved or sinuous, elongate, cylindrical</td><td
+class="right"><i>fruticosa</i>, p.&nbsp;<a
+href="#Page_217">217</a>.</td></tr>
+
+<tr><td class="right_a">B.</td><td class="left_a">Ectocyst rigid;
+zo&oelig;cia (or at any rate some of the zo&oelig;cia) emarginate and
+furrowed.</td></tr>
+
+<tr><td></td><td class="left_a"><i>b</i>. Ectocyst darkly pigmented over
+the greater part of each zo&oelig;cium, white at the tip; branching of
+the zoarium practically dichotomous, profuse, as a rule both horizontal
+and vertical; zo&oelig;cia straight or slightly curved or
+sinuous</td><td class="right"><i>emarginata</i>, p.&nbsp;<a
+href="#Page_220">220</a>.</td></tr>
+
+<tr><td></td><td class="left_a"><i>b'</i>. Ectocyst colourless and
+hyaline; branching of the zoarium sparse, lateral, irregular,
+horizontal; zo&oelig;cia nearly straight, strongly emarginate and
+furrowed</td><td class="right"><i>javanica</i>, p.&nbsp;<a
+href="#Page_221">221</a>.</td></tr>
+
+<tr><td></td><td class="left_a"><i>b''</i>. The majority of the
+zo&oelig;cia distinctly <b>L</b>-shaped, one limb being as a rule
+adherent; ectocyst never densely pigmented.</td></tr>
+
+<tr><td></td><td class="left_a">&nbsp;&nbsp;&#946;. Zo&oelig;cia
+cylindrical, their furrowed keel never prominent</td><td
+class="right"><i>diffusa</i>, p.&nbsp;<a
+href="#Page_223">223</a>.</td></tr>
+
+<tr><td></td><td class="left_a">&nbsp;&nbsp;&#946;'. Zo&oelig;cia (or at
+any rate some of the zo&oelig;cia) constricted or tapering at the base,
+their emargination and furrow conspicuous</td><td
+class="right"><i>allmani</i>, p.&nbsp;<a
+href="#Page_224">224</a>.</td></tr>
+
+<tr><td class="left_a">II.</td><td class="left_a">Ectocyst stiff;
+zo&oelig;cia truncated when the polypide is retracted. Surface of
+zo&oelig;cia minutely roughened, distinctly annulate on the distal
+part</td><td class="right"><i>tanganyik�</i>, p.&nbsp;<a
+href="#Page_225">225</a>.</td></tr>
+
+<tr><td class="left_a">III.</td><td class="left_a">Ectocyst swollen and
+contractile, capable of transverse wrinkling all over the zo&oelig;cium;
+zo&oelig;cia never emarginate</td><td class="right"><i>punctata</i>,
+p.&nbsp;<a href="#Page_227">227</a>.</td></tr>
+
+</table>
+
+<p>There has always been much difficulty in separating the species of
+<i>Plumatella</i>, and even now there is no general consensus of<span
+class='pagenum'><a name="Page_215" id="Page_215">[Pg 215]</a></span>
+opinion as to the number that should be recognized. The difficulty,
+however, is much reduced if the following precautions are
+observed:&mdash;</p>
+
+<p class="blockquote_b">(1) If the zoarium appears to be tangled, if the
+branches intertwine or overlap, or if the zo&oelig;cia are closely
+pressed together, the whole mass should be carefully dissected out. This
+is necessary not only because zoaria belonging to different species are
+sometimes found entangled together but also because it is often
+difficult to recognize the characteristic method of branching and shape
+of the zo&oelig;cia unless it is done.</p>
+
+<p class="blockquote_b">(2) As large a part as possible of each zoarium
+should be examined, preferably with a binocular microscope, and
+allowance should be made for irregularities and abnormalities of all
+kinds. What must be observed is the rule rather than the exceptions.</p>
+
+<p class="blockquote_b">(3) When the statoblasts are being examined,
+care must be taken that they lie flat and that their surface is parallel
+to that of the nose-piece of the microscope. If they are viewed
+obliquely it is impossible to see their true outlines and
+proportions.</p>
+
+<p class="blockquote_b">(4) In order to see the relative proportions of
+the capsule and the swim-ring it is necessary that the statoblast should
+be rendered transparent. This is often difficult owing to the presence
+of air in the air-cells, but strong nitric acid applied judiciously will
+render it possible (p. <a href="#Page_240">240</a>).</p>
+
+<p>In supervising the preparation of the plates that illustrate this
+genus I have impressed upon the artist the importance of representing
+what he saw rather than what he thought he ought to see, and the figures
+are very close copies of actual specimens. I have deliberately chosen
+for representation specimens of <i>Plumatella</i> preserved by the
+simple methods which are often the only ones that it is possible for a
+traveller to adopt, for the great majority of naturalists will probably
+have no opportunity of examining living specimens or specimens preserved
+by special methods, and the main object, I take it, of this series is to
+enable naturalists first to distinguish the species described and then
+to learn something of their habitat and habits.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;Of the
+seven species included in this key five have been found in Europe
+(namely <i>P. fruticosa</i>, <i>P. emarginata</i>, <i>P. diffusa</i>,
+<i>P. allmani</i>, and <i>P. punctata</i>), while of these five all but
+<i>P. allmani</i> are known to occur in N. America also. <i>P.
+javanica</i> is apparently peculiar to the Oriental Region, while <i>P.
+tanganyik�</i> has only been taken in Central Africa and in the Bombay
+Presidency.</p>
+
+<p><span class="smcap">Types.</span>&mdash;Very few of the
+type-specimens of the older species of <i>Plumatella</i> are in
+existence. Allman's are neither in Edinburgh nor in London, and Mr. E.
+Leonard Gill, who has been kind enough to go through the Hancock
+Collection at Newcastle-on-Tyne, tells me that he cannot trace
+Hancock's. Those of the<span class='pagenum'><a name="Page_216"
+id="Page_216">[Pg 216]</a></span> forms described by Kraepelin are in
+Hamburg and that of <i>P. tanganyik�</i> in the British Museum, and
+there are schizotypes or paratypes of this species and of <i>P.
+javanica</i> in Calcutta. The types of Leidy's species were at one time
+in the collection of the Philadelphia Academy of Science.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;The zoaria of the species
+of <i>Plumatella</i> are found firmly attached to stones, bricks, logs
+of wood, sticks, floating seeds, the stems and roots of water-plants,
+and occasionally to the shells of molluscs such as <i>Vivipara</i> and
+<i>Unio</i>. Some species shun the light, but all are apparently
+confined to shallow water.</p>
+
+<p>Various small oligoch�te worms (e.&nbsp;g., <i>Ch�togaster
+spongill�</i>,<a name="fnanchor_BG" id="fnanchor_BG"></a><a
+href="#footnote_BG" class="fnanchor"><sup>[BG]</sup></a> <i>Nais
+obtusa</i>, <i>Nais elinguis</i>, <i>Slavina appendiculata</i> and
+<i>Pristina longiseta</i><a name="fnanchor_BH" id="fnanchor_BH"></a><a
+href="#footnote_BH" class="fnanchor"><sup>[BH]</sup></a>), take shelter
+amongst them; dipterous larv� of the genus <i>Chironomus</i> often build
+their protective tubes at the base of the zoaria, and the surface of the
+zo&oelig;cia commonly bears a more or less profuse growth of such
+protozoa as <i>Vorticella</i> and <i>Epistylis</i>. I have seen a worm
+of the genus <i>Ch�togaster</i> devouring the tentacles of a polypide
+that had been accidentally injured, but as a rule the movements of the
+lophophore are too quick to permit attacks of the kind, and I know of no
+active enemy of the genus. The growth of sponges at the base of the
+zoaria probably chokes some species, but one form (<i>F. fruticosa</i>)
+is able to surmount this difficulty by elongating its zo&oelig;cia
+(p.&nbsp;219). A small worm (<i>Aulophorus tonkinensis</i>) which is
+common in ponds in Burma and the east of India as far west as Lucknow,
+often builds the tube in which it lives mainly of the free statoblasts
+of this genus. It apparently makes no selection in so doing but merely
+gathers the commonest and lightest objects it can find, for small seeds
+and minute fragments of wood as well as sponge gemmules and statoblasts
+of other genera are also collected by it. I know of no better way of
+obtaining a general idea as to what sponges and phylactol�mata are
+present in a pond than to examine the tubes of <i>Aulophorus
+tonkinensis</i>.</p>
+
+<p>I am indebted to Mr. F. H. Gravely, Assistant Superintendent in the
+Indian Museum, for an interesting note regarding the food of
+<i>Plumatella</i>. His observations, which were made in
+Northamptonshire, were unfortunately interrupted at a critical moment,
+but I have reproduced them with his consent in order that other
+observers may investigate the phenomena he saw. Mr. Gravely noted that a
+small green flagellate which was abundant in water in which
+<i>Plumatella repens</i> was growing luxuriantly, was swallowed by the
+polypides, and that if the polyparium was kept in a shallow dish of
+water, living flagellata of the same species congregated in a little
+pile under the anus of each polypide. His preparations show very clearly
+that the flagellates were passing through the alimentary canal without
+apparent change, but the method of<span class='pagenum'><a
+name="Page_217" id="Page_217">[Pg 217]</a></span> preservation does not
+permit the retractile granules, which were present in large numbers in
+the cell-substance of the flagellates, to be displayed and it is
+possible that these granules had disappeared from those flagellates
+which are present in the recta of his specimens. It is clear, therefore,
+either that certain flagellates must pass through the alimentary canal
+of <i>Plumatella</i> unchanged, or that the polyzoon must have the power
+of absorbing the stored food material the flagellates contain without
+doing them any other injury.</p>
+
+<p>The free statoblasts of <i>Plumatella</i> are as a rule set free
+before the cells they contain become differentiated, and float on the
+surface of the water for some time before they germinate; but
+occasionally a small polypide is formed inside the capsule while it is
+still in its parent zo&oelig;cium. I have, however, seen only one
+instance of this premature development, in a single statoblast contained
+in a small zoarium of <i>P. fruticosa</i> found in Lower Burma in March.
+The fixed statoblasts usually remain fixed to the support of the
+zoarium, even when their parent-zo&oelig;cium decays, and germinate
+<i>in situ</i>.</p>
+
+<p>The larva (fig. 40 C, p.&nbsp;207) that originates from the egg of
+<i>Plumatella</i> is a minute pear-shaped, bladder-like body covered
+externally with fine vibratile threads (cilia) and having a pore at the
+narrow end. At the period at which it is set free from the parent
+zo&oelig;cium it already contains a fully formed polypide or pair of
+polypides with the tentacles directed towards the narrow end. After a
+brief period of active life, during which it moves through the water by
+means of its cilia, it settles down on its broad end, which becomes
+adhesive; the polypide or pair of polypides is everted through the pore
+at the narrow end, the whole of this end is turned inside out, and a
+fresh polyparium is rapidly formed by budding.</p>
+
+<p class="p2">29. <b>Plumatella fruticosa</b>, <i>Allman</i>. (<a
+href="#Plate_III">Plate&nbsp;III</a>, fig.&nbsp;1; <a
+href="#Plate_IV">plate&nbsp;IV</a>, fig.&nbsp;4; <a
+href="#Plate_V">plate&nbsp;V</a>, fig.&nbsp;1.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Plumatella fruticosa</i>, Allman, Ann. Nat. Hist.
+xiii, p.&nbsp;331 (1844).</span>
+
+<span class="i0"><i>Plumatella repens</i>, van Beneden (? <i>nec</i>
+Linn�), M�m. Acad. Roy. Belg. 1847, p.&nbsp;21, pl. i, figs. 1-4.</span>
+
+<span class="i0"><i>Plumatella fruticosa</i>, Johnston, Brit. Zooph.
+(ed. 2), p.&nbsp;404 (1847).</span>
+
+<span class="i0"><i>Plumatella coralloides</i>, Allman, Rep. Brit.
+Assoc. 1850, p.&nbsp;335.</span>
+
+<span class="i0"><i>Plumatella stricta</i>, <i>id.</i>, Mon. Fresh-Water
+Polyzoa, p.&nbsp;99, fig. 14 (1857).</span>
+
+<span class="i0"><i>Plumatella fruticosa</i>, <i>id.</i>, <i>ibid.</i>
+p.&nbsp;102, pl. vi, figs. 3-5.</span>
+
+<span class="i0"><i>Plumatella coralloides</i>, <i>id.</i>, <i>ibid.</i>
+p.&nbsp;103, pl. vii, figs. 1-4.</span>
+
+<span class="i0"><i>Plumatella repens</i> and <i>P. stricta</i>, Carter,
+Ann. Nat. Hist. (3) iii, p.&nbsp;341 (1859).</span>
+
+<span class="i0"><i>Plumatella lucifuga</i>, Jullien (<i>partim</i>),
+Bull. Soc. zool. France, x, p.&nbsp;114 (1885).</span>
+
+<span class="i0"><i>Plumatella princeps</i> var. <i>fruticosa</i>,
+Kraepelin, Deutsch. S�sswasserbryozoen, i, p.&nbsp;120, pl. vii, fig.
+148 (1887).</span>
+
+<span class="i0"><i>Plumatella fruticosa</i>, Braem, Unter. ii. Bryozoen
+des s�ssen Wassers, p.&nbsp;9, pl. i, fig. 15 (Bibl. Zool. ii)
+(1890).</span>
+
+<span class="i0"><i>Plumatella repens</i>, Annandale, J. As. Soc. Bengal
+(new series) iii, 1907, p.&nbsp;88.</span>
+
+<span class='pagenum'><a name="Page_218" id="Page_218">[Pg
+218]</a></span>
+
+<span class="i0"><i>Plumatella emarginata</i>, Loppens (<i>partim</i>),
+Ann. Biol. <ins title="capitalized in the original">lacustre</ins>, iii,
+p.&nbsp;161 (1908).</span>
+
+<span class="i0"><i>Plumatella fruticosa</i>, Annandale, Rec. Ind. Mus.
+v, p.&nbsp;45 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoarium in the typical form has a loose
+appearance due to the fact that the branches are far apart and the
+ectocyst by no means rigid. When young the zoarium is adherent, but in
+well-grown polyparia vertical branches, often an inch or more in length,
+are freely produced. As a rule they have not the strength to stand
+upright if removed from the water. Branching is ordinarily lateral and
+as a rule occurs chiefly on one side of a main branch or trunk. In
+certain circumstances upright zo&oelig;cia are pressed together and
+reach a great length without branching, and in this form (<i>P.
+coralloides</i>, Allman) daughter-zo&oelig;cia are often produced at the
+tip of an elongated mother-zo&oelig;cium in fan-like formation. A
+depauperated form (<i>P. stricta</i>, Allman), occurs in which the
+vertical branches are absent or very short. In all forms internal
+partitions are numerous and stout.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia are cylindrical and bear a
+simple keel on their dorsal surface. They are never emarginate or
+furrowed. In the typical form their diameter is more than half a
+millimetre, and they are always of considerable length. The ectocyst is
+thin and never very rigid or deeply pigmented, the colour usually being
+an almost uniform pale pinkish brown and fading little towards the tip
+of the zo&oelig;cium.</p>
+
+<p><i>Statoblasts.</i> Both free and stationary statoblasts are formed,
+but the latter are rare and do not always adhere. They resemble the free
+statoblasts in general form but have a solid margin instead of a
+swim-ring and are often minutely serrated round the edge. The free
+statoblasts are at least considerably, sometimes very elongate; in all
+zoaria it is possible to find specimens that are more than twice as long
+as broad. The capsule is relatively large and resembles the swim-ring in
+outline, so that the free portion of the latter is not much narrower at
+the sides than at the ends. The sides are distinctly convex and the ends
+rounded; the swim-ring encroaches little on the surface of the
+capsule.</p>
+
+<p><i>Polypide.</i> The tentacles number between 40 and 50 and are not
+festooned at the base. The stomach is slender and elongate.</p>
+
+<p><span class="smcap">Type</span> not in existence.</p>
+
+<p><span class="smcap">Systematic Remarks.</span>&mdash;<i>P.
+fruticosa</i> is closely allied to <i>P. repens</i> (European and N.
+American) but always has much longer statoblasts. Three phases of the
+species may be distinguished as follows:&mdash;</p>
+
+<p class="blockquote_b">A. (<i>Forma typica</i>). Zo&oelig;cia stout in
+form, not greatly elongate; free branches produced in profusion.</p>
+
+<p class="blockquote_b">B. (<i>P. stricta</i>, Allman, <i>P. repens</i>,
+van Beneden). Zo&oelig;cia slender; free branches absent or consisting
+of two or three zo&oelig;cia only.</p>
+
+<p class="blockquote_b">C. (<i>P. coralloides</i>, Allman). Vertical
+zo&oelig;cia pressed together and greatly elongated.</p>
+
+<p><span class='pagenum'><a name="Page_219" id="Page_219">[Pg
+219]</a></span>Indian specimens of the typical form agree well with
+German specimens labelled by Prof. Kraepelin <i>P. princeps</i> var.
+<i>fruticosa</i>, and specimens of the <i>coralloides</i> phase could
+hardly be distinguished from similar specimens from Scotland.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>P.
+fruticosa</i> is widely distributed in Europe and probably in N.
+America. I have seen Indian specimens from the Punjab (Lahore,
+<i>Stephenson</i>), from Bombay, from Travancore, from Calcutta and
+other places in the Ganges delta, from Rajshahi (Rampur Bhoolia) on the
+R. Ganges, from Kurseong in the E. Himalayas (alt. 4,500 feet), and from
+Kawkareik in Tenasserim. Statoblasts found on the surface of a pond near
+Simla in the W. Himalayas (alt. <i>ca.</i> 8,000 feet), probably belong
+to this species.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;Allman states that in
+England <i>P. fruticosa</i> is fond of still and slowly-running water.
+The typical form and the <i>coralloides</i> phase grow abundantly in the
+Calcutta tanks, the former often attaining an extraordinary luxuriance.
+I have found the var. <i>stricta</i> only in water in which there was
+reason to suspect a lack of minute life (and therefore of food), viz. in
+Shasthancottah Lake in Travancore, in a swamp in Lower Burma, and in a
+small jungle stream near the base of the Western Ghats in Travancore.
+The species is the only one that I have seen in running water in India,
+and the specimens obtained in the jungle stream in Travancore are the
+only specimens I have taken in these circumstances. <i>P. fruticosa</i>
+always grows near the surface or near the edge of water; it is found
+attached to the stems of bulrushes and other aquatic plants, to floating
+seeds and logs and (rarely) to stones and bricks. So far as my
+experience goes it is only found, at any rate in Calcutta, in the cold
+weather and does not make its appearance earlier than October.</p>
+
+<p>The form Allman called <i>P. coralloides</i> was found by him,
+"attached to floating logs of wood, together with <i>P. repens</i> and
+<i>Cordylophora lacustris</i>, and generally immersed in masses of
+<i>Spongilla fluviatilis</i>." I have always found it immersed in
+sponges (<i>S. lacustris</i>, <i>S. alba</i>, <i>S. carteri</i>, and
+<i>S. crassissima</i>), except when the sponge in which it had been
+immersed had decayed. Indeed, the peculiar form it has assumed appears
+to be directly due to the pressure of the growing sponge exerted on the
+zo&oelig;cia, for it is often possible to find a zoarium that has been
+partially overgrown by a sponge and has retained its typical form so
+long as it was free but has assumed the <i>coralloides</i> form where
+immersed.<a name="fnanchor_BI" id="fnanchor_BI"></a><a
+href="#footnote_BI" class="fnanchor"><sup>[BI]</sup></a> In
+Shasthancottah Lake, Travancore, I found specimens of the <i>stricta</i>
+phase<span class='pagenum'><a name="Page_220" id="Page_220">[Pg
+220]</a></span> embedded in the gelatinous mass formed by a social
+rotifer and to some extent assimilated to the <i>coralloides</i>
+form.</p>
+
+<p class="p2">30. <b>Plumatella emarginata</b>, <i>Allman</i>. (<a
+href="#Plate_III">Plate III</a>, fig. 2; <a href="#Plate_IV">plate
+IV</a>, figs. 1, 1 <i>a.</i>)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Plumatella emarginata</i>, Allman, Ann. Nat. Hist.
+xiii, p.&nbsp;330 (1844).</span>
+
+<span class="i0"><i>Plumatella emarginata</i>, Johnston, Brit. Zooph.
+(ed. 2), p.&nbsp;404 (1847).</span>
+
+<span class="i0"><i>Alcyonella benedeni</i>, Allman, Mon. Fresh-Water
+Polyzoa, p.&nbsp;89, pl. iv, figs. 5-11 (1857).</span>
+
+<span class="i0"><i>Plumatella emarginata</i>, <i>id.</i>, <i>ibid.</i>
+p.&nbsp;104, pl. vii, figs. 5-10.</span>
+
+<span class="i0"><i>Plumatella lucifuga</i>, Jullien, Bull. Soc. zool.
+France, x, figs. 89, 90, p.&nbsp;114 (1885).</span>
+
+<span class="i0"><i>Plumatella princeps</i> var. <i>emarginata</i>,
+Kraepelin (<i>partim</i>), Deutsch. S�sswasserbryoz. p.&nbsp;120, pl.
+iv, fig. 108, pl. v, fig. 123 (1887).</span>
+
+<span class="i0"><i>Plumatella emarginata</i>, Braem, Unter. ii. Bryoz.
+s�ssen Wassers, p.&nbsp;9, pl. i, figs. 12, 14 (Bibl. Zool. ii)
+(1890).</span>
+
+<span class="i0"><i>Plumatella emarginata</i>, Annandale
+(<i>partim</i>), J. As. Soc. Bengal, (new series) iii, 1907,
+p.&nbsp;89.</span>
+
+<span class="i0"><i>Plumatella princeps</i>, Loppens (<i>partim</i>),
+Ann. Biol. lacustre, iii, p.&nbsp;162, fig. 7 (1908).</span>
+
+<span class="i0"><i>Plumatella emarginata</i>, Annandale, Rec. Ind. Mus.
+v, p.&nbsp;47 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoarium often covers a considerable area on flat
+surfaces and is sometimes entirely recumbent. More usually, however, the
+younger part is vertical. In either case the branching is practically
+dichotomous, two young zo&oelig;cia arising almost simultaneously at the
+tip of a mother-zo&oelig;cium and diverging from one another at a small
+angle. When the zoarium becomes vertical, rigid branches of as much as
+an inch in length are sometimes produced in this way and, arising
+parallel to one another, are pressed together to form an almost solid
+mass (=<i>Alcyonella benedeni</i>, Allman). In such cases the basal
+zo&oelig;cium or at any rate the basal part of each upright branch is
+considerably elongated. In recumbent zo&oelig;cia the main branches
+often radiate outwards from a common centre.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia are of almost equal width
+throughout, slender, and moderately elongate when recumbent. Their
+ectocyst is stiff; they are emarginate at the tip and more or less
+distinctly furrowed on the dorsal surface, the keel in which the furrow
+runs not being prominent. The orifice is often on the dorsal surface
+even in upright branches. Each zo&oelig;cium is of a dark brown or
+almost black colour for the greater part of its length but has a
+conspicuous white tip which is extended down the dorsal surface in the
+form of a triangle, its limits being rather more extensive than and
+parallel to those of the emargination.</p>
+
+<p><i>Statoblast.</i> The majority of the free statoblasts are elongate
+and truncate or subtruncate at the extremities, the sides being as a
+rule straight and parallel. In every polyparium specimens will be found
+that are between twice and thrice as long as broad. The capsule is,
+however, relatively much broader than the swim-ring,<span
+class='pagenum'><a name="Page_221" id="Page_221">[Pg 221]</a></span>
+often being nearly circular, and there is therefore at either end a
+considerable extent of free air-cells, while the extent of these cells
+at the sides of the capsule is small. The air-cells cover a considerable
+part of the dorsal surface of the capsule. Fixed statoblasts are usually
+found in old colonies, especially at the approach of the hot weather.
+They have an oval form and are surrounded by a membranous margin on
+which traces of reticulation can often be detected. As a rule
+statoblasts of both types are produced in considerable but not in
+excessive numbers.</p>
+
+<p><i>Polypide.</i> There are about 40 tentacles, the velum at the base
+of which extends upwards for a considerable distance without being
+festooned. The stomach is elongate and slender and narrowly rounded at
+the base.</p>
+
+<p>The method of branching, the coloration of the zo&oelig;cia and the
+form of the free statoblast are all characteristic. Luxuriant or closely
+compressed zoaria of <i>P. diffusa</i> often bear a superficial
+resemblance to those of <i>P. emarginata</i>, but the resemblance
+disappears if they are carefully dissected out. Indian specimens of
+<i>P. emarginata</i> agree closely with European ones.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>P.
+emarginata</i> is a common species in Europe, N. America, and southern
+Asia and probably also occurs in Africa and Australia. I have examined
+specimens from Calcutta, Rangoon, and Mandalay in Indian territory, and
+also from Jalor in the Patani States (Malay Peninsula) and the Tal� Noi,
+Lakon Sitamarat, Lower Siam. Gemmules found by Apstein (Zool. Jahrb.
+(Syst.) xxv, 1907, p.&nbsp;201) in plankton from the Colombo lake may
+belong to this species or to any of the others included by Kraepelin in
+his <i>P. princeps</i>.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;In Ireland Allan found
+<i>P. emarginata</i> in streams and rivulets, but it also occurs in
+European lakes. In India I have only found it in ponds. It prefers to
+adhere to the surface of stones or bricks, but when these are not
+available is found on the stems of water-plants. In the latter position
+the form called <i>Alcyonella benedeni</i> by Allman is usually
+produced, owing to the fact that the upright branches are crowded
+together through lack of space, very much in the same way (although
+owing to a different cause) as those of <i>P. fruticosa</i> are crowded
+together in the <i>coralloides</i> phase, to which the <i>benedeni</i>
+phase of <i>P. emarginata</i> is in many respects analogous.</p>
+
+<p>Although it is essentially a cold-weather species in Calcutta, <i>P.
+emarginata</i> is sometimes found in a living condition during the
+"rains." Zoaria examined at this season, however, contains few living
+polypides, the majority of the zo&oelig;cia having rotted away and left
+fixed statoblasts only to mark their former position.</p>
+
+<p class="p2">31. <b>Plumatella javanica</b>, <i>Kraepelin</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Plumatella javanica</i>, Kraepelin, Mitt. Nat. Mus.
+Hamb. xxiii, p.&nbsp;143, figs. 1-3 (1903).</span>
+
+<span class="i0"><i>Plumatella emarginata</i> var. <i>javanica</i>,
+Loppens, Ann. Biol. lacustre, iii, p.&nbsp;162 (1908).</span>
+
+<span class='pagenum'><a name="Page_222" id="Page_222">[Pg
+222]</a></span>
+
+<span class="i0"><i>Plumatella javanica</i>, Annandale, Rec. Ind. Mus.
+v, p.&nbsp;50 (1910).</span>
+
+<span class="i0"><i>Plumatella allmani</i> var. <i>dumortieri</i>,
+<i>id.</i> (<i>partim</i>) (<i>nec</i> Allman), <i>ibid.</i>
+p.&nbsp;49.</span>
+
+</div>
+
+<p>This species is related to <i>P. emarginata</i>, from which it may be
+distinguished by the following characters:&mdash;
+
+<i>Zoarium.</i> The zoarium is always entirely recumbent and branches
+sparingly; its method of branching does not approach the dichotomous
+type but is lateral and irregular. Linear series of zo&oelig;cia without
+lateral branches are often formed.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia are slender and often very
+long; they are strongly emarginate and furrowed, and the keel that
+contains the furrow is conspicuous. The ectocyst is hyaline and as a
+rule absolutely colourless.</p>
+
+<p><i>Statoblasts.</i> The free statoblasts are variable in length,
+sometimes distinctly elongate, sometimes elongate only to a moderate
+degree; they are rounded at the extremities and have the sides slightly
+or distinctly convex outwards. The capsule is relatively large, and the
+free portion of the swim-ring is not much broader at the ends than at
+the sides. The fixed statoblasts are elongate and surrounded by an
+irregularly shaped chitinous membrane, which is often of considerable
+extent. The whole of the dorsal surface is covered with what appear to
+be rudimentary air-spaces some of which even contain air.</p>
+
+<p>The transparent glassy ectocyst and strong furrowed keel of this
+species are very characteristic, but the former character is apt to be
+obscured by staining due to external causes, especially when the zoarium
+is attached to dead wood. The shape of the free statoblasts is too
+variable to be regarded as a good diagnostic character, but the fixed
+statoblasts, when they are to be found, are very characteristic in
+appearance. <i>P. javanica</i> appears to be closely related to Allman's
+<i>P. dumortieri</i>, with which stained zoaria are apt to be confused.
+The character of the ectocyst is, however, different, and the free part
+of the swim-ring is distinctly narrower at the sides of the free
+statoblasts. Dr. Kraepelin has been kind enough to send me one of the
+types.</p>
+
+<p><span class="smcap">Types</span> in the Hamburg and Indian
+Museums.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;Java,
+Penang, India. Indian localities are:&mdash;<span
+class="smcap">Bengal</span>, Calcutta; Berhampore, Murshidabad; R.
+Jharai, Siripur, Saran district, Tirhut: <span class="smcap">E.
+Himalayas</span>, Kurseong, Darjiling district (alt. 4,500 feet): <span
+class="smcap">Madras Presidency</span>, canal near Srayikaad,
+Travancore. Mr. C. W. Beebe has recently sent me a specimen taken by him
+in the Botanical Gardens at Penang.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;Very little is known about
+the biology of this species. Kraepelin took it in Java on the leaves of
+water-lilies. It is not uncommon during the cold weather in the Calcutta
+Zoological Gardens on floating seeds and sticks and on the stems of
+bulrushes; in Travancore I took it in November on the submerged leaves
+of <i>Pandani</i> growing at the edge of a canal of<span
+class='pagenum'><a name="Page_223" id="Page_223">[Pg 223]</a></span>
+slightly brackish water. Mr. Hodgart, the collector of the Indian
+Museum, found it in the R. Jharai on the stems of water-plants at a time
+of flood in the "rains." In Calcutta it is often found entangled with
+<i>P. fruticosa</i> and <i>P. emarginata</i>.</p>
+
+<p>32. <b>Plumatella diffusa</b>, <i>Leidy</i>. (<a
+href="#Plate_IV">Plate IV</a>, fig. 2.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Plumatella diffusa</i>, Leidy, P. Ac. Philad. v,
+p.&nbsp;261 (1852).</span>
+
+<span class="i0"><i>Plumatella diffusa</i>, Allman, Mon. Fresh-Water
+Polyzoa, p.&nbsp;105 (1857).</span>
+
+<span class="i0"><i>Plumatella diffusa</i>, Hyatt, Comm. Essex Inst. iv,
+pl. viii, figs. 11, 12 (1866).</span>
+
+<span class="i0"><i>Plumatella diffusa</i>, <i>id.</i>, <i>ibid.</i> v,
+p.&nbsp;107, fig. 12 (1868).</span>
+
+<span class="i0"><i>Plumatella repens</i>, Jullien, Bull. Soc. zool.
+France, x, fig. 37 (<i>lapsus</i> for 73), p.&nbsp;110 (1885).</span>
+
+<span class="i0"><i>Plumatella diffusa</i>, <i>id.</i>, <i>ibid.</i>
+figs. 155, 157, pp.&nbsp;130, 131.</span>
+
+<span class="i0"><i>Plumatella allmani</i> var. <i>diffusa</i>,
+Annandale, Rec. Ind. Mus. v, p.&nbsp;49 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoarium often covers a considerable area on flat
+surfaces and is sometimes found crowded together on the stems of plants.
+In the latter case the arrangement of the main branches is distinctly
+radiate. Upright branches occur rarely and never consist of more than
+three zo&oelig;cia. The characteristic method of branching is best
+represented by the following diagram:&mdash;</p>
+
+<div class="figcenter">
+<img src="images/fig_043.jpg"
+width="223" height="72"  alt="Illustration: Fig. 43." title="Fig. 43."
+/>
+<p class="caption">Fig. 43.</p>
+</div>
+
+<p>The partitions are stout and numerous.</p>
+
+<p><i>Zo&oelig;cia.</i> The great majority of the zo&oelig;cia in each
+zoarium are distinctly <b>L</b>-shaped, the long limb being usually
+adherent. The vital organs of the polypide are contained in the vertical
+limb, while the horizontal one, in mature polyparia, is packed full of
+free statoblasts. The zo&oelig;cia are cylindrical and as a rule
+obscurely emarginate and furrowed. The ectocyst is stiff; it is never
+deeply pigmented but is usually of a transparent horn-colour at the base
+of each zo&oelig;cium and colourless at the tip, the contrast between
+the two portions never being very strong. The basal portion is rough on
+the surface, the distal portion smooth.</p>
+
+<p><i>Statoblasts.</i> Free statoblasts are produced in very great
+profusion and fixed statoblasts are also to be found as a rule. The
+latter resemble those of <i>P. emarginata</i>. The free statoblasts are
+never very large or relatively broad, but they vary considerably as
+regards size and outline. The capsule is large, the sides convex
+outwards and the extremity more or less broadly rounded. The air-cells
+are unusually large and extend over a great part of the dorsal surface
+of the statoblast.</p>
+
+<p><span class='pagenum'><a name="Page_224" id="Page_224">[Pg
+224]</a></span><i>Polypide.</i> The polypide is shorter and stouter than
+that of <i>P. emarginata</i> and as a rule has fewer tentacles.</p>
+
+<p>The most characteristic feature of this species is the form of the
+zo&oelig;cia, which differ greatly from those of any other Indian
+species but <i>P. allmani</i>. In the latter they are distinctly
+"keg-shaped" (<i>i. e.</i>, constricted at the base and swollen in the
+middle), and the zoarium never spreads out over large surfaces in the
+way in which that of <i>P. diffusa</i> does.</p>
+
+<p><span class="smcap">Type</span>&mdash;? in the Philadelphia Academy
+of Sciences.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;This
+species was originally described from North America (in which it is
+apparently common) and occurs also in Europe. I have seen Indian
+specimens from the following localities:&mdash;<span
+class="smcap">Bengal</span>, Calcutta and neighbourhood; Rajshahi
+(Rampur Bhulia): <span class="smcap">E. Himalayas</span>, Gangtok,
+Native Sikhim (alt. 6,150 feet) (<i>Kirkpatrick</i>, <i>Stewart</i>):
+<span class="smcap">Punjab</span>, Lahore (<i>Stephenson</i>).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;<i>P. diffusa</i> in Lower
+Bengal is a cold-weather species. It is remarkable for the enormous
+number of gemmules it produces and is usually found either on floating
+objects such as the stems of certain water-plants, or on stones or
+bricks at the edge of ponds.</p>
+
+<p class="p2">33. <b>Plumatella allmani</b>, <i>Hancock</i>. (<a
+href="#Plate_IV">Plate IV</a>, figs. 3, 3 <i>a</i>.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Plumatella allmani</i>, Hancock, Ann. Nat. Hist. (2)
+v, p.&nbsp;200, pl. v, fig. 3-4, pl. iii, fig. 2-3 (1850).</span>
+
+<span class="i0"><i>Plumatella allmani</i>, Allman, Mon. Fresh-Water
+Polyzoa, p.&nbsp;106, fig. 16 (1857).</span>
+
+<span class="i0"><i>Plumatella elegans</i>, <i>id.</i>, <i>ibid.</i>
+p.&nbsp;107, pl. viii, figs. 6-10.</span>
+
+<span class="i0"><i>Plumatella lucifuga</i> ("forme rampante") Jullien,
+Bull. Soc. zool. France, x, p.&nbsp;114 (1885).</span>
+
+</div>
+
+<p>This species is closely allied to <i>P. diffusa</i>, from which it
+differs in the following characters:&mdash;</p>
+
+<p class="blockquote_b">(1) The zoarium never covers a large area and as
+a rule grows sparingly and mainly in two directions.</p>
+
+<p class="blockquote_b">(2) The zo&oelig;cia are more irregular in
+shape, not so distinctly elbowed, smaller; they have a much more
+prominently keeled ridge. The great majority of them are constricted at
+the base and taper towards the orifice. In young zoaria they are almost
+colourless but in older ones there is a band of not very dense pigment
+round the base of the vertical limb.</p>
+
+<p class="blockquote_b">(3) The free statoblasts are comparatively large
+and usually show a tendency to taper at the extremities, often being
+almost rhomboidal in form. The swim-ring does not extend so far over the
+dorsal surface as it does in those of <i>P. diffusa</i>; the "cells" of
+which it is composed are small.</p>
+
+<p><span class="smcap">Type</span> not in existence.</p>
+
+<p><span class='pagenum'><a name="Page_225" id="Page_225">[Pg
+225]</a></span>I have seen every gradation between this form and
+Allman's <i>P. elegans</i>.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>P.
+allmani</i> is apparently a rare species to which there are few
+references in literature. It was originally described from England and
+is stated by Jullien to occur in France. I have found specimens only in
+the lake Bhim Tal (alt. 4,500 feet) in the W. Himalayas.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;The original specimens were
+found by Hancock on stones. My own were growing on the leaves of
+water-plants, usually on the under side. When the zo&oelig;cia were
+forced to stretch across from one leaflet to another they assumed the
+sinuous form characteristic of Allman's <i>P. elegans</i>.</p>
+
+<p>34. <b>Plumatella tanganyik�</b>, <i>Rousselet</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Plumatella tanganyik�</i>, Rousselet, Proc. Zool.
+Soc. London, 1907 (i), p.&nbsp;252, pl. xiv, figs. 1-4.</span>
+
+<span class="i0"><i>Plumatella bombayensis</i>, Annandale, Rec. Ind.
+Mus. ii, p.&nbsp;169, figs. 1, 2 (1908).</span>
+
+<span class="i0"><i>Plumatella bombayensis</i>, <i>id.</i>, <i>ibid.</i>
+v, p.&nbsp;51 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The whole colony is recumbent but branches freely and
+at short intervals in a horizontal plane, so that the zo&oelig;cia
+become crowded together and the branches sometimes overlap one another.
+The zoarium often covers a considerable area, but growth seems to be
+mainly in two directions. When growing on the stems of water-plants the
+branches are often parallel and closely pressed together but remain
+recumbent in this position. A stout membrane sometimes extends between
+branches and individual zo&oelig;cia.</p>
+
+<p><i>Zo&oelig;cia.</i> The walls of the zo&oelig;cia are thick, stiff,
+and more or less darkly but not opaquely pigmented; the external
+surface, although not very smooth, is always clean. The two most
+noteworthy characters of the zo&oelig;cia are (i) their truncated
+appearance when the polypide is retracted, and (ii) the conspicuous,
+although often irregular external annulation of their walls. The tip of
+each zo&oelig;cium, owing to the fact that the invaginated part of the
+ectocyst is soft and sharply separated from the stiffened wall of the
+tube, terminates abruptly and is not rounded off gradually as is the
+case in most species of the genus; sometimes it expands into a
+trumpet-like mouth. The annulation of the external surface is due to
+numerous thickened areas of the ectocyst which take the form of slender
+rings surrounding the zo&oelig;cium; they are most conspicuous on its
+distal half. On the dorsal surface of the base of each zo&oelig;cium
+there is a conspicuous furrowed keel, which, however, does not usually
+extend to the distal end; the latter is oval in cross-section. The
+zo&oelig;cia are short and broad; their base is always recumbent, and,
+when the zoarium is attached to a stone or shell, often seems to be
+actually embedded in the support; the distal part turns upwards and is
+free, so that the aperture is terminal; the zo&oelig;cia of the older
+parts of the zoarium<span class='pagenum'><a name="Page_226"
+id="Page_226">[Pg 226]</a></span> exhibit the specific characters much
+more clearly than those at the growing points.</p>
+
+<p><i>Polypide.</i> The lophophore bears 20 to 30 tentacles, which are
+long and slender; the velum at their base extends up each tentacle in
+the form of a sharply pointed projection, but these projections do not
+extend for more than one-fifth of the length of the tentacles. Both the
+velum and the tentacular sheath bear numerous minute tubercles on the
+external surface. The base of the stomach is rounded, and the whole of
+the alimentary canal has a stout appearance.</p>
+
+<div class="figcenter">
+<img src="images/fig_044.jpg"
+width="414" height="500"  alt="Illustration: Fig. 44.&mdash;Plumatella
+tanganyik� from Igatpuri Lake." title="Fig. 44.&mdash;Plumatella
+tanganyik� from Igatpuri Lake." />
+<p class="caption">Fig. 44.&mdash;<i>Plumatella tanganyik�</i> from
+Igatpuri Lake.</p>
+</div>
+
+<p class="captionj">A=outline of part of zoarium from a stone, � 16;
+B=outline of the tip of a single zo&oelig;cium, � 70; C=free statoblast,
+� 70.</p>
+
+<p><span class='pagenum'><a name="Page_227" id="Page_227">[Pg
+227]</a></span><i>Statoblasts.</i> Both fixed and free statoblasts are
+produced, but not in very large numbers. The latter are broadly oval and
+are surrounded by a stout chitinous ring, which often possesses
+irregular membranous projections; the surface is smooth. The free
+statoblasts are small and moderately elongate, the maximum breadth as a
+rule measuring about 2/3 of the length; the capsule is relatively large
+and the ring of air-cells is not very much broader at the ends than at
+the sides; the dorsal surface of the central capsule is profusely
+tuberculate. The outline of the whole structure is often somewhat
+irregular.</p>
+
+<p>In deference to Mr. Rousselet's opinion expressed in a letter I have
+hitherto regarded the Bombay form of this species as distinct from the
+African one, and there certainly is a great difference in the appearance
+of specimens taken on the lower surface of stones in Igatpuri Lake and
+of the types of <i>P. tanganyik�</i>, one of which is now in the
+collection of the Indian Museum. The dark colour of the former, however,
+and their vigorous growth appear to be directly due to environment, for
+these characters disappear to a large extent in specimens growing on the
+stems of water-plants in the same lake. Indeed, such specimens are
+exactly intermediate between the form "<i>bombayensis</i>" and the
+typical form of the species. <i>P. tanganyik�</i> is closely allied to
+<i>P. philippinensis</i>, Kraepelin, from the island of Luzon, but the
+latter has a smooth and polished ectocyst devoid of annulations, and
+zo&oelig;cia of a more elongate and regular form.</p>
+
+<p><span class="smcap">Types</span> of the species in the British and
+Indian Museums, those of <i>P. bombayensis</i> in the latter
+collection.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>P.
+tanganyik�</i> is only known as yet from L. Tanganyika in Central Africa
+and from Igatpuri in the Bombay Presidency.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;In both localities the
+zoaria were found in shallow water. In L. Tanganyika they were
+encrusting stones and shells, while at Igatpuri they were fixed for the
+most part to the lower surface of stones but were also found on the
+stems of water-plants. My specimens from the Bombay Presidency were
+taken, on two separate occasions, at the end of November. At that date
+the zoaria were already decaying and large blanks, marked out by fixed
+statoblasts, were often observed on the stones. Probably, therefore, the
+species flourishes during the "rains."</p>
+
+<p>35. <b>Plumatella punctata</b>, <i>Hancock</i>. (<a
+href="#Plate_IV">Plate IV</a>, fig. 5.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Plumatella punctata</i>, Hancock, Ann. Nat. Hist.
+(2) v, p.&nbsp;200, pl. iii, fig. 1, and pl. v, figs. 6, 7
+(1850).</span>
+
+<span class="i0"><i>Plumatella vesicularis</i>, Leidy, P. Ac. Philad.
+vii, p.&nbsp;192 (1854).</span>
+
+<span class="i0"><i>Plumatella vitrea</i>, Hyatt, Comm. Essex Inst. iv,
+pl. ix, figs. 1, 2 (1866).</span>
+
+<span class="i0"><i>Plumatella punctata</i>, Allman, Mon. Fresh-Water
+Polyzoa, p.&nbsp;100, fig. 15 (1857).</span>
+
+<span class="i0"><i>Plumatella vesicularis</i>, <i>id.</i>, <i>ibid.</i>
+p.&nbsp;101.</span>
+
+<span class='pagenum'><a name="Page_228" id="Page_228">[Pg
+228]</a></span>
+
+<span class="i0"><i>Plumatella vitrea</i>, Hyatt, Proc. Essex Inst. v,
+p.&nbsp;225, figs. 18, 19 (1868).</span>
+
+<span class="i0"><i>Plumatella vesicularis</i>, <i>id.</i>, <i>ibid.</i>
+p.&nbsp;225.</span>
+
+<span class="i0"><i>Hyalinella vesicularis</i>, Jullien, Bull. Soc.
+zool. France, x, p.&nbsp;133, figs. 165-172 (1885).</span>
+
+<span class="i0"><i>Hyalinella vitrea</i>, <i>id.</i>, <i>ibid.</i>
+p.&nbsp;134, figs. 173-179.</span>
+
+<span class="i0"><i>Plumatella punctata</i>, Kraepelin, Deutsch.
+S�sswasserbryozoen, i, p.&nbsp;126, pl. iv, figs. 115, 116; pl. v, figs.
+124, 125; pl. vii, figs. 153, 154 (1887).</span>
+
+<span class="i0"><i>Plumatella vesicularis</i>, Braem, Unters. �.
+Bryozoen s�ssen Wassers, p.&nbsp;8, pl. i, fig. 8 (Bibl. Zool. ii)
+(1890).</span>
+
+<span class="i0"><i>Hyalinella punctata</i>, Loppens, Ann. Biol.
+lacustre, iii, p.&nbsp;163 (1908).</span>
+
+<span class="i0"><i>Plumatella punctata</i>, Annandale, Rec. Ind. Mus.
+v, p.&nbsp;52 (1910).</span>
+
+</div>
+
+<p class="p2"><i>Zoarium.</i> The zoarium is entirely recumbent and
+often appears to form an almost uniform flat layer instead of a
+dendritic body. Sometimes, however, it is distinctly linear, with
+lateral branches produced irregularly at considerable distances
+apart.</p>
+
+<p><i>Zo&oelig;cia.</i> The zo&oelig;cia differ from those of all other
+species in having a greatly swollen, soft ectocyst which can be
+transversely wrinkled all over the zo&oelig;cium by the action of the
+muscles of the polypide and is distinctly contractile. It is mainly
+owing to the swollen and almost gelatinous nature of the ectocyst that
+the dendritic character of the zoarium is frequently concealed, for the
+method of branching is essentially the same as that of <i>P.
+diffusa</i>, although the zo&oelig;cia are not so distinctly elbowed.
+The ectocyst is colourless or faintly tinted with brown; as a rule it is
+not quite hyaline and the external surface is minutely roughened or
+tuberculate. The zo&oelig;cia are not emarginate or furrowed.</p>
+
+<p><i>Statoblasts.</i> Stationary statoblasts are not found.  The free
+statoblasts are variable and often asymmetrical in outline, but the free
+portion of the swim-ring is always of nearly equal diameter all round
+the periphery and the capsule relatively large. Some of the statoblasts
+are always broad in comparison with their length.</p>
+
+<p><i>Polypide.</i> The polypide is comparatively short and stout.
+European specimens are said to have from 30 to 40 tentacles, but Indian
+specimens have only from 20 to 30.</p>
+
+<p>Shrunken specimens of the less congested forms of this species
+closely resemble specimens of <i>P. repens</i>, but the statoblasts are
+more variable in shape and the ectocyst, even in such specimens, is
+thicker. Living or well-preserved specimens cannot be mistaken for those
+of any other species. Jullien regarded <i>P. punctata</i> as the type of
+a distinct genus (<i>Hyalinella</i>) but included in <i>Plumatella</i>
+at least one form (P. "<i>arethusa</i>") which probably belongs to this
+species. Kraepelin distinguishes as "varieties" two phases, a summer
+phase ("var. <i>prostrata</i>") and an autumn phase ("var.
+<i>densa</i>"). The former often forms linear series of considerable
+length with only an occasional side-branch, while in the autumn phase
+branching is so profuse and the branches are so closely pressed together
+that the zoarium comes to resemble a uniform gelatinous patch rather
+than a dendritic growth. A<span class='pagenum'><a name="Page_229"
+id="Page_229">[Pg 229]</a></span> phase resembling the European autumn
+form is the commonest in Calcutta and I have also found one intermediate
+between this and Kraepelin's "var. <i>prostrata</i>," neither having any
+seasonal significance in India.</p>
+
+<p><span class="smcap">Geographical Distribution</span>.&mdash;<i>P.
+punctata</i> is widely distributed in Europe and N. America, but in the
+Oriental Region it has only been found in Calcutta and the
+neighbourhood.</p>
+
+<p><span class="smcap">Biology</span>.&mdash;In this part of India <i>P.
+punctata</i> flourishes both during the "rains" and in winter. I have
+found specimens in June and July and also in December and January. The
+majority of them were attached to bricks, but some were on the roots of
+duckweed, the stems of water-plants, and the tips of creepers falling
+into water. The species is often found together with <i>Stolella
+indica</i> and also with other species of its own genus. It is most
+common, in the neighbourhood of Calcutta, in that part of the town which
+is near the Salt Lakes, and occurs in ponds the water of which is
+slightly brackish.</p>
+
+<p class="p2 center">Genus 2. <b>STOLELLA</b>, <i>Annandale</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Stolella</i>, Annandale, Rec. Ind. Mus. iii,
+p.&nbsp;279 (1909).</span>
+
+<span class="i0"><i>Stolella</i>, <i>id.</i>, <i>ibid.</i> v, p.&nbsp;53
+(1910).</span>
+
+</div>
+
+<p><span class="smcap">Type</span>, <i>Stolella indica</i>,
+Annandale.</p>
+
+<p><i>Zoarium</i>. The zoarium consists of groups of zo&oelig;cia (or
+occasionally of single zo&oelig;cia) joined together by an adherent
+rhizome. There is no gelatinous investment.</p>
+
+<p><i>Zo&oelig;cia.</i> The adult zo&oelig;cia resemble those of
+<i>Plumatella</i> except in being sometimes more or less upright.</p>
+
+<p><i>Polypide</i> and <i>Statoblasts.</i> The polypide and statoblasts
+resemble those of <i>Plumatella</i>. Fixed as well as free statoblasts
+occur.</p>
+
+<p>This genus is closely allied to <i>Plumatella</i>, from which it is
+probably derived. The root-like tube from which the zo&oelig;cia arise
+is formed by the great elongation of the basal part of a zo&oelig;cium,
+and the zoaria closely resemble those of <i>P. punctata</i>, for it is
+not until several zo&oelig;cia have been produced that the
+characteristic mode of growth becomes apparent.</p>
+
+<p><i>Stolella</i> has only been found in India and is monotypic<a
+name="fnanchor_BJ" id="fnanchor_BJ"></a><a href="#footnote_BJ"
+class="fnanchor"><sup>[BJ]</sup></a>.</p>
+
+<p class="p2">36. <b>Stolella indica</b>, <i>Annandale</i>. (<a
+href="#Plate_V">Plate V</a>, figs. 3, 4.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Stolella indica</i>, Annandale, Rec. Ind. Mus. iii,
+p.&nbsp;279, fig. (1909).</span>
+
+<span class="i0"><i>Stolella indica</i>, <i>id.</i>, <i>ibid.</i> v,
+p.&nbsp;53 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoarium is adherent and linear, having neither
+lateral nor vertical branches.</p>
+
+<p><span class='pagenum'><a name="Page_230" id="Page_230">[Pg
+230]</a></span><i>Zo&oelig;cia.</i> The zo&oelig;cia are short and
+slender, erect or nearly so, distinctly emarginate and furrowed. Their
+ectocyst is soft, colourless and transparent but minutely roughened on
+the surface.</p>
+
+<p><i>Polypide.</i> The tentacles number from 30 to 35 and are rather
+short and stout, sometimes being slightly expanded at the tips. The
+stomach is comparatively short and abruptly truncated posteriorly.</p>
+
+<p><i>Statoblasts.</i> Both free and fixed statoblasts are found, and
+both are variable in form, the latter varying in outline from the
+circular to the broadly oval. The free statoblasts resemble those of
+<i>Plumatella punctata</i>, but are sometimes rather more elongate.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<div class="figcenter">
+<img src="images/fig_045.png"
+width="166" height="400"  alt="Illustration: Fig. 45.&mdash;Zoarium of
+Stolella indica on stem of water-plant (from Calcutta), � 6."
+title="Fig. 45.&mdash;Zoarium of Stolella indica on stem of water-plant
+(from Calcutta), � 6." />
+<p class="caption">Fig. 45.&mdash;Zoarium of <i>Stolella indica</i> on
+stem of water-plant (from Calcutta), � 6.</p>
+</div>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;So far as
+we know, this species is confined to the Indo-Gangetic Plain. Major
+Walton found it at Bulandshahr in the United Provinces, and it is not
+uncommon in the neighbourhood of Calcutta.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;The zoaria of <i>S.
+indica</i> are usually fixed to the roots of duckweed or to the stems of
+other plants. They are often found together with those of <i>P.
+punctata</i>. A slight infusion of brackish water into the ponds in
+which it lives does not seem to be inimical to this species, but I have
+found it in ponds in which nothing of the kind was possible. It
+flourishes during the "rains" and, to judge from specimens kept in an
+aquarium, is very short-lived. Major Walton found it growing over a
+zoarium of <i>Hislopia lacustris</i>.</p>
+
+<p class="p2 center"><span class='pagenum'><a name="Page_231"
+id="Page_231">[Pg 231]</a></span>Subfamily B. LOPHOPIN�.</p>
+
+<p>The zoaria of this subfamily are never dendritic but form gelatinous
+masses which, except in <i>Australella</i>, are cushion-shaped or
+sack-like. With the possible exception of <i>Australella</i>, they
+possess to a limited extent the power of moving along vertical or
+horizontal surfaces, but it is by no means clear how they do so (see
+p.&nbsp;172). The statoblasts are remarkable for their large size, and
+it is noteworthy that <i>Australella</i>, which is intermediate in
+structure between the Plumatellin� and the Lophopin�, possesses
+statoblasts of intermediate size. The swim-ring is always well
+developed, and fixed statoblasts are unknown.</p>
+
+<p>Only two genera (<i>Lophopodella</i> and <i>Pectinatella</i>) have
+been definitely proved to occur in India, but a third (<i>Lophopus</i><a
+name="fnanchor_BK" id="fnanchor_BK"></a><a href="#footnote_BK"
+class="fnanchor"><sup>[BK]</sup></a>) is stated to have been found in
+Madras. Should it be met with it will easily be recognized by the
+upright position of its polypides when their tentacles are expanded and
+by the fact that the statoblasts never bear marginal processes.</p>
+
+<p class="p2 center">Genus 3. <b>LOPHOPODELLA</b>, <i>Rousselet</i>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Lophopodella</i>, Rousselet, Journ. Quek. Micr. Club
+(2) ix, p.&nbsp;45 (1904).</span>
+
+<span class="i0"><i>Lophopodella</i>, Annandale, Rec. Ind. Mus. v,
+p.&nbsp;54 (1910).</span>
+
+</div>
+
+<p><span class="smcap">Type</span>, <i>Pectinatella carteri</i>,
+Hyatt.</p>
+
+<p><i>Zoarium.</i> The zoarium consists of a circular or oval mass of no
+great size. Polyparia do not form compound colonies.</p>
+
+<p><i>Polypides.</i> The polypides lie semi-recumbent in the mass and
+never stand upright in a vertical position.</p>
+
+<p><i>Statoblasts.</i> The statoblasts are of considerable size and
+normally bear at both ends a series of chitinous processes armed with
+double rows of small curved spinules.</p>
+
+<p>As a rule the genus is easily recognized by means of the statoblasts,
+but sometimes the processes at the ends of these structures are absent
+or abortive and it is then difficult to distinguish them from those of
+<i>Lophopus</i>. There is, however, no species of that<span
+class='pagenum'><a name="Page_232" id="Page_232">[Pg 232]</a></span>
+genus known that has statoblasts shaped like those of the Indian species
+of <i>Lophopodella</i>.</p>
+
+<p>Three species of <i>Lophopodella</i>, all of which occur in Africa,
+have been described; <i>L. capensis</i> from S. Africa, which has the
+ends of the statoblast greatly produced, <i>L. thomasi</i> from
+Rhodesia, in which they are distinctly concave, and <i>L. carteri</i>
+from E. Africa, India and Japan, in which they are convex or
+truncate.</p>
+
+<p>The germination of the gemmule and the early stages in the
+development of the polyparium of <i>L. capensis</i> have been described
+by Miss Sollas (Ann. Nat. Hist. (8) ii, p.&nbsp;264, 1908).</p>
+
+<p class="p2">37. <b>Lophopodella carteri</b> (<i>Hyatt</i>). (<a
+href="#Plate_III">Plate III</a>, figs. 4, 4<i>a</i>.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Lophopus</i> sp., Carter, Ann. Nat. Hist. (3) iii,
+p.&nbsp;335, pl. viii, figs. 8-15 (1859).</span>
+
+<span class="i0">? <i>Lophopus</i> sp., Mitchell, Q. J. Micr. Sci.
+London (3) ii, p.&nbsp;61 (1862).</span>
+
+<span class="i0"><i>Pectinatella carteri</i>, Hyatt, Comm. Essex Inst.
+iv, p.&nbsp;203 (footnote) (1866).</span>
+
+<span class="i0"><i>Pectinatella carteri</i>, Meissner, Die Moosthiere
+Ost-Afrikas, p.&nbsp;4 (in Mobius's Deutsch-Ost-Afrika, iv,
+1898).</span>
+
+<span class="i0"><i>Lophopodella carteri</i>, Rousselet, Journ. Quek.
+Micr. Club, (2) ix, p.&nbsp;47, pl. iii, figs. 6, 7 (1904).</span>
+
+<span class="i0"><i>Lophopus carteri</i>, Annandale, Rec. Ind. Mus. ii,
+p.&nbsp;171, fig. 3 (1908).</span>
+
+<span class="i0"><i>Lophopodella carteri</i>, <i>id.</i>, <i>ibid.</i>
+v, p.&nbsp;55 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoarium as a rule has one horizontal axis longer
+than the other so that it assumes an oval form when the polypides are
+expanded; when they are retracted its outline is distinctly lobular.
+Viewed from the side it is mound-shaped. The polypides radiate, as a
+rule in several circles, from a common centre. The ectocyst is much
+swollen, hyaline and colourless.</p>
+
+<p><i>Polypide.</i> The polypide has normally about 60 tentacles, the
+velum at the base of which is narrow and by no means strongly festooned.
+The stomach is yellow or greenish in colour. The extended part of the
+polypide measures when fully expanded rather less than 3 mm., and each
+limb of the lophophore about the same.</p>
+
+<p><i>Statoblast.</i> The statoblast is variable in shape and size but
+measures on an average about 0.85 � 0.56 mm. The ends are truncate or
+subtruncate; the capsule is small as compared with the swim-ring and as
+a rule circular or nearly so. The processes at the two ends are variable
+in number; so also are their spinules, which are arranged in two
+parallel rows, one row on each side of the process, and are neither very
+numerous nor set close together; as a rule they curve round through the
+greater part of a circle and are absent from the basal part of the
+process.</p>
+
+<p><span class='pagenum'><a name="Page_233" id="Page_233">[Pg
+233]</a></span></p>
+
+<div class="figcenter">
+<img src="images/fig_046.jpg"
+width="298" height="400"  alt="Illustration: Fig. 46.&mdash;Lophopodella
+carteri (from Igatpuri Lake)." title="Fig. 46.&mdash;Lophopodella
+carteri (from Igatpuri Lake)." />
+<p class="caption">Fig. 46.&mdash;Lophopodella carteri (from Igatpuri
+Lake).</p>
+</div>
+
+<p class="captionj">A=outline of a zoarium with the polypides expanded,
+as seen from below through glass to which it was attached, �&nbsp;4;
+B=outline of a zoarium with the polypides highly contracted, as seen
+from above, �&nbsp;4; C=statoblast, �&nbsp;75.</p>
+
+<p class="p2">37 <i>a.</i> Var. <b>himalayana</b>.</p>
+
+<div class="genus">
+
+<span class="i0"><i>Lophopus lendenfeldi</i>, Annandale (<i>nec</i>
+Ridley), J. As. Soc. Bengal, (n. s.) iii, 1907, p.&nbsp;92, pl. ii,
+figs. 1-4 (1907).</span>
+
+<span class="i0"><i>Lophopus lendenfeldi</i> var. <i>himalayanus</i>,
+<i>id.</i>, Rec. Ind. Mus. i, p.&nbsp;147, figs. 1, 2 (1907).</span>
+
+<span class="i0"><i>Lophopus himalayanus</i>, <i>id.</i>, <i>ibid.</i>
+ii, p.&nbsp;172, fig. 4 (1908).</span>
+
+</div>
+
+<p>This variety differs from the typical form in having fewer tentacles
+and in the fact that the marginal processes of the statoblast are
+abortive or absent.</p>
+
+<p><span class='pagenum'><a name="Page_234" id="Page_234">[Pg
+234]</a></span><i>Pectinatella davenporti</i>, Oka<a name="fnanchor_BL"
+id="fnanchor_BL"></a><a href="#footnote_BL"
+class="fnanchor"><sup>[BL]</sup></a> from Japan is evidently a local
+race of <i>L. carteri</i>, from the typical form of which it differs in
+having the marginal processes of the statoblast more numerous and better
+developed. The abortive structure of these processes in var.
+<i>himalayana</i> points to an arrest of development, for they are the
+last part of the statoblast to be formed.</p>
+
+<p><span class="smcap">Types.</span> The statoblasts mounted in Canada
+balsam by Carter and now in the British Museum must be regarded as the
+types of the species named but not seen by Hyatt. The types of the var.
+<i>himalayana</i> are in the Indian Museum and those of the subspecies
+<i>davenporti</i> presumably in the possession of Dr. Oka in Tokyo.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;The
+typical form occurs in Bombay, the W. Himalayas and possibly Madras, and
+its statoblasts have been found in E. Africa; the var. <i>himalayana</i>
+has only been taken in the W. Himalayas and the subspecies
+<i>davenporti</i> in Japan. Indian localities are:&mdash;<span
+class="smcap">Bombay Presidency</span>, Igatpuri Lake, W. Ghats (alt.
+<i>ca.</i> 2,000 feet); the Island of Bombay (<i>Carter</i>): <span
+class="smcap">W. Himalayas</span>, Bhim Tal, Kumaon (alt. 4,500
+feet).</p>
+
+<p><span class="smcap">Biology.</span>&mdash;<i>L. carteri</i> is found
+on the lower surface of stones and on the stems and leaves of
+water-plants, usually in lakes or large ponds. Although the zoaria do
+not form compound colonies by secreting a common membrane or investment,
+they are markedly gregarious. The most closely congregated and the
+largest zoaria I have seen were assembled amongst a gelatinous green
+alga of the genus <i>Tolypothrix</i><a name="fnanchor_BM"
+id="fnanchor_BM"></a><a href="#footnote_BM"
+class="fnanchor"><sup>[BM]</sup></a> (Myxophyce�) that grows on the
+vertical stems of a plant at the edge of Igatpuri Lake; it is noteworthy
+that in this case the alga seemed to take the place of the common
+investment of <i>Pectinatella burmanica</i>, in which green cells are
+present in large numbers (p.&nbsp;237). The zoaria of <i>L. carteri</i>
+are able to change their position, and I found that if a number of them
+were placed in a bottle of water they slowly came together at one spot,
+thus apparently forming temporary compound colonies. Before a movement
+of the whole zoarium commences its base becomes detached from its
+support at the anterior end (fig. 32, p.&nbsp;172), but the whole action
+is extremely slow and I have not been able to discover any facts that
+cast light on its exact method of production. At Igatpuri statoblasts
+are being produced in considerable numbers at the end of November, but
+many young zoaria can be found in which none have as yet been
+formed.</p>
+
+<p>The larva of a fly of the genus <i>Chironomus</i> is often found
+inhabiting a tube below zoaria of <i>L. carteri</i>. It is thus
+protected from its enemies but can protrude its head from beneath the
+zoarium and seize the small animals on which it preys.</p>
+
+<p class="p2 center">Genus 4. <b>PECTINATELLA</b>, <i>Leidy</i>.<span
+class='pagenum'><a name="Page_235" id="Page_235">[Pg 235]</a></span></p>
+
+<div class="genus">
+
+<span class="i0"><i>Cristatella</i>, Leidy, P. Ac. Philad. v,
+p.&nbsp;265 (1852).</span>
+
+<span class="i0"><i>Pectinatella</i>, <i>id.</i>, <i>ibid.</i>,
+p.&nbsp;320.</span>
+
+<span class="i0"><i>Pectinatella</i>, Allman, Mon. Fresh-Water Polyzoa,
+p.&nbsp;81 (1857).</span>
+
+<span class="i0"><i>Pectinatella</i>, Hyatt, Proc. Essex Inst. v,
+p.&nbsp;227, fig. 20 (1867).</span>
+
+<span class="i0"><i>Pectinatella</i>, Kraepelin, Deutsch.
+S�sswasserbryozoen, i, p.&nbsp;133 (1887).</span>
+
+<span class="i0"><i>Pectinatella</i>, Oka, Journ. Coll. Sci. Tokyo, iv,
+p.&nbsp;89 (1891).</span>
+
+</div>
+
+<p><span class="smcap">Type</span>, <i>Pectinatella magnifica</i>,
+Leidy.</p>
+
+<p>This genus is closely allied to <i>Lophopodella</i>, from which it is
+often difficult to distinguish young specimens. Adult zoaria are,
+however, always embedded together in groups in a gelatinous investment
+which they are thought to secrete in common<a name="fnanchor_BN"
+id="fnanchor_BN"></a><a href="#footnote_BN"
+class="fnanchor"><sup>[BN]</sup></a>, and the statoblasts are entirely
+surrounded by processes that bear curved spinules at their tips only.
+The polypides have the same semi-recumbent position as those of
+<i>Lophopodella</i> but are larger than those of any species of
+<i>Lophopodella</i> or <i>Lophopus</i> yet known. The statoblasts are
+larger than those of any other Plumatellid�.</p>
+
+<p>The type-species was originally found in N. America but has since
+been taken in several localities in continental Europe. Except this and
+the Indian form only one species is known, namely <i>P. gelatinosa</i>
+from Japan. <i>P. magnifica</i> has circular statoblasts with long
+marginal processes, while in <i>P. gelatinosa</i> the statoblasts are
+subquadrate and in <i>P. burmanica</i> almost circular, both Asiatic
+forms having very short marginal processes.</p>
+
+<p>The compound colonies formed by <i>Pectinatella</i> are often of
+great size. Those of <i>P. gelatinosa</i> are sometimes over 2 metres in
+length, while those of <i>P. burmanica</i> in the Sur Lake appeared to
+be only limited as regards their growth by the shallowness of the water
+in which the reeds to which they were attached were growing. Some were
+observed that were over 2 feet long.</p>
+
+<p class="p2">38. <b>Pectinatella burmanica</b>, <i>Annandale</i>. (<a
+href="#Plate_III">Plate III</a>, fig. 5.)</p>
+
+<div class="genus">
+
+<span class="i0"><i>Pectinatella burmanica</i>, Annandale, Rec. Ind.
+Mus. ii, p.&nbsp;174, fig. 5 (1908).</span>
+
+<span class="i0"><i>Pectinatella burmanica</i>, <i>id.</i>, <i>ibid.</i>
+v, p.&nbsp;56 (1910).</span>
+
+<span class="i0"><i>Pectinatella burmanica</i>, <i>id.</i>, Spol. Zeyl.
+vii, p.&nbsp;63, pl. i, fig. 3 (1910).</span>
+
+</div>
+
+<p><i>Zoarium.</i> The zoaria are circular or nearly so except when
+about to undergo division, in which case they are constricted in the
+middle. As a rule they measure nearly an inch (2 cm.) in<span
+class='pagenum'><a name="Page_236" id="Page_236">[Pg 236]</a></span>
+diameter. The polypides have a definite arrangement in each zoarium,
+being divided into four groups, each of which has a fan-like form. In
+the first place they are separated into two main divisions in a line
+running through the centre of the zoarium, and secondly each main
+division is separated into two subordinate ones in a line running across
+the other at right angles. The number of zoaria joined together in a
+single compound colony is very variable; sometimes there are only about
+half a dozen and sometimes several hundreds. The common investment in
+living colonies is often as much as two inches thick and has a
+translucent dark greenish colour due to the presence in it of green
+cells.</p>
+
+<div class="figcenter">
+<img src="images/fig_047.png"
+width="525" height="376"  alt="Illustration: Fig. 47.&mdash;Pectinatella
+burmanica." title="Fig. 47.&mdash;Pectinatella burmanica." />
+<p class="caption">Fig. 47.&mdash;<i>Pectinatella burmanica.</i></p>
+</div>
+
+<p class="captionj">A=polypide with the lophophore expanded, � 15;
+<i>a</i>=&oelig;sophagus; <i>b</i>=cardiac limb of stomach;
+<i>c</i>=stomach; <i>d</i>=rectum; <i>e</i>=anus; <i>f</i>=funiculus.
+[The muscles are omitted and the external tubercles are only shown on
+part of the polypide. The specimen is from the Sur Lake, Orissa.]
+B=statoblast from Ceylon, � 35.</p>
+
+<p><i>Polypide.</i> The polypide can be extruded for a distance of at
+least 5 mm. Its whole external surface is covered with minute tubercles.
+There are about 90 tentacles, which are long and slender, the velum at
+their base being narrow and almost straight. The stomach is of
+considerable stoutness.</p>
+
+<p><i>Statoblast.</i> The statoblasts are of large size, measuring from
+1 to 1.75 mm. in diameter. In form they are almost circular, but one
+side is always slightly flattened. The marginal processes are very<span
+class='pagenum'><a name="Page_237" id="Page_237">[Pg 237]</a></span>
+short and bear a single pair of hooks at the tip. The capsule is
+circular and small as compared with the free part of the swim-ring.</p>
+
+<p><span class="smcap">Type</span> in the Indian Museum.</p>
+
+<p><i>P. burmanica</i> is evidently a near relation of <i>P.
+gelatinosa</i>, Oka, from Japan, differing from that species in the
+shape of the statoblasts and in having much longer tentacles. The
+arrangement of the polypides in the zoarium and the general structure of
+the statoblasts are very similar in the two species.</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>P.
+burmanica</i> was originally described from a swamp at Kawkareik in the
+Amherst district of Tenasserim but has also been found in the Sur Lake
+near Puri in Orissa. Dr. A. Willey obtained specimens from a pool by the
+roadside between Maradankadewela and Galapitagala, at the foot of
+Ritigala, N. Central Province, Ceylon.</p>
+
+<p><span class="smcap">Biology.</span>&mdash;The first specimen obtained
+was a statoblast fixed to a tube of the oligoch�te worm <i>Aulophorus
+tonkinensis</i> taken at Kawkareik in March. At the same time young
+zoaria, which did not yet possess a common investment, were found on a
+leaf growing on a twig which drooped into the water. Large compound
+colonies were taken in Orissa in October. They completely encased the
+stems of reeds, thus forming hollow cylinders, but slipped from their
+supports when the reeds were pulled out of the water. In life they
+resembled gelatinous alg� rather than animals and exhibited a striking
+similarity to masses of zoaria of <i>Lophopodella carteri</i> surrounded
+by such alg�. Some of the colonies were evidently dying and contained
+few polypides in a living condition, but many statoblasts; others were
+in a flourishing condition and were producing larv� and statoblasts
+simultaneously.</p>
+
+<p>A piece of a colony full of larv� was placed before midday in an
+aquarium, which was kept in a shady verandah. Large numbers of larv�
+were set free almost immediately. They measured about 2 mm. in length
+and were distinctly pear-shaped; each contained a pair of polypides,
+which occupied a comparatively small part of the interior, the whole of
+the broader half being hollow. The larv� swam slowly, broad-end-first,
+by means of the cilia with which their surface was covered, occasionally
+gyrating on their long axis and always adopting an erratic course.
+Towards evening they showed signs of settling down, frequently touching
+the glass of the aquarium with their broad ends and sometimes remaining
+still in this position for some minutes. Many attempts were, however,
+made before fixation was completed, and this did not occur until after
+nightfall. By next morning every larva was fixed to the glass and had
+everted its two polypides. Unfortunately I was not able to trace the
+development further, but young compound colonies were found in which the
+secretion of the common investment had just commenced. The zoaria in
+these colonies measured about 1 cm. in diameter and already contained
+many polypides each.</p>
+
+<p><span class='pagenum'><a name="Page_238" id="Page_238">[Pg
+238]</a></span>Oka has described the development from the statoblast of
+the allied Japanese species. He found that each statoblast produced in
+the first instance a single polypide, and that the statoblasts, which
+were produced in autumn, lay dormant through the winter and germinated
+in spring. As the Sur Lake begins to undergo desiccation as soon as the
+"rains" cease, the statoblasts in it probably do not germinate until the
+break of the next "rains" about the middle of June. I have had dried
+statoblasts in my possession for over two years. Their cellular contents
+appear to be in good condition, although the cells show no signs of
+development; but they have not germinated in my aquarium, in which some
+of them have now been kept for more than six months.</p>
+
+<p>The green cells of the common investment are peculiar bodies that
+deserve further study than it has yet been possible to devote to them.
+Each cell is of ovoid form, varying somewhat in size but as a rule
+measuring about 0.03 � 0.008 mm. There can be no doubt that these bodies
+represent a stage in the life-history of an alga<a name="fnanchor_BO"
+id="fnanchor_BO"></a><a href="#footnote_BO"
+class="fnanchor"><sup>[BO]</sup></a>. Diatoms, bacilli and other minute
+plants are often present in the membrane as well as the characteristic
+green cells, but do not form a constant feature of it.</p>
+
+<p class="footnote">
+<a name="footnote_BC" id="footnote_BC"></a>
+<a href="#fnanchor_BC">[BC]</a>
+Proc. Linn. Soc. N. S. Wales, xxxiv, p.&nbsp;489 (1909).</p>
+
+<p class="footnote">
+<a name="footnote_BD" id="footnote_BD"></a>
+<a href="#fnanchor_BD">[BD]</a>
+Rousselet, Proc. Zool. Soc. London, 1907 (1), p.&nbsp;254.</p>
+
+<p class="footnote">
+<a name="footnote_BE" id="footnote_BE"></a>
+<a href="#fnanchor_BE">[BE]</a>
+See Rec. Ind. Mus. v, p.&nbsp;40, footnote (1910).</p>
+
+<p class="footnote">
+<a name="footnote_BF" id="footnote_BF"></a>
+<a href="#fnanchor_BF">[BF]</a>
+In specimens preserved in spirit they are apt to collapse and therefore
+to become somewhat concave.</p>
+
+<p class="footnote">
+<a name="footnote_BG" id="footnote_BG"></a>
+<a href="#fnanchor_BG">[BG]</a>
+Annandale, J. As. Soc. Bengal (n. s.) ii, p.&nbsp;188, pl. i (1906).</p>
+
+<p class="footnote">
+<a name="footnote_BH" id="footnote_BH"></a>
+<a href="#fnanchor_BH">[BH]</a>
+See Michaelsen, Mem. Ind. Mus. i, pp.&nbsp;131-135 (1908).</p>
+
+<p class="footnote">
+<a name="footnote_BI" id="footnote_BI"></a>
+<a href="#fnanchor_BI">[BI]</a>
+Braem (<i>op. cit.</i>, p.&nbsp;3, pl. i, fig. 1), has described and
+figured under the name <i>P. fungosa</i> var. <i>coralloides</i>,
+Allman, a dense form that somewhat resembles this phase of <i>P.
+fruticosa</i> but has become compacted without external pressure. It is,
+however, probably a form of <i>P. repens</i> rather than <i>P.
+fungosa</i> and differs in its broad statoblasts from any form of <i>P.
+fruticosa</i>. I have examined specimens of the same form from
+England.</p>
+
+<p class="footnote">
+<a name="footnote_BJ" id="footnote_BJ"></a>
+<a href="#fnanchor_BJ">[BJ]</a>
+But see p.&nbsp;246 (addenda).</p>
+
+<p class="footnote">
+<a name="footnote_BK" id="footnote_BK"></a>
+<a href="#fnanchor_BK">[BK]</a>
+Only two species are known, <i>L. crystallinus</i> (Pallas) from Europe
+and N. America, with oval statoblasts that are produced and pointed at
+the two ends, and <i>L. jheringi</i>, Meissner from Brazil, with
+irregularly polygonal or nearly circular statoblasts.</p>
+
+<p class="footnote">
+<a name="footnote_BL" id="footnote_BL"></a>
+<a href="#fnanchor_BL">[BL]</a>
+Zool. Anz. xxxi, p.&nbsp;716 (1907), and Annot. Zool. Japon. vi,
+p.&nbsp;117 (1907).</p>
+
+<p class="footnote">
+<a name="footnote_BM" id="footnote_BM"></a>
+<a href="#fnanchor_BM">[BM]</a>
+Prof. W. West will shortly describe this alga, which represents a new
+species, in the Journ. Asiat. Soc. Bengal, under the name <i>Tolypothrix
+lophopodellophila</i>.&mdash;<i>April 1911</i>.</p>
+
+<p class="footnote">
+<a name="footnote_BN" id="footnote_BN"></a>
+<a href="#fnanchor_BN">[BN]</a>
+It is now perhaps open to doubt whether the investment is actually
+secreted by the polyzoon, for Prof. W. West has discovered in it the
+cells of an alga belonging to a genus which habitually secretes a
+gelatinous investment of its own (see p.&nbsp;238,
+<i>post.</i>).&mdash;<i>April 1911.</i></p>
+
+<p class="footnote">
+<a name="footnote_BO" id="footnote_BO"></a>
+<a href="#fnanchor_BO">[BO]</a>
+Professor W. West identifies this alg� as <ins title="changed from
+'Dactyloccopsis'"><i>Dactylococcopsis</i></ins>
+<i>pectinatellophila</i>, new species. It will be described, before the
+publication of this book, in the Journ. As. Soc. Bengal (1911). Prof.
+West has found, associated more or less fortuitously with <i>P.
+burmanica</i>, another alga, namely <i>Microcystis orissica</i>, also a
+new species.&mdash;<i>April 1911.</i></p>
+
+<p><span class='pagenum'><a name="Page_239" id="Page_239">[Pg
+239]</a></span></p>
+
+<h3 class="p4">APPENDIX TO THE VOLUME.</h3>
+
+<p class="p2 center"><span class="smcap">Hints on the Preparation of
+Specimens.</span></p>
+
+<p><i>To preserve Spongillid�.</i>&mdash;Spongillid� must be preserved
+dry or in very strong alcohol. Formalin should not be used.</p>
+
+<p><i>To clean siliceous sponge spicules.</i>&mdash;Place small
+fragments of the dried sponge (if alcohol is present, the reaction is
+apt to be violent) in a test tube, cover them with strong nitric acid
+and boil over the flame of a Bunsen burner or small spirit lamp until
+the solid particles disappear. Add a large quantity of water to the acid
+and filter through pure cellulose filter-paper, agitating the liquid
+repeatedly. Pass clean water in considerable quantities through the
+filter-paper and dry the latter carefully; place it in a spirally coiled
+wire and ignite with a match, holding the wire in such a way that the
+spicules released by the burning of the paper fall into a suitable
+receptacle. They may then be picked up with a camel's-hair brush and
+mounted in Canada balsam.</p>
+
+<p><i>To examine the skeleton of a Spongillid.</i>&mdash;Cut thin
+hand-sections with a sharp scalpel, dehydrate if necessary, and mount in
+Canada balsam.</p>
+
+<p><i>To prepare gemmules for examination.</i>&mdash;Place the gemmules
+dry in a watch-glass with a few drops of strong nitric acid. When gas is
+given off freely add water in considerable quantities. Remove the
+gemmules with a camel's-hair brush to clean water, then to 50%, 70%, 90%
+and absolute alcohol in succession, leaving them for an hour in each
+strength of spirit. Clear with oil of cloves and mount in Canada
+balsam.</p>
+
+<p><i>To ascertain the presence of bubble-cells in the parenchyma of a
+Spongillid.</i>&mdash;Tease up a small piece of the sponge with a pair
+of needles, mount under a thin cover-slip in strong spirit, and examine
+under a high power of the microscope.</p>
+
+<p><i>To preserve Hydra in an expanded condition.</i>&mdash;Place the
+polyp in a watch-glass of clean water and wait until its tentacles are
+expanded. Heat a few drops of commercial formaldehyde and squirt the
+liquid while still hot at the <i>Hydra</i>, which will be killed<span
+class='pagenum'><a name="Page_240" id="Page_240">[Pg 240]</a></span>
+instantaneously. Remove it to a solution of formaldehyde and spirit of
+the following formula:&mdash;</p>
+
+<table cellpadding="5" cellspacing="10" summary="formaldehyde formula">
+
+<tr><td class="left_a">Commercial formaldehyde</td><td class="left_a">1
+part.</td></tr>
+
+<tr><td class="left_a">Absolute alcohol</td><td class="left_a">3
+parts.</td></tr>
+
+<tr><td class="left_a">Distilled water</td><td class="left_a">7
+parts.</td></tr>
+
+</table>
+
+<p>Then pass the <i>Hydra</i> through 50% and 70% alcohol and keep in
+90%.</p>
+
+<p><i>To examine the capsules of the nettle-cells.</i>&mdash;Place a
+living <i>Hydra</i> in a small drop of water on a slide and press a thin
+cover-slip down upon it.</p>
+
+<p><i>To preserve freshwater polyzoa in an expanded
+condition.</i>&mdash;Place the polyzoa in a glass tube full of clean
+water and allow them to expand their tentacles. Drop on them gradually
+when they are fully expanded a 2% aqueous solution of cocaine, two or
+three drops at a time, until movement ceases in the tentacles. Then pour
+commercial formaldehyde into the tube in considerable quantities. Allow
+the whole to stand for half an hour. If it is proposed to stain the
+specimens for anatomical investigation, they should then be removed
+through 50% and 70% to 90% alcohol. If, on the other hand, it is desired
+to keep them in a life-like condition they may be kept permanently in a
+solution of one part of commercial formaldehyde in four parts of water.
+Care must be taken that the process of paralyzing the polypides is not
+unduly prolonged, and it is always as well to preserve duplicate
+specimens in spirit or formalin with the lophophore retracted.</p>
+
+<p><i>To prepare statoblasts for examination.</i>&mdash;Place the
+statoblasts for a few minutes in strong nitric acid. Then remove the
+acid with water, pass through alcohol, clear with oil of cloves, and
+mount in a small quantity of Canada balsam under a cover-slip, taking
+care that the statoblasts lie parallel to the latter.</p>
+
+<p><span class='pagenum'><a name="Page_241" id="Page_241">[Pg
+241]</a></span></p>
+
+<h3 class="p4">ADDENDA.</h3>
+
+<p class="p2">The following addenda are due mainly to an expedition to
+the lakes of Kumaon in the W. Himalayas undertaken by Mr. S. W. Kemp in
+May, 1911.</p>
+
+<p class="p2 center">PART I.</p>
+
+<p class="center">Genus <b>SPONGILLA</b>.</p>
+
+<p class="center">Subgenus <b>EUSPONGILLA</b> (p.&nbsp;<a
+href="#Page_69">69</a>).</p>
+
+<p class="center">1 a. <b>Spongilla lacustris</b>, subsp.
+<b>reticulata</b> (p.&nbsp;<a href="#Page_71">71</a>).</p>
+
+<p>Specimens were taken in the lake Malwa Tal (alt. 3600 feet) in
+Kumaon, while others have recently been obtained from the Kalichedu
+irrigation-tank in the Pagnor <i>talug</i> of the Nellore district,
+Madras (<i>G. H. Tipper</i>).</p>
+
+<p class="center">4. <b>Spongilla cinerea</b> (p.&nbsp;<a
+href="#Page_79">79</a>).</p>
+
+<p>Specimens were taken in Naukuchia Tal (alt. 4200 feet) in Kumaon.
+They have a pale yellow colour when dry. This sponge has not hitherto
+been found outside the Bombay Presidency.</p>
+
+<p class="center">Subgenus <b>EUNAPIUS</b> (p.&nbsp;<a
+href="#Page_86">86</a>).</p>
+
+<p class="center">8. <b>Spongilla carteri</b> (p.&nbsp;<a
+href="#Page_87">87</a>).</p>
+
+<p>Specimens were taken in Bhim Tal (alt. 4450 feet) and Sat Tal (alt.
+4500 feet). Some of them approach the variety <i>cava</i> in
+structure.</p>
+
+<p class="center">Subgenus <b>STRATOSPONGILLA</b> (p.&nbsp;<a
+href="#Page_100">100</a>).</p>
+
+<p class="center">12. <b>Spongilla bombayensis</b> (p.&nbsp;<a
+href="#Page_102">102</a>).</p>
+
+<p>Add a new variety:&mdash;</p>
+
+<p class="center">13 a. Var. <b>pneumatica</b>, nov.</p>
+
+<p>This variety differs from the typical form in the following
+characters:&mdash;</p>
+
+<p class="blockquote_b">(i.) The sponge forms a flat layer of a pale
+brownish colour as a rule with short and very delicate vertical
+branches.<span class='pagenum'><a name="Page_242" id="Page_242">[Pg
+242]</a></span>In one specimen it takes the form of an elegant cup
+attached, only at the base, to a slender twig.</p>
+
+<p class="blockquote_b">(ii.) The gemmules are covered, outside the
+spicules, by a thick pneumatic coat of irregular formation and with
+comparatively large air-spaces.</p>
+
+<p class="blockquote_b">(iii.) The gemmule-spicules are regularly
+sausage-shaped.</p>
+
+<p><span class="smcap">Types</span> in the Indian Museum.</p>
+
+<p><span class="smcap">Habitat.</span> Naukuchia Tal (alt. 4200 feet),
+Kumaon, W. Himalayas (<i>S. W. Kemp</i>).</p>
+
+<p class="p2 center">Genus <b>EPHYDATIA</b> (p.&nbsp;<a
+href="#Page_108">108</a>).</p>
+
+<p>After <i>Ephydatia meyeni</i>, p.&nbsp;108, add:&mdash;</p>
+
+<p class="center"><b>Ephydatia fluviatilis</b>, <i>auct.</i></p>
+
+<div class="genus">
+
+<span class="i0">? <i>Ephydatia fluviatilis</i>, Lamouroux, Encyclop.
+M�thod. ii, p.&nbsp;327 (1824).</span>
+
+<span class="i0"><i>Spongilla fluviatilis</i>, Bowerbank
+(<i>partim</i>), Proc. Zool. Soc. London, 1863, p.&nbsp;445, pl.
+xxxviii, fig. 1.</span>
+
+<span class="i0"><i>Ephydatia fluviatilis</i>, J. E. Gray
+(<i>partim</i>), Proc. Zool. Soc. London, 1867, p.&nbsp;550.</span>
+
+<span class="i0"><i>Meyenia fluviatilis</i>, Carter (<i>partim</i>),
+Ann. Nat. Hist. (5) vii, p.&nbsp;92, pl. vi, fig. 11 <i>a</i>, <i>b</i>
+(1881).</span>
+
+<span class="i0"><i>Ephydatia fluviatilis</i>, Vejdovsky, Abh. k. B�hm.
+Gesellschaft Wiss. xii, p.&nbsp;24, pl. i, figs. 1, 2, 7, 10, 14, 19
+(1883).</span>
+
+<span class="i0"><i>Ephydatia fluviatilis</i>, <i>id.</i>, P. Ac.
+Philad. 1887, p.&nbsp;178.</span>
+
+<span class="i0"><i>Meyenia fluviatilis</i> var. <i>gracilis</i>, Potts,
+<i>ibid.</i>, p.&nbsp;224.</span>
+
+<span class="i0"><i>Meyenia robusta</i>, <i>id.</i>, <i>ibid.</i>,
+p.&nbsp;225, pl. ix, fig. 5.</span>
+
+<span class="i0"><i>Ephydatia fluviatilis</i>, Weltner, Arch. Naturg.
+Berlin, 1895 (i) p.&nbsp;122.</span>
+
+<span class="i0"><i>Ephydatia robusta</i>, Annandale, Journ. As. Soc.
+Bengal, 1907, p.&nbsp;24, fig. 7.</span>
+
+<span class="i0"><i>Ephydatia fluviatilis</i>, Weltner, in Brauer's
+S�sswasserfauna Deutschlands xix, S�sswasserschw�mme, p.&nbsp;185, figs.
+316, 317 (1909).</span>
+
+<span class="i0"><i>Ephydatia fluviatilis</i>, Annandale, P. U. S. Mus.
+xxxviii, p.&nbsp;649 (1910).</span>
+
+</div>
+
+<p class="blockquote">[Many more references to this common species might
+be cited, but those given above will be sufficient.]</p>
+
+<p>This species only differs from <i>E. meyeni</i> in the following
+characters:&mdash;</p>
+
+<p class="blockquote_b">(i.)   there are no bubble-cells in the
+parenchyma;</p>
+
+<p class="blockquote_b">(ii.)  there is less spongin in the skeleton,
+which is less compact;</p>
+
+<p class="blockquote_b">(iii.) the gemmule-spicules are longer, the
+shafts being as a rule longer than the diameter of the rotul�;</p>
+
+<p class="blockquote_b"><span class='pagenum'><a name="Page_243"
+id="Page_243">[Pg 243]</a></span>(iv.) the gemmules are armed with a
+single row of regularly arranged spicules embedded in pneumatic tissue
+with minute air-spaces.</p>
+
+<p>The sponge is a variable one and several "varieties" have been
+described from different parts of the world. My Indian specimens come
+nearest to the form described by Potts as <i>Meyenia robusta</i>, but
+have rather more slender skeleton-spicules and more elongate
+gemmule-spicules. The latter also appear to be less frequently
+"monstrous."</p>
+
+<p><span class="smcap">Type</span> ?</p>
+
+<p><span class="smcap">Geographical Distribution.</span>&mdash;<i>E.
+fluviatilis</i> is widely distributed in Europe and occurs in N.
+America,<a name="fnanchor_BP" id="fnanchor_BP"></a><a
+href="#footnote_BP" class="fnanchor"><sup>[BP]</sup></a> S. Africa (var.
+<i>capensis</i>, Kirkpatrick), Australia, and Japan. Specimens were
+obtained by Mr. Kemp from several lakes in Kumaon, namely Naukuchia Tal
+(alt. 4200 feet), Bhim Tal (4450 feet), Sat Tal (4500 feet), and Naini
+Tal (6300 feet). The gemmules from Bhim Tal referred by me to <i>E.
+robusta</i> (Potts) also belong to this species.</p>
+
+<p><i>Biology.</i> The external form of the sponge is due in great part
+to its environment. Specimens on small stones from the bottom of the
+Kumaon Lakes consist of thin disk-like films, often not more than a few
+centimetres in diameter and a few millimetres thick: others, growing on
+thin twigs, are elevated and compressed, resembling a cockscomb in
+appearance, while others again form nodules and masses of irregular form
+among the branches of delicate water-weeds. Some of these last are
+penetrated by zoaria of <i>Fredericella indica</i>.</p>
+
+<p>Weltner has published some very interesting observations on the
+seasonal variation of minute structure in European representatives of
+the species (Arch. Naturg. Berlin, lxxiii (i), p.&nbsp;273 1907) and has
+discussed the formation of the abnormal spicules that sometimes occur
+(<i>ibid.</i> lxvii (Special Number), p.&nbsp;191, pls. vi, vii, figs.
+27-59, 1901).</p>
+
+<p class="p2 center">Genus <b>CORVOSPONGILLA</b> (p.&nbsp;<a
+href="#Page_122">122</a>).</p>
+
+<p>After <i>Corvospongilla burmanica</i>, p.&nbsp;123, add a new
+species:&mdash;</p>
+
+<p class="center"><b>Corvospongilla caunteri</b>, nov.</p>
+
+<p><i>Sponge</i> forming thin films of considerable area not more than 3
+or 4 mm. thick, of a bright green colour, moderately hard but friable.
+The surface smooth; oscula inconspicuous, surrounded by shallow and
+ill-defined radiating furrows; a very stout basal membrane present.</p>
+
+<p><span class='pagenum'><a name="Page_244" id="Page_244">[Pg
+244]</a></span><i>Skeleton</i> reticulate but almost devoid of spongin,
+the reticulations close but formed mainly by single spicules;
+skeleton-fibres barely distinguishable. A close layer of spicules lying
+parallel to the basal membrane.</p>
+
+<div class="figcenter">
+<img src="images/fig_048.jpg"
+width="404" height="450"  alt="Illustration: Fig.
+48.&mdash;Corvospongilla caunteri (type, from Lucknow)." title="Fig.
+48.&mdash;Corvospongilla caunteri (type, from Lucknow)." />
+<p class="caption">Fig. 48.&mdash;<i>Corvospongilla caunteri</i> (type,
+from Lucknow).</p>
+</div>
+
+<p class="captionj">A=Gemmule; B=gemmule-spicules; C=flesh-spicules;
+D=Skeleton-spicules.</p>
+
+<p><i>Spicules.</i> Skeleton-spicules variable in size and shape, almost
+straight, as a rule smooth, moderately stout, blunt or abruptly pointed;
+sometimes roughened or spiny at the tips, often sharply pointed.
+Flesh-spicules minute, few in number, with smooth, slender shafts which
+are variable in length, never very strongly curved; the terminal spines
+relatively short, not strongly recurved. Gemmule-spicules
+amphistrongylous or <ins title="changed from
+'amphioxus'">amphioxous</ins>, irregularly spiny, slender, of variable
+length.</p>
+
+<p><i>Gemmules</i> free in the substance of the sponge, spherical or
+somewhat depressed, very variable in size but never large, having a
+thick external pneumatic coat in which the air-spaces are extremely
+small and, inside this coat, a single rather sparse layer of spicules
+lying parallel to the gemmule. A single depressed aperture present.</p>
+
+<p><span class='pagenum'><a name="Page_245" id="Page_245">[Pg
+245]</a></span><span class="smcap"><span
+class="smcap">Type</span></span> in the Indian Museum.</p>
+
+<p><span class="smcap">Habitat.</span> Hazratganj, Lucknow; on piers of
+bridge in running water (<i>J. Caunter</i>, 29-30. iv. 11).</p>
+
+<p>The structure of the gemmules of this species differs considerably
+from that in any other known species of the genus, in which these
+structures are usually adherent and devoid of a true pneumatic coat. In
+some of the gemmules before me this coat measures in thickness about 1/9
+of the total diameter of the gemmule. <i>C. caunteri</i> is the first
+species of <i>Corvospongilla</i> to be found in the Indo-Gangetic
+plain.</p>
+
+<p class="p2 center">PART II.</p>
+
+<p class="center">Genus <b>HYDRA</b> (p.&nbsp;<a
+href="#Page_147">147</a>).</p>
+
+<p>25. <b>Hydra oligactis</b> (p.&nbsp;<a href="#Page_158">158</a>).</p>
+
+<p>Mr. Kemp found this species common in Bhim Tal in May. His specimens,
+which were of a reddish-brown colour in life, appear to have been of
+more vigorous constitution than those taken by Major Stephenson in
+Lahore. Some of them had four buds but none were sexually mature.</p>
+
+<p class="p2 center">PART III.</p>
+
+<p class="center">Genus <b>FREDERICELLA</b> (p.&nbsp;<a
+href="#Page_208">208</a>).</p>
+
+<p>28. <b>Fredericella indica</b> (p.&nbsp;<a
+href="#Page_210">210</a>).</p>
+
+<p>This species is common in some of the Kumaon lakes, in which it
+grows, at any rate at the beginning of summer, much more luxuriantly
+than it does in the lakes of the Malabar Zone in autumn, forming dense
+bushy masses on the under surface of stones, on sticks, &amp;c.  The
+vertical branches often consist of many zo&oelig;cia. Mr. Kemp took
+specimens in Malwa Tal, Sath Tal, and Naini Tal (alt. 3600-6300
+feet).</p>
+
+<p class="p2 center">Genus <b>PLUMATELLA</b> (p.&nbsp;<a
+href="#Page_212">212</a>).</p>
+
+<p>30. <b>Plumatella emarginata</b> (p.&nbsp;<a
+href="#Page_220">220</a>).</p>
+
+<p>Mr. Kemp took bushy masses of this species in Malwa Tal and Bhim
+Tal.</p>
+
+<p>32. <b>Plumatella diffusa</b> (p.&nbsp;<a
+href="#Page_223">223</a>).</p>
+
+<p>This species is common in Malwa Tal and Bhim Tal in May.</p>
+
+<p><span class='pagenum'><a name="Page_246" id="Page_246">[Pg
+246]</a></span>33. <b>Plumatella allmani</b> (p.&nbsp;<a
+href="#Page_224">224</a>).</p>
+
+<p>Mr. Kemp only found this species in Malwa Tal, in which (at any rate
+in May) it appears to be less abundant than it is in Bhim Tal in autumn.
+Mr. Kemp's specimens belong to the form called <i>P. elegans</i> by
+Allman.</p>
+
+<p>34. <b>Plumatella tanganyik�</b> (p.&nbsp;<a
+href="#Page_225">225</a>).</p>
+
+<p>Specimens taken by Mr. Kemp, somewhat sparingly, in Bhim Tal and Sath
+Tal in May exhibit a somewhat greater tendency towards uprightness of
+the zo&oelig;cia than those I found in autumn in Igatpuri lake. The
+ectocyst is, in the former specimens, of a deep but bright
+reddish-brown. The zoaria are attached to twigs and small stones.</p>
+
+<p class="p2 center">Genus <b>STOLELLA</b> (p.&nbsp;<a
+href="#Page_229">229</a>).</p>
+
+<p>After Stolella indica, p.&nbsp;229, add a new species:&mdash;</p>
+
+<p class="center"><b>Stolella himalayana</b>, nov.</p>
+
+<p>This species may be distinguished from <i>S. indica</i> by (i) its
+entirely recumbent zo&oelig;cia, and (ii) the lateral branches of its
+zoarium.</p>
+
+<div class="figcenter">
+<img src="images/fig_049.png"
+width="475" height="299"  alt="Illustration: Fig. 49.&mdash;Stolella
+himalayana (types, from the Kumaon lakes)." title="Fig.
+49.&mdash;Stolella himalayana (types, from the Kumaon lakes)." />
+<p class="caption">Fig. 49.&mdash;<i>Stolella himalayana</i> (types,
+from the Kumaon lakes).</p>
+</div>
+
+<p class="captionj">A. The greater part of a young zoarium. B. Part of a
+much older zoarium.</p>
+
+<p><i>Zoarium</i> entirely recumbent, consisting of zo&oelig;cia joined
+together, often in groups of three, by slender, transparent, tubular
+processes. These processes are often of great relative length; they are
+formed by a modification of the posterior or proximal part of the
+zo&oelig;cia, from which they are not separated by a partition, and they
+increase in length up to a certain point more rapidly than<span
+class='pagenum'><a name="Page_247" id="Page_247">[Pg 247]</a></span> the
+zo&oelig;cia proper. A zo&oelig;cium often gives rise first to an
+anterior daughter-zo&oelig;cium, the proximal part of which becomes
+elongate and attenuated in due course, and then to a pair of lateral
+daughter-zo&oelig;cia situated one on either side. As a result of this
+method of budding a zoarium with a close superficial resemblance to that
+of <i>Paludicella</i> is at first produced, but as the colony increases
+in age and complexity this resemblance largely disappears, for the
+zo&oelig;cia and their basal tubules grow over one another and often
+become strangely contorted (fig. 49).</p>
+
+<p><i>Zo&oelig;cia</i> elongate and slender, flattened on the ventral,
+strongly convex on the dorsal surface; rather deep in proportion to
+their breadth; the ectocyst colourless, not very transparent except on
+the stolon-like tubular part; dorsal keel and furrow as a rule absent;
+orifice unusually inconspicuous, situated on a tubercle on the dorsal
+surface.</p>
+
+<p><i>Polypide</i> stout and short; the tip of the fundus of the stomach
+capable of very complete constriction; the retractor muscles unusually
+short and stout.</p>
+
+<p><i>Statoblasts.</i> Only free statoblasts have been observed. They
+resemble those of <i>S. indica</i>, but are perhaps a little longer and
+more elongate.</p>
+
+<p><span class="smcap">Types</span> in the Indian Museum.</p>
+
+<p>The discovery of this species makes it necessary to modify the
+diagnosis of the genus, the essential character of which, as
+distinguishing it from <i>Plumatella</i>, is the differentiation of the
+proximal part of some or all of the zo&oelig;cia to form stolon-like
+tubules. From <i>Stephanella</i>, Oka, it is distinguished by the
+absence of a gelatinous covering, and by the fact that all the
+zo&oelig;cia are attached, at least at the base, to some extraneous
+object.</p>
+
+<p><span class="smcap">Habitat.</span> Malwa Tal, Kumaon (alt. 3600
+feet), W. Himalayas (<i>Kemp</i>, May 1911).</p>
+
+<p><span class="smcap">Biology.</span> Mr. Kemp took three specimens,
+all attached to the lower surface of stones. They contained few
+statoblasts and were evidently in a condition of vigorous growth.
+Between the lateral branches new polyparia were developing in several
+instances from free statoblasts, each of which appeared to contain two
+polypides.</p>
+
+<p class="footnote">
+<a name="footnote_BP" id="footnote_BP"></a>
+<a href="#fnanchor_BP">[BP]</a>
+Most of the forms assigned by Potts to this species belong to the
+closely allied <i>E. m�lleri</i> (Lieberk�hn).</p>
+
+<p><span class='pagenum'><a name="Page_248" id="Page_248">[Pg
+248]</a></span><br /> <span class='pagenum'><a name="Page_249"
+id="Page_249">[Pg 249]</a></span></p>
+
+<h3 class="p4">ALPHABETICAL INDEX.</h3>
+
+<p class="p2">All names printed in italics are synonyms.</p>
+
+<p>When more than one reference is given, the page on which the
+description occurs is indicated by thickened numerals.</p>
+
+<ul class="IX none">
+
+<li>alba (Euspongilla) (Spongilla), <a href="#Page_8">8</a>, <a
+href="#Page_9">9.</a></li>
+
+<li>alba (Spongilla), <a href="#Page_4">4</a>, <a
+href="#Page_22">22</a>, <a href="#Page_63">63</a>, <a
+href="#Page_76"><b>76</b></a>.</li>
+
+<li>alba <i>var.</i> bengalensis (Spongilla), <a href="#Page_4">4</a>,
+<a href="#Page_22">22</a>, <a href="#Page_63">63</a>, <a
+href="#Page_77"><b>77</b></a>.</li>
+
+<li>alba <i>var</i>. cerebellata (Spongilla), <a href="#Page_22">22</a>,
+<a href="#Page_63">63</a>, <a href="#Page_76"><b>76</b></a>.</li>
+
+<li><i>alba</i> var. <i>marina</i> (<i>Spongilla</i>), <a
+href="#Page_77"><b>77</b></a>.</li>
+
+<li><i>Alcyonella</i>, <a href="#Page_212">212</a>.</li>
+
+<li>Alcyonellea, <a href="#Page_185">185</a>.</li>
+
+<li>allmani (Plumatella), <a href="#Page_7">7</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_23">23</a>, <a href="#Page_188">188</a>, <a
+href="#Page_224"><b>224</b></a>, <a href="#Page_246">246</a>.</li>
+
+<li><i>allmani</i> var. <i>diffusa</i> (<i>Plumatella</i>), <a
+href="#Page_223">223</a>.</li>
+
+<li><i>allmani</i> var. <i>dumortieri</i> (<i>Plumatella</i>), <a
+href="#Page_222">222</a>.</li>
+
+<li><i>attenuata</i> (<i>Hydra</i>), <a href="#Page_148">148</a>, <a
+href="#Page_158">158</a>.</li>
+
+<li><i>aurantiaca</i> (<i>Hydra</i>), <a href="#Page_148">148</a>.</li>
+
+<li>aurea (Pectispongilla), <a href="#Page_9">9</a>, <a
+href="#Page_22">22</a>, <a href="#Page_63">63</a>, <a
+href="#Page_106"><b>106</b></a>.</li>
+
+<li>aurea <i>var.</i> subspinosa (Pectispongilla), <a
+href="#Page_63">63</a>, <a href="#Page_107"><b>107</b></a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li><i>benedeni</i> (<i>Alcyonella</i>), <a
+href="#Page_220">220</a>.</li>
+
+<li>bengalensis (Bowerbankia), <a href="#Page_189">189</a>.</li>
+
+<li>bengalensis (Membranipora), <a href="#Page_23">23</a>.</li>
+
+<li>bengalensis (Spongilla), <a href="#Page_77">77</a>.</li>
+
+<li>bengalensis (Victorella), <a href="#Page_4">4</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_23">23</a>, <a href="#Page_187">187</a>, <a
+href="#Page_195"><b>195</b></a>.</li>
+
+<li>blembingia (Ephydatia), <a href="#Page_54">54</a>.</li>
+
+<li>bogorensis (Ephydatia), <a href="#Page_54">54</a>.</li>
+
+<li><i>bombayensis</i> (<i>Plumatella</i>), <a
+href="#Page_225">225</a>.</li>
+
+<li>bombayensis (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_100">100</a>, <a
+href="#Page_102"><b>102</b></a>, <a href="#Page_241">241</a>.</li>
+
+<li>bombayensis (Stratospongilla) (Spongilla), <a href="#Page_8">8</a>,
+<a href="#Page_9">9</a>.</li>
+
+<li>Bowerbankia, <a href="#Page_187">187</a>, <a
+href="#Page_189"><b>189</b></a>.</li>
+
+<li><i>brunnea</i> (<i>Hydra</i>), <a href="#Page_148">148</a>.</li>
+
+<li>burmanica (Corvospongilla), <a href="#Page_8">8</a>, <a
+href="#Page_22">22</a>, <a href="#Page_64">64</a>, <a
+href="#Page_122"><b>122</b></a>.</li>
+
+<li>burmanica (Pectinatella), <a href="#Page_8">8</a>, <a
+href="#Page_10">10</a>, <a href="#Page_23">23</a>, <a
+href="#Page_188">188</a>, <a href="#Page_235"><b>235</b></a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>calcuttana (Spongilla), <a href="#Page_96">96</a>.</li>
+
+<li><i>cambodgiensis</i> (<i>Norodonia</i>), <a
+href="#Page_202">202</a>.</li>
+
+<li><i>Carterella</i>, <a href="#Page_108">108</a>.</li>
+
+<li>carteri (Eunapius) (Spongilla), <a href="#Page_7">7</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_10">10</a>.</li>
+
+<li><i>carteri</i> (<i>Eunapius</i>), <a href="#Page_87">87</a>.</li>
+
+<li>carteri (Lophopodella), <a href="#Page_7">7</a>, <a
+href="#Page_8">8</a>, <a href="#Page_23">23</a>, <a
+href="#Page_188">188</a>, <a href="#Page_232"><b>232</b></a>, <a
+href="#Page_233">233</a>.</li>
+
+<li><i>carteri</i> (<i>Lophopus</i>), <a href="#Page_232">232</a>.</li>
+
+<li><i>carteri</i> (<i>Pectinatella</i>), <a href="#Page_231">231</a>,
+<a href="#Page_232">232</a>.</li>
+
+<li>carteri (Spongilla), <a href="#Page_4">4</a>, <a
+href="#Page_22">22</a>, <a href="#Page_63">63</a>, <a
+href="#Page_86">86</a>, <a href="#Page_87"><b>87</b></a>, <a
+href="#Page_241">241</a>.</li>
+
+<li>carteri <i>var.</i> cava (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>.</li>
+
+<li>carteri <i>var.</i> himalayana (Lophopodella), <a
+href="#Page_23">23</a>, <a href="#Page_188">188</a>.</li>
+
+<li>carteri <i>var.</i> lobosa (Spongilla), <a href="#Page_22">22</a>,
+<a href="#Page_63">63</a>.</li>
+
+<li>carteri <i>var.</i> mollis (Spongilla), <a href="#Page_22">22</a>,
+<a href="#Page_63">63</a>.</li>
+
+<li>caudata (Bowerbankia), <a href="#Page_189">189</a>.</li>
+
+<li>caudata <i>subsp.</i> bengalensis (Bowerbankia), <a
+href="#Page_23">23</a>, <a href="#Page_189">189</a>.</li>
+
+<li>caunteri (Corvospongilla), <a href="#Page_243">243</a>.</li>
+
+<li>cava (Spongilla), <a href="#Page_88">88</a>.</li>
+
+<li>cerebellata (Spongilla), <a href="#Page_76">76</a>.</li>
+
+<li>ceylonensis (Irene), <a href="#Page_22">22</a>, <a
+href="#Page_140">140</a>.</li>
+
+<li>Cheilostomata, <a href="#Page_184">184</a>.</li>
+
+<li>Chlorella, <a href="#Page_50">50</a>.</li>
+
+<li>cinerea (Euspongilla) (Spongilla), <a href="#Page_9">9</a>.</li>
+
+<li>cinerea (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_72">72</a>, <a
+href="#Page_79">79</a>, <a href="#Page_241">241</a>.</li>
+
+<li>clementis (Stratospongilla) (Spongilla), <a
+href="#Page_53">53</a>.</li>
+
+<li>coggini (Stratospongilla) (Spongilla), <a
+href="#Page_53">53</a>.</li>
+
+<li>colonialis (Loxosomatoides), <a href="#Page_23">23</a>.</li>
+
+<li><i>contecta</i> (<i>Spongilla</i>), <a href="#Page_95">95</a>.</li>
+
+<li><i>coralloides</i> (<i>Plumatella</i>), <a
+href="#Page_217">217</a>.</li>
+
+<li>Corvospongilla, <a href="#Page_64">64</a>, <a
+href="#Page_122"><b>122</b></a>, <a href="#Page_243">243</a>.</li>
+
+<li>crassior (Spongilla), <a href="#Page_98">98</a>.</li>
+
+<li>crassissima (Eunapius) (Spongilla), <a href="#Page_9">9</a>.</li>
+
+<li>crassissima (Spongilla), <a href="#Page_4">4</a>, <a
+href="#Page_22">22</a>, <a href="#Page_63">63</a>, <a
+href="#Page_98"><b>98</b></a>.</li>
+
+<li>crassissima <i>var.</i> crassior (Spongilla), <a
+href="#Page_23">23</a>, <a href="#Page_63">63</a>.</li>
+
+<li><i>crateriformis</i> (<i>Meyenia</i>), <a
+href="#Page_83">83</a>.</li>
+
+<li><i>crateriformis</i> (<i>Ephydatia</i>), <a href="#Page_83">83</a>,
+<a href="#Page_84">84</a>.</li>
+
+<li>crateriformis (Euspongilla) (Spongilla), <a href="#Page_8">8</a>, <a
+href="#Page_9">9</a>.</li>
+
+<li><i>crateriformis</i> (<i>Meyenia</i>), <a
+href="#Page_83">83</a>.</li>
+
+<li>crateriformis (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_83"><b>83</b></a>.</li>
+
+<li><i>Cristatella</i>, <a href="#Page_235">235</a>.</li>
+
+<li>Cristatellina, <a href="#Page_206">206</a>.</li>
+
+<li><span class='pagenum'><a name="Page_250" id="Page_250">[Pg
+250]</a></span>Ctenostomata, <a href="#Page_184">184</a>, <a
+href="#Page_185">185</a>, <a href="#Page_187">187</a>, <a
+href="#Page_189"><b>189</b></a>.</li>
+
+<li>Cyclostomata, <a href="#Page_184">184</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>decipiens (Spongilla), <a href="#Page_54">54</a>, <a
+href="#Page_96">96</a>, <a href="#Page_97"><b>97</b></a>.</li>
+
+<li>diffusa (Plumatella), <a href="#Page_7">7</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_23">23</a>, <a href="#Page_188">188</a>, <a
+href="#Page_223"><b>223</b></a>, <a href="#Page_245">245</a>.</li>
+
+<li><i>di&oelig;cia</i> (<i>Hydra</i>), <a
+href="#Page_158">158</a>.</li>
+
+<li>Dosilia, <a href="#Page_64">64</a>, <a
+href="#Page_110"><b>110</b></a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li><i>Echinella</i>, <a href="#Page_199">199</a>.</li>
+
+<li><i>elegans</i> (<i>Plumatella</i>), <a
+href="#Page_224">224</a>.</li>
+
+<li>Eleutheroblastea, <a href="#Page_146">146</a>, <a
+href="#Page_147">147</a>.</li>
+
+<li>emarginata (Plumatella), <a href="#Page_4">4</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_10">10</a>, <a href="#Page_23">23</a>, <a
+href="#Page_188">188</a>, <a href="#Page_218">218</a>, <a
+href="#Page_220"><b>220</b></a>, <a href="#Page_245">245</a>.</li>
+
+<li><i>emarginata</i> var. <i>javanica</i> (<i>Plumatella</i>), <a
+href="#Page_221">221</a>.</li>
+
+<li>Entoprocta, <a href="#Page_183">183</a>.</li>
+
+<li>Ephydatia, <a href="#Page_64">64</a>, <a
+href="#Page_108"><b>108</b></a>, <a href="#Page_242">242</a>.</li>
+
+<li><i>erinaceus</i> (<i>Spongilla</i>), <a
+href="#Page_114">114</a>.</li>
+
+<li>Eunapius, <a href="#Page_63">63</a>, <a
+href="#Page_86"><b>86</b></a>, <a href="#Page_241">241</a>.</li>
+
+<li>Euspongilla, <a href="#Page_63">63</a>, <a href="#Page_67">67</a>,
+<a href="#Page_69"><b>69</b></a>, <a href="#Page_241">241</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>filamentata (Syncoryne), <a href="#Page_22">22</a>, <a
+href="#Page_140">140</a>.</li>
+
+<li>fluviatilis (Ephydatia), <a href="#Page_109">109</a>, <a
+href="#Page_242"><b>242</b></a>.</li>
+
+<li><i>fluviatilis</i> (<i>Meyenia</i>), <a
+href="#Page_242">242</a>.</li>
+
+<li>fluviatilis (Spongilla), <a href="#Page_108">108</a>, <a
+href="#Page_242">242</a>.</li>
+
+<li><i>fluviatilis</i> var. <i>gracilis</i> (<i>Meyenia</i>), <a
+href="#Page_242">242</a>.</li>
+
+<li>fortis (Ephydatia), <a href="#Page_52">52</a>, <a
+href="#Page_53">53</a>.</li>
+
+<li>fragilis (Spongilla), <a href="#Page_95"><b>95</b></a>, <a
+href="#Page_96">96</a>.</li>
+
+<li>fragilis <i>subsp.</i> calcuttana (Eunapius) (Spongilla), <a
+href="#Page_9">9</a>.</li>
+
+<li>fragilis <i>subsp.</i> calcuttana (Spongilla), <a
+href="#Page_22">22</a>, <a href="#Page_63">63</a>.</li>
+
+<li>fragilis <i>subsp.</i> decipiens (Spongilla), <a
+href="#Page_22">22</a>, <a href="#Page_63">63</a>.</li>
+
+<li>Fredericella, <a href="#Page_188">188</a>, <a
+href="#Page_208"><b>208</b></a>, 245.</li>
+
+<li><span class="smcap">Fredericellid�</span>, <a href="#Page_188">188</a>,
+<a href="#Page_208"><b>208</b></a>.</li>
+
+<li><i>friabilis</i> (<i>Spongilla</i>), <a href="#Page_87">87</a>.</li>
+
+<li>fruticosa (Plumatella), <a href="#Page_4">4</a>, <a
+href="#Page_7">7</a>, <a href="#Page_8">8</a>, <a href="#Page_9">9</a>,
+<a href="#Page_23">23</a>, <a href="#Page_188">188</a>, <a
+href="#Page_217"><b>217</b></a>, <a href="#Page_218">218</a>.</li>
+
+<li><i>fusca</i> (<i>Hydra</i>), <a href="#Page_158">158</a>, <a
+href="#Page_159">159</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>Gecarcinucus, <a href="#Page_10">10</a>.</li>
+
+<li>gemina (Eunapius) (Spongilla), <a href="#Page_8"><b>8</b></a>.</li>
+
+<li>gemina (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_97"><b>97</b></a>.</li>
+
+<li><i>glomerata</i> (<i>Spongilla</i>), <a href="#Page_95">95</a>.</li>
+
+<li><i>grisea</i> (<i>Hydra</i>), <a href="#Page_148">148</a>, <a
+href="#Page_149">149</a>.</li>
+
+<li>Gymnol�mata, <a href="#Page_184">184</a>, <a
+href="#Page_187">187</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>Halichondrina, <a href="#Page_65">65</a>.</li>
+
+<li>hemephydatia (Euspongilla) (Spongilla), <a
+href="#Page_8">8</a>.</li>
+
+<li>hemephydatia (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_82"><b>82</b></a>.</li>
+
+<li><i>hexactinella</i> (<i>Hydra</i>), <a
+href="#Page_148">148</a>.</li>
+
+<li>himalayana (Lophopodella), <a href="#Page_233">233</a>.</li>
+
+<li>himalayana (Stolella), <a href="#Page_246">246</a>.</li>
+
+<li><i>himalayanus</i> (<i>Lophopus</i>), <a
+href="#Page_233">233</a>.</li>
+
+<li>Hislopia, <a href="#Page_187">187</a>, <a
+href="#Page_199"><b>199</b></a>.</li>
+
+<li>Hislopid�es, <a href="#Page_199">199</a>.</li>
+
+<li><span class="smcap">Hislopiid�</span>, <a href="#Page_187">187</a>, <a
+href="#Page_199"><b>199</b></a>.</li>
+
+<li>Homodi�tid�, <a href="#Page_191">191</a>.</li>
+
+<li><i>Hyalinella</i>, <a href="#Page_212">212</a>.</li>
+
+<li>Hydra, <a href="#Page_146">146</a>, <a
+href="#Page_147"><b>147</b></a>, <a href="#Page_245">245</a>.</li>
+
+<li>Hydraid�, <a href="#Page_147">147</a>.</li>
+
+<li><span class="smcap">Hydrid�</span>, <a href="#Page_146">146</a>, <a
+href="#Page_147">147</a>.</li>
+
+<li>hydriforme (Polypodium), <a href="#Page_142">142</a>.</li>
+
+<li>Hydrozoa, <a href="#Page_146">146</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li><i>indica</i> (<i>Ephydatia</i>), <a href="#Page_83">83</a>.</li>
+
+<li>indica (Fredericella), <a href="#Page_9">9</a>, <a
+href="#Page_23">23</a>, <a href="#Page_188">188</a>, <a
+href="#Page_209"><b>209</b></a>, <a href="#Page_245">245</a>.</li>
+
+<li>indica (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_100"><b>100</b></a>.</li>
+
+<li>indica (Stolella), <a href="#Page_4">4</a>, <a href="#Page_9">9</a>,
+<a href="#Page_23">23</a>, <a href="#Page_188">188</a>, <a
+href="#Page_229"><b>229</b></a>.</li>
+
+<li>indica (Stratospongilla), (Spongilla), <a href="#Page_9">9</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>javanica (Plumatella), <a href="#Page_4">4</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_23">23</a>, <a href="#Page_188">188</a>, <a
+href="#Page_221"><b>221</b></a>, <a href="#Page_222">222</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>kawaii (Limnocodium), <a href="#Page_141">141</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>lacroixii (Membranipora), <a href="#Page_23">23</a>.</li>
+
+<li>lacustris (Cordylophora), <a href="#Page_141">141</a>.</li>
+
+<li><i>lacustris</i> (<i>Euspongilla</i>), <a
+href="#Page_69">69</a>.</li>
+
+<li>lacustris (Hislopia), <a href="#Page_4">4</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_23">23</a>, <a href="#Page_187">187</a>, <a
+href="#Page_199">199</a>, <a href="#Page_202"><b>202</b></a>, <a
+href="#Page_204">204</a>.</li>
+
+<li>lacustris (Spongilla), <a href="#Page_63">63</a>, <a
+href="#Page_67">67</a>, <a href="#Page_69"><b>69</b></a>.</li>
+
+<li>lacustris <i>subsp.</i> moniliformis (Hislopia), <a
+href="#Page_9">9</a>, <a href="#Page_23">23</a>, <a
+href="#Page_187">187</a>.</li>
+
+<li>lacustris <i>subsp.</i> reticulata (Spongilla), <a
+href="#Page_4">4</a>, <a href="#Page_8">8</a>, <a href="#Page_9">9</a>,
+<a href="#Page_22">22</a>, <a href="#Page_63">63</a>, <a
+href="#Page_71"><b>71</b></a>, <a href="#Page_241">241</a>.</li>
+
+<li><i>lacustris</i> var. <i>bengalensis</i> (<i>Spongilla</i>), <a
+href="#Page_77">77</a>.</li>
+
+<li>lapidosa (Corvospongilla), <a href="#Page_9">9</a>, <a
+href="#Page_22">22</a>, <a href="#Page_64">64</a>, <a
+href="#Page_124"><b>124</b></a>.</li>
+
+<li><i>lapidosa</i> (<i>Spongilla</i>), <a
+href="#Page_124">124</a>.</li>
+
+<li>latouchiana (Trochospongilla), <a href="#Page_4">4</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_22">22</a>, <a href="#Page_64">64</a>, <a
+href="#Page_115"><b>115</b></a>.</li>
+
+<li><i>leidyi</i> (<i>Trochospongilla</i>), <a
+href="#Page_115">115</a>.</li>
+
+<li><i>lendenfeldi</i> (<i>Lophopus</i>), <a
+href="#Page_233">233</a>.</li>
+
+<li><i>lendenfeldi</i> var. <i>himalayanus</i> (<i>Lophopus</i>), <a
+href="#Page_233">233</a>.</li>
+
+<li>lobosa (Spongilla), <a href="#Page_89">89</a>.</li>
+
+<li><span class="smcap">Lophopin�</span>, <a href="#Page_188">188</a>, <a
+href="#Page_211">211</a>, <a href="#Page_231"><b>231</b></a>.</li>
+
+<li>Lophopodella, <a href="#Page_8">8</a>, <a href="#Page_188">188</a>,
+<a href="#Page_231"><b>231</b></a>.</li>
+
+<li><i>Lophopus</i>, <a href="#Page_8">8</a>, <a
+href="#Page_232">232</a>.</li>
+
+<li><i>lordii</i> (<i>Spongilla</i>), <a href="#Page_95">95</a>.</li>
+
+<li>loricata (Spongilla), <a href="#Page_122"><b>122</b></a>.</li>
+
+<li><i>loricata</i> var. <i>burmanica</i>, (<i>Spongilla</i>), <a
+href="#Page_122">122</a>.</li>
+
+<li><i>lucifuga</i> (<i>Plumatella</i>), <a href="#Page_217">217</a>, <a
+href="#Page_220">220</a>, <a href="#Page_224">224</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>magnifica (Pectinatella), <a href="#Page_235">235</a>.</li>
+
+<li>meyeni (Ephydatia), <a href="#Page_7">7</a>, <a
+href="#Page_9">9</a>, <a href="#Page_17">17</a>, <a
+href="#Page_22">22</a>, <a href="#Page_64">64</a>, <a
+href="#Page_108"><b>108</b></a>.</li>
+
+<li><i>meyeni</i> (<i>Spongilla</i>), <a href="#Page_108">108</a>.</li>
+
+<li><i>Meyenia</i>, <a href="#Page_108">108</a>, <a
+href="#Page_113">113</a>.</li>
+
+<li>microsclerifera (Euspongilla) (Spongilla), <a
+href="#Page_53">53</a>.</li>
+
+<li>mollis (Spongilla), <a href="#Page_88">88</a>.</li>
+
+<li>moniliformis (Hislopia), <a href="#Page_204">204</a>.</li>
+
+<li><i>mon&oelig;cia</i> (<i>Hydra</i>), <a
+href="#Page_158">158</a>.</li>
+
+<li><i>morgiana</i> (<i>Spongilla</i>), <a href="#Page_95">95</a>.</li>
+
+<li><i>m�lleri</i> (<i>Ephydatia</i>), <a href="#Page_109">109</a>, <a
+href="#Page_243">243</a>.</li>
+
+<li><i>m�lleri</i> subsp. <i>meyeni</i> (<i>Ephydatia</i>), <a
+href="#Page_109">109</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li><i>Norodonia</i>, <a href="#Page_199">199</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li><span class='pagenum'><a name="Page_251" id="Page_251">[Pg
+251]</a></span>oligactis (Hydra), <a href="#Page_7">7</a>, <a
+href="#Page_22">22</a>, <a href="#Page_146">146</a>, <a
+href="#Page_158"><b>158</b></a>, <a href="#Page_159">159</a>, <a
+href="#Page_245">245</a>.</li>
+
+<li><i>orientalis</i> (<i>Hydra</i>), <a href="#Page_148">148</a>, <a
+href="#Page_149">149</a>.</li>
+
+<li><i>ottav�nsis</i> (<i>Spongilla</i>), <a
+href="#Page_95">95</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li><i>pallens</i> (<i>Hydra</i>), <a href="#Page_148">148</a>.</li>
+
+<li>Paludicella, <a href="#Page_187">187</a>, <a
+href="#Page_192"><b>192</b></a>.</li>
+
+<li><span class="smcap">Paludicellid�</span>, <a
+href="#Page_187">187</a>, <a href="#Page_191"><b>191</b></a>.</li>
+
+<li>Paludicellid�es, <a href="#Page_191">191</a>.</li>
+
+<li>Paludicellides, <a href="#Page_191">191</a>.</li>
+
+<li>Paludicellina, <a href="#Page_186">186</a>, <a
+href="#Page_187">187</a>, <a href="#Page_190"><b>190</b></a>.</li>
+
+<li>paulula (Spongilla), <a href="#Page_120">120</a>.</li>
+
+<li><i>pavida</i> (<i>Victorella</i>), <a href="#Page_194">194</a>, <a
+href="#Page_195">195</a>.</li>
+
+<li>Pectinatella, <a href="#Page_188">188</a>, <a
+href="#Page_235"><b>235</b></a>.</li>
+
+<li>pectinatellophila (Dactyloccopsis), <a
+href="#Page_238">238</a>.</li>
+
+<li>Pectispongilla, <a href="#Page_63">63</a>, <a
+href="#Page_106"><b>106</b></a>.</li>
+
+<li>pennsylvanica (Trochospongilla), <a href="#Page_9">9</a>, <a
+href="#Page_22">22</a>, <a href="#Page_64">64</a>, <a
+href="#Page_118"><b>118</b></a>.</li>
+
+<li><i>pennsylvanica</i> (<i>Tubella</i>), <a
+href="#Page_118">118</a>.</li>
+
+<li><i>pentactinella</i> (<i>Hydra</i>), <a
+href="#Page_149">149</a>.</li>
+
+<li>philippinensis (Euspongilla) (Spongilla), <a
+href="#Page_53">53</a>.</li>
+
+<li>phillottiana (Trochospongilla), <a href="#Page_4">4</a>, <a
+href="#Page_8">8</a>, <a href="#Page_9">9</a>, <a
+href="#Page_22">22</a>, <a href="#Page_64">64</a>, <a
+href="#Page_117"><b>117</b></a>.</li>
+
+<li>Phylactol�mata, <a href="#Page_185">185</a>, <a
+href="#Page_188">188</a>, <a href="#Page_206"><b>206</b></a>.</li>
+
+<li>Plumatella, <a href="#Page_188">188</a>, <a
+href="#Page_208">208</a>, <a href="#Page_212"><b>212</b></a>, <a
+href="#Page_245">245</a>.</li>
+
+<li><span class="smcap">Plumatellid�</span>, <a
+href="#Page_188">188</a>, <a href="#Page_211"><b>211</b></a>.</li>
+
+<li>Plumatellina, <a href="#Page_188">188</a>, <a
+href="#Page_206"><b>206</b></a>.</li>
+
+<li><span class="smcap">Plumatellin�</span>, <a
+href="#Page_188">188</a>, <a href="#Page_211">211</a>, <a
+href="#Page_212"><b>212</b></a>.</li>
+
+<li>plumosa (Dosilia), <a href="#Page_8">8</a>, <a href="#Page_9">9</a>,
+<a href="#Page_22">22</a>, <a href="#Page_64">64</a>, <a
+href="#Page_111"><b>111</b></a>.</li>
+
+<li><i>plumosa</i> (<i>Ephydatia</i>), <a href="#Page_111">111</a>.</li>
+
+<li><i>plumosa</i> (<i>Meyenia</i>), <a href="#Page_111">111</a>.</li>
+
+<li><i>plumosa</i> (<i>Spongilla</i>), <a href="#Page_111">111</a>.</li>
+
+<li>pneumatica (Stratospongilla) (Spongilla), <a
+href="#Page_241">241</a>.</li>
+
+<li><i>polypus</i> (<i>Hydra</i>), <a href="#Page_148">148</a>, <a
+href="#Page_159">159</a>.</li>
+
+<li>Polyzoa, <a href="#Page_183">183</a>.</li>
+
+<li><i>princeps</i> (<i>Plumatella</i>), <a
+href="#Page_220">220</a>.</li>
+
+<li><i>princeps</i> var. <i>emarginata</i> (<i>Plumatella</i>), <a
+href="#Page_220">220</a>.</li>
+
+<li><i>princeps</i> var. <i>fruticosa</i> (<i>Plumatella</i>), <a
+href="#Page_217">217</a>.</li>
+
+<li>proliferens (Euspongilla) (Spongilla), <a href="#Page_8">8</a>, <a
+href="#Page_9">9</a>, <a href="#Page_10">10</a>.</li>
+
+<li>proliferens (Spongilla), <a href="#Page_4">4</a>, <a
+href="#Page_8">8</a>, <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_72"><b>72</b></a>.</li>
+
+<li>Proterospongia, <a href="#Page_27">27</a>.</li>
+
+<li><i>punctata</i> (<i>Hyalinella</i>), <a
+href="#Page_228">228</a>.</li>
+
+<li>punctata (Plumatella), <a href="#Page_9">9</a>, <a
+href="#Page_188">188</a>, <a href="#Page_227"><b>227</b></a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li><i>repens</i> (<i>Plumatella</i>), <a href="#Page_217">217</a>, <a
+href="#Page_223">223</a>.</li>
+
+<li>reticulata (Spongilla), <a href="#Page_71">71</a>.</li>
+
+<li><i>rh�tica</i> (<i>Hydra</i>), <a href="#Page_158">158</a>.</li>
+
+<li><i>robusta</i> (<i>Ephydatia</i>), <a href="#Page_109">109</a>, <a
+href="#Page_242">242</a>.</li>
+
+<li><i>robusta</i> (<i>Meyenia</i>), <a href="#Page_242">242</a>.</li>
+
+<li><i>roeselii</i> (<i>Hydra</i>), <a href="#Page_158">158</a>.</li>
+
+<li>ryderi (Microhydra), <a href="#Page_141">141</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>schilleriana (Sagartia), <a href="#Page_2">2</a>, <a
+href="#Page_22">22</a>, <a href="#Page_140">140</a>.</li>
+
+<li>schilleriana <i>subsp</i>. exul (Sagartia), <a
+href="#Page_22">22</a>.</li>
+
+<li><i>sibirica</i> (<i>Spongilla</i>), <a href="#Page_95">95</a>.</li>
+
+<li><i>sinensis</i> (<i>Norodonia</i>), <a
+href="#Page_202">202</a>.</li>
+
+<li>sinensis (Stratospongilla) (Spongilla), <a
+href="#Page_53">53</a>.</li>
+
+<li><i>socialis</i> (<i>Hydra</i>), <a href="#Page_158">158</a>.</li>
+
+<li>sowerbii (Limnocodium), <a href="#Page_141">141</a>.</li>
+
+<li>Spongilla, <a href="#Page_63">63</a>, <a
+href="#Page_67"><b>67</b></a>, <a href="#Page_86">86</a>, <a
+href="#Page_241">241</a>.</li>
+
+<li>Spongillad�, <a href="#Page_65">65</a>.</li>
+
+<li><span class="smcap">Spongillid�</span>, <a
+href="#Page_65">65</a>.</li>
+
+<li>Stolella, <a href="#Page_188">188</a>, <a
+href="#Page_229"><b>229</b></a>, <a href="#Page_246">246</a>.</li>
+
+<li>Stolonifera, <a href="#Page_185">185</a>.</li>
+
+<li>Stratospongilla, <a href="#Page_63">63</a>, <a
+href="#Page_100"><b>100</b></a>, <a href="#Page_241">241</a>.</li>
+
+<li><i>stricta</i> (<i>Plumatella</i>), <a
+href="#Page_217">217</a>.</li>
+
+<li>subspinosa (Pectispongilla), <a href="#Page_107">107</a>.</li>
+
+<li>sumatrana (Stratospongilla) (Spongilla), <a
+href="#Page_53">53</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>tanganyik� (Limnocnida), <a href="#Page_142">142</a>.</li>
+
+<li>tanganyik� (Plumatella), <a href="#Page_9">9</a>, <a
+href="#Page_23">23</a>, <a href="#Page_188">188</a>, <a
+href="#Page_225"><b>225</b></a>, <a href="#Page_246">246</a>.</li>
+
+<li>Trachospongilla, <a href="#Page_64">64</a>, <a
+href="#Page_113"><b>113</b></a>.</li>
+
+<li><i>Trachyspongilla</i>, <a href="#Page_108">108</a>.</li>
+
+<li>travancorica (Euspongilla) (Spongilla), <a
+href="#Page_9">9</a>.</li>
+
+<li>travancorica (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_81"><b>81</b></a>.</li>
+
+<li><i>trembleyi</i> (<i>Hydra</i>), <a href="#Page_148">148</a>.</li>
+
+<li>Tubella, <a href="#Page_64">64</a>, <a href="#Page_113">113</a>, <a
+href="#Page_120"><b>120</b></a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>ultima (Spongilla), <a href="#Page_22">22</a>, <a
+href="#Page_63">63</a>, <a href="#Page_105"><b>105</b></a>.</li>
+
+<li>ultima (Stratospongilla) (Spongilla), <a href="#Page_9">9</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li><span class="smcap">Vesicularid�</span>, <a
+href="#Page_189">189</a>.</li>
+
+<li>Vesicularina, <a href="#Page_186">186</a>, <a
+href="#Page_187">187</a>, <a href="#Page_189"><b>189</b></a>.</li>
+
+<li><i>vesicularis</i> (<i>Hyalinella</i>), <a
+href="#Page_228">228</a>.</li>
+
+<li><i>vesicularis</i> (<i>Plumatella</i>), <a href="#Page_227">227</a>,
+<a href="#Page_228">228</a>.</li>
+
+<li>vesparioides (Tubella), <a href="#Page_8">8</a>, <a
+href="#Page_22">22</a>, <a href="#Page_64">64</a>, <a
+href="#Page_120"><b>120</b></a>.</li>
+
+<li>vesparium (Tubella), <a href="#Page_54">54</a>.</li>
+
+<li>vestita (Bimeria), <a href="#Page_22">22</a>, <a
+href="#Page_139">139</a>.</li>
+
+<li>Victorella, <a href="#Page_189">189</a>, <a
+href="#Page_194"><b>194</b></a>.</li>
+
+<li>Victorellid�, <a href="#Page_191">191</a>.</li>
+
+<li>Victorellides, <a href="#Page_191">191</a>.</li>
+
+<li>viridis (Hydra), <a href="#Page_147">147</a>.</li>
+
+<li><i>vitrea</i> (<i>Hyalinella</i>), <a href="#Page_228">228</a>.</li>
+
+<li><i>vitrea</i> (<i>Plumatella</i>), <a href="#Page_227">227</a>, <a
+href="#Page_228">228</a>.</li>
+
+<li>vulgaris (Hydra), <a href="#Page_4">4</a>, <a href="#Page_8">8</a>,
+<a href="#Page_9">9</a>, <a href="#Page_10">10</a>, <a
+href="#Page_22">22</a>, <a href="#Page_130">130</a>, <a
+href="#Page_146">146</a>, <a href="#Page_148"><b>148</b></a>, <a
+href="#Page_149">149</a>, <a href="#Page_158">158</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>whiteleggei (Cordylophora), <a href="#Page_141">141</a>.</li>
+
+</ul>
+
+<ul class="IX none">
+
+<li>yunnanensis (Euspongilla) (Spongilla), <a
+href="#Page_53">53</a>.</li>
+
+</ul>
+
+<div class="p4 tnote">
+<h4> Transcriber's Note:</h4>
+<p class="center">Clicking on each plate, below, will take you to a
+larger image.</p>
+
+</div>
+
+<h3 class="p4"><a name="Plate_I" id="Plate_I">PLATE I.</a></h3>
+
+<p class="center"><span class="smcap">Specimens of</span>
+<i>Spongilla</i> <span class="smcap">preserved in spirit.</span></p>
+
+<table summary="PLATE I">
+
+<tr><td class="left_a"><span style="white-space:nowrap;">Figs.
+1-3.</span></td><td class="left_a"><i>S. (Euspongilla) alba</i> var.
+<i>bengalensis</i> (nat. size) from ponds of brackish water at Port
+Canning in the delta of the Ganges. Fig. 1 represents the type-specimen
+of the variety, and was taken in the winter of 1905-6. Figs. 2 and 3
+represent specimens taken in the same ponds in the winters of 1907 and
+1908 respectively.</td></tr>
+
+<tr><td class="left_a">Fig. 4.</td><td class="left_a"><i>Spongilla</i>
+sp. (? abnormal form of <i>S. (Eunapius carteri</i>)) from an aquarium
+in Calcutta (� 10).</td></tr>
+
+</table>
+
+<div class="figcenter">
+<a href="images/plate_1_lg.png"><img src="images/plate_1_th.png"
+width="152" height="250"  alt="Illustration: SPONGILLA."
+title="SPONGILLA." /></a>
+<p class="caption">SPONGILLA</p>
+</div>
+
+<h3 class="p4"><a name="Plate_II" id="Plate_II">PLATE II.</a></h3>
+
+<p class="center"><span class="smcap">Photographs of dried specimens
+of</span> <i>Spongilla</i>, <i>Tubella</i>, <span
+class="smcap">AND</span> <i>Corvospongilla</i>.</p>
+
+<table summary="PLATE II">
+
+<tr><td class="left_a">Fig.&nbsp;1.</td><td class="left_a">Part of a
+large specimen of <i>S. (Eunapius) carteri</i> from Calcutta, to show
+the conspicuous rounded oscula (reduced).</td></tr>
+
+<tr><td class="left_a">Fig. 2.</td><td class="left_a">Gemmules of <i>S.
+(Stratospongilla) bombayensis</i> on a stone from the edge of Igatpuri
+Lake, Bombay Presidency (nat. size).</td></tr>
+
+<tr><td class="left_a">Fig. 3.</td><td class="left_a">Part of one of the
+type-specimens of <i>S. (Stratospongilla) ultima</i> from Cape Comorin,
+Travancore, to show the star-shaped oscula (slightly
+enlarged).</td></tr>
+
+<tr><td class="left_a">Fig. 4.</td><td class="left_a">Part of the type
+specimen of <i>T. vesparioides</i> (external membrane destroyed), to
+show the reticulate skeleton and the numerous gemmules (nat.
+size).</td></tr>
+
+<tr><td class="left_a">Fig. 5.</td><td class="left_a">Part of a
+schizotype of <i>C. burmanica</i> to show the elevated oscula (nat.
+size).</td></tr>
+
+</table>
+
+<div class="figcenter">
+<a href="images/plate_2_lg.png"><img src="images/plate_2_th.png"
+width="250" height="165"  alt="Illustration: Spongilla, Tubella,
+Corvospongilla." title="Spongilla, Tubella, Corvospongilla." /></a>
+<p class="caption">Spongilla, Tubella, Corvospongilla.</p>
+</div>
+
+<h3 class="p4"><a name="Plate_III" id="Plate_III">PLATE III.</a></h3>
+
+<p class="center"><span class="smcap">Photographs of specimens of</span>
+<i>Plumatella</i>, <i>Lophopodella</i>, <span class="smcap">and</span>
+<i>Pectinatella</i>.</p>
+
+<table summary="PLATE III">
+
+<tr><td class="left_a">Fig.&nbsp;1.</td><td class="left_a">Specimen in
+spirit of <i>P. fruticosa</i> (typical form) on the leaf of a bulrush
+from a pond in the Calcutta Zoological Gardens (nat. size).</td></tr>
+
+<tr><td class="left_a">Fig. 2.</td><td class="left_a">A small zoarium of
+the <i>benedeni</i> phase of <i>P. emarginata</i> from Rangoon (nat.
+size). Part of the mass has been removed at one end to show the
+structure. The specimen was preserved in spirit.</td></tr>
+
+<tr><td class="left_a">Fig. 3.</td><td class="left_a">Part of a large
+zoarium of <i>P. diffusa</i> on a log of wood from Gangtok, Sikhim (nat.
+size). An enlarged figure of another part of the same specimen is given
+in fig. 2, Pl. IV. The specimen was preserved in spirit.</td></tr>
+
+<tr><td class="left_a">Figs.&nbsp;4,&nbsp;4&nbsp;<i>a</i>.</td><td
+class="left_a">Specimens of <i>L. carteri</i> from Igatpuri Lake,
+Bombay, preserved in formalin. Fig. 4 represents a mass of polyparia
+surrounded by a green gelatinous alga on the stem of a water-plant; fig.
+4<i>a</i> an isolated polyparium with the polypides fully expanded from
+the under surface of a stone in the same lake. Both figures are of
+natural size.</td></tr>
+
+<tr><td class="left_a">Fig. 5.</td><td class="left_a">Part of a compound
+colony of <i>P. burmanica</i> on the stem of a reed from the Sur Lake,
+Orissa (nat. size, preserved in formalin).</td></tr>
+
+</table>
+
+<div class="figcenter">
+<a href="images/plate_3_lg.png"><img src="images/plate_3_th.png"
+width="167" height="270"  alt="Illustration: Plumatella, Lophopodella,
+Pectinatella." title="Plumatella, Lophopodella, Pectinatella." /></a>
+<p class="caption">Plumatella, Lophopodella, Pectinatella.</p>
+</div>
+
+<h3 class="p4"><a name="Plate_IV" id="Plate_IV">PLATE IV.</a></h3>
+
+<p class="center"><span class="smcap">Specimens of</span>
+<i>Plumatella</i>.</p>
+
+<table summary="PLATE III">
+
+<tr><td class="left_a">Fig. 1.</td><td class="left_a">Vertical branch of
+a polyparium of <i>P. emarginata</i> from Calcutta, to show method of
+branching (� 8). The specimen was preserved in formalin, stained with
+h�malum, and after dehydration and clearing, mounted in canada
+balsam.</td></tr>
+
+<tr><td class="left_a">Fig. 1 <i>a.</i></td><td class="left_a">Part of a
+young, horizontal zoarium of <i>P. emarginata</i> from Rangoon (� 4,
+preserved in spirit).</td></tr>
+
+<tr><td class="left_a">Fig. 2.</td><td class="left_a">Part of a zoarium
+of <i>P. diffusa</i> from Gangtok, Sikhim (� 4). See Pl. III, fig.
+3.</td></tr>
+
+<tr><td class="left_a">Figs.&nbsp;3,&nbsp;3&nbsp;<i>a.</i></td><td
+class="left_a">Specimens in spirit of <i>P. allmani</i> from Bhim Tal
+(lake), W. Himalayas. Fig. 3 represents a mature polyparium; fig. 3
+<i>a</i> a young polyparium to which the valves of the statoblast (�)
+whence it had arisen are still attached.</td></tr>
+
+<tr><td class="left_a">Fig. 4.</td><td class="left_a">Part of a zoarium
+of the <i>coralloides</i> phase of <i>P. fruticosa</i> (from Calcutta)
+preserved in spirit, as seen on the surface of the sponge in which it is
+embedded (� 3).</td></tr>
+
+<tr><td class="left_a">Fig. 5.</td><td class="left_a">Part of the margin
+of a living polyparium of <i>P. punctata</i> from Calcutta (� 8) with
+the polypides fully expanded.</td></tr>
+
+</table>
+
+<div class="figcenter">
+<a href="images/plate_4_lg.png"><img src="images/plate_4_th.png"
+width="152" height="250"  alt="PLUMATELLA." title="PLUMATELLA." /></a>
+<p class="caption">PLUMATELLA.</p>
+</div>
+
+<h3 class="p4"><a name="Plate_V" id="Plate_V">PLATE V.</a></h3>
+
+<p class="center"><span class="smcap">Specimens of</span>
+<i>Plumatella</i>, <i>Stolella</i>, <span class="smcap">and</span>
+<i>Pectinatella</i>.</p>
+
+<table summary="PLATE V">
+
+<tr><td class="left_a">Fig. 1.</td><td class="left_a">Part of a zoarium
+of the <i>coralloides</i> phase of <i>P. fruticosa</i> (� 10) from
+Calcutta. The specimen, which was preserved in spirit, had been removed
+from a sponge of <i>Spongilla carteri</i>.</td></tr>
+
+<tr><td class="left_a">Fig. 2.</td><td class="left_a">Terminal branch of
+a polyparium of <i>P. punctata</i> from Calcutta (� 30). The specimen
+was preserved in formalin, stained with h�matoxylin, and finally mounted
+in canada balsam.</td></tr>
+
+<tr><td class="left_a">Fig. 3.</td><td class="left_a">Part of an adult
+polyparium of <i>S. indica</i> from the United Provinces (� 30). The
+specimen was preserved in formalin, stained with h�malum, and finally
+mounted in canada balsam. The lower zo&oelig;cium contains a mature free
+statoblast, the upper one a fixed one.</td></tr>
+
+<tr><td class="left_a">Fig. 4.</td><td class="left_a">The growing point
+of a young polyparium of the same species from Calcutta (� 30), to show
+the method of formation of the stolon that connects the different groups
+of zo&oelig;cia. The specimen had been treated in the same way as that
+represented in fig. 3.</td></tr>
+
+<tr><td class="left_a">Figs.&nbsp;5,&nbsp;5&nbsp;<i>a</i>.</td><td
+class="left_a">Zoaria from a compound colony of <i>P. burmanica</i> from
+the Sur Lake, Orissa (� 2). The specimens, which were preserved in
+formalin, are represented as seen from the adherent surface of the
+colony.</td></tr>
+
+</table>
+
+<div class="figcenter">
+<a href="images/plate_5_lg.png"><img src="images/plate_5_th.png"
+width="149" height="250"  alt="Illustration: Plumatella, Stolella,
+Pectinatella." title="Plumatella, Stolella, Pectinatella." /></a>
+<p class="caption">Plumatella, Stolella, Pectinatella..</p>
+</div>
+
+<hr class="c10" />
+
+<div class="p4 tnote">
+
+<h3>Transcriber's Note:</h3>
+
+<p>In the Systematic Index, pages vii-viii, sub-family items were
+renumbered from 15. through 38., to correspond to the numbers used in
+the text of the book. Letters missing or mis-typeset were inserted, e.g.
+'practica ly' to 'practically.' Footnotes were moved to the end of the
+section to which they pertain. Raised dots were replaced with decimal
+points in numeric notations. Prime marker for b' was added to Figure 20.
+Punctuation was standardized.</p>
+
+<p>The remaining changes are indicated by dotted lines under the text.
+Scroll the mouse over the word and the original text will <ins
+title="Original reads 'apprear'"> appear</ins>.</p>
+
+</div>
+
+<p>&nbsp;</p>
+<p>&nbsp;</p>
+<hr class="full" />
+<p>***END OF THE PROJECT GUTENBERG EBOOK FRESHWATER SPONGES, HYDROIDS &amp; POLYZOA***</p>
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+The Project Gutenberg eBook, Freshwater Sponges, Hydroids & Polyzoa, by
+Nelson Annandale
+
+
+This eBook is for the use of anyone anywhere at no cost and with
+almost no restrictions whatsoever.  You may copy it, give it away or
+re-use it under the terms of the Project Gutenberg License included
+with this eBook or online at www.gutenberg.org
+
+
+
+
+
+Title: Freshwater Sponges, Hydroids & Polyzoa
+
+
+Author: Nelson Annandale
+
+
+
+Release Date: June 24, 2011  [eBook #36504]
+
+Language: English
+
+Character set encoding: ISO-646-US (US-ASCII)
+
+
+***START OF THE PROJECT GUTENBERG EBOOK FRESHWATER SPONGES, HYDROIDS &
+POLYZOA***
+
+
+E-text prepared by Bryan Ness, Carol Brown, Sharon Joiner, and
+the Online Distributed Proofreading Team (http://www.pgdp.net)
+from page images generously made available by Internet Archive
+(http://www.archive.org)
+
+
+
+Note: Project Gutenberg also has an HTML version of this
+      file which includes the original illustrations.
+      See 36504-h.htm or 36504-h.zip:
+      (http://www.gutenberg.org/files/36504/36504-h/36504-h.htm)
+      or
+      (http://www.gutenberg.org/files/36504/36504-h.zip)
+
+
+      Images of the original pages are available through
+      Internet Archive. See
+      http://www.archive.org/details/freshwatersponge00anna
+
+
+
+
+
+The Fauna of British India, Including Ceylon and Burma.
+
+Published Under the Authority of the Secretary of
+State for India in Council.
+
+Edited by A. E. Shipley, M.A., Sc.D., HON. D.Sc., F.R.S.
+
+
+FRESHWATER SPONGES, HYDROIDS & POLYZOA.
+
+by
+
+N. ANNANDALE, D.SC.,
+
+Superintendent and Trustee (_Ex Officio_) of the Indian Museum,
+Fellow of the Asiatic Society of Bengal and of the Calcutta University.
+
+
+
+
+
+
+
+London:
+Taylor and Francis, Red Lion Court, Fleet Street.
+
+Calcutta:
+Thacker, Spink, & Co.
+
+Bombay:
+Thacker & Co., Limited.
+
+Berlin:
+R. Friedlaender & Sohn, 11 Carlstrasse.
+
+August, 1911.
+
+Printed at Today & Tomorrow's Printers & Publishers, Faridabad
+
+
+
+
+CONTENTS.
+
+                                                                   Page
+
+  EDITOR'S PREFACE                                                    v
+
+  SYSTEMATIC INDEX                                                  vii
+
+  GENERAL INTRODUCTION                                                1
+    Biological Peculiarities                                          2
+    Geographical Distribution                                         5
+    Geographical List                                                 7
+    Special Localities                                               13
+    Nomenclature and Terminology                                     17
+    Material                                                         20
+
+  INTRODUCTION TO PART I. (_Spongillidae_)                           27
+    The Phylum Porifera                                              27
+    General Structure                                                29
+    Skeleton and Spicules                                            33
+    Colour and Odour                                                 35
+    External Form and Consistency                                    37
+    Variation                                                        39
+    Nutrition                                                        41
+    Reproduction                                                     41
+    Development                                                      45
+    Habitat                                                          47
+    Animals and Plants commonly associated with Freshwater Sponges   49
+    Freshwater Sponges in relation to Man                            50
+    Indian Spongillidae compared with those of other Countries       51
+    Fossil Spongillidae                                              52
+    Oriental Spongillidae not yet found in India                     52
+    History of the Study of Freshwater Sponges                       54
+    Literature                                                       55
+
+  GLOSSARY OF TECHNICAL TERMS USED IN PART I.                        61
+
+  SYSTEMATIC LIST OF THE INDIAN SPONGILLIDAE                         63
+
+  INTRODUCTION TO PART II. (_Hydrida_)                              129
+    The Phylum Coelenterata and the Class Hydrozoa                  129
+    Structure of Hydra                                              130
+    Capture and Ingestion of Prey: Digestion                        133
+    Colour                                                          134
+    Behaviour                                                       135
+    Reproduction                                                    136
+    Development of the Egg                                          139
+    Enemies                                                         139
+    Coelenterates of Brackish Water                                 139
+    Freshwater Coelenterates other than Hydra                       141
+    History of the Study of Hydra                                   142
+    Bibliography of Hydra                                           143
+
+  GLOSSARY OF TECHNICAL TERMS USED IN PART II.                      145
+
+  LIST OF THE INDIAN HYDRIDA                                        146
+
+  INTRODUCTION TO PART III. (_Ctenostomata_ and _Phylactolaemata_)  163
+    Status and Structure of the Polyzoa                             163
+    Capture and Digestion of Food: Elimination of Waste Products    166
+    Reproduction: Budding                                           168
+    Development                                                     170
+    Movements                                                       172
+    Distribution of the Freshwater Polyzoa                          173
+    Polyzoa of Brackish Water                                       174
+    History of the Study of Freshwater Polyzoa                      177
+    Bibliography of the Freshwater Polyzoa                          178
+
+  GLOSSARY OF TECHNICAL TERMS USED IN PART III.                     181
+
+  SYNOPSIS OF THE CLASSIFICATION OF THE POLYZOA                     183
+
+  SYNOPSIS OF THE SUBCLASSES, ORDERS, AND SUBORDERS                 183
+
+  SYNOPSIS OF THE LEADING CHARACTERS OF THE DIVISIONS OF
+    THE SUBORDER CTENOSTOMATA                                       185
+
+  SYSTEMATIC LIST OF THE INDIAN FRESHWATER POLYZOA                  187
+
+  APPENDIX TO THE VOLUME                                            239
+    Hints on the Preparation of Specimens                           239
+
+  ADDENDA                                                           242
+    Part I.                                                         242
+    Part II.                                                        245
+    Part III.                                                       245
+
+  ALPHABETICAL INDEX                                                249
+
+  EXPLANATION OF PLATES.
+
+
+
+
+EDITOR'S PREFACE.
+
+
+Dr. N. Annandale's volume on the Freshwater SPONGES, POLYZOA, and
+HYDRIDA contains an account of three of the chief groups of freshwater
+organisms. Although he deals mainly with Indian forms the book contains
+an unusually full account of the life-history and bionomics of
+freshwater Sponges, Polyzoa, and Hydrozoa.
+
+I have to thank Dr. Annandale for the great care he has taken in the
+preparation of his manuscript for the press, and also the Trustees of
+the Indian Museum, Calcutta, for their kindness in placing material at
+the disposal of the Author.
+
+                   A. E. SHIPLEY.
+  Christ's College, Cambridge,
+  March 1911.
+
+
+
+
+  SYSTEMATIC INDEX.
+
+
+                                            Page
+  PORIFERA.
+
+  Order HALICHONDRINA                         65
+
+  Fam. 1. SPONGILLIDAE                        65
+
+  1. Spongilla, _Lamarck_                     67
+    1A. Euspongilla, _Vejdovsky_              69
+      1.     lacustris, _auct._               69
+      1_a_.  reticulata, _Annandale_     71, 241
+      2.     proliferens, _Annandale_         72
+      3.     alba, _Carter_                   76
+      3_a_.  cerebellata, _Bowerbank_         76
+      3_b_.  bengalensis, _Annandale_         77
+      4.     cinerea, _Carter_           79, 241
+      5.     travancorica, _Annandale_        81
+      6.     hemephydatia, _Annandale_        82
+      7.     crateriformis (_Potts_)          83
+    1B. Eunapius, _J. E. Gray_                86
+      8.     carteri, _Carter_           87, 241
+      8_a_.  mollis, _Annandale_              88
+      8_b_.  cava, _Annandale_                88
+      9.     fragilis, _Leidy_                95
+      9_a_.  calcuttana, _Annandale_          96
+      9_b_.  decipiens, _Weber_               97
+     10.    gemina, _Annandale _              97
+     11.    crassissima, _Annandale_          98
+     11_a_. crassior, _Annandale_             98
+    1C. Stratospongilla, _Annandale_         100
+     12.    indica, _Annandale_              100
+     13.    bombayensis, _Carter_       102, 241
+     13_a_. pneumatica, _Annandale_          241
+     14.    ultima, _Annandale_              104
+  2. Pectispongilla, _Annandale_             106
+     15.     aurea, _Annandale_              106
+     15 _a_.  subspinosa, _Annandale_        107
+  3. Ephydatia, _Lamouroux_                  108
+     16.     meyeni (_Carter_)               108
+             fluviatilis, _auct._            242
+  4. Dosilia, _Gray_                         110
+     17.     plumosa (_Carter_)              111
+  5. Trochospongilla, _Vejdovsky_            113
+     18.     latouchiana, _Annandale_        115
+     19.     phillottiana, _Annandale_       117
+     20.     pennsylvanica (_Potts_)         118
+  6. Tubella, _Carter_                       120
+     21.     vesparioides, _Annandale_       120
+  7. Corvospongilla, _Annandale_             122
+     22.     burmanica (_Kirkpatrick_)       123
+             caunteri, _Annandale_           243
+     23.     lapidosa (_Annandale_)          124
+
+  HYDROZOA.
+
+  Order ELEUTHEROBLASTEA                     147
+
+  Fam. 1. HYDRIDAE                           147
+
+  1. Hydra, _Linne_                          147
+     24.     vulgaris, _Pallas_              148
+     25.     oligactis, _Pallas_        158, 245
+
+  POLYZOA.
+
+  Order CTENOSTOMATA                         189
+
+  Div. 1.    Vesicularina                    189
+
+  Fam. 1. VESICULARIDAE                      189
+
+  1. Bowerbankia, _Farre_                    189
+         caudata, _Hincks_                   189
+         bengalensis, _Annandale_            189
+
+  Div. 2. Paludicellina                      190
+
+  Fam. 1. PALUDICELLIDAE                     191
+
+  1. Paludicella, _Gervais_                  192
+  2. Victorella, _Kent_                      194
+     26.     bengalensis, _Annandale_        195
+
+  Fam. 2. HISLOPIIDAE                        199
+
+  1. Hislopia, _Carter_                      199
+     27.     lacustris, _Carter_             202
+     27 _a_.  moniliformis, _Annandale_      204
+
+  Order PHYLACTOLAEMATA                      206
+
+  Div. 1. Plumatellina                       206
+
+  Fam. 1. FREDERICELLIDAE                    208
+
+  1. Fredericella, _Gervais_                 208
+     28.     indica, _Annandale_        210, 245
+
+  Fam. 2. PLUMATELLIDAE                      211
+
+  Subfam. A. _Plumatellinae_                 212
+
+  1. Plumatella, _Lamarck_                   212
+     29.     fruticosa, _Allman_             217
+     30.     emarginata, _Allman_       220, 245
+     31.     javanica, _Kraepelin_           221
+     32.     diffusa, _Leidy_           223, 245
+     33.     allmani, _Hancock_         224, 246
+     34.     tanganyikae, _Rousselet_   225, 246
+     35.     punctata, _Hancock_             227
+  2. Stolella, _Annandale_                   229
+     36.     indica, _Annandale_             229
+             himalayana, _Annandale_         246
+
+  Subfam. B. _Lophopinae_                    231
+
+  1. Lophopodella, _Rousselet_               231
+     37.     carteri (_Hyatt_)               232
+     37 _a_.  himalayana (_Annandale_)       233
+  2. Pectinatella, _Leidy_                   235
+     38.     burmanica, _Annandale_          235
+
+
+
+
+GENERAL INTRODUCTION TO THE VOLUME.
+
+
+Although some zoologists have recently revived the old belief that the
+sponges and the coelenterates are closely allied, no one in recent times
+has suggested that there is any morphological relationship between
+either of these groups and the polyzoa. Personally I do not think that
+any one of the three groups is allied to any other so far as anatomy is
+concerned; but for biological reasons it is convenient to describe the
+freshwater representatives of the three groups in one volume of the
+"Fauna."
+
+Indeed, I originally proposed to the Editor that this volume should
+include an account not only of the freshwater species, but of all those
+that have been found in stagnant water of any kind. It is often
+difficult to draw a line between the fauna of brackish ponds and marshes
+and that of pure fresh water or that of the sea, and this is
+particularly the case as regards the estuarine tracts of India and
+Burma.
+
+Pelseneer[A] has expressed the opinion that the Black Sea and the
+South-east of Asia are the two districts in the world most favourable
+for the study of the origin of a freshwater fauna from a marine one. The
+transition in particular from the Bay of Bengal, which is much less salt
+than most seas, to the lower reaches of the Ganges or the Brahmaputra is
+peculiarly easy, and we find many molluscs and other animals of marine
+origin in the waters of these rivers far above tidal influence.
+Conditions are unfavourable in the rivers themselves for the development
+and multiplication of organisms of many groups, chiefly because of the
+enormous amount of silt held in suspension in the water and constantly
+being deposited on the bottom, and a much richer fauna exists in ponds
+and lakes in the neighbourhood of the rivers and estuaries than in
+running water. I have only found three species of polyzoa and three of
+sponges in running water in India, and of these six species, five have
+also been found in ponds or lakes. I have, on the other hand, found
+three coelenterates in an estuary, and all three species are essentially
+marine forms, but two have established themselves in ponds of brackish
+water, one (the sea-anemone _Sagartia schilleriana_) undergoing in so
+doing modifications of a very peculiar and interesting nature. It is not
+uncommon for animals that have established themselves in pools of
+brackish water to be found occasionally in ponds of fresh water; but I
+have not been able to discover a single instance of an estuarine species
+that is found in the latter and not in the former.
+
+     [Footnote A: "L'origine des animaux d'eau douce," Bull. de
+     l'Acad. roy. de Belgique (Classe des Sciences), No. 12,
+     1905, p. 724.]
+
+For these reasons I intended, as I have said, to include in this volume
+descriptions of all the coelenterates and polyzoa known to occur in
+pools of brackish water in the estuary of the Ganges and elsewhere in
+India, but as my manuscript grew I began to realize that this would be
+impossible without including also an amount of general introductory
+matter not justified either by the scope of the volume or by special
+knowledge on the part of its author. I have, however, given in the
+introduction to each part a list of the species found in stagnant
+brackish water with a few notes and references to descriptions.
+
+
+BIOLOGICAL PECULIARITIES OF THE SPONGES, COELENTERATES, AND POLYZOA OF
+FRESH WATER.
+
+There is often an external resemblance between the representatives of
+the sponges, coelenterates, and polyzoa that causes them to be classed
+together in popular phraseology as "zoophytes"; and this resemblance is
+not merely a superficial one, for it is based on a similarity in habits
+as well as of habitat, and is correlated with biological phenomena that
+lie deeper than what are ordinarily called habits. These phenomena are
+of peculiar interest with regard to difficult questions of nutrition and
+reproduction that perhaps can only be solved by a close study of animals
+living together in identical conditions and exhibiting, apparently in
+consequence of so living, similar but by no means identical tendencies,
+either anatomical or physiological, in certain directions.
+
+One of the most important problems on which the study of the sponges,
+coelenterates, and polyzoa of stagnant water throws light is that of the
+production of resting buds and similar reproductive bodies adapted to
+withstand unfavourable conditions in a quiescent state and to respond to
+the renewal of favourable conditions by a renewed growth and activity.
+
+Every autumn, in an English pond or lake, a crisis takes place in the
+affairs of the less highly organized inhabitants, and preparations are
+made to withstand the unfavourable conditions due directly or indirectly
+to the low winter temperature of the water: the individual must perish
+but the race may be preserved. At this season _Hydra_, which has been
+reproducing its kind by means of buds throughout the summer, develops
+eggs with a hard shell that will lie dormant in the mud until next
+spring; the phylactolaematous polyzoa produce statoblasts, the
+ctenostomatous polyzoa resting-buds ("hibernacula"), and the sponges
+gemmules. Statoblasts, hibernacula, and gemmules are alike produced
+asexually, but they resemble the eggs of _Hydra_ in being provided with
+a hard, resistant shell, and in having the capacity to lie dormant until
+favourable conditions return.
+
+In an Indian pond or lake a similar crisis takes place in the case of
+most species, but it does not take place at the same time of year in the
+case of all species. Unfortunately the phenomena of periodic
+physiological change have been little studied in the freshwater fauna of
+most parts of the country, and as yet we know very little indeed of the
+biology of the Himalayan lakes and tarns, the conditions in which
+resemble those to be found in similar masses of water in Europe much
+more closely than they do those that occur in ponds and lakes in a
+tropical plain. In Bengal, however, I have been able to devote
+considerable attention to the subject, and can state definitely that
+some species flourish chiefly in winter and enter the quiescent stage at
+the beginning of the hot weather (that is to say about March), while
+others reach their maximum development during the "rains" (July to
+September) and as a rule die down during winter, which is the driest as
+well as the coolest time of year.
+
+The following is a list of the forms that in Bengal are definitely known
+to produce hard-shelled eggs, gemmules, resting-buds, or statoblasts
+only or most profusely at the approach of the hot weather and to
+flourish during winter:--
+
+     _Spongilla carteri._
+     _Sponging alba._
+     _Spongilla alba_ var. _bengalensis_.
+     _Spongilla crassissima._
+     _Hydra vulgaris._
+     _Victorella bengalensis._
+     _Plumatella fruticosa._
+     _Plumatella emarginata._
+     _Plumatella javanica._
+
+The following forms flourish mainly during the "rains":--
+
+     _Spongilla lacustris_ subsp. _reticulata_.
+     _Trochospongilla latouchiana._
+     _Trochospongilla phillottiana._
+     _Stolella indica._
+
+The following flourish throughout the year:--
+
+     _Spongilla proliferens._
+     _Hislopia lacustris._
+
+It is particularly interesting to note that three of the species that
+flourish in the mild winter of Bengal, namely _Hydra vulgaris_,
+_Plumatella emarginata_, and _P. fruticosa_, are identical with species
+that in Europe perish in winter. There is evidence, moreover, that the
+statoblasts of the genus to which two of them belong burst more readily,
+and thus give rise to new colonies, after being subjected to a
+considerable amount of cold. In Bengal they only burst after being
+subjected to the heat of the hot weather. Does extreme heat have a
+similar effect on aquatic organisms as extreme cold? There is some
+evidence that it has.
+
+The species that flourish in India during the rains are all forms which
+habitually live near the surface or the edge of ponds or puddles, and
+are therefore liable to undergo desiccation as soon as the rains cease
+and the cold weather supervenes.
+
+The two species that flourish all the year round do not, properly
+speaking, belong to one category, for whereas _Hislopia lacustris_
+produces no form of resting reproductive body but bears eggs and
+spermatozoa at all seasons, _Spongilla proliferens_ is a short-lived
+organism that undergoes a biological crisis every few weeks; that is to
+say, it begins to develop gemmules as soon as it is fully formed, and
+apparently dies down as soon as the gemmules have attained maturity. The
+gemmules apparently lie dormant for some little time, but incessant
+reproduction is carried on by means of external buds, a very rare method
+of reproduction among the freshwater sponges.
+
+The facts just stated prove that considerable specific idiosyncrasy
+exists as regards the biology of the sponges, hydroids, and polyzoa of
+stagnant water in Bengal; but an even more striking instance of this
+phenomenon is afforded by the sponges _Spongilla bombayensis_ and
+_Corvospongilla lapidosa_ in Bombay. These two sponges resemble one
+another considerably as regards their mode of growth, and are found
+together on the lower surface of stones. In the month of November,
+however, _C. lapidosa_ is in full vegetative vigour, while _C.
+bombayensis_, in absolutely identical conditions, is already reduced to
+a mass of gemmules, having flourished during the "rains." It is thus
+clear that the effect of environment is not identical in different
+species. This is more evident as regards the groups of animals under
+consideration in India (and therefore probably in other tropical
+countries) than it is in Europe. The subject is one well worthy of study
+elsewhere than in India, for it is significant that specimens of _S.
+bombayensis_ taken in November in S. Africa were in a state of activity,
+thus contrasting strongly with specimens taken at the same time of year
+(though not at the same season from a climatic point of view) in the
+Bombay Presidency.
+
+
+GEOGRAPHICAL DISTRIBUTION OF THE INDIAN SPECIES.
+
+The geographical distribution of the lower invertebrates of fresh and of
+stagnant water is often an extremely wide one, probably because the
+individual of many species exists at certain seasons or in certain
+circumstances in a form that is not only resistant to unfavourable
+environment, but also eminently capable of being transported by wind or
+currents. We therefore find that some genera and even species are
+practically cosmopolitan in their range, while others, so far as our
+knowledge goes, appear to have an extraordinarily discontinuous
+distribution. The latter phenomenon may be due solely to our ignorance
+of the occurrence of obscure genera or species in localities in which
+they have not been properly sought for, or it may have some real
+significance as indicating that certain forms cannot always increase and
+multiply even in those localities that appear most suitable for them. As
+an example of universally distributed species we may take the European
+polyzoa of the genus _Plumatella_ that occur in India, while of species
+whose range is apparently discontinuous better examples could not be
+found than the sponges _Trochospongilla pennsylvanica_ and _Spongilla
+crateriformis_, both of which are only known from N. America, the
+British Isles, and India.
+
+My geographical list of the species of sponges, coelenterates, and
+polyzoa as yet found in fresh water in India is modelled on Col.
+Alcock's recently published list of the freshwater crabs (Potamonidae) of
+the Indian Empire[B]. I follow him in accepting, with slight
+modifications of my own, Blanford's physiographical rather than his
+zoogeographical regions, not because I think that the latter have been
+or ought to be superseded so far as the vertebrates are concerned, but
+rather because the limits of the geographical distribution of aquatic
+invertebrates appear to depend on different factors from those that
+affect terrestrial animals or even aquatic vertebrates.
+
+     [Footnote B: Cat. Ind. Dec. Crust. Coll. Ind. Mus., part i,
+     fasc. ii (Potamonidae), 1910.]
+
+"Varieties" are ignored in this list, because they are not considered to
+have a geographical significance. The parts of India that are least
+known as regards the freshwater representatives of the groups under
+consideration are the valley of the Indus, the lakes of Kashmir and
+other parts of the Himalayas, the centre of the Peninsula, and the basin
+of the Brahmaputra. Those that are best known are the districts round
+Bombay, Calcutta, Madras and Bangalore, Travancore and Northern
+Tenasserim. Little is known as regards Ceylon, and almost nothing as
+regards the countries that surround the Indian Empire, a few species
+only having been recorded from Yunnan and the Malay Peninsula, none from
+Persia, Afghanistan, or Eastern Turkestan, and only one from Tibet.
+Professor Max Weber's researches have, however, taught us something as
+regards Sumatra and Java, while the results of various expeditions to
+Tropical Africa are beginning to cast light on the lower invertebrates
+of the great lakes in the centre of that continent and of the basin of
+the Nile.
+
+It is not known to what altitude the three groups range in the Himalayas
+and the hills of Southern India. No sponge has been found in Indian
+territory at an altitude higher than that of Bhim Tal in Kumaon (4,500
+feet), and _Hydra_ is only known from the plains; but a variety of _H.
+oligactis_ was taken by Capt. F. H. Stewart in Tibet at an altitude of
+about 15,000 feet. _Plumatella diffusa_ flourishes at Gangtok in Sikhim
+(6,100 feet), and I have found statoblasts of _P. fruticosa_ in the
+neighbourhood of Simla on the surface of a pond situated at an altitude
+of about 8,000 feet; Mr. R. Kirkpatrick obtained specimens of the genus
+in the Botanical Gardens at Darjiling (6,900 feet), and two species have
+been found at Kurseong (4,500-5,000 feet) in the same district.
+
+
+GEOGRAPHICAL LIST OF THE FRESHWATER SPONGES, HYDROIDS, AND POLYZOA OF
+INDIA, BURMA, AND CEYLON.
+
+[A * indicates that a species or subspecies has only been found in one
+physiographical region or subregion so far as the Indian Empire is
+concerned; a ! that the species has also been found in Europe, a $ in
+North America, a + in Africa, and a @ in the Malay Archipelago.]
+
+1. Western Frontier Territory[C].
+
+(Baluchistan, the Punjab, and the N.W. Frontier Province.)
+
+     [Footnote C: I include Baluchistan in this territory largely
+     for climatic reasons.]
+
+  SPONGES:--
+    1. _Spongilla_ (_Eunapius_) _carteri_!@ (Lahore).
+
+  HYDROIDS:--
+    1. _Hydra oligactis_!$ (Lahore).
+
+  POLYZOA:--
+    1. _Plumatella fruticosa_!$ (Lahore).
+    2. _Plumatella diffusa_!$ (Lahore).
+
+
+2. Western Himalayan Territory.
+
+(Himalayas from Hazara eastwards as far as Nepal.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Eunapius_) _carteri_!@ (Bhim Tal).
+    2. _Ephydatia meyeni_@ (Bhim Tal).
+
+  HYDROIDS:--None known (_Hydra oligactis_ recorded from Tibet).
+
+  POLYZOA:--
+    1. _Plumatella allmani_! (Bhim Tal).
+    2. _Plumatella fruticosa_!$ (Simla).
+    3. _Lophopodella carteri_+ (Bhim Tal).
+
+
+3. North-Eastern Frontier Territory.
+
+(Sikhim, Darjiling and Bhutan, and the Lower Brahmaputra
+Drainage-System.)
+
+  SPONGES:--
+    _Spongilla proliferens_@ (Assam).
+
+  HYDROIDS:--None known.
+
+  POLYZOA:--
+    1. _Plumatella fruticosa_! (Kurseong and Assam).
+    2. _Plumatella diffusa_!$ (Sikhim).
+    3. _Plumatella javanica_@ (Kurseong).
+
+
+4. Burma Territory.
+
+(Upper Burma, Arrakan, Pegu, Tenasserim.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _proliferens_@ (Upper Burma, Pegu).
+    2. _Spongilla_ (_Euspongilla_) _crateriformis_!$ (Tenasserim).
+    3. _Spongilla_ (_Eunapius_) _carteri_!@ (Upper Burma, Pegu,
+         Tenasserim).
+    4. _Trochospongilla latouchiana_ (Tenasserim).
+    5. _Trochospongilla phillottiana_ (Tenasserim).
+    6. _Tubella vesparioides_* (Tenasserim).
+    7. _Corvospongilla  burmanica_* (Pegu).
+
+  HYDROIDS:--
+    1. _Hydra vulgaris_!$ (Upper Burma and Tenasserim).
+
+  POLYZOA:--
+    1. _Plumatella emarginata_!$ (Pegu, Upper Burma).
+    2. _Plumatella allmani_! (Tenasserim).
+    3. _Pectinatella burmanica_ (Tenasserim).
+    4. _Hislopia lacustris_ (Pegu).
+
+
+5 _a._ Peninsular Province--Main Area.
+
+(The Peninsula east of the Western Ghats.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _lacustris_ subsp. _reticulata_
+         (Orissa, Madras).
+    2. _Spongilla_ (_Euspongilla_) _proliferens_@ (Madras).
+    3. _Spongilla_ (_Euspongilla_) _alba_+ (N. Madras, Orissa, Hyderabad).
+    4. _Spongilla_ (_Euspongilla_) _hemephydatia_* (Orissa).
+    5. _Spongilla_ (_Euspongilla_) _crateriformis_!$.
+    6. _Spongilla_ (_Eunapius_) _carteri_!@.
+    7. _Spongilla_ (_Eunapius_) _gemina_* (Bangalore).
+    8. _Spongilla_ (_Stratospongilla_) _bombayensis_+ (Mysore).
+    9. _Dosilia plumosa_ (N. Madras).
+
+  HYDROIDS:--
+    1. _Hydra vulgaris_!$.
+
+  POLYZOA:--
+    1. _Plumatella fruticosa_! (Madras, Bangalore).
+    2. _Lophopus_ (?_Lophopodella_), sp. (Madras).
+    3. _Pectinatella burmanica_ (Orissa).
+    4. _Victorella bengalensis_ (Madras).
+    5. _Hislopia lacustris_ (Nagpur).
+
+
+5b. Peninsular Province--Malabar Zone.
+
+(Western Ghats from Tapti R. to Cape Comorin and eastwards
+to the sea.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _lacustris_ subsp. _reticulata_
+         (W. Ghats).
+    2. _Spongilla_ (_Euspongilla_) _proliferens_@ (Cochin).
+    3. _Spongilla_ (_Euspongilla_) _alba_+.
+    4. _Spongilla_ (_Euspongilla_) _cinerea_*.
+    5. _Spongilla_ (_Euspongilla_) _travancorica_* (Travancore).
+    6. _Spongilla_ (_Euspongilla_) _crateriformis_!$ (Cochin).
+    7. _Spongilla_ (_Eunapius_) _carteri_!@.
+    8. _Spongilla_ (_Stratospongilla_) _indica_* (W. Ghats).
+    9. _Spongilla _ (_Stratospongilla_) _bombayensis_+ (Bombay, W. Ghats).
+   10. _Spongilla_ (_Stratospongilla_) _ultima_* (Travancore).
+   11. _Pectispongilla aurea_* (Travancore, Cochin).
+   12. _Ephydatia meyeni_@ (Bombay, Travancore).
+   13. _Dosilia plumosa_ (Bombay).
+   14. _Trochospongilla pennsylvanica_*!$ (Travancore).
+   15. _Corvospongilla lapidosa_* (W. Ghats).
+
+  HYDROIDS:--None recorded.
+
+  POLYZOA:--
+    1. _Fredericella indica_* (W. Ghats and Travancore).
+    2. _Plumatella fruticosa_! (Bombay).
+    3. _Plumatella javanica_@ (Travancore).
+    4. _Plumatella tanganyikae_*+ (W. Ghats).
+    5. _Lophopodella carteri_+ (Bombay, W. Ghats).
+
+
+6. Indo-Gangetic Plain.
+
+(From Sind to the Brahmaputra.)
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _lacustris_ subsp. _reticulata_
+         (Gangetic delta).
+    2. _Spongilla_ (_Euspongilla_) _proliferens_@ (Lower Bengal, etc.).
+    3. _Spongilla_ (_Euspongilla_) _alba_+ (Lower Bengal).
+    4. _Spongilla_ (_Euspongilla_) _crateriformis_!$.
+    5. _Spongilla_ (_Eunapius_) _carteri_!@ (Lower Bengal, etc.).
+    6. _Spongilla_ (_Eunapius_) _fragilis_ subsp. _calcuttana_* (Lower
+         Bengal).
+    7. _Spongilla_ (_Eunapius_) _crassissima_ (Bengal).
+    8. _Ephydatia meyeni_@ (Lower Bengal).
+    9. _Trochospongilla latouchiana_ (Lower Bengal).
+   10. _Trochospongilla phillottiana_ (Lower Bengal).
+
+  HYDROIDS:--
+    1. _Hydra vulgaris_!$.
+
+  POLYZOA:--
+    1. _Plumatella fruticosa_!.
+    2. _Plumatella emarginata_!$.
+    3. _Plumatella javanica_@ (Lower Bengal).
+    4. _Plumatella diffusa_!$.
+    5. _Plumatella allmani_!.
+    6. _Plumatella punctata_!$ (Lower Bengal).
+    7. _Stolella indica_* (Lower Bengal, United Provinces).
+    8. _Victorella bengalensis_ (Lower Bengal).
+    9. _Hislopia lacustris_ (United Provinces, N. Bengal).
+    9a. _Hislopia lacustris_ subsp. _moniliformis_* (Lower Bengal).
+
+
+7. Ceylon.
+
+  SPONGES:--
+    1. _Spongilla_ (_Euspongilla_) _proliferens_@.
+    2. _Spongilla_ (_Eunapius_) _carteri_!@.
+
+  HYDROIDS:--
+    1. _Hydra vulgaris_!$.
+
+  POLYZOA:--
+    1. ? _Plumatella emarginata_!$.
+    2. _Pectinatella burmanica._
+
+The most striking feature of this list is the evidence it affords as to
+the distinct character of the fauna of the Malabar Zone, a feature that
+is also remarkably clear as regards the Potamonidae, one genus of which
+(_Gecarcinucus_) is peculiar, so far as India is concerned, to that
+zone. As regards the sponges we may note the occurrence of no less than
+three species of the subgenus _Stratospongilla_, which has not been
+found elsewhere in India except on one occasion in Mysore, and of a
+species of the genus _Corvospongilla_, which is unknown from the rest of
+Peninsular India and from the Himalayas. The genus _Pectispongilla_ is
+only known from the Malabar Zone. Among the polyzoa the genus
+_Fredericella_[D] appears to be confined, so far as the Indian and
+Burmese fauna is concerned, to the Malabar Zone, and the same is true as
+regards the group of species to which _Plumatella tanganyikae_, an
+African form, belongs.
+
+     [Footnote D: Mr. S. W. Kemp recently obtained at Mangaldai,
+     near the Bhutan frontier of Assam, a single specimen of what
+     may be a species of _Fredericella_.]
+
+A further examination of the list of Malabar species and a consideration
+of allied forms shows that the majority of the forms restricted to the
+Malabar Zone are either African or else closely allied to African forms.
+The genus _Corvospongilla_, except for one Burmese species, is otherwise
+peculiar to Tropical Africa; while _Stratospongilla_, although not
+confined to Africa, is more prolific in species in that continent than
+in any other. _Spongilla (Stratospongilla) bombayensis_ has only been
+found in Bombay, the Western Ghats, Mysore, and Natal, and _Plumatella
+tanganyikae_ only in the Western Ghats and Central Africa. The genus
+_Fredericella_ (which also occurs in Europe, N. America, and Australia)
+is apparently of wide distribution in Africa, while _Lophopodella_
+(which in India is not confined to the Malabar Zone) is, except for a
+Japanese race of the Indian species, restricted outside India, so far as
+we know, to East Africa.
+
+A less definite relationship between the sponges and polyzoa of the
+Malabar Zone and those of countries to the east of India is suggested by
+the following facts:--
+
+     (1) The occurrence of the genus _Corvospongilla_ in Burma;
+
+     (2) the occurrence of the subgenus _Stratospongilla_ in
+     Sumatra, China, and the Philippines;
+
+     (3) the occurrence of a race of _Lophopodella carteri_ in
+     Japan;
+
+     (4) the occurrence of a species allied to _Plumatella
+     tanganyikae_ in the Philippines.
+
+It will be noted that in each of these instances the relationship
+extends to Africa as well as to the Eastern countries, and is more
+marked in the former direction. The species of _Stratospongilla_,
+moreover, that occurs in Sumatra (_S. sumatrensis_) also occurs in
+Africa, while those that have been found in China and the Philippines
+are aberrant forms.
+
+At first sight it might appear that these extra-Indian relationships
+might be explained by supposing that gemmules and statoblasts were
+brought to the Malabar Coast from Africa by the aerial currents of the
+monsoon or by marine currents and carried from India eastwards by the
+same agency, this agency being insufficient to transport them to the
+interior and the eastern parts of the Peninsula. The work of La
+Touche[E] on wind-borne foraminifera in Rajputana is very suggestive in
+this direction; but that the peculiar sponge and polyzoon fauna of
+Malabar is due to the agency either of wind or of marine currents may be
+denied with confidence, for it is a striking fact that most of the
+characteristic genera and subgenera of the Zone have resting
+reproductive bodies that are either fixed to solid objects or else are
+devoid of special apparatus to render them light. The former is the case
+as regards all species of _Corvospongilla_ and all Indian and most other
+species of _Stratospongilla_, the gemmules of which not only are
+unusually heavy but also adhere firmly; while the statoblasts of
+_Fredericella_ have no trace of the air-cells that render the free
+statoblasts of all other genera of phylactolaematous polyzoa peculiarly
+light and therefore peculiarly liable to be transported by wind.
+
+     [Footnote E: See Mem. Geol. Surv. Ind. XXXV (1), p. 39
+     (1902).]
+
+A true geographical or geological explanation must therefore be sought
+for the relationship between the sponges and polyzoa of Malabar, of
+Africa, and of the Eastern countries--a relationship that is well known
+to exist as regards other groups of animals. No more satisfactory
+explanation has as yet been put forward than that of a former land
+connection between Africa and the Malaysia through Malabar at a period
+(probably late Cretaceous) when the Western Ghats were much higher than
+they now are[F].
+
+     [Footnote F: See Ortmann, "The Geographical Distribution of
+     Freshwater Decapods and its bearing upon Ancient Geography,"
+     Proc. Amer. Phil. Soc. xli, p. 380, fig. 6 (1902); also
+     Suess, "The Face of the Earth" (English ed.) i, p. 416
+     (1904).]
+
+There is little to be said as regards the distribution of the sponges,
+hydroids, and polyzoa of fresh water in other parts of India. It may be
+noted, however, that the species known from the Punjab are all widely
+distributed Palaearctic forms, and that the genus _Stolella_ is
+apparently confined to the Indo-Gangetic Plain. Two species of sponge
+are peculiar to Lower Burma, one of them (_Corvospongilla burmanica_)
+representing the geographical alliance already discussed as regards the
+Malabar Zone, the other (_Tubella vesparioides_) closely related to a
+Malaysian species (_T. vesparium_ from Borneo) and perhaps representing
+the northern limit of the Malaysian element well known in the fauna of
+Lower Burma. Of the sponges and polyzoa of Ceylon we know as yet too
+little to make it profitable to discuss their affinities. All that have
+as yet been discovered occur also in Peninsular India; nor do they
+afford any evidence of a connection with the Malabar Zone.
+
+The question of the geographical range of the sponges, hydroids, and
+polyzoa of brackish water may be considered briefly, for it is of
+importance in considering that of those which are confined to fresh
+water. Some of these species from brackish water (e. g., _Membranipora
+lacroixii_) are identical with others (e. g., _Victorella bengalensis_
+and _Bowerbankia caudata_ subsp. _bengalensis_) closely related to
+European forms. Others again (e. g., _Loxosomatoides colonialis_ and
+_Sagartia schilleriana_) are known as yet from the Ganges delta only. In
+our ignorance of the Indian representatives of the groups to which they
+belong, it is impossible to assert that their distribution is actually
+so restricted as it seems.
+
+
+SOME SPECIAL LOCALITIES.
+
+In order to avoid constant repetition as regards the conditions that
+prevail at the places most frequently mentioned in this volume, a few
+details as regards them may be conveniently stated here.
+
+_Lower Bengal._
+
+CALCUTTA is situated on the River Hughli at a point about 90 miles from
+the open sea. The water of the river is practically fresh, but is
+strongly affected by the tides; it is always turbid and of a brownish
+colour. The river, however, is not a good collecting ground for sponges,
+coelenterates, and polyzoa, and none of the species described in this
+volume have been obtained from it. It is in the Calcutta "tanks" that
+most of my investigations have been made. These tanks are ponds, mostly
+of artificial origin, very numerous, of varying size but never very
+large or deep. Most of them contain few solid objects to which sedentary
+organisms can fix themselves, and such ponds are of course poor in
+sponges and polyzoa. Others, however, support a prolific growth of weeds
+such as _Pistia stratiotes_, _Lemna_, and _Limnanthemum_, and a few have
+brickwork or artificial stonework at their sides. In those parts of the
+town that approach the Salt Lakes (large lagoons and swamps of brackish
+water connected with the sea by the Mutlah River) the water of the ponds
+is slightly brackish and permits few plants except algae to flourish. Few
+of the bigger tanks ever dry up. The best of the tanks from the
+sponge-collector's point of view, so far as I have been able to
+discover, is the one in the compound of the Indian Museum. It enjoys all
+the advantages of light and shade, solid supports, prolific aquatic
+vegetation, considerable depth, and the vicinity of human dwellings that
+seem to be favourable to the growth of sponges, no less than nine
+species of which, representing three genera and two subgenera, grow
+abundantly in it. _Hydra_ also flourishes in this pond, but for some
+reasons there are few polyzoa. The phylactolaematous species of the
+latter group, however, are extraordinarily abundant in one of the tanks
+in the Zoological Gardens at Alipore. In this tank, which unlike the
+Museum tank is directly connected with the river, no less than six
+species and varieties of the genus _Plumatella_ have been found growing
+together on sticks, floating seeds, and water-plants. Except _Hislopia_,
+which is common on _Vallisneria_ in one tank on the Maidan (opposite the
+Bengal Club), the ctenostomes of stagnant water are only found in the
+tanks near the Salt Lakes.
+
+PORT CANNING is situated on the Mutlah River about 30 miles from
+Calcutta and about 60 from the open sea. The Mutlah is really a tidal
+creek rather than a river, in spite of the fact that it runs for a
+considerable number of miles, and its waters are distinctly brackish.
+Water taken from the edge at Port Canning in March was found to contain
+25.46 per thousand of saline residue. The interesting feature of Port
+Canning, however, is from a zoological point of view not the Mutlah but
+certain ponds of brackish water now completely separated from it, except
+occasionally when the river is in flood, but communicating regularly
+with it in the memory of living persons. These ponds, which were
+apparently not in existence in 1855, have on an average an area of about
+half an acre each, and were evidently formed by the excavation of earth
+for the construction of an embankment along the Mutlah. They are very
+shallow and lie exposed to the sun. The salinity differs considerably in
+different ponds, although the fauna seems to be identical; the water of
+one pond was found to contain 22.88 per thousand of saline residue in
+May, 20.22 per thousand in March, and 12.13 in December. A second pond
+in the neighbourhood of the first and apparently similar to it in every
+way contained only 9.82 per thousand in July, after the rains had
+broken. The fauna of these ponds includes not only a freshwater sponge
+(_Spongilla alba_ var. _bengalensis_) but also many aquatic insects
+(_e. g._, larvae of mosquitos and of _Chironomus_ and several species of
+beetles and Rhynchota); while on the other hand essentially marine
+coelenterates (_Irene ceylonensis_, etc.) and worms (_e. g._, the
+gephyrean _Physcosoma lurco_[G]) form a part of it, together with forms
+of intermediate habitat such as _Bowerbankia caudata_ subsp.
+_bengalensis_, _Victorella bengalensis_, and several fish and crustacea
+common in brackish water.
+
+     [Footnote G: I am indebted to Mr. W. F. Lanchester for the
+     identification of this species.]
+
+_Orissa._
+
+Orissa may be described in general terms as consisting of the coastal
+area of Bengal south of the Gangetic delta. It extends in inland,
+however, for a considerable distance and includes hilly tracts. There is
+no geographical boundary between it and the north-eastern part of the
+Madras Presidency or the eastern part of the Central Provinces.
+
+CHILKA LAKE.--This marine lake is a shallow lagoon measuring about 40
+miles in length and 10 miles in breadth, and formed in geologically
+recent times by the growth of a narrow sand-bank across the mouth of a
+wide bay. At its northern end it communicates with the sea by a narrow
+channel, and throughout its length it is strongly affected by the tides.
+At its south end, which is actually situated in the Ganjam district of
+Madras, the water is distinctly brackish and is said to be nearly fresh
+at certain times of year. At this end there are numerous small
+artificial pools of brackish water somewhat resembling those of Port
+Canning as regards their fauna.
+
+SUR (or SAR) LAKE.--A shallow, freshwater lake of very variable size
+situated a few miles north of Puri on the Orissa coast. In origin it
+probably resembled the Chilka Lake, but it is now separated from the sea
+by about 3 miles of barren sand dunes, among which numerous little pools
+of rain-water are formed during the rains. These dry up completely in
+winter, and even the lake itself is said sometimes almost to disappear,
+although when it is full it is several miles in length. The fauna is
+essentially a freshwater one, but includes certain Mysidae and other
+crustacea usually found in brackish water.
+
+_Bombay Presidency._
+
+BOMBAY.--The town of Bombay, built on an island near the mainland, is
+situated close to swamps and creeks of brackish water not unlike those
+that surround Calcutta. Its "tanks," however, differ from those of
+Calcutta in having rocky bottoms and, in many cases, in drying up
+completely in the hot weather. Of the fauna of the swamps extremely
+little is known, but so far as the sponges and polyzoa of the tanks are
+concerned the work undertaken by Carter was probably exhaustive.
+
+IGATPURI.--Igatpuri is situated at an altitude of about 2000 feet, 60
+miles north-east of Bombay. Above the town there is a lake of several
+square miles in area whence the water-supply of several stations in the
+neighbourhood is obtained. The water is therefore kept free from
+contamination. The bottom is composed of small stones and slopes
+gradually up at the edges. During the dry weather its level sinks
+considerably. Several interesting sponges and polyzoa have been found in
+this lake, most of them also occurring in a small pond in the
+neighbourhood in which clothes are washed and the water is often full of
+soap-suds.
+
+_Southern India._
+
+MADRAS.--The city of Madras is built by the sea, straggling over a large
+area of the sandy soil characteristic of the greater part of the east
+coast of India. In wet weather this soil retains many temporary pools of
+rain-water, and there are numerous permanent tanks of no great size in
+the neighbourhood of the town. The so-called Cooum River, which flows
+through the town, is little more than a tidal creek, resembling the
+Mutlah River of Lower Bengal on a much smaller scale. The sponges and
+polyzoa as yet found in the environs of Madras are identical with those
+found in the environs of Calcutta.
+
+BANGALORE.--Bangalore (Mysore State) is situated near the centre of the
+Madras Presidency on a plateau about 3000 feet above sea-level. The
+surrounding country is formed of laterite rock which decomposes readily
+and forms a fine reddish silt in the tanks. These tanks are numerous,
+often of large size, and as a rule at least partly of artificial origin.
+Their water supports few phanerogamic plants and is, as my friend Dr.
+Morris Travers informs me, remarkably free from salts in solution. The
+sponge fauna of the neighbourhood of Bangalore appears to be
+intermediate between that of Madras and that of Travancore.
+
+THE BACKWATERS OF COCHIN AND TRAVANCORE.--The "backwaters" of Cochin and
+Travancore were originally a series of shallow lagoons stretching along
+the coast of the southern part of the west coast of India for a distance
+of considerably over a hundred miles. They have now been joined together
+by means of canals and tunnels to form a tidal waterway, which
+communicates at many points directly with the sea. The salinity of the
+water differs greatly at different places and in different seasons, and
+at some places there is an arrangement to keep out sea-water while the
+rice-fields are being irrigated. The fauna is mainly marine, but in the
+less saline parts of the canals and lakes many freshwater species are
+found.
+
+_Shasthancottah._--There are two villages of this name, one situated on
+the backwater near Quilon (coast of Travancore), the other about three
+miles inland on a large freshwater lake. This lake, which does not
+communicate with the backwater, occupies a narrow winding rift several
+miles in length at a considerable depth below the surrounding country.
+Its bottom is muddy and it contains few water-plants, although in some
+places the water-plants that do exist are matted together to form
+floating islands on which trees and bushes grow. The fauna, at any rate
+as regards mollusca and microscopic organisms, is remarkably poor, but
+two species of polyzoa (_Fredericella indica_ and _Plumatella
+fruticosa_) and one of sponge (_Trochospongilla pennsylvanica_) grow in
+considerable abundance although not in great luxuriance.
+
+_The Himalayas._
+
+BHIM TAL[H] is a lake situated at an altitude of 4500 feet in that part
+of the Western Himalayas known as Kumaon, near the plains. It has a
+superficial area of several square miles, and is deep in the middle. Its
+bottom and banks are for the most part muddy. Little is known of its
+fauna, but two polyzoa (_Plumatella allmani_ and _Lophopodella carteri_)
+and the gemmules of two sponges (_Spongilla carteri_ and _Ephydatia
+meyeni_) have been found in it.
+
+     [Footnote H: The fauna of this lake and of others in the
+     neighbourhood has recently been investigated by Mr. S. W.
+     Kemp. See the addenda at the end of this volume.--_June
+     1911._]
+
+       *     *     *     *     *
+
+NOMENCLATURE AND TERMINOLOGY.
+
+The subject of nomenclature may be considered under four heads:--(I.)
+the general terminology of the various kinds of groups of individuals
+into which organisms must be divided; (II.) the general nomenclature of
+specimens belonging to particular categories, such as types, co-types,
+etc.; (III.) the nomenclature that depends on such questions as that of
+"priority"; and (IV.) the special terminology peculiar to the different
+groups. The special terminology peculiar to the different groups is
+dealt with in the separate introductions to each of the three parts of
+this volume.
+
+
+(I.)
+
+No group of animals offers greater difficulty than the sponges,
+hydroids, and polyzoa (and especially the freshwater representatives of
+these three groups) as regards the question "What is a species?" and the
+kindred questions, "What is a subspecies?" "What is a variety?" and
+"What is a phase?" Genera can often be left to look after themselves,
+but the specific and kindred questions are answered in so many different
+ways, if they are even considered, by different systematists, especially
+as regards the groups described in this volume, that I feel it necessary
+to state concisely my own answers to these questions, not for the
+guidance of other zoologists but merely to render intelligible the
+system of classification here adopted. The following definitions should
+therefore be considered in estimating the value of "species," etc.,
+referred to in the following pages.
+
+_Species._--A group of individuals differing in constant characters of a
+definite nature and of systematic[I] importance from all others in the
+same genus.
+
+     [Footnote I: "What characters are of systematic importance?"
+     is a question to which different answers must be given in
+     the case of different groups.]
+
+_Subspecies._--An isolated or local race, the individuals of which
+differ from others included in the same species in characters that are
+constant but either somewhat indefinite or else of little systematic
+importance.
+
+_Variety._--A group of individuals not isolated geographically from
+others of the same species but nevertheless exhibiting slight, not
+altogether constant, or indefinite differences from the typical form of
+the species (_i. e._, the form first described).
+
+_Phase._--A peculiar form assumed by the individuals of a species which
+are exposed to peculiarities in environment and differ from normal
+individuals as a direct result.
+
+There are cases in which imperfection of information renders it
+difficult or impossible to distinguish between a variety and a
+subspecies. In such cases it is best to call the form a variety, for
+this term does not imply any special knowledge as regards its
+distribution or the conditions in which it is found.
+
+I use the term "form" in a general sense of which the meaning or
+meanings are clear without explanation.
+
+
+(II.)
+
+The question of type specimens must be considered briefly. There are two
+schools of systematists, those who assert that one specimen and one only
+must be the type of a species, and those who are willing to accept
+several specimens as types. From the theoretical point of view it seems
+impossible to set up any one individual as the ideal type of a species,
+but those who possess collections or are in charge of museums prefer,
+with the natural instinct of the collector, to have a definite single
+type (of which no one else can possibly possess a duplicate) in their
+possession or care, and there is always the difficulty that a zoologist
+in describing a species, if he recognizes more than one type, may
+include as types specimens that really belong to more than one species.
+These difficulties are met by some zoologists by the recognition of
+several specimens as paratypes, all of equal value; but this, after all,
+is merely a terminological means of escaping from the difficulty,
+calculated to salve the conscience of a collector who feels unwilling to
+give up the unique type of a species represented by other specimens in
+his collection. The difficulty as regards the confounding of specimens
+of two or more species as the types of one can always be adjusted if the
+author who discovers the mistake redescribes one of the species under
+the original name and regards the specimen that agrees with his
+description as the type, at the same time describing a new species with
+another of the specimens as its type. Personally I always desire to
+regard the whole material that forms the basis of an original
+description of a species as the type, but museum rules often render this
+impossible, and the best that can be done is to pick out one specimen
+that seems particularly characteristic and to call it the type, the rest
+of the material being termed co-types. A peculiar difficulty arises,
+however, as regards many of the sponges, coelenterates, and polyzoa,
+owing to the fact that they are often either compound animals, each
+specimen consisting of more than one individual, or are easily divisible
+into equivalent fragments. If the single type theory were driven to its
+logical conclusion, it would be necessary to select one particular polyp
+in a hydroid colony, or even the part of a sponge that surrounded a
+particular osculum as the type of the species to which the hydroid or
+the sponge belonged. Either by accident or by design specimens of
+Spongillidae, especially if kept dry, are usually broken into several
+pieces. There is, as a matter of fact, no reason to attribute the
+peculiarly sacrosanct nature of a type to one piece more than another.
+In such cases the biggest piece may be called the type, while the
+smaller pieces may be designated by the term "schizotype."
+
+The more precise definition of such terms as topotype, genotype, _et
+hujus generis omnis_ is nowadays a science (or at any rate a form of
+technical industry) by itself and need not be discussed here.
+
+
+(III.)
+
+In 1908 an influential committee of British zoologists drew up a
+strenuous protest against the unearthing of obsolete zoological names
+(see 'Nature,' Aug. 1908, p. 395). To no group does this protest apply
+with greater force than to the three discussed in this volume. It is
+difficult, however, to adopt any one work as a standard of nomenclature
+for the whole of any one of them. As regards the Spongillidae it is
+impossible to accept any monograph earlier than Potts's "Fresh-Water
+Sponges" (P. Ac. Philad., 1887), for Bowerbank's and Carter's earlier
+monographs contained descriptions of comparatively few species. Even
+Potts's monograph I have been unable to follow without divergence, for
+it seems to me necessary to recognize several genera and subgenera that
+he ignored. The freshwater polyzoa, however, were dealt with in so
+comprehensive a manner by Allman in his "Fresh-Water Polyzoa" (London,
+1856) that no difficulty is experienced in ignoring, so far as
+nomenclature is concerned, any earlier work on the group; while as
+regards other divisions of the polyzoa I have followed Hincks's "British
+Marine Polyzoa" (1880), so far as recent researches permit. In most
+cases I have not attempted to work out an elaborate synonymy of species
+described earlier than the publication of the works just cited, for to
+do so is a mere waste of time in the case of animals that call for a
+most precise definition of species and genera and yet were often
+described, so far as they were known earlier than the dates in question,
+in quite general terms. I have been confirmed in adopting this course by
+the fact that few of the types of the earlier species are now in
+existence, and that a large proportion of the Indian forms have only
+been described within the last few years.
+
+
+MATERIAL.
+
+The descriptions in this volume are based on specimens in the collection
+of the Indian Museum, the Trustees of which, by the liberal manner in
+which they have permitted me to travel in India and Burma on behalf of
+the Museum, have made it possible not only to obtain material for study
+and exchange but also to observe the different species in their natural
+environment. This does not mean to say that specimens from other
+collections have been ignored, for many institutions and individuals
+have met us generously in the matter of gifts and exchanges, and our
+collection now includes specimens of all the Indian forms, named in
+nearly all cases by the author of the species, except in those of
+species described long ago of which no authentic original specimens can
+now be traced. Pieces of the types of all of the Indian Spongillidae
+described by Carter have been obtained from the British Museum through
+the kind offices of Mr. R. Kirkpatrick. The Smithsonian Institution has
+sent us from the collection of the United States National Museum
+specimens named by Potts, and the Berlin Museum specimens named by
+Weltner, while to the Imperial Academy of Sciences of St. Petersburg we
+owe many unnamed but interesting sponges. Dr. K. Kraepelin and Dr. W.
+Michaelsen have presented us with specimens of most of the species and
+varieties of freshwater polyzoa described by the former in his great
+monograph and elsewhere. We owe to Dr. S. F. Harmer, formerly of the
+Cambridge University Museum and now Keeper in Zoology at the British
+Museum, to Professor Max Weber of Amsterdam, Professor Oka of Tokyo, and
+several other zoologists much valuable material. I would specially
+mention the exquisite preparations presented by Mr. C. Rousselet.
+Several naturalists in India have also done good service to the Museum
+by presenting specimens of the three groups described in this volume,
+especially Major H. J. Walton, I.M.S., Major J. Stephenson, I.M.S., Dr.
+J. R. Henderson and Mr. G. Matthai of Madras, and Mr. R. Shunkara
+Narayana Pillay of Trivandrum.
+
+The following list shows where the types of the various species,
+subspecies, and varieties are preserved, so far as it has been possible
+to trace them. I have included in this list the names of all species
+that have been found in stagnant water, whether fresh or brackish, but
+those of species not yet found in fresh water are enclosed in square
+brackets.
+
++-----------------------------------------------------------------------+
+|                       INDIAN SPONGILLIDAE.                            |
+|                                                                       |
++---------------------------------+----------------------+--------------+
+|         NAME.                   |   TYPE IN COLL.      |  MATERIAL    |
+|                                 |                      |  EXAMINED.   |
++---------------------------------+----------------------+--------------+
+| _Spongilla lacustris_ subsp.    | Ind. Mus.            |    Type.     |
+| _reticulata_                    |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla proliferens_         |   "   "              |       "      |
++---------------------------------+----------------------+--------------+
+| _Spongilla alba_                | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| [_Spongilla alba_ var.          | Ind. Mus.            |     Type     |
+| _bengalensis_]                  |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla alba_ var.           | Brit. Mus.           | {Specimens   |
+| _cerebellata_                   |                      | {compared    |
+|                                 |                      | {with type.  |
++---------------------------------+----------------------+--------------+
+| _Spongilla cinerea_             | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| [_Spongilla travancorica_]      | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Spongilla hemephydatia_        |   "     "            |      "       |
++---------------------------------+----------------------+--------------+
+| _Spongilla crateriformis_       | U.S. Nat. Mus.       |   Co-type.   |
++---------------------------------+----------------------+--------------+
+| _Spongilla carteri_             | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| _Spongilla carteri_ var.        | Ind. Mus.            |    Type.     |
+| _mollis_                        |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla carteri_ var.        |  "     "             |      "       |
+| _cava_                          |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla carteri_ var.        |  "     "             |      "       |
+| _lobosa_                        |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla fragilis_ subsp.     |  "     "             |      "       |
+| _calcuttana_                    |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla fragilis_ subsp.     | Amsterdam Mus.       |   Co-type.   |
+| _decipiens_                     |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla gemina_              | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Spongilla crassissima_         |  "     "             |      "       |
++---------------------------------+----------------------+--------------+
+| _Spongilla crassissima_ var.    |  "     "             |      "       |
+| _crassior_                      |                      |              |
++---------------------------------+----------------------+--------------+
+| _Spongilla bombayensis_         | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| _Spongilla indica_              | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Spongilla ultima_              |  "    "              |      "       |
++---------------------------------+----------------------+--------------+
+| _Pectispongilla aurea_          |  "    "              |      "       |
++---------------------------------+----------------------+--------------+
+| _Ephydatia meyeni_              | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| _Dosilia plumosa_               |  "   "  "   "        |      "       |
++---------------------------------+----------------------+--------------+
+| _Trochospongilla latouchiana_   | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Trochospongilla phillottiana_  |  "    "              |      "       |
++---------------------------------+----------------------+--------------+
+| _Trochospongilla pennsylvanica_ | U.S. Nat. Mus.       |   Co-type.   |
++---------------------------------+----------------------+--------------+
+| _Tubella vesparioides_          | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Corvospongilla burmanica_      | Brit. and Ind. Mus.  | Schizotype.  |
++---------------------------------+----------------------+--------------+
+| _Corvospongilla lapidosa_       | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+|               INDIAN COELENTERATES OF STAGNANT WATER.                 |
++---------------------------------+----------------------+--------------+
+|          HYDROZOA.              |                      |              |
++---------------------------------+----------------------+--------------+
+| _Hydra oligactis_               | Not in existence.    |              |
++---------------------------------+----------------------+--------------+
+| _Hydra vulgaris_                |  "    "              |              |
++---------------------------------+----------------------+--------------+
+| [_Syncoryne filamentata_]       | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| [_Bimeria vestita_]             | ? Not in existence.  |              |
++---------------------------------+----------------------+--------------+
+| [_Irene ceylonensis_]           |  {Hydroid in Ind.}   | Hydroid type |
+|                                 |  {Mus.,  Medusa}     |              |
+|                                 |  {in Brit. Mus.}     |              |
++---------------------------------+----------------------+--------------+
+|         ACTINIARIA.             |                      |              |
++---------------------------------+----------------------+--------------+
+| [_Sagartia schilleriana_]       | Ind. Mus.            |    Types.    |
++---------------------------------+----------------------+--------------+
+| [_Sagartia schilleriana_        |  "    "              |      "       |
+| subsp. _exul_]                  |                      |              |
++---------------------------------+----------------------+--------------+
+|                   INDIAN POLYZOA OF STAGNANT WATER.                   |
++---------------------------------+----------------------+--------------+
+|       ENTOPROCTA.               |                      |              |
++---------------------------------+----------------------+--------------+
+| [_Loxosomatoides colonialis_]   | Ind. Mus.            |    Types.    |
++---------------------------------+----------------------+--------------+
+|   ECTOPROCTA CHEILOSTOMATA.     |                      |              |
++---------------------------------+----------------------+--------------+
+| [_Membranipora lacroixii_]      | ? Paris Mus.         |              |
++---------------------------------+----------------------+--------------+
+| [_Membranipora bengalensis_]    | Ind. Mus.            |    Types.    |
++---------------------------------+----------------------+--------------+
+|   ECTOPROCTA STENOSTOMATA.      |                      |              |
++---------------------------------+----------------------+--------------+
+| [_Bowerbankia caudata_ subsp.   | Ind. Mus.            |    Types.    |
+| _bengalensis_]                  |                      |              |
++---------------------------------+----------------------+--------------+
+| _Victorella bengalensis_        |  "    "              |      "       |
++---------------------------------+----------------------+--------------+
+| _Hislopia lacustris_            | ? Not in existence.  |              |
++---------------------------------+----------------------+--------------+
+| _Hislopia lacustris_ subsp.     | Ind. Mus.            |      "       |
+| _moniliformis_                  |                      |              |
++---------------------------------+----------------------+--------------+
+|   ECTOPROCTA PHYLACTOLAEMATA.   |                      |              |
++---------------------------------+----------------------+--------------+
+| _Fredericella indica_           | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Plumatella fruticosa_          | Not in existence.    |              |
++---------------------------------+----------------------+--------------+
+| _Plumatella diffusa_            |?Philadelphia Acad.[J]|              |
++---------------------------------+----------------------+--------------+
+| _Plumatella allmani_            | Not in existence.    |              |
++---------------------------------+----------------------+--------------+
+| _Plumatella emarginata_         |  "        "          |              |
++---------------------------------+----------------------+--------------+
+|                                 | {Hamburg and}        | One of the   |
+| _Plumatella javanica_           | {Ind.  Mus. }        | types.       |
++---------------------------------+----------------------+--------------+
+|                                 | {Brit. and Ind.}     | One of the   |
+| _Plumatella tanganyikae_        | {Mus.          }     | types.       |
++---------------------------------+----------------------+--------------+
+| _Stolella indica_               | Ind. Mus.            |    Type.     |
++---------------------------------+----------------------+--------------+
+| _Lophopodella carteri_          | Brit. Mus.           |      "       |
++---------------------------------+----------------------+--------------+
+| _Lophopodella carteri_ var.     | Ind. Mus.            |      "       |
+| _himalayana_                    |                      |              |
++---------------------------------+----------------------+--------------+
+| _Pectinatella burmanica_        | Ind. Mus.            |       "      |
++---------------------------------+----------------------+--------------+
+
+     [Footnote J: I have failed to obtain from the Philadelphia
+     Academy of Science a statement that the type of this species
+     is still in existence.]
+
+
+The literature dealing with the various groups described in the volume
+is discussed in the introductions to the three parts. Throughout the
+volume I have, so far as possible, referred to works that can be
+consulted in Calcutta in the libraries of the Indian Museum, the
+Geological Survey of India, or the Asiatic Society of Bengal. The names
+of works that are not to be found in India are marked with a *. The
+rarity with which this mark occurs says much for the fortunate position
+in which zoologists stationed in Calcutta find themselves as regards
+zoological literature, for I do not think that anything essential has
+been omitted.
+
+It remains for me to express my gratitude to those who have assisted me
+in the preparation of this volume. The names of those who have
+contributed specimens for examination have already been mentioned. I
+have to thank the Trustees of the Indian Museum not only for their
+liberal interpretation of my duties as an officer of the Museum but also
+for the use of all the drawings and photographs and some of the blocks
+from which this volume is illustrated. Several of the latter have
+already been used in the "Records of the Indian Museum." From the Editor
+of the "Fauna" I have received valuable suggestions, and I am indebted
+to Dr. Weltner of the Berlin Museum for no less valuable references to
+literature. Mr. F. H. Gravely, Assistant Superintendent in the Indian
+Museum, has saved me from several errors by his criticism.
+
+The majority of the figures have been drawn by the draftsmen of the
+Indian Museum, Babu Abhoya Charan Chowdhary, and of the Marine Survey of
+India, Babu Shib Chandra Mondul, to both of whom I am much indebted for
+their accuracy of delineation.
+
+No work dealing with the sponges of India would be complete without a
+tribute to the memory of H. J. Carter, pioneer in the East of the study
+of lower invertebrates, whose work persists as a guide and an
+encouragement to all of us who are of the opinion that biological
+research on Indian animals can only be undertaken in India, and that
+even systematic zoological work can be carried out in that country with
+success. I can only hope that this, the first volume in the official
+Fauna of the Indian Empire to be written entirely in India, may prove
+not unworthy of his example.
+
+Indian Museum, Calcutta      Oct. 23rd, 1910.
+
+
+
+
+PART I.
+
+FRESHWATER SPONGES
+
+(SPONGILLIDAE).
+
+
+
+
+INTRODUCTION TO PART I.
+
+
+I.
+
+THE PHYLUM PORIFERA.
+
+The phylum Porifera or Spongiae includes the simplest of the Metazoa or
+multicellular animals. From the compound Protozoa its members are
+distinguished by the fact that the cells of which they are composed
+exhibit considerable differentiation both in structure and in function,
+and are associated together in a definite manner, although they are not
+combined to form organs and systems of organs as in the higher Metazoa.
+Digestion, for instance, is performed in the sponges entirely by
+individual cells, into the substance of which the food is taken, and the
+products of digestion are handed on to other cells without the
+intervention of an alimentary canal or a vascular system, while there is
+no structure in any way comparable to the nervous system of more highly
+organized animals.
+
+The simplest form of sponge, which is known as an olynthus, is a hollow
+vase-like body fixed at one end to some solid object, and with an
+opening called the osculum at the other. The walls are perforated by
+small holes, the pores, from which the name Porifera is derived.
+
+Externally the surface is protected by a delicate membrane formed of
+flattened cells and pierced by the pores, while the interior of the vase
+is covered with curious cells characteristic of the sponges, and known
+as choanocytes or collar-cells. They consist of minute oval or
+pear-shaped bodies, one end of which is provided with a rim or collar of
+apparently structureless membrane, while a flagellum or whip-like lash
+projects from the centre of the surface surrounded by the collar. These
+collar-cells are practically identical with those of which the Protozoa
+known as Choanoflagellata consist; but it is only in the sponges[K] that
+they are found constantly associated with other cells unlike themselves.
+
+     [Footnote K: Except in "_Proterospongia_," an organism of
+     doubtful affinities but not a sponge. It consists of a mass
+     of jelly containing ordinary cells, with collar-cells
+     _outside_.]
+
+In addition to the collar-cells, which form what is called the gastral
+layer, and the external membrane (the derma or dermal membrane), the
+sponge contains cells of various kinds embedded in a structureless
+gelatinous substance, through which they have the power of free
+movement. Most of these cells have also the power of changing their form
+in an "amoeboid" manner; that is to say, by projecting and withdrawing
+from their margin mobile processes of a more or less finger-like form,
+but unstable in shape or direction. The protoplasm of which some of the
+cells are formed is granular, while that of others is clear and
+translucent. Some cells, which (for the time being at any rate) do not
+exhibit amoeboid movements, are glandular in function, while others
+again give rise in various ways to the bodies by means of which the
+sponge reproduces its kind. There is evidence, however, that any one
+kind of cell, even those of the membrane and the gastral layer, can
+change its function and its form in case of necessity.
+
+Most sponges possess a supporting framework or skeleton. In some it is
+formed entirely of a horny substance called spongin (as in the
+bath-sponge), in others it consists of spicules of inorganic matter
+(either calcareous or siliceous) secreted by special cells, or of such
+spicules bound together by spongin. Extraneous objects, such as
+sand-grains, are frequently included in the skeleton. The spongin is
+secreted like the spicules by special cells, but its chemical structure
+is much more complicated than that of the spicules, and it is not
+secreted (at any rate in most cases) in such a way as to form bodies of
+a definite shape. In the so-called horny sponges it resembles the chitin
+in which insects and other arthropods are clothed.
+
+       *     *     *     *     *
+
+In no adult sponge do the collar-cells completely cover the whole of the
+internal surface, the olynthus being a larval form, and by no means a
+common larval form. It is only found in certain sponges with calcareous
+spicules. As the structure of the sponge becomes more complicated the
+collar-cells are tucked away into special pockets or chambers known as
+ciliated chambers, and finally the approach to these chambers, both from
+the external surface and from the inner or gastral cavity, takes the
+form of narrow tubes or canals instead of mere pores. With further
+complexity the simple internal cavity tends to disappear, and the sponge
+proliferates in such a way that more than one osculum is formed. In the
+class Demospongiae, to which the sponges described in this volume belong,
+the whole system is extremely complicated.
+
+The skeleton of sponges, when it is not composed wholly of spongin,
+consists of, or at any rate contains, spicules that have a definite
+chemical composition and definite shapes in accordance with the class,
+order, family, genus, and species of the sponge. Formerly sponges were
+separated into calcareous, siliceous, and horny sponges by the nature of
+their skeleton; and although the system of classification now adopted
+has developed into a much more complex one and a few sponges are known
+that have both calcareous and siliceous spicules, the question whether
+the spicules are formed of salts of lime or of silica (strictly speaking
+of opal) is very important. All Demospongiae that have spicules at all
+have them of the latter substance, and the grade Monaxonida, in which
+the freshwater sponges constitute the family Spongillidae, is
+characterized by the possession of spicules that have typically the form
+of a needle pointed at both ends. Although spicules of this simple form
+may be absent in species that belong to the grade, the larger spicules,
+which are called megascleres, have not normally more than one main axis
+and are always more or less rod-like in outline. They are usually
+arranged so as to form a reticulate skeleton. Frequently, however, the
+megascleres or skeleton-spicules are not the only spicules present, for
+we find smaller spicules (microscleres) of one or more kinds lying loose
+in the substance of the sponge and in the external membrane, or, in the
+Spongillidae only, forming a special armature for the reproductive bodies
+known as gemmules.
+
+All sponges obtain their food in the same way, namely by means of the
+currents of water set up by the flagella of the collar-cells. These
+flagella, although apparently there is little concerted action among
+them, cause by their rapid movements changes of pressure in the water
+contained in the cavities of the sponge. The water from outside
+therefore flows in at the pores and finally makes its way out of the
+oscula. With the water minute particles of organic matter are brought
+into the sponge, the collar-cells of which, and probably other cells,
+have the power of selecting and engulfing suitable particles. Inside the
+cells these particles undergo certain chemical changes, and are at least
+partially digested. The resulting substances are then handed on directly
+to other cells, or, as some assert, are discharged into the common
+jelly, whence they are taken up by other cells.
+
+Sponges reproduce their kind in more ways than one, _viz._, by means of
+eggs (which are fertilized as in other animals by spermatozoa), by means
+of buds, and by means of the peculiar bodies called gemmules the
+structure and origin of which is discussed below (p. 42). They are of
+great importance in the classification of the Spongillidae. Sponges can
+also be propagated artificially by means of fission, and it is probable
+that this method of reproduction occurs accidentally, if not normally,
+in natural circumstances.
+
+
+GENERAL STRUCTURE OF THE SPONGILLIDAE.
+
+It would be impracticable in this introduction to give a full account of
+the structure of the Spongillidae, which in some respects is still
+imperfectly known. Students who desire further information should
+consult Professor Minchin's account of the sponges in Lankester's
+'Treatise on Zoology,' part ii, or, if a less technical description is
+desired, Miss Sollas's contribution to the 'Cambridge Natural History,'
+vol. i, in which special attention is paid to _Spongilla_.
+
+The diagram reproduced in fig. 1 gives a schematic view of a vertical
+section through a living freshwater sponge. Although it represents the
+structure of the organism as being very much simpler than is actually
+the case, and entirely omits the skeleton, it will be found useful as
+indicating the main features of the anatomy.
+
+[Illustration: Fig. 1.--Diagram of a vertical section through a
+freshwater sponge (_modified from Kuekenthal_).
+
+A=pores; B=subdermal cavity; C=inhalent canal; D=ciliated chamber;
+E=exhalent canal; F=osculum; G=dermal membrane; H=eggs; J=gemmule.]
+
+It will be noted that the diagram represents an individual with a single
+osculum or exhalent aperture. As a rule adult Demospongiae have several
+or many oscula, but even in the Spongillidae sponges occur in which there
+is only one. New oscula are formed by a kind of proliferation that
+renders the structure still more complex than it is when only one
+exhalent aperture is present.
+
+The little arrows in the figure indicate the direction of the currents
+of water that pass through the sponge. It enters through small holes in
+the derma into a subdermal cavity, which separates the membrane from the
+bulk of the sponge. This space differs greatly in extent in different
+species. From the subdermal space the water is forced by the action of
+the flagella into narrow tubular canals that carry it into the ciliated
+chambers. Thence it passes into other canals, which communicate with
+what remains of the central cavity, and so out of the oscula.
+
+The ciliated chambers are very minute, and the collar-cells excessively
+so. It is very difficult to examine them owing to their small size and
+delicate structure. Fig. 2 D represents a collar-cell of a sponge seen
+under a very high power of the microscope in ideal conditions.
+
+[Illustration: Fig. 2.--Sponge cells.
+
+A=bubble-cells of _Ephydatia muelleri_, x 350 (_after Weltner_).
+B=gemmule-cell of _Spongilla lacustris_ containing green corpuscles
+(shaded dark), x 800 (_after Weltner_). C=gemmule-cell of _Ephydatia
+blembingia_ showing "tabloids" of food-material, x 1150 (_after Evans_).
+D=collar-cell of _Esperella aegagrophila_, x 1600 (_after Vosmaer and
+Pekelharing_). E=three stages in the development of a gemmule-spicule of
+_E. blembingia_ (_after Evans_), x 665. F=outline of porocytes of _S.
+proliferens_, x ca. 1290: _e_=dermal cell; _n_=nucleus; _p_=pore;
+_p.c._=pore-cell.]
+
+The nature of the inhalent apertures in the external membrane has been
+much discussed as regards the Demospongiae, but the truth seems to be
+that their structure differs considerably even in closely allied
+species. At any rate this is the case as regards the Indian _Spongillae_.
+In all species the membrane is composed of flattened cells of irregular
+shape fitted together like the pieces of a puzzle-picture. In some
+species (e. g., _Spongilla carteri_) the apertures in the membrane
+consist merely of spaces between adjacent cells, which may be a little
+more crowded together than is usual. But in others (e. g., _Spongilla
+proliferens_ and _Spongilla crassissima_) in which the pores are
+extremely small, each pore normally pierces the middle of a flat,
+ring-shaped cell or porocyte. Occasionally, however, a pore may be found
+that is enclosed by two narrow, crescent-shaped cells joined together at
+their tips to form a ring. The porocytes of sponges like _Spongilla
+carteri_ are probably not actually missing, but instead of being in the
+external membrane are situated below the derma at the external entrance
+to the canals that carry water to the flagellated chambers or even at
+the entrance to the chambers themselves[L]. Some authors object on
+theoretical grounds to the statement that porocytes exist in the
+Demospongia, and it is possible that these cells have in this grade
+neither the same origin as, nor a precisely similar function to, the
+porocytes of other sponges. When they occur in the dermal membrane no
+great difficulty is experienced in seeing them under a sufficiently high
+power of the microscope, if the material is well preserved and mounted
+and stained in a suitable manner[M]. In most sponges the porocytes can
+contract in such a way that the aperture in their centre is practically
+closed, but this power appears to be possessed by the porocytes of
+_Spongilla_ only to a very limited extent, although they closely
+resemble the porocytes of other sponges in appearance.
+
+     [Footnote L: _Cf._ Weltner, "Spongillidenstudien, V," Arch.
+     Naturg. Berlin, lxxiii (i), p. 273 (1907).]
+
+     [Footnote M: It is difficult to see any trace of them in
+     thin microtome sections. A fragment of the membrane must be
+     mounted whole.]
+
+The external membrane in many Spongillidae is prolonged round and above
+the oscula so as to form an oscular collar. This structure is highly
+contractile, but cannot close together. As a rule it is much more
+conspicuous in living sponges than in preserved specimens.
+
+It is not necessary to deal here with most of the cells that
+occur in the parenchyma or gelatinous part of the sponge. A full
+list of the kinds that are found is given by Dr. Weltner in his
+"Spongillidenstudien, V," p. 276 (Arch. Naturg. Berlin, lxxiii (i),
+1907). One kind must, however, be briefly noticed as being of some
+systematic importance, namely the "bubble-cells" (fig. 2 A) that are
+characteristic of some species of _Ephydatia_ and other genera. These
+cells are comparatively large, spherical in form; each of them contains
+a globule of liquid which not only occupies the greater part of the
+cell, but forces the protoplasm to assume the form of a delicate film
+lining the cell-wall and covering the globule. In optical section
+"bubble-cells" have a certain resemblance to porocytes, but the cell is
+of course imperforate and not flattened.
+
+
+SKELETON AND SPICULES.
+
+[Illustration: Fig. 3.--Radial sections of fragments of the skeletons of
+_Spongillae_.
+
+A, _S. crassissima_ var. _crassior_ (from Rajshahi); B, _S. carteri_
+(from Calcutta); _a_=transverse, _b_=radiating fibres; _e_=external
+surface of the sponge.]
+
+In the Spongillidae the spicules and the skeleton are more important as
+regards the recognition of genera and species than the soft parts. The
+skeleton is usually reticulate, but sometimes consists of a mass of
+spicules almost without arrangement. The amount of spongin present is
+also different in different species. The spicules in a reticulate
+skeleton are arranged so as to form fibres of two kinds--radiating
+fibres, which radiate outwards from the centre of the sponge and
+frequently penetrate the external membrane, and transverse fibres, which
+run across from one radiating fibre to another. The fibres are composed
+of relatively large spicules (megascleres) arranged parallel to one
+another, overlapping at the ends, and bound together by means of a more
+or less profuse secretion of spongin. In some species they are actually
+enclosed in a sheath of this substance. The radiating fibres are usually
+more distinct and stouter than the transverse ones, which are often
+represented by single spicules but are sometimes splayed out at the ends
+so as to assume in outline the form of an hour-glass (fig. 3 B). The
+radiating fibres frequently raise up the membrane at their free
+extremities just as a tent-pole does a tent.
+
+Normal spicules of the skeleton are always rod-like or needle-like, and
+either blunt or pointed at both ends; they are either smooth, granular,
+or covered with small spines. Sometimes spicules of the same type form a
+more or less irregular transverse network at the base or on the surface
+of the sponge.
+
+[Illustration: Fig. 4.--Part of an oscular collar of _Spongilla
+lacustris_ subsp. _reticulata_, showing arrangement of microscleres in
+the derma (magnified).]
+
+From the systematist's point of view, the structure of the free spicules
+found scattered in the substance and membrane of the sponge, and
+especially of those that form the armature of the gemmules, is of more
+importance than that of the skeleton-spicules. Free spicules are absent
+in many species; when present they are usually needle-like and pointed
+at the tips. In a few species, however, they are of variable or
+irregular form, or consist of several or many shafts meeting in a common
+central nodule. In one genus (_Corvospongilla_) they resemble a double
+grappling-iron in form, having a circle of strongly recurved hooks at
+both ends. The free microscleres, or flesh-spicules as they are often
+called, are either smooth, granular, or spiny.
+
+Gemmule-spicules, which form a characteristic feature of the
+Spongillidae, are very seldom absent when the gemmules are mature. They
+are of the greatest importance in distinguishing the genera. In their
+simplest form they closely resemble the free microscleres, but in
+several genera they bear, either at or near one end or at or near both
+ends, transverse disks which are either smooth or indented round the
+edge. In one genus (_Pectispongilla_) they are provided at both ends not
+with disks but with vertically parallel rows of spines resembling combs
+in appearance.
+
+The simpler spicules of the Spongillidae are formed in single cells (see
+fig. 2 E), but those of more complicated shape are produced by several
+cells acting in concert. Each spicule, although it is formed mainly of
+hydrated silica (opal), contains a slender organic filament running
+along its main axis inside the silica. This filament, or rather the tube
+in which it is contained, is often quite conspicuous, and in some
+species (e. g., _Spongilla crassissima_) its termination is marked at
+both ends of the megasclere by a minute conical protuberance in the
+silica.
+
+Unless sponges are alchemists and can transmute one element into
+another, the material of which the spicules are made must ultimately
+come from the water in which the sponges live, or the rocks or other
+bodies to or near which they are attached. The amount of water that must
+pass through a large specimen of such a sponge as _Spongilla carteri_ in
+order that it may obtain materials for its skeleton must be enormous,
+for silica is an insoluble substance. I have noticed, however, that this
+sponge is particularly abundant and grows with special luxuriance in
+ponds in which clothes are washed with soap, and my friend Mr. G. H.
+Tipper has suggested to me that possibly the alkali contained in the
+soap-suds may assist the sponge in dissolving out the silica contained
+in the mud at the bottom of the ponds. The question of how the mineral
+matter of the skeleton is obtained is, however, one about which we know
+nothing definite.
+
+The spongin that binds the skeleton-spicules together takes the form of
+a colourless or yellowish transparent membrane, which is often
+practically invisible. When very abundant it sometimes extends across
+the nodes of the skeleton as a delicate veil. In some sponges it also
+forms a basal membrane in contact with the object to which the sponge is
+attached, and in some such cases the spongin of the radiating fibres is
+in direct continuity with that of the basal membrane.
+
+
+COLOUR AND ODOUR.
+
+Most freshwater sponges have a bad odour, which is more marked in some
+species than in others. This odour is not peculiar to the Spongillidae,
+for it is practically identical with that given out by the common marine
+sponge _Halichondria panicea_. Its function is probably protective, but
+how it is produced we do not know.
+
+The coloration of freshwater sponges is usually dull and uniform, but
+_Pectispongilla aurea_ is of the brilliant yellow indicated by its name,
+while many species are of the bright green shade characteristic of
+chlorophyll, the colouring matter of the leaves of plants. Many species
+are brown or grey, and some are almost white.
+
+These colours are due to one of three causes, or to a combination of
+more than one of them, viz.:--(1) the inhalation of solid inorganic
+particles, which are engulfed by the cells; (2) the presence in the
+cells of coloured substances, solid or liquid, produced by the vital
+activities of the sponge; and (3) the presence in the cells of peculiar
+organized living bodies known as "green corpuscles."
+
+Sponges living in muddy water are often nearly black. This is because
+the cells of their parenchyma are gorged with very minute solid
+particles of silt. If a sponge of the kind is kept in clean water for a
+few days, it often becomes almost white. An interesting experiment is
+easily performed to illustrate the absorption and final elimination of
+solid colouring matter by placing a living sponge (small specimens of
+_Spongilla carteri_ are suitable) in a glass of clean water, and
+sprinkling finely powdered carmine in the water. In a few hours the
+sponge will be of a bright pink colour, but if only a little carmine is
+used at first and no more added, it will regain its normal greyish hue
+in a few days.
+
+The colouring matter produced by the sponge itself is of two
+kinds--pigment, which is probably a waste product, and the substances
+produced directly by the ingestion of food or in the process of its
+digestion. When pigment is produced it takes the form of minute granules
+lying in the cells of the parenchyma, the dermal membrane being as a
+rule colourless. Very little is known about the pigments of freshwater
+sponges, and even less about the direct products of metabolism. It is
+apparently the latter, however, that give many otherwise colourless
+sponges a slight pinkish or yellowish tinge directly due to the presence
+in cells of the parenchyma of minute liquid globules. In one form of
+_Spongilla carteri_ these globules turn of a dark brown colour if
+treated with alcohol. The brilliant colour of _Pectispongilla aurea_ is
+due not to solid granules but to a liquid or semi-liquid substance
+contained in the cells.
+
+The green corpuscles of the Spongillidae are not present in all species.
+There is every reason to think that they represent a stage in the
+life-history of an alga, and that they enter the sponge in an active
+condition (see p. 49).
+
+A fourth cause for the coloration of freshwater sponges may be noted
+briefly. It is not a normal one, but occurs commonly in certain forms
+(e. g., _Spongilla alba_ var. _bengalensis_). This cause is the growth
+in the canals and substance of the sponge of parasitic algaae, which turn
+the whole organism of a dull green colour. They do not do so, however,
+until they have reduced it to a dying state. The commonest parasite of
+the kind is a filamentous species particularly common in brackish water
+in the Ganges delta.
+
+
+EXTERNAL FORM AND CONSISTENCY.
+
+[Illustration: Fig. 5.--Part of a type-specimen of _Spongilla lacustris_
+subsp. _reticulata_ (nat. size).]
+
+The external form of sponges is very variable, but each species,
+subspecies, or variety of the Spongillidae has normally a characteristic
+appearance. The European race of _Spongilla lacustris_, for example,
+consists in favourable circumstances of a flattened basal part from
+which long cylindrical branches grow out; while in the Indian race of
+the species these branches are flattened instead of being cylindrical,
+and anastomose freely. The structure of the branches is identical with
+that of the basal part. Many other species (for instance, _Spongilla
+bombayensis_ and _S. ultima_) never produce branches but always consist
+of lichenoid or cushion-shaped masses. The appearance of _Spongilla
+crateriformis_, when it is growing on a flattened surface which allows
+it to develop its natural form, is very characteristic, for it consists
+of little flattened masses that seem to be running out towards one
+another, just as though the sponge had been dropped, spoonful by
+spoonful, in a viscous condition from a teaspoon. Some species, such as
+_Trochospongilla phillottiana_, cover large areas with a thin film of
+uniform thickness, while others (e. g., _Spongilla alba_ and _Ephydatia
+meyeni_) consist of irregular masses, the surface of which bears
+numerous irregular ridges or conical, subquadrate, or digitate
+processes. In a few forms (e. g., _Corvospongilla burmanica_) the
+surface is covered with small turret-like projections of considerable
+regularity, and some (e. g., _Spongilla crassissima_) naturally assume a
+spherical or oval shape with an absolutely smooth surface.
+
+The production of long branches is apparently rare in tropical
+freshwater sponges.
+
+The form of the oscula is characteristic in many cases. No other Indian
+species has them so large, or with such well-defined margins as
+_Spongilla carteri_ (Pl. II, fig. 1). In many species (Pl. II, fig. 3)
+they have a stellate appearance owing to the fact that grooves in the
+substance of the sponge radiate round them beneath the external
+membrane. In other species they are quite inconspicuous and very small.
+
+[Illustration: Fig. 6.--Radial section through part of a dried sponge of
+_Spongilla crassissima_ (from Calcutta), x 5.]
+
+Spongillidae differ greatly in consistency. _Spongilla crassissima_ and
+_Corvospongilla lapidosa_ are almost stony, although the former is
+extremely light, more like pumice than true stone. Other species (e. g.,
+_Trochospongilla latouchiana_) are hard but brittle, while others again
+are soft and easily compressed, as _Spongilla lacustris_, the variety
+_mollis_ of _S. carteri_, and _S. crateriformis_. The consistency of a
+sponge depends on two factors--the number of spicules present, and the
+amount of spongin. In _Corvospongilla lapidosa_ the number of spicules
+is very large indeed. They are not arranged so as to form a reticulate
+skeleton but interlock in all directions, and there is hardly any
+spongin associated with them. In _Spongilla crassissima_, on the other
+hand, the number of spicules although large is not unusually so; but
+they form a very definitely reticulate skeleton, and are bound together
+by an unusually profuse secretion of spongin. In _S. carteri_ var.
+_mollis_ both spicules and spongin are reduced to a minimum, and the
+parenchyma is relatively more bulky than usual.
+
+
+VARIATION.
+
+Sponges are very variable organisms, and even a slight change in the
+environment of the freshwater species often produces a considerable
+change in form and structure. Some species vary in accordance with the
+season, and others without apparent cause. Not only have many given rise
+to subspecies and "varieties" that possess a certain stability, but most
+if not all are liable to smaller changes that apparently affect both the
+individual and the breed, at any rate for a period.
+
+(a) _Seasonal Variation._
+
+Weltner has shown in a recent paper (Arch. Natg. Berlin, lxxiii (i), p.
+276, 1907) that in Europe those individuals of _Ephydatia_ which are
+found (exceptionally) in an active condition in winter differ
+considerably both as regards the number of their cells and their anatomy
+from those found in summer. In Calcutta the majority of the individuals
+of _Spongilla carteri_ that are found in summer have their external
+surface unusually smooth and rounded, and contain in their parenchyma
+numerous cells the protoplasm of which is gorged with liquid. These
+cells give the whole sponge a faint pinkish tinge during life; but if it
+is plunged in spirit, both the liquid in the cells and the spirit turn
+rapidly of a dark brown colour. Specimens of _Spongilla crateriformis_
+taken in a certain tank in Calcutta during the cold weather had the
+majority of the skeleton-spicules blunt, while the extremities of the
+gemmule-spicules were distinctly differentiated. Specimens of the same
+species taken from the same tank in July had the skeleton-spicules
+pointed, while the extremities of the gemmule-spicules were much less
+clearly differentiated. I have been unable to confirm this by
+observations made on sponges from other tanks, but it would certainly
+suggest that at any rate the breed of sponges in the tank first
+investigated was liable to seasonal variation.
+
+(b) _Variation due directly to Environment._
+
+The characteristic external form of freshwater sponges is liable in most
+cases to be altered as a direct result of changes in the environment.
+The following are two characteristic instances of this phenomenon.
+
+Certain shrubs with slender stems grow in the water at the edge of
+Igatpuri Lake. The stems of these shrubs support many large examples of
+_Spongilla carteri_, which are kept in almost constant motion owing to
+the action of the wind on those parts of the shrubs that are not under
+water. The surface of the sponges is so affected by the currents of
+water thus set up against it that it is covered with deep grooves and
+high irregular ridges like cockscombs. Less than a hundred yards from
+the lake there is a small pond in which _Spongilla carteri_ is also
+abundant. Here it grows on stones at the bottom and has the
+characteristic and almost smooth form of the species.
+
+My second instance also refers in part to Igatpuri Lake. _Corvospongilla
+lapidosa_ is common in the lake on the lower surface of stones, and also
+occurs at Nasik, about thirty miles away, on the walls of a conduit of
+dirty water. In the latter situation it has the form of large sheets of
+a blackish colour, with the surface corrugated and the oscula
+inconspicuous, while in the clear waters of the lake it is of a pale
+yellowish colour, occurs in small lichenoid patches, and has its oscula
+rendered conspicuous, in spite of their minute size, by being raised on
+little conical eminences in such a way that they resemble the craters of
+volcanoes in miniature.
+
+Both the European and the Indian races of _Spongilla lacustris_ fail to
+develop branches if growing in unfavourable conditions. In specimens
+obtained from the River Spree near Berlin these structures are sometimes
+many inches in length; while in mature specimens taken under stones in
+Loch Baa in the Island of Mull the whole organism consisted of a minute
+cushion-shaped mass less than an inch in diameter, and was also
+deficient in spicules. Both these breeds belong to the same species, and
+probably differ as a direct result of differences in environment.
+
+(c) _Variation without apparent cause._
+
+Plate I in this volume illustrates an excellent example of variation in
+external form to which it is impossible to assign a cause with any
+degree of confidence. The three specimens figured were all taken in the
+same pond, and at the same season, but in different years. It is
+possible that the change in form, which was not peculiar to a few
+individuals but to all those in several adjacent ponds, was due to a
+difference in the salinity of the water brought about by a more or less
+abundant rainfall; but of this I have been able to obtain no evidence in
+succeeding years.
+
+Many Spongillidae vary without apparent cause as regards the shape, size,
+and proportions of their spicules. This is the case as regards most
+species of _Euspongilla_ and _Ephydatia_, and is a fact to which careful
+consideration has to be given in separating the species.
+
+
+NUTRITION.
+
+Very little is known about the natural food of freshwater sponges,
+except that it must be of an organic nature and must be either in a very
+finely divided or in a liquid condition. The cells of the sponge seem to
+have the power of selecting suitable food from the water that flows past
+them, and it is known that they will absorb milk. The fact that they
+engulf minute particles of silt does not prove that they lack the power
+of selection, for extraneous matter is taken up by them not only as food
+but in order that it may be eliminated. Silt would soon block up the
+canals and so put a stop to the vital activity of the sponge, if it were
+not got rid of, and presumably it is only taken into the cells in order
+that they may pass it on and finally disgorge it in such a way or in
+such a position that it may be carried out of the oscula. The siliceous
+part of it may be used in forming spicules.
+
+It is generally believed that the green corpuscles play an important
+part in the nutrition of those sponges in which they occur, and there
+can be no doubt that these bodies have the power peculiar to all
+organisms that produce chlorophyll of obtaining nutritive substances
+direct from water and carbonic oxide through the action of sunlight.
+Possibly they hand on some of the nourishment thus obtained to the
+sponges in which they live, or benefit them by the free oxygen given out
+in the process, but many Spongillidae do well without them, even when
+living in identical conditions with species in which they abound.
+
+
+REPRODUCTION.
+
+Both eggs and buds are produced by freshwater sponges (the latter rarely
+except by one species), while their gemmules attain an elaboration of
+structure not observed in any other family of sponges.
+
+Probably all Spongillidae are potentially monoecious, that is to say,
+able to produce both eggs and spermatozoa. In one Indian species,
+however, in which budding is unusually common (viz. _Spongilla
+proliferens_), sexual reproduction takes place very seldom, if ever. It
+is not known whether the eggs of sponges are fertilized by spermatozoa
+from the individual that produces the egg or by those of other
+individuals, but not improbably both methods of fertilization occur.
+
+The egg of a freshwater sponge does not differ materially from that of
+other animals. When mature it is a relatively large spherical cell
+containing abundant food-material and situated in some natural cavity of
+the sponge. In the earlier stages of its growth, however, it exhibits
+amoeboid movements, and makes its way through the common jelly. As it
+approaches maturity it is surrounded by other cells which contain
+granules of food-material. The food-material is apparently transferred
+by them in a slightly altered form to the egg. The egg has no shell, but
+in some species (e. g. _Ephydatia blembingia_[N]) it is surrounded,
+after fertilization, by gland-cells belonging to the parent sponge,
+which secrete round it a membrane of spongin. Development goes on within
+the chamber thus formed until the larva is ready to assume a free life.
+
+     [Footnote N: Rec. Ind. Mus. i, p. 269 (1907).]
+
+The spermatozoon is also like that of other animals, consisting of a
+rounded head and a lash-like tail, the movements of which enable it to
+move rapidly through the water. Spermatozoa are produced in _Spongilla_
+from spherical cells not unlike the eggs in general appearance. The
+contents of these cells divide and subdivide in such a way that they
+finally consist of a mass of spermatozoa surrounded by a single covering
+cell, which they finally rupture, and so escape.
+
+[Illustration: Fig. 7.--Diagram of a vertical section through the
+gemmule of _Spongilla proliferens_.
+
+A=cellular contents; B=internal chitinous layer; C=external chitinous
+layer; D=pneumatic coat; E=gemmule-spicule; F=external membrane;
+G=foraminal tubule.]
+
+Gemmules are asexual reproductive bodies peculiar to the sponges, but
+not to the Spongillidae. They resemble the statoblasts of the
+phylactolaematous polyzoa in general structure as well as in function,
+which is mainly that of preserving the race from destruction by such
+agencies as drought, starvation, and temperatures that are either too
+high or too low for its activities. This function they are enabled to
+perform by the facts that they are provided with coverings not only very
+hard but also fitted to resist the unfavourable agencies to which the
+gemmules are likely to be exposed, and that they contain abundant
+food-material of which use can be made as soon as favourable conditions
+occur again.
+
+Internally the gemmule consists of a mass of cells containing
+food-material in what may be called a tabloid form, for it consists of
+minutely granular plate-like bodies. These cells are enclosed in a
+flask-like receptacle, the walls of which consist of two chitinous
+layers, a delicate inner membrane and an outer one of considerable
+stoutness. The mouth of the flask is closed by an extension of the inner
+membrane, and in some species is surrounded by a tubular extension of
+the external membrane known as the foraminal tubule. Externally the
+gemmule is usually covered by what is called a "pneumatic coat," also of
+"chitin" (spongin), but usually of great relative thickness and
+honeycombed by spaces which contain air, rendering the structure
+buoyant. The pneumatic coat also contains the microscleres
+characteristic of the species; it is often limited externally by a third
+chitinous membrane, on which more gemmule-spicules sometimes lie
+parallel to the surface.
+
+The cells from which those of the gemmules are derived are akin in
+origin to those that give rise to eggs and spermatozoa. Some zoologists
+are therefore of the opinion that the development of the gemmule is an
+instance of parthenogenesis--that is to say of an organism arising from
+an egg that has not been fertilized. But some of the collar-cells,
+although most of them originate from the external ciliated cells of the
+larva, have a similar origin. The building-up of the gemmule affords an
+excellent instance of the active co-operation that exists between the
+cells of sponges, and of their mobility, for the food-material that has
+to be stored up is brought by cells from all parts of the sponge, and
+these cells retire after discharging their load into those of the young
+gemmule.
+
+The formation of the gemmule of _Ephydatia blembingia_, a Malayan
+species not yet found in India, is described in detail by Dr. R. Evans
+(Q. J. Microsc. Sci. London, xliv, p. 81, 1901).
+
+Gemmules are produced by the freshwater sponges of Europe, N. America
+and Japan at the approach of winter, but in the tropical parts of India
+they are formed more frequently at the approach of the hot weather (p.
+4). After they are fully formed the sponge that has produced them dies,
+and as a rule disintegrates more or less completely. In some species,
+however, the greater part of the skeleton remains intact, if it is not
+disturbed, and retains some of the gemmules in its meshwork, where they
+finally germinate. Other gemmules are set free. Some of them float on
+the surface of the water; others sink to the bottom. In any case all of
+them undergo a period of quiescence before germinating. It has been
+found that they can be kept dry for two years without dying.
+
+The function of the special spicules with which the gemmules of the
+Spongillidae are provided appears to be not only to protect them but more
+especially to weight them to the extent suitable to the habits of each
+species. Species that inhabit running water, for example, in some cases
+have heavier gemmule-spicules than those that live in stagnant water,
+and their gemmules are the less easily carried away by the currents of
+the river. The gemmules of sponges growing in lakes are sometimes
+deficient in spicules. This is the case as regards the form of
+_Spongilla lacustris_ found in Lake Baa, Isle of Mull, as regards _S.
+helvetica_ from the Lake of Geneva, _S. moorei_ from Lake Tanganyika,
+and _S. coggini_ from Tali-Fu in Yunnan; also as regards the species of
+_Spongilla_ and _Ephydatia_ found in Lake Baikal, many of the sponges of
+which are said never to produce gemmules.
+
+Except in the genus _Corvospongilla_ and the subgenus _Stratospongilla_,
+in both of which the air-spaces of the gemmules are usually no more than
+cavities between different chitinous membranes, the pneumatic coat is
+either "granular" or "cellular." Neither of these terms, however, must
+be understood in a physiological sense, for what appear to be granules
+in a granular coat are actually minute bubbles of air contained in
+little cavities in a foam-like mass of chitin (or rather spongin), while
+the cells in a cellular one are only larger and more regular air-spaces
+with thin polygonal walls and flat horizontal partitions. The walls of
+these spaces are said in some cases to contain a considerable amount of
+silica.
+
+The gemmules with their various coverings are usually spherical in
+shape, but in some species they are oval or depressed in outline. They
+lie as a rule free in the substance of the sponge, but in some species
+adhere at its base to the object to which it is attached. In some
+species they are joined together in groups, but in most they are quite
+free one from another.
+
+Reproductive buds[O] are produced, so far as is known, by very few
+Spongillidae, although they are common enough in some other groups of
+sponges. In the only freshwater species in which they have been found to
+form a habitual means of reproduction, namely in _Spongilla
+proliferens_, they have much the appearance of abortive branches, and it
+is possible that they have been overlooked for this reason in other
+species, for they were noticed by Laurent in _Spongilla lacustris_ as
+long ago as 1840 (CR. Se. Acad. Sci. Paris, xi, p. 478). The buds
+noticed by Laurent, however, were only produced by very young sponges,
+and were of a different nature from those of _S. proliferens_, perhaps
+representing a form of fission rather than true budding (see 'Voyage de
+la Bonite: Zoophytologie,' Spongiaires, pl. i (Paris, 1844)).
+
+     [Footnote O: Proliferation whereby more than one osculum is
+     produced is really a form of budding, but in most sponges
+     this has become no longer a mode of reproduction but the
+     normal method by which size is increased, and must therefore
+     be considered merely as a vegetative process.]
+
+In _Spongilla proliferens_, a common Indian species, the buds arise as
+thickenings of the strands of cells accompanying the radiating
+spicule-fibres of the skeleton, which project outwards from the surface
+of the sponge. The thickenings originate beneath the surface and
+contain, at the earliest stage at which I have as yet examined them, all
+the elements of the adult organism (_i. e._ flesh-spicules, ciliated
+chambers, efferent and afferent canals, parenchyma-cells of various
+sorts) except skeleton fibres, gemmules, and a dermal membrane. A
+section at this period closely resembles one of an adult sponge, except
+that the structure is more compact, the parenchyma being relatively
+bulky and the canals of small diameter.
+
+Laurent observed reproduction by splitting in young individuals of
+_Spongilla_, but I have not been able to obtain evidence myself that
+this method of reproduction occurs normally in Indian species. In
+injured specimens of _Spongilla carteri_, however, I have observed a
+phenomenon that seems to be rather an abnormal form of budding, little
+rounded masses of cells making their way to the ends of the radiating
+skeleton fibres and becoming transformed into young sponges, which break
+loose and so start an independent existence. Possibly the buds observed
+by Laurent in _S. lacustris_ were of a similar nature.
+
+
+DEVELOPMENT.
+
+
+(a) _From the Egg._
+
+After fertilization, the egg, lying in its cavity in the sponge,
+undergoes a complete segmentation; that is to say, becomes divided into
+a number of cells without any residuum remaining. The segmentation,
+however, is not equal, for it results in the formation of cells of two
+distinct types, one larger and less numerous than the other. As the
+process continues a pear-shaped body is produced, solid at the broader
+end, which consists of the larger cells, but hollow at the other.
+Further changes result in the whole of the external surface becoming
+ciliated or covered with fine protoplasmic lashes, each of which arises
+from a single small cell; considerable differentiation now takes place
+among the cells, and spicules begin to appear. At this stage or earlier
+(for there seem to be differences in different species and individuals
+as to the stage at which the young sponge escapes) the larva makes its
+way out of the parent sponge. After a brief period of free life, in
+which it swims rapidly through the water by means of its cilia, it fixes
+itself by the broad end to some solid object (from which it can never
+move again) and undergoes a final metamorphosis. During this process the
+ciliated cells of the external layer make their way, either by a
+folding-in of the whole layer or in groups of cells, into the interior,
+there change into collar-cells and arrange themselves in special
+cavities--the ciliated chambers of the adult. Finally an osculum, pores,
+&c., are formed, and the sponge is complete.
+
+This, of course, is the merest outline of what occurs; other changes
+that take place during the metamorphosis are of great theoretical
+interest, but cannot be discussed here. The student may refer to Dr. R.
+Evans's account of the larval development of _Spongilla lacustris_ in
+the Q. J. Microsc. Sci. London, xlii, p. 363 (1899).
+
+(b) _From the Gemmule._
+
+The period for which the gemmule lies dormant probably depends to some
+extent upon environment and to some extent on the species to which it
+belongs. Carter found that if he cleaned gemmules with a handkerchief
+and placed them in water exposed to sunlight, they germinated in a few
+days; but in Calcutta gemmules of _Spongilla alba_ var. _bengalensis_
+treated in this way and placed in my aquarium at the beginning of the
+hot weather, did not germinate until well on in the "rains." Even then,
+after about five months, only a few of them did so. Zykoff found that in
+Europe gemmules kept for two years were still alive and able to
+germinate.
+
+Germination consists in the cellular contents of the gemmule bursting
+the membrane or membranes in which they are enclosed, and making their
+way out of the gemmule in the form of a delicate whitish mass, which
+sometimes issues through the natural aperture in the outer chitinous
+coat and sometimes through an actual rent in this coat. In the latter
+case the development of the young sponge is more advanced than in the
+former.
+
+The fullest account of development from the gemmule as yet published is
+by Zykoff, and refers to _Ephydatia_ in Europe (Biol. Centralbl. Berlin,
+xii, p. 713, 1892).
+
+His investigations show that the bursting of the gemmule is not merely a
+mechanical effect of moisture or any such agency but is due to
+development of the cellular contents, which at the time they escape have
+at least undergone differentiation into two layers. Of the more
+important soft structures in the sponge the osculum is the first to
+appear, the ciliated chambers being formed later. This is the opposite
+of what occurs in the case of the bud, but in both cases the aperture
+appears to be produced by the pressure of water in the organism. The
+manner and order in which the different kinds of cells originate in the
+sponge derived from a gemmule give support to the view that the
+primitive cell-layers on which morphologists lay great stress are not of
+any great importance so far as sponges are concerned.
+
+(c) _Development of the Bud._
+
+As the bud of _Spongilla proliferens_ grows it makes its way up the
+skeleton-fibre to which it was originally attached, pushing the dermal
+membrane, which expands with its growth, before it. The skeleton-fibre
+does not, however, continue to grow in the bud, in which a number of
+finer fibres make their appearance, radiating from a point approximately
+at the centre of the mass. As the bud projects more and more from the
+surface of the sponge the dermal membrane contracts at its base, so as
+finally to separate it from its parent. Further details are given on p.
+74.
+
+
+HABITAT.
+
+Mr. Edward Potts[P], writing on the freshwater sponges of North America,
+says:--"These organisms have occasionally been discovered growing in
+water unfit for domestic uses; but as a rule they prefer pure water, and
+in my experience the finest specimens have always been found where they
+are subjected to the most rapid currents." True as this is of the
+Spongillidae of temperate climates, it is hardly applicable to those of
+tropical India, for in this country we find many species growing most
+luxuriantly and commonly in water that would certainly be considered
+unfit for domestic purposes in a country in which sanitation was treated
+as a science. Some species, indeed, are only found in ponds of water
+polluted by human agency, and such ponds, provided that other conditions
+are favourable, are perhaps the best collecting grounds. Other
+favourable conditions consist in a due mixture of light and shade, a
+lack of disturbance such as that caused by cleaning out the pond, and
+above all in the presence of objects suitable for the support of
+sponges.
+
+     [Footnote P: P. Ac. Philad. 1887, p. 162.]
+
+I do not know exactly why light and shade must be mixed in a habitat
+favourable for the growth of sponges, for most species prefer shade, if
+it be not too dense; but it is certainly the case that, with a few
+exceptions, Indian Spongillidae flourish best in water shaded at the
+edges by trees and exposed to sunlight elsewhere. One of the exceptions
+to this rule is the Indian race of _Spongilla lucustris_, which is found
+in small pools of water in sand-dunes without a particle of shade.
+Several species are only found on the lower surface of stones and roots
+in circumstances which do not suggest that their position merely
+protects them from mud, which, as Mr. Potts points out, is their "great
+enemy." A notable instance is _Trochospongilla pennsylvanica_, which is
+found hiding away from light in America and Europe as well as in India.
+
+It is curious that it should be easy to exterminate the sponges in a
+pond by cleaning it out, for one would have thought that sufficient
+gemmules would have remained at the edge, or would have been brought
+rapidly from elsewhere, to restock the water. Mr. Green has, however,
+noted that _Spongilla carteri_ has disappeared for some years from a
+small lake at Peradeniya in which it was formerly abundant, owing to the
+lake having been cleaned out, and I have made similar observations on
+several occasions in Calcutta.
+
+The question of the objects to which sponges attach themselves is one
+intimately connected with that of the injury done them by mud. The delta
+of the Ganges is one of the muddiest districts on earth. There are no
+stones or rocks in the rivers and ponds, but mud everywhere. If a sponge
+settles in the mud its canals are rapidly choked, its vital processes
+cease, and it dies. In this part of India, therefore, most sponges are
+found fixed either to floating objects such as logs of wood, to vertical
+objects such as the stems of bulrushes and other aquatic plants, or to
+the tips of branches that overhang the water and become submerged during
+the "rains." In Calcutta man has unwittingly come to the assistance of
+the sponges, not only by digging tanks but also by building
+"bathing-ghats" of brick at the edge, and constructing, with aesthetic
+intentions if not results, masses of artificial concrete rocks in or
+surrounding the water. There are at least two sponges (the typical form
+of _Spongilla alba_ and _Ephydatia meyeni_) which in Calcutta are only
+found attached to such objects. The form of _S. alba_, however, that is
+found in ponds of brackish water in the Gangetic delta has not derived
+this artificial assistance from man, except in the few places where
+brick bridges have been built, and attaches itself to the stem and roots
+of a kind of grass that grows at the edge of brackish water. This sponge
+seems to have become immune even to mud, the particles of which are
+swallowed by its cells and finally got rid of without blocking up the
+canals.
+
+Several Indian sponges are only found adhering to stones and rocks.
+Among these species _Corvospongilla lapidosa_ and our representatives of
+the subgenus _Stratospongilla_ are noteworthy. Some forms (e. g.
+_Spongilla carteri_ and _S. crateriformis_) seem, however, to be just as
+much at home in muddy as in rocky localities, although they avoid the
+mud itself.
+
+There is much indirect evidence that the larvae of freshwater sponges
+exercise a power of selection as regards the objects to which they affix
+themselves on settling down for life.
+
+Few Spongillidae are found in salt or brackish water, but _Spongilla
+alba_ var. _bengalensis_ has been found in both, and is abundant in the
+latter; indeed, it has not been found in pure fresh water. _Spongilla
+travancorica_ has only been found in slightly brackish water, while _S.
+lacustris_ subsp. _reticulata_ and _Dosilia plumosa_ occur in both fresh
+and brackish water, although rarely in the latter. The Spongillidae are
+essentially a freshwater family, and those forms that are found in any
+but pure fresh water must be regarded as aberrant or unusually tolerant
+in their habits, not as primitive marine forms that still linger halfway
+to the sea.
+
+
+ANIMALS AND PLANTS COMMONLY ASSOCIATED WITH
+FRESHWATER SPONGES.
+
+
+(a) _Enemies._
+
+Freshwater sponges have few living enemies. Indeed, it is difficult to
+say exactly what is an enemy of a creature so loosely organized as a
+sponge. There can be little doubt, in any case, that the neuropteroid
+larva (_Sisyra indica_) which sucks the cells of several species should
+be classed in this category, and it is noteworthy that several species
+of the same genus also occur in Europe and N. America which also attack
+sponges. Other animals that may be enemies are a midge larva (_Tanypus_
+sp.) and certain worms that bore through the parenchyma (p. 93), but I
+know of no animal that devours sponges bodily, so long as they are
+uninjured. If their external membrane is destroyed, they are immediately
+attacked by various little fish and also by snails of the genera
+_Limnaea_ and _Planorbis_, and prawns of the genus _Palaemon_.
+
+Their most active and obvious enemy is a plant, not an animal,--to wit,
+a filamentous alga that blocks up their canals by its rapid growth (p.
+79).
+
+(b) _Beneficial Organisms._
+
+The most abundant and possibly the most important organisms that may be
+considered as benefactors to the Spongillidae are the green corpuscles
+that live in the cells of certain species (fig. 2, p. 31), notably
+_Spongilla lacustris_, _S. proliferens_, and _Dosilia plumosa_. I have
+already said that these bodies are in all probability algae which live
+free in the water and move actively at one stage of their existence, but
+some of them are handed on directly from a sponge to its descendants in
+the cells of the gemmule. In their quiescent stage they have been
+studied by several zoologists, notably by Sir Ray Lankester[Q] and Dr.
+W. Weltner[R], but the strongest light that has been cast on their
+origin is given by the researches of Dr. F. W. Gamble and Mr. F. Keeble
+(Q. J. Microsc. Sci. London, xlvii, p. 363, 1904, and li, p. 167, 1907).
+These researches do not refer directly to the Spongillidae but to a
+little flat-worm that lives in the sea, _Convoluta roscoffiensis_. The
+green corpuscles of this worm so closely resemble those of _Spongilla_
+that we are justified in supposing a similarity of origin. It has been
+shown by the authors cited that the green corpuscles of the worm are at
+one stage minute free-living organisms provided at one end with four
+flagella and at the other with a red pigment spot. The investigators are
+of the opinion that these organisms exhibit the essential characters of
+the algae known as Chlamydomonadae, and that after they have entered the
+worm they play for it the part of an excretory system.
+
+     [Footnote Q: Q. J. Microsc. Sci. London, xxii. p. 229
+     (1882).]
+
+     [Footnote R: Arch. Naturg. Berlin, lix (i), p. 260 (1893).]
+
+As they exist in the cells of _Spongilla_ the corpuscles are minute oval
+bodies of a bright green colour and each containing a highly refractile
+colourless granule. A considerable number may be present in a single
+cell. It is found in European sponges that they lose their green colour
+if the sponge is not exposed to bright sunlight. In India, however,
+where the light is stronger, this is not always the case. Even when the
+colour goes, the corpuscles can still be distinguished as pale images of
+their green embodiment. They are called _Chlorella_ by botanists, who
+have studied their life-history but have not yet discovered the full
+cycle. See Beyerinck in the Botan. Zeitung for 1890 (vol. xlviii, p.
+730, pl. vii; Leipzig), and for further references West's 'British
+Freshwater Algae,' p. 230 (1904).
+
+The list of beneficent organisms less commonly present than the green
+corpuscles includes a _Chironomus_ larva that builds parchment-like
+tubes in the substance of _Spongilla carteri_ and so assists in
+supporting the sponge, and of a peculiar little worm (_Chaetogaster
+spongillae_[S]) that appears to assist in cleaning up the skeleton of the
+same sponge at the approach of the hot weather and in setting free the
+gemmules (p. 93).
+
+     [Footnote S: Journ. As. Soc. Beng. n. s. ii, 1906, p. 189.]
+
+(c) _Organisms that take shelter in the Sponge or adhere to it
+externally._
+
+There are many animals which take shelter in the cavities of the sponge
+without apparently assisting it in any way. Among these are the little
+fish _Gobius alcockii_, which lays its eggs inside the oscula of _S.
+carteri_, thus ensuring not only protection but also a proper supply of
+oxygen for them (p. 94); the molluscs (_Corbula_, spp.) found inside _S.
+alba_ var. _bengalensis_ (p. 78); and the Isopod (_Tachaea
+spongillicola_) that makes its way into the oscula of _Spongilla
+carteri_ and _S. crateriformis_ (pp. 86, 94).
+
+In Europe a peculiar ciliated Protozoon (_Trichodina spongillae_) is
+found attached to the external surface of freshwater sponges. I have
+noticed a similar species at Igatpuri on _Spongilla crateriformis_, but
+it has not yet been identified. It probably has no effect, good or bad,
+on the sponge.
+
+
+FRESHWATER SPONGES IN RELATION TO MAN.
+
+In dealing with _Spongilla carteri_ I have suggested that sponges may be
+of some hygienic importance in absorbing putrid organic matter from
+water used both for ablutionary and for drinking purposes, as is so
+commonly the case with regard to ponds in India. Their bad odour has
+caused some species of Spongillidae to be regarded as capable of
+polluting water, but a mere bad odour does not necessarily imply that
+they are insanitary.
+
+Unless my suggestion that sponges purify water used for drinking
+purposes by absorbing putrid matter should prove to be supported by
+fact, the Spongillidae cannot be said to be of any practical benefit to
+man. The only harm that has been imputed to them is that of polluting
+water[T], of blocking up water-pipes by their growth--a very rare
+occurrence,--and of causing irritation to the human skin by means of
+their spicules--a still rarer one. At least one instance is, however,
+reported in which men digging in a place where a pond had once been were
+attacked by a troublesome rash probably due to the presence of
+sponge-spicules in the earth, and students of the freshwater sponges
+should be careful not to rub their eyes after handling dried specimens.
+
+     [Footnote T: See Potts, Proc. Ac. Philad. 1884, p. 28.]
+
+
+INDIAN SPONGILLIDAE COMPARED WITH THOSE OF OTHER COUNTRIES.
+
+In Weltner's catalogue of the freshwater sponges (1895) seventy-six
+recent species of Spongillidae (excluding _Lubosmirskia_) are enumerated,
+and the number now known is well over a hundred. In India we have
+twenty-nine species, subspecies, and varieties, while from the whole of
+Europe only about a dozen are known. In the neighbourhood of Calcutta
+nine species, representing three genera and a subgenus, have been found;
+all of them occur in the Museum tank. The only other region of similar
+extent that can compare with India as regards the richness of its
+freshwater sponge fauna is that of the Amazon, from which about twenty
+species are known. From the whole of North America, which has probably
+been better explored than any other continent so far as Spongillidae are
+concerned, only twenty-seven or twenty-eight species have been recorded.
+
+The Indian species fall into seven genera, one of which (_Spongilla_)
+consists of three subgenera. With one exception (that of
+_Pectispongilla_, which has only been found in Southern India) these
+genera have a wide distribution over the earth's surface, and this is
+also the case as regards the subgenera of Spongilla. Four genera
+(_Heteromeyenia_, _Acalle_, _Parmula_, and _Uruguaya_) that have not yet
+been found in India are known to exist elsewhere.
+
+Five of the Indian species are known to occur in Europe, viz.,
+_Spongilla lacustris_, _S. crateriformis_, _S. carteri_, _S. fragilis_,
+_Trochospongilla pennsylvanica_; while _Ephydatia meyeni_ is
+intermediate between the two commonest representatives of its genus in
+the Holarctic Zone, _Ephydatia fluviatilis_ and _E. muelleri_. Of the
+species that occur both in India and in Europe, two (_Spongilla
+lacustris_ and _S. fragilis_) are found in this country in forms
+sufficiently distinct to be regarded as subspecies or local races.
+Perhaps this course should also be taken as regards the Indian forms of
+_S. carteri_, of which, however, the commonest of the Indian races would
+be the typical one; but _S. crateriformis_ and _T. pennsylvanica_ seem
+to preserve their specific characters free from modification, whether
+they are found in Europe, Asia, or America.
+
+The freshwater sponges of Africa have been comparatively little studied,
+but two Indian species have been discovered, _S. bombayensis_ in Natal
+and _S. alba_ var. _cerebellata_ in Egypt. Several of the species from
+the Malabar Zone are, moreover, closely allied to African forms (p. 11).
+
+
+FOSSIL SPONGILLIDAE.
+
+The Spongillidae are an ancient family. Young described a species
+(_Spongilla purbeckensis_) from the Upper Jurassic of Dorset (Geol. Mag.
+London (new series) v, p. 220 (1878)), while spicules, assigned by
+Ehrenberg to various genera but actually those of _Spongilla lacustris_
+or allied forms, have been found in the Miocene of Bohemia (see
+Ehrenberg's 'Atlas fuer Micro-Geologie,' pl. xi (Leipzig, 1854), and
+Traxler in Foeldt. Koezl., Budapest, 1895, p. 211). _Ephydatia_ is also
+known in a fossil condition, but is probably less ancient than
+_Spongilla_.
+
+Ehrenberg found many sponge spicules in earth from various parts of the
+Indian Empire (including Baluchistan, Mangalore, Calcutta, the Nicobars
+and Nepal) and elsewhere, and it might be possible to guess at the
+identity of some of the more conspicuous species figured in his 'Atlas.'
+The identification of sponges from isolated spicules is, however, always
+a matter of doubt, and in some cases Ehrenberg probably assigned
+spicules belonging to entirely different families or even orders to the
+same genus, while he frequently attributed the different spicules of the
+same species to different genera. Among his fossil (or supposed fossil)
+genera that may be assigned to the Spongillidae wholly or in part are
+_Aphidiscus_, _Spongolithis_, _Lithastericus_ and _Lithosphaeridium_,
+many of the species of these "genera" certainly belonging to _Spongilla_
+and _Ephydatia_.
+
+
+ORIENTAL SPONGILLIDAE NOT YET FOUND IN INDIA.
+
+Few freshwater sponges that have not been found in India are as yet
+known from the Oriental Region, and there is positive as well as
+negative evidence that Spongillidae are less abundant in Malaysia than in
+this country. The following list includes the names of those that have
+been found, with notes regarding each species. It is quite possible that
+any one of them may be found at any time within the geographical
+boundaries laid down for this 'Fauna.' I have examined types or co-types
+in all cases except that of _Ephydatia fortis_, Weltner.
+
+I. _Spongilla_ (_Euspongilla_) _microsclerifera_*, Annandale
+(Philippines). P. U.S. Mus. xxxvii, p. 131 (1909).
+
+This sponge is closely related to _S. lacustris_, but apparently does
+not produce branches. It is remarkable for the enormous number of
+microscleres in its parenchyma.
+
+II. _S._ (_Euspongilla_) _philippinensis_*, Annandale (Philippines). P.
+U.S. Mus. xxxvi, p. 629 (1909).
+
+Related to _S. alba_ and still more closely to _S. sceptrioides_ of
+Australia. From the former it is readily distinguished by having
+minutely spined megascleres, green corpuscles, slender gemmule-spicules
+with short spines and no free microscleres.
+
+III. _S._ (? _Euspongilla_) _yunnanensis_*, Annandale (W. China). Rec.
+Ind. Mus. v, p. 197 (1910).
+
+Apparently allied to _S. philippinensis_ but with smooth
+skeleton-spicules and a more delicate skeleton.
+
+IV. _S._ (_Stratospongilla_) _sinensis_*, Annandale (Foochow, China). P.
+U.S. Mus. xxxviii, p. 183 (1910).
+
+This species and _S. clementis_ are referred to _Stratospongilla_ with
+some doubt. Their gemmules are intermediate in structure between those
+of that subgenus and those of _Euspongilla_.  In _S. sinensis_ the
+gemmules are packed together in groups at the base of the sponge, and
+their spicules are smooth, stout, and gradually pointed.
+
+V. _S._ (_Stratospongilla_) _clementis_*, Annandale (Philippines). P.
+U.S. Mus. xxxvi, p. 631 (1909).
+
+The gemmules are single and closely adherent at the base of the sponge.
+Their spicules are very slender and minutely spined.
+
+VI. _S._ (? _Stratospongilla_) _coggini_*, Annandale (W. China). Rec.
+Ind. Mus. v, p. 198 (1910).
+
+The gemmules apparently lack microscleres. They resemble those of _S.
+clementis_, to which the species is probably related, in other respects.
+The skeleton-spicules are spiny and rather stout, the species being
+strongly developed at the two ends.
+
+VII. _S._ (_Stratospongilla_) _sumatrana_*, Weber (Malay Archipelago).
+Zool. Ergebnisse einer Reise in Niederlaendisch Ost-Indien, i. p. 38
+(1890).
+
+Closely allied to _S. indica_ (p. 100) but with pointed
+skeleton-spicules.
+
+VIII. _Ephydatia fortis_, Weltner (Philippines). Arch. Naturgesch.
+lxi(i), p. 141 (1895).
+
+This species is remarkable for the great development of the spines on
+the shaft of the gemmule-spicules.
+
+IX. _Ephydatia bogorensis_*, Weber (Malay Archipelago). Zool. Ergebnisse
+einer Reise in Niederlaendisch Ost-Indien, i, p. 33 (1890).
+
+The gemmule-spicules have rather narrow flattish disks, the edge of
+which is feebly but closely serrated.
+
+X. _E. blembingia_*, Evans (Malay Peninsula). Q. J. Microsc. Sci.
+London, xliv, p. 81 (1901).
+
+The gemmules resemble those of _Dosilia plumosa_ but are spherical.
+There are no free microscleres.
+
+XI. _Tubella vesparium_*, v. Martens (Borneo). Arch. Naturg.
+
+Berlin, xxxiv, p. 62 (1868).
+
+Closely related to _T. vesparioides_ (p. 189), but with spiny
+megascleres.
+
+As regards _Spongilla decipiens_*, Weber, from the Malay Archipelago,
+see p. 97.
+
+
+II.
+
+HISTORY OF THE STUDY OF FRESHWATER SPONGES.
+
+The bath-sponge was known to the Greeks at an early date, and Homer
+refers to it as being used for cleansing furniture, for expunging
+writing, and for ablutionary purposes. He also mentions its peculiar
+structure, "with many holes." "Many things besides," wrote the English
+naturalist Ray in his 'Historia Plantarum' (1686), "regarding the powers
+and uses of sponges have the Ancients: to them refer." Ray himself
+describes at least one freshwater species, which had been found in an
+English river, and refers to what may be another as having been brought
+from America. In the eighteenth century Linne, Pallas and other authors
+described the commoner European Spongillidae in general terms, sometimes
+as plants and sometimes as animals, more usually as zoophytes or
+"plant-animals" partaking of the nature of both kingdoms. The gemmules
+were noted and referred to as seeds. The early naturalists of the
+Linnaean Epoch, however, added little to the general knowledge of the
+Spongillidae, being occupied with theory in which theological disputes
+were involved rather than actual observation, and, notwithstanding the
+fact that the animal nature of sponges was clearly demonstrated by
+Ellis[U] in 1765, it was not until the nineteenth century was well
+advanced that zoologists could regard sponges in anything like an
+impartial manner.
+
+          [Footnote U: Phil. Trans. Roy. Soc. lv, p. 280.]
+
+One of the pioneers in the scientific study of the freshwater forms was
+the late Dr. H. J. Carter, who commenced his investigations, and carried
+out a great part of them, in Bombay with little of the apparatus now
+considered necessary, and with a microscope that must have been grossly
+defective according to modern ideas. His long series of papers
+(1848-1887) published in the 'Annals and Magazine of Natural History' is
+an enduring monument to Indian zoology, and forms the best possible
+introduction to the study of the Spongillidae. Even his earlier mistakes
+are instructive, for they are due not so much to actual errors in
+observation as to a faithful transcription of what was observed with
+faulty apparatus.
+
+Contemporary with Carter were two authors whose monographs on the
+freshwater sponges did much to advance the study of the group, namely,
+J. S. Bowerbank, whose account of the species known at the time was
+published in the 'Proceedings of the Zoological Society of London' in
+1882, and the veteran American naturalist Mr. Edward Potts, whose study
+of the freshwater sponges culminated in his monograph published in the
+'Proceedings of the Academy of Natural Sciences of Philadelphia' in
+1887. Carter's own revision of the group was published in the 'Annals
+and Magazine of Natural History' in 1881. The names of Vejdovsky, who
+prefaced Potts's monograph with an account of the European species, and
+of Dybowsky, who published several important papers on classification,
+should also be mentioned, while Weltner's catalogue of the known species
+(1895) is of the greatest possible value to students of the group.
+
+Many authors have dealt with the physiology, reproduction and
+development of the Spongillidae, especially in recent years; Dr. R.
+Evans's description of the larva of _Spongilla lacustris_ (1899), and
+his account of the development of the gemmule in _Ephydatia blembingia_
+(1901), Zykoff's account of the development of the gemmule and of the
+sponge from the gemmule (1892), and Weltner's observations on colour and
+other points (1893, 1907), may be mentioned in particular. Laurent's
+observations on development (1844), which were published in the 'Voyage
+de la Bonite,' and especially the exquisite plates which accompany them,
+have not received the notice they deserve, probably on account of their
+method of publication.
+
+
+LITERATURE.
+
+The fullest account of the literature on the Spongillidae as yet
+published will be found in the first of Weltner's 'Spongillidenstudien'
+(Archiv fuer Naturgeschichte, lix (i), p. 209, 1893). Unfortunately it
+contains no references of later date than 1892. The following list is
+not a complete bibliography, but merely a list of books and papers that
+should prove of use to students of the Oriental Spongillidae.
+
+(a) _Works of Reference._
+
+1863. BOWERBANK, "A Monograph of the Spongillidae," P. Zool. Soc. London,
+1863, pp. 440-472, pl. xxxviii.
+
+1867. GRAY, J. E., "Notes on the arrangement of Sponges, with the
+description of some new genera." _ibid._ 1867, pp. 492-558.
+
+1881. CARTER, "History and classification of the known species of
+_Spongilla_," Ann. Nat. Hist. (5) vii, pp. 77-107, pls. v, vi.
+
+1883. VEJDOVSKY, "Die Suesswasserschwaemme Boehmens," Abh. Koen. Boehm. Ges.
+Wiss. (math.-natur. Classe), xii, pp. 1-43, pls. i-iii.
+
+1887. VOSMAER, "Spongien (Porifera)," in Bronn's Thier-Reichs.
+
+1887. POTTS, "Contributions towards a synopsis of the American forms of
+Fresh-Water Sponges, with descriptions of those named by other authors
+and from all parts of the world," P. Ac. Philad. pp. 158-279, pls.
+v-xii.
+
+1887. VEJDOVSKY, "Diagnosis of the European Spongillidae," _ibid._ pp.
+172-180.
+
+1888. WIERZEJSKI, "Beitrag zur Kenntnis der Suesswasserschwaemme," Verh.
+k.-k. zool.-bot. Ges. Wien, xxxviii, pp. 529-536, pl. xii.
+
+1891. WELTNER, in Zacharias's Die Tier- und Pflanzenwelt des
+Suesswassers: I, Die Suesswasserschwaemme.
+
+1895. WELTNER, "Spongillidenstudien, III," Arch. Naturg. Berlin, lxi
+(i), pp. 114-144.
+
+1895. KORSCHELT and HEIDER, Text-book of the Embryology of
+Invertebrates: English edition, prepared by E. L. Mark and W. McM.
+Woodworth, Vol. I, chap. i.
+
+1900. MINCHIN, Sponges--Phylum Porifera in Lankester's "Treatise on
+Zoology," ii.
+
+1905. KUEKENTHAL, W., Leitfaden fuer das Zoologische Praktikum (3rd Ed.,
+Jena), 2. Kursus: Porifera, Schwaemme, p. 31.
+
+1906. SOLLAS, I. B. J., Cambridge Natural History--I. Porifera
+(Sponges).
+
+1909. WELTNER, "Spongillidae, Suesswasserschwaemme," in Brauer's "Die
+Suesswasserfauna Deutschlands," Heft xix, pp. 177-190.
+
+1910. LLOYD, An Introduction to Biology for Students in India.
+
+(b) _Special Memoirs on Anatomy, Physiology, and Development._
+
+1844. LAURENT, "Recherches sur l'Hydre et l'Eponge d'eau douce," Voyage
+de la Bonite, ii, pp. 113-276.
+
+1854. CARTER, "Zoosperms in _Spongilla_," Ann. Nat. Hist. (2) xiv, pp.
+334-336, pl. xi, figs. 1-6.
+
+1857. CARTER, "On the ultimate structure of _Spongilla_, and additional
+notes on Freshwater Infusoria," Ann. Nat. Hist. (2) xx, pp. 21-41, pl.
+i, figs. 1-11.
+
+1859. CARTER, "On the identity in structure and composition of the
+so-called 'seed-like body' of _Spongilla_ with the winter-egg of the
+Bryozoa, and the presence of starch-granules in each," Ann. Nat. Hist.
+(3) iii, pp. 331-343, pl. viii.
+
+1859. LIEBERKUEHN, "Neue Beitraege zur Anatomie der Spongien," Arch. Anat.
+Phys. J. Mueller, pp. 374-375, 526-528.
+
+1871. CARTER, "Discovery of the animal of the Spongiadae confirmed," Ann.
+Nat. Hist. (4) vii, p. 445.
+
+1871. HAECKEL, "Ueber die sexuelle Fortpflanzung und das natuerliche
+System der Schwaemme," Jenaische Zeitschr. f. Naturw. vi, pp. 643, 645.
+
+1874. CARTER, "On the nature of the seed-like body of _Spongilla_; on
+the origin of the mother-cell of the spicule; and on the presence of
+spermatozoa in the _Spongida_," Ann. Nat. Hist. (4) xiv, pp. 97-111.
+
+1874. LANKESTER, E. RAY, "The mode of occurrence of chlorophyll in
+_Spongilla_," Q. J. Micr. Sci. xiv, pp. 400-401.
+
+1875. SORBY, H., "On the Chromatological relations of _Spongilla
+fluviatilis_," Q. J. Micr. Sci. xv, pp. 47-52.
+
+1878. GANIN, "Zur Entwickelung der _Spongilla fluviatilis_," Zool. Anz.
+I, pp. 195-199.
+
+1882. CARTER, "Spermatozoa, polygonal cell-structure, and the green
+colour in _Spongilla_, together with a new species," Ann. Nat. Hist. (5)
+x, pp. 362-372, pl. 16.
+
+1882. GEDDES, "Further researches on animals containing chlorophyll,"
+Nature, xxv, pp. 303-305, 361-362.
+
+1882. LANKESTER, E. RAY, "On the chlorophyll-corpuscles and amyloid
+deposits of _Spongilla_ and _Hydra_," Q. J. Micr. Sci. xxii (n. s.), pp.
+229-254, pl. xx.
+
+1883. MARSHALL, W., "Einige vorlaeutige Bemerkungen ueber die Gemmulae der
+Suesswasserschwaemme," Zool. Anz. vi, pp. 630-634, 648-652.
+
+1884. CARTER, "The branched and unbranched forms of the Freshwater
+Sponges considered generally," Ann. Nat. Hist. (5) xiii, pp. 269-273.
+
+1884. MARSHALL, W., "Vorlaeutige Bemerkungen ueber die
+Fortpflanzungsverhaeltnisse von _Spongilla lacustris_," Ber. Naturf. Ges.
+Leipzig,* pp. 22-29.
+
+1884. POTTS, "Freshwater Sponges as improbable causes of the pollution
+of river-water," P. Ac. Philad. pp. 28-30.
+
+1885. SCHULZE, F. E., "Ueber das Verhaeltniss der Spongien zu den
+Choanoflagellaten," SB. preuss. Akad. Wiss. Berlin, pp. 179-191.
+
+1886. GOETTE, Untersuchungen zur Entwickelungsgeschichte von _Spongilla
+fluviatilis_*, Hamburg und Leipzig (5 plates).
+
+1886. WIERZEJSKI, "Le developpement des Gemmules des Eponges d'eau douce
+d'Europe," Arch. Slaves Biologie, i, pp. 26-47 (1 plate).
+
+1887. CARTER, "On the reproductive elements of the _Spongida_," Ann.
+Nat. Hist. (5) xix, pp. 350-360.
+
+1889. MAAS, "Zur Metamorphose der Spongillalarve," Zool. Anz. xii, pp.
+483-487.
+
+1890. MAAS, "Ueber die Entwickelung des Suesswasserschwaemmes," Zeitschr.
+Wiss. Zool. 1, pp. 527-554, pls. xxii, xxiii.
+
+1890. WEBER, M. et Mme. A., "Quelques nouveau cas de Symbiose," Zool.
+Ergebn. einer Reise Niederlaend. Ost-Indien, i, pp. 48-72, pl. v.
+
+1892. ZYKOFF, "Die Entwicklung der Gemmulae der _Ephydatia fluviatilis_
+auct.," Zool. Anz. xv, pp. 95-96.
+
+1892. ZYKOFF, "Die Bildung der Gemmulae bei _Ephydatia Fluviatilis_," Revue
+Sc. Nat. Soc. St. Petersbourg,* pp. 342-344.
+
+1892. ZYKOFF, "Die Entwicklung der Gemmulae bei _Ephydatia fluviatilis_
+auct.," Bull. Soc. Imp. Natur. Moscou, n. s. vi, pp. 1-16, pl. i, ii.
+
+1892. ZYKOFF, "Entwickelungsgeschichte von _Ephydatia muelleri_, Liebk.
+aus den Gemmulae," Biol. Centralbl. xii, pp. 713-716.
+
+1893. WELTNER, "Spongillidenstudien, II," Arch. Naturg. Berlin, lix (1),
+pp. 245-282, pls. viii, ix.
+
+1899. EVANS, R., "The structure and metamorphosis of the larva of
+_Spongilla lacustris_," Q. J. Micr. Sci. xlii, pp. 363-476, pls.
+xxxv-xli.
+
+1901. EVANS, R., "A description of _Ephydatia blembingia_, with an
+account of the formation and structure of the gemmule," Q. J. Micr. Sci.
+xliv, pp. 71-109, pls. i-iv.
+
+1907. WELTNER, "Spongillideustudien, V.: Zur Biologie von _Ephydatia
+fluviatilis_ and die Bedeutung der Amoebocyten fuer die Spongilliden,"
+Arch. Naturg. Berlin, lxxiii (i), pp. 273-286.
+
+1907. ANNANDALE, "The buds of _Spongilla proliferens_, Annand.," Rec.
+Ind. Mus. i, pp. 267, 268.
+
+1907. ANNANDALE, "Embryos of _Ephydatia blembingia_, Evans," _ibid._ p.
+269.
+
+1907. ANNANDALE, "The nature of the pores in _Spongilla_," _ibid._ pp.
+270-271.
+
+(c) _Descriptions of Asiatic Species[V] and of Animals associated with
+them._
+
+     [Footnote V: Descriptions of Siberian sponges are not
+     included in these references.]
+
+1847-1848. CARTER, "Notes on the species, structure, and animality of
+the Freshwater Sponges in the tanks of Bombay (Genus _Spongilla_),"
+Trans. Bombay Med. & Phys. Soc., 1847, and Ann. Nat. Hist. (2) i, pp.
+303-311, 1848.
+
+1849. CARTER, "A descriptive account of the Freshwater Sponges (Genus
+_Spongilla_) in the Island of Bombay, with observations on their
+structure and development," Ann. Nat. Hist. (2) iv, pp. 81-100, pls.
+iii-v.
+
+1868. MARTENS, E. VON, "Ueber einige oestasiatische Suesswasserthiere,"
+Arch. Naturg. Berlin, xxxiv, pp. 1-67: IV., Ein Suesswasserschwamm aus
+Borneo, pp. 61-64, pl. i, fig. 1.
+
+1881. CARTER, "On _Spongilla cinerea_," Ann. Nat. Hist. (5) vii, p. 263.
+
+1890. WEBER, M., "Zoologische Ergebnisse einer Reise in Niederlaendisch
+Ost-Indien," i, pp. 30-47, pl. iv.
+
+1901. EVANS, R., "A description of _Ephydatia blembingia_, with an
+account of the formation and structure of the gemmule," Q. J. Micr. Sci.
+xliv, pp. 71-109, pls. i-iv.
+
+1901. WELTNER, "Suesswasserspongien von Celebes (Spongillidenstudien,
+IV.)," Arch. Naturg. Berlin, lxvii (1) (Special Number), pp. 187-204,
+pls. vi, vii.
+
+1906. ANNANDALE, "A variety of _Spongilla lacustris_ from brackish water
+in Bengal," J. As. Soc. Bengal, (n. s.) ii, pp. 55-58.
+
+1906. ANNANDALE, "Some animals found associated with _Spongilla carteri_
+in Calcutta," _ibid._ pp. 187-196.
+
+1907. WILLEY, "Freshwater Sponge and Hydra in Ceylon," Spolia Zeylanica,
+iv, pp. 184-185.
+
+1907. ANNANDALE, "On Freshwater Sponges from Calcutta and the
+Himalayas," J. As. Soc. Bengal, (n. s.) iii, pp. 15-26.
+
+1907. ANNANDALE, "Gemmules of _Trochospongilla phillottiana_, Annand.,"
+Rec. Ind. Mus. i, p. 269.
+
+1907. ANNANDALE, "Description of two new Freshwater Sponges from Eastern
+Bengal, with remarks on allied forms," _ibid._ pp. 387-392.
+
+1908. ANNANDALE, "Preliminary notice of a collection of Sponges from W.
+India, with descriptions of two new species," Rec. Ind. Mus. ii, pp.
+25-28.
+
+1908. KIRKPATRICK, "Description of a new variety of _Spongilla
+loricata_, Weltner," _ibid._ pp. 97-99.
+
+1908. ANNANDALE, "Preliminary notice of a collection of Sponges from
+Burma, with the description of a new species of _Tubella_," _ibid._ pp.
+157-158.
+
+1909. ANNANDALE, "Report on a small collection of Sponges from
+Travancore," Rec. Ind. Mus. iii, pp. 101-104, pl. xii.
+
+1909. NEEDHAM, "Notes on the Neuroptera in the collection of the Indian
+Museum," _ibid._ pp. 206-207.
+
+1909. ANNANDALE, "Description of a new species of _Spongilla_ from
+Orissa," _ibid._ p. 275.
+
+1909. ANNANDALE, "Beitraege zur Kenntnis der Fauna von Sued-Afrika: IX.
+Freshwater Sponges," Zool. Jahrb. (Syst.) xxvii, pp. 559-568.
+
+1909. ANNANDALE, "Report on a collection of Freshwater Sponges from
+Japan," Annot. Zool. Japon, vii, pp. 105-112, pl. ii.
+
+1909. ANNANDALE, "Freshwater Sponges in the collection of the United
+States National Museum: Part I. Specimens from the Philippines and
+Australia," P. U.S. Mus. xxxvi, pp. 627-632.
+
+1909. ANNANDALE, "Freshwater Sponges collected in the Philippines by the
+'Albatross' Expedition," _ibid._ xxxvii, pp. 131-132.
+
+1909. ANNANDALE, "Freshwater Sponges in the collection of the United
+States National Museum: Part II. Specimens from North and South
+America," _ibid._ pp. 401-406.
+
+1910. ANNANDALE, "Freshwater Sponges in the collection of the United
+States National Museum: Part III. Description of a new species of
+_Spongilla_ from China," _ibid._ xxxviii, p. 183.
+
+1910. ANNANDALE, "Description of a new species of Sponge from Cape
+Comorin," Rec. Ind. Mus. v, p. 31.
+
+1910. STEPHENSON, "On some aquatic Oligochaete worms commensal in
+_Spongilla carteri_," _ibid._ pp. 233-240.
+
+1910. ANNANDALE, "Note on a Freshwater Sponge and Polyzoon from Ceylon,"
+Spolia Zeylanica, vii. p. 63, pl. i.
+
+
+
+
+GLOSSARY OF TECHNICAL TERMS USED IN PART I.
+
+
+  _Amphioxi_ (adj.               Rod-like spicules sharp at both ends.
+  _amphioxous_)
+
+  _Amphistrongyli_ (adj.         Rod-like spicules blunt at both ends.
+  _amphistrongylous_)
+
+  _Basal membrane_               A horny, structureless membrane found
+                                 at the base of some sponges.
+
+  _Birotulate_ (subst. or adj.)  Spicule with a transverse disk at both
+                                 ends.
+
+  _Bubble-cells_                 Spherical cells of the parenchyma the
+                                 contents of which consist of a drop of
+                                 liquid covered by a thin film of
+                                 protoplasm.
+
+  _Ciliated_ (or _flagellated_)  A cavity lined with collar-cells.
+  _chamber_
+
+  _Collar-cell_ (_choanocyte_)   Cell provided at one end with a
+                                 membranous collar and a vibratile lash
+                                 or flagellum that springs from within
+                                 the collar.
+
+  _Derma_ or _ectodermal layer_  A layer of flat cells arranged like a
+                                 pavement on the surface of the sponge.
+
+  _Exhalent_ (or _efferent_)     A tubular canal through which water
+  _canal_                        passes from a ciliated chamber towards
+                                 the osculum.
+
+  _Fibres_ (skeleton)            Thread-like structures that compose the
+                                 skeleton of the sponge and are formed
+                                 (in the Spongillidae) mainly of
+                                 overlapping spicules.
+
+  _Flesh-spicules_               Microscleres (_q. v._) that lie free in
+                                 the parenchyma and the derma.
+
+  _Foramen_                      An orifice of the gemmule.
+
+  _Foraminal tubule_             A horny tube that surrounds the foramina
+                                 of some gemmules.
+
+  _Gemmule_                      A mass of cells packed with food-material,
+                                 surrounded by at least one horny coat,
+                                 capable of retaining vitality in
+                                 unfavourable conditions and finally of
+                                 giving origin to a new sponge.
+
+  _Green corpuscles_             Minute green bodies found inside cells
+                                 of sponges and other animals and
+                                 representing a stage in the life-history
+                                 of an alga (_Chlorella_).
+
+  _Inhalent_ (or _afferent_)     A tubular canal through which water
+  canal                          passes from the exterior towards a
+                                 ciliated chamber.
+
+  _Megascleres_                  The larger spicules that (in the
+                                 Spongillidae) form the basis of the
+                                 skeleton of the sponge.
+
+  _Microscleres_                 Smaller spicules that lie free in the
+                                 substance or the derma of the sponge, or
+                                 are associated with the gemmule.
+
+  _Monaxon_                      (Of spicules) having a single main axis;
+                                 (of sponges) possessing skeleton spicules
+                                 of this type.
+
+  _Osculum_                      An aperture through which water is
+                                 ejected from the sponge.
+
+  _Oscular collar_               A ring-shaped membrane formed by an
+                                 extension of the derma round an osculum.
+
+  _Parenchyma_                   The gelatinous part of the sponge.
+
+  _Pavement layer_               Adherent gemmules arranged close together
+                                 in a single layer at the base of a sponge.
+
+  _Pneumatic coat_               A horny or chitinous layer on the surface
+                                 of the gemmule containing air-spaces.
+                                 If these spaces are of regular form and
+                                 arrangement it is said to be _cellular_;
+                                 if they are minute and irregular it is
+                                 called _granular_.
+
+  _Pore_                         A minute hole through which water is
+                                 taken into the sponge.
+
+  _Pore-cell_ (_porocyte_)       A cell pierced by a pore.
+
+  _Radiating fibres_             Fibres in the skeleton of a sponge that
+                                 are vertical or radiate from its centre.
+
+  _Rotula_                       A transverse disk borne by a microsclere.
+
+  _Rotulate_ (subst. or adj.)    Spicule bearing one or two transverse
+                                 disks.
+
+  _Spicule_                      A minute mineral body of regular and
+                                 definite shape due not to the forces of
+                                 crystallization but to the activity of
+                                 the living cell or cells in which it is
+                                 formed.
+
+  _Spongin_                      The horny substance found in the skeletal
+                                 framework and the coverings of gemmules
+                                 of sponges. Structures formed of
+                                 this substance are often referred to as
+                                 _chitinous_.
+
+  _Subdermal cavity_             A cavity immediately below the derma
+                                 (_q. v._).
+
+  _Transverse fibres_            Fibres in the skeleton of a sponge that
+                                 run across between the radiating fibres.
+
+  _Tubelliform_ (of spicule)     Having a straight shaft with a transverse
+                                 disk at one end and a comparatively
+                                 small knob-like projection at the other.
+
+
+
+
+SYSTEMATIC LIST OF THE INDIAN SPONGILLIDAE.
+
+
+[Types, schizotypes, or cotypes have been examined in the case of all
+species, &c., whose names are marked thus, *.]
+
+  Genus 1. SPONGILLA, Lamarck (1816).
+    Subgenus A. EUSPONGILLA, Vejdovsky (1883).
+       1.     ? _S. lacustris_, auct. (perhaps in N.W. India).
+       1_a_. _S. lacustris_ subsp. _reticulata_*, Annandale (1907).
+       2.    _S. proliferens_*, Annandale (1907).
+       3.    _S. alba_*, Carter (1849).
+       3_a_. _S. alba_ var. _cerebellata_, Bowerbank (1863).
+       3_b_. _S. alba_ var. _bengalensis_*, Annandale (1906).
+       4.    _S. cinerea_*, Carter (1849).
+       5.    _S. travancorica_*, Annandale (1909).
+       6.    _S. hemephydatia_*, Annandale (1909).
+       7.    _S. crateriformis_* (Potts) (1882).
+    Subgenus B. EUNAPIUS, J. E. Gray (1867).
+       8_a_. _S. carteri_ var. _mollis_*, nov.
+       8_b_. _S. carteri_ var. _cava_*, nov.
+       8_c_. _S. carteri_ var. _lobosa_*, nov.
+       9_a_. _S. fragilis_ subsp. _calcuttana_*, nov.
+       9_b_. _S. fragilis_ var. _decipiens_, Weber (probably Malaysian,
+              not Indian).
+      10.    _S. gemina_*, sp. nov.
+      11.    _S. crassissima_*, Annandale (1907).
+      11_a_. _S. crassissima_ var. _crassior_*, Annandale (1907).
+    Subgenus C. STRATOSPONGILLA, Annandale (1909).
+      12.    _S. indica_*, Annandale (1908).
+      13.    _S. bombayensis_*, Carter (1882).
+      14.    _S. ultima_*, Annandale (1910).
+
+  Genus 2. PECTISPONGILLA, Annandale (1909).
+      15.    _P. aurea_*, Annandale (1909).
+      15_a_. _P. aurea_ var. _subspinosa_*, nov.
+
+  Genus 3. EPHYDATIA, Lamouroux (1816).
+      16.    _E. meyeni_* (Carter) (1849).
+
+  Genus 4. DOSILIA, J. E. Gray (1867).
+      17.    _D. plumosa_* (Carter) (1849).
+
+  Genus 5. TROCHOSPONGILLA, Vejdovsky (1883).
+      18.    _T. latouchiana_*, Annandale (1907).
+      19.    _T. phillottiana_*, Annandale (1907).
+      20.    _T. pennsylvanica_* (Potts) (1882).
+
+  Genus 6. TUBELLA, Carter (1881).
+      21.    _T. vesparioides_*, Annandale (1908).
+
+  Genus 7. CORVOSPONGILLA, nov.
+      22.    _C. burmanica_* (Kirkpatrick) (1908).
+      23.    _C. lapidosa_* (Annandale) (1908).
+
+
+Order HALICHONDRINA.
+
+
+Siliceous monaxon sponges in which the horny skeleton is much reduced or
+absent and the spicular skeleton is more or less definitely reticulate.
+The microscleres are usually rod-like and rarely have more than one main
+axis.
+
+
+Family SPONGILLIDAE.
+
+SPONGILLADAE, J. E. Gray, P. Zool. Soc. London, 1867, p. 550.
+
+Freshwater Halichondrina which at certain seasons produce gemmules armed
+with peculiar microscleres. Two distinct kinds of microsclere are often
+present, that associated with the gemmule sometimes consisting of a
+vertical shaft at the ends of which transverse disks or rotulae are
+borne. There is always at least a trace of a subdermal cavity.
+
+Many authors divide the Spongillidae into two subfamilies:--Spongillinae
+(or Euspongillinae), in which the gemmule-spicules have no transverse
+rotulae, and Meyeninae (or Ephydatiinae), in which they have rotules at one
+or both ends. So gradual, however, is the transition that I find it
+difficult to decide in one instance to which of two genera, typical
+respectively of the two "subfamilies," a species should be assigned.
+Minchin in his account of the Porifera in Lankester's "Treatise on
+Zoology" (1900) regards the Spongillidae merely as a subfamily of the
+Heterorrhaphidae, and there certainly are few differences of a definite
+nature between them and the marine family (or subfamily) Remeridae.
+
+
+  _Key to the Indian Genera of_ Spongillidae.
+
+    I. Microscleres without transverse disks.
+       A. Microscleres of the parenchyma similar
+          in general structure to those or the
+          gemmule; the latter without comb-like
+          vertical rows of spines at the ends           SPONGILLA, p. 67.
+       B. Microscleres of the gemmule with comb-like
+          vertical rows of spines at both ends    PECTISPONGILLA, p. 106.
+
+   II. Some or all of the microscleres birotulate.
+       (Birotulate microscleres of one kind only.)
+       A. Microscleres of the gemmule birotulate, the
+          rotules with serrated or strongly sinuous
+          edges; parenchyma spicules usually absent,
+          never of complicated structure               EPHYDATIA, p. 108.
+       B. Microscleres of the gemmule as in
+          _Ephydatia_; microscleres of the parenchyma
+          consisting of numerous shafts
+          meeting in different planes in a central
+          nodule                                         DOSILIA, p. 110.
+       C. Microscleres as in _Ephydatia_ except
+          that the rotulae of the gemmule-spicules
+          have smooth edges                      TROCHOSPONGILLA, p. 113.
+       D. Microscleres of the gemmule without a
+          trace of rotules, those of the parenchyma
+          birotulate                        CORVOSPONGILLA, nov., p. 122.
+
+  III. Microscleres of the gemmule with a well-developed
+       basal rotule and a vertical shaft
+       ending above in a mere knob.                      TUBELLA, p. 120.
+
+The most distinct genus of Spongillidae not yet found in India is
+_Heteromeyenia_, Potts. It is easily distinguished from all others by
+the fact that the birotulate spicules of the gemmule are of two quite
+distinct kinds, which occur together on every mature gemmule.
+_Heteromeyenia_ is represented by several American species, one of which
+has been found in Europe. _Acalle_, J. E. Gray, which is represented by
+a single South American species (_Spongilla recurvata_, Bowerbank), is
+related to _Heteromeyenia_ but has one kind of gemmule-spicule
+tubelliform, the other birotulate. Probably _Uraguaya_, Carter, should
+be regarded as a subgenus of _Trochospongilla_ with an unusually solid
+skeleton; it is peculiar to S. America. _Parmula_, Carter (=_Drulia_,
+Gray) includes South American forms allied to _Tubella_, but with the
+shaft of the gemmule-spicule degenerate and consisting of a mere
+projection in the centre of a shield-like body, which represents the
+lower rotule. The status of _Potamolepis_, Marshall, originally
+described from the Lake of Galilee, is very doubtful; possibly some or
+all of its species belong to the subgenus of _Spongilla_ here called
+_Stratospongilla_ (p. 100); but they are stated never to produce
+gemmules. The same is the case as regards _Pachydictyum_, Weltner, which
+consists of a single species from Celebes.
+
+The sponges from Lake Baikal assigned by Weltner (Arch. Naturg. lxi (i)
+p. 131) to the subfamily Lubomirskinae are of doubtful position and need
+not be considered here; while _Lessepsia_, Keller, from one of the salt
+lakes on the Suez Canal, certainly does not belong to the family,
+although it is assigned to it by von Lendenfeld (Mon. Horny Sponges, p.
+904 (1889)) and subsequently by Minchin (Porifera, p. 152, in
+Lankester's Treatise on Zoology, part ii (1900)).
+
+
+Genus 1. SPONGILLA, _Lamarck_ (Carter _emend._).
+
+    _Spongilla_, Lamarck, Histoire des Animaux sans Vertebres, ii, p. 111
+      (1836).
+    _Spongilla_, Carter, Ann. Nat. Hist. (5) vii, p. 86 (1881).
+    _Euspongilla_, Vejdovsky, Abh. Boehm. Ges. xii, p. 15 (1883).
+    _Spongilla_, Potts, P. Ac. Philad. 1887, p. 182.
+
+TYPE, _Spongilla lacustris_, auctorum.
+
+Spongillidae in which the gemmules have (normally) cylindrical or
+subcylindrical spicules that are sharp or blunt at the ends, without a
+distinct transverse disk or disks and without comb-like vertical rows of
+spines.
+
+The skeleton is variable in structure, sometimes being almost amorphous,
+sometimes having well-defined radiating and transverse fibres firmly
+compacted with spongin. The skeleton-spicules are either sharp or blunt
+at the ends. Flesh-spicules are often absent; when present they are
+needle-like and resemble the gemmule-spicules in general structure; they
+have not even rudimentary rotules at their ends. The gemmules either lie
+free in the substance of the sponge or are attached to its support;
+sometimes they adhere together in free or attached groups.
+
+_Spongilla_ is undoubtedly the most primitive genus of the Spongillidae,
+its spicules showing less sign of specialization than those of any other
+genus included in the family. As a fossil it goes back at any rate to
+the Upper Jurassic (p. 52).
+
+GEOGRAPHICAL DISTRIBUTION.--Cosmopolitan. In most countries the majority
+of the freshwater sponges belong to this genus, but in Japan _Ephydatia_
+seems to predominate.
+
+
+_Key to the Indian Species of_ Spongilla.
+
+  I. Gemmule provided with a thick, apparently
+      granular pneumatic coat in
+      which the gemmule-spicules are arranged
+      tangentially or vertically. (Subgenus
+      _Euspongilla_, p. 69.)
+    A. No foraminal tubule.
+      _a._  Sponge bright green, soft and
+            compressiblewhen fresh, very fragile
+            dry                                    _lacustris_, p. 69.
+      _a'._ Sponge white or grey, hard both
+            fresh and dry                          _alba_, p. 76.
+    B. A foraminal tubule present.
+      _b._  Skeleton-spicules smooth.
+        beta.   Gemmules free; gemmule-spicules
+                arranged tangentially and
+                horizontally                       _proliferens_, p. 72.
+        beta'.  Gemmules free; gemmule-spicules
+                arranged vertically or nearly
+                so in a single series              _hemephydatia_, p. 82.
+        beta''. Gemmules firmly fixed
+                to the support of the sponge;
+                gemmule-spicules almost vertical,
+                irregularly arranged, as a rule in
+                more than one series               _travancorica_, p. 81.
+      _b'._ Skeleton-spicules spiny or
+            irregular in outline.
+        beta'''. Gemmule-spicules tangential
+                 and horizontal, without
+                 rudimentary rotules               _cinerea_, p. 79.
+        beta''''. Gemmule-spicules vertical or
+                 nearly so, often with
+                 rudimentary rotules at the tips   _crateriformis_, p. 83.
+
+  II. Gemmules surrounded in several layers
+      by distinct polygonal air-spaces with
+      chitinous walls. (Subgenus _Eunapius_,
+      p. 86.)
+    A. Gemmules single. Skeleton- and
+       gemmule-spicules smooth, pointed,
+       not very stout                              _carteri_, p. 87.
+    B. Gemmules bound together in pairs.
+       Skeleton friable; skeleton-spicules
+       slender                                     _gemina_, nov., p. 97.
+    C. Gemmules bound together in free
+       groups of more than two or forming
+       a "pavement-layer" at the base of
+       the sponge.
+      _c._  Skeleton friable;
+            skeleton-spicules slender              _fragilis_, p. 95.
+      _c'._ Skeleton very hard and
+            resistant; skeleton-spicules stout     _crassissima_, p. 98.
+
+  III. Gemmules without or with irregular
+       pneumatic coat, covered by a chitinous
+       membrane or membranes in which the
+       gemmule-spicules lie parallel to the
+       surface. (Subgenus _Stratospongilla_,
+       p. 100.)
+
+    A. Skeleton spicules spiny or irregular in
+       outline.
+
+      _a._  Skeleton-spicules blunt; gemmules
+            covered by a single chitinous
+            membrane                               _indica_, p. 100.
+
+      _a'._ Skeleton-spicules sharp; gemmules
+            covered by two chitinous membranes     _bombayensis_, p. 102.
+
+    B. Skeleton-spicules smooth.
+       Skeleton-spicules sharp; gemmule
+       spicules very irregular in form             _ultima_, p. 104.
+
+
+Subgenus A. EUSPONGILLA, _Vejdovsky_.
+
+    _Euspongilla_, Vejdovsky, Abh. Boehm. Ges. xii, p. 15 (1883).
+    _Euspongilla_, _id._, in Potts's "Fresh-Water Sponges," P. Ac. Philad.
+      1887, p. 172.
+    _Euspongilla_, Weltner, in Zacharias's Tier- und Pflanzenwelt des
+      Suesswassers, i, p. 210 (1891).
+
+TYPE, _Spongilla lacustris_, auctorum.
+
+Spongillae in which the gemmules are covered with a thick, apparently
+granular pneumatic coat. A delicate membrane often occurs outside this
+coat, but it is never thick or horny. The gemmules usually lie free in
+the sponge but sometimes adhere to its support; rarely they are fastened
+together in groups (_e. g._ in _S. aspinosa_, Potts). The
+skeleton-spicules are never very stout and the skeleton is always
+delicate.
+
+The species in this subgenus are closely allied and must be
+distinguished rather by the sum of their peculiarities than by any one
+character. They occur in all countries in which Spongillidae are found.
+Seven Indian species may be recognized.
+
+
+1. Spongilla lacustris, _auctorum_.
+
+    _Spongilla lacustris_, Bowerbank, P. Zool. Soc. London, 1863, p. 441,
+      pl. xxxviii, fig. 14.
+    _Spongilla lacustris_, Carter, Ann. Nat. Hist. (5) vii, p. 87 (1881).
+    _Euspongilla lacustris_, Vejdovsky, in Potts's "Fresh-Water Sponges,"
+      P. Ac. Philad. 1887, p. 172.
+    _Spongilla lacustris_, Potts, _ibid._, p. 186, pl. v, fig. 1, pl. vii,
+      figs. 1-6.
+    _Euspongilla lacustris_, Weltner, in Zacharias's Tier- und Pflanzenwelt
+      des Suesswassers, i, p. 211, figs. 36-38 (1891).
+    _Spongilla lacustris_, _id._, Arch. Naturg. lxi (i), pp. 118, 133-135
+      (1895).
+    _Spongilla lacustris_, Annandale, J. Linn. Soc., Zool., xxx, p. 245
+      (1908).
+
+     [I have not attempted to give a detailed synonymy of this
+     common species. There is no means of telling whether many of
+     the earlier names given to forms or allies of _S. lacustris_
+     are actual synonyms, and it would serve no useful purpose,
+     so far as the fauna of India is concerned, to complicate
+     matters by referring to obscure descriptions or possible
+     descriptions of a species only represented in India, so far
+     as we know, by a specialized local race, to which separate
+     references are given.]
+
+_Sponge_ soft and easily compressed, very brittle when dry, usually
+consisting of a flat or rounded basal portion of no great depth and of
+long free cylindrical branches, which droop when removed from the water;
+branches occasionally absent. Colour bright green when the sponge is
+growing in a strong light, dirty flesh-colour when it is growing in the
+shade. (Even in the latter case traces of the "green corpuscles" can be
+detected in the cells of the parenchyma.) Oscula star-shaped, of
+moderate size, as a rule rendered conspicuous by the furrows that
+radiate from them over the outer surface of the parenchyma below the
+external membrane; oscular collars well developed.
+
+_Skeleton_ reticulate, loose, with definite radiating and transverse
+fibres held together by a small quantity of spongin; the fibres slender
+but not extremely so.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, long, slender.
+Flesh-spicules slender, covered with small spines, sharply pointed,
+nearly straight. Gemmule-spicules resembling the flesh-spicules but
+shorter and as a rule more strongly curved, sometimes bent so as to form
+semicircular figures, usually pointed somewhat abruptly; their spines
+relatively longer than those of the flesh-spicules, often curved
+backwards, especially near the ends of the spicules, at which points
+they are often longer than elsewhere.
+
+_Gemmules_ usually numerous in autumn, lying free in the sponge,
+spherical, variable in size but usually rather large, as a rule covered
+with a thick granular coat in which the spicules are arranged
+tangentially; a horizontal layer of spicules often present in the
+external membrane; the granular coat and its spicules occasionally
+deficient. No foraminal tubule; its place sometimes taken by an open,
+bowl-shaped chitinous structure the base of which is in continuity with
+the inner chitinous coat of the gemmule.
+
+_S. lacustris_ is an extremely variable species, varying in the size,
+proportions and shape of its spicules, in its external form and in the
+size and structure of the gemmule. A considerable number of varieties
+have been described from different parts of Europe and N. America, but
+some of these may represent distinct but closely-allied species;
+descriptions of most of them will be found in Potts's "Fresh-Water
+Sponges." The embryology and the earlier stages of the development from
+the egg have been described in great detail by Evans (Quart. J. Micr.
+Sci. (n. s.) xlii, p. 363 (1899)), while the anatomy and physiology are
+discussed by most authors who have written on these features in the
+Spongillidae.
+
+TYPE.--It is impossible to say who was the first authority to use the
+name _Spongilla lacustris_ in the sense in which it is used by recent
+authors. No type can therefore be recognized.
+
+GEOGRAPHICAL DISTRIBUTION.--_S. lacustris_ occurs all over Europe and N.
+America and is probably the commonest species in most parts of both
+continents. It has also been found in Northern Asia and may occur in the
+Himalayan lakes and in the north-west of India.
+
+
+1 _a._ Subspecies reticulata*, _Annandale_.
+
+     _Spongilla reticulata_, Annandale, Rec. Ind. Mus. i, p. 387,
+     pl. xiv, fig. 1 (1907).
+
+     _Spongilla lacustris_ subspecies _reticulata_, _id._, P.
+     U.S. Mus. xxxvii, p. 401 (1909).
+
+This race differs from the typical _S. lacustris_ in the following
+particulars:--
+
+     (1) The branches are always compressed and anastomose
+     freely when well developed (fig. 5, p. 37);
+
+     (2) the skeleton-fibres are finer;
+
+     (3) the skeleton-spicules are longer;
+
+     (4) the gemmule-spicules are longer and more slender and are
+     never strongly bent.
+
+[Illustration: Fig. 8.
+
+A=gemmule-spicules of _Spongilla lacustris_ subsp. _reticulata_ (from
+type); B=gemmule-spicules of _S. alba_ from Calcutta: both highly
+magnified.]
+
+As regards the form of the skeleton- and gemmule-spicules and also that
+of the branches the subspecies _reticulata_ resembles _S. alba_ rather
+than _S. lacustris_, but owing to the fact that it agrees with _S.
+lacustris_ in its profuse production of branches, in possessing green
+corpuscles and in its fragility, I think it should be associated with
+that species.
+
+The branches are sometimes broad (fig. 5, p. 37), sometimes very
+slender. In the latter condition they resemble blades of grass growing
+in the water.
+
+TYPE in the Indian Museum; a co-type in the British Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--All over Eastern India and Burma; also in
+the Bombay Presidency. _Localities:_--BENGAL, Port Canning, Ganges
+delta; Rajshahi (Rampur Bhulia) on the Ganges, 150 miles N. of Calcutta
+(_Annandale_); Puri district, Orissa (_Annandale_); R. Jharai, Siripur,
+Saran district, Tirhut (_M. Mackenzie_): MADRAS PRESIDENCY, Madras
+(town) (_J. R. Henderson_): BOMBAY PRESIDENCY, Igatpuri, W. Ghats
+(_Annandale_).
+
+BIOLOGY.--This subspecies is usually found in small masses of water,
+especially in pools of rain-water, but Mr. Mackenzie found it growing
+luxuriantly in the Jharai at a time of flood in September. It is very
+abundant in small pools among the sand-dunes that skirt the greater part
+of the east coast of India. Here it grows with great rapidity during the
+"rains," and often becomes desiccated even more rapidly as soon as the
+rain ceases. As early in the autumn as October I have seen masses of the
+sponge attached, perfectly dry, to grass growing in the sand near the
+Sur Lake in Orissa. They were, of course, dead but preserved a life-like
+appearance. Some of them measured about six inches in diameter. At Port
+Canning the sponge grows during the rains on the brickwork of bridges
+over ditches of brackish water that dry up at the beginning of winter,
+while at Rajshahi and at Igatpuri I found it at the edges of small
+ponds, at the latter place in November, at the former in February.
+Specimens taken at Madras by Dr. Henderson during the rains in small
+ponds in the sand contained no gemmules, but these structures are very
+numerous in sponges examined in autumn or winter.
+
+Numerous larvae of _Sisyra indica_ (p. 92) were found in this sponge at
+Rajshahi. Unlike those obtained from _S. alba_, they had a green colour
+owing to the green matter sucked from the sponge in their stomachs. The
+_coralloides_ phase of _Plumatella fruticosa_ (p. 219) was also found in
+_S. lacustris_ subsp. _reticulata_ at Rajshahi.
+
+So far as my experience goes, this subspecies has always a bright green
+colour due to the presence of "green corpuscles," even when it is
+growing in a pond heavily shaded by trees or under the arch of a small
+bridge. Probably the more intense light of India enables the corpuscles
+to flourish in situations in which in Europe they would lose their
+chlorophyll.
+
+
+2. Spongilla proliferens*, _Annandale_.
+
+     _Spongilla cinerea_, Weber (_nec_ Carter), Zool. Ergeb.
+     Niederl. Ost-Ind. vol. i, pp. 35, 46 (1890).
+
+     _Spongilla proliferens_, Annandale, J. Asiat. Soc. Bengal,
+     1907, p. 15, fig. 1.
+
+     _Spongilla proliferens_, _id._, Rec. Ind. Mus. i, pp. 267,
+     271 (1907).
+
+_Sponge_ forming soft, shallow cushions rarely more than 10 cm. in
+diameter on the leaves of water-plants, or small irregular masses on
+their roots and stems. Colour bright green. Oscula moderate, flat,
+surrounded by deep, cone-shaped collars; radiating furrows and canals in
+the parenchyma surrounding them often deep. External pores contained
+normally in single cells. The surface frequently covered by small
+rounded buds; true branches if present more or less flattened or
+conical, always short, as a rule absent.
+
+_Skeleton_ loose, feebly reticulate at the base of the sponge;
+transverse fibres slender in the upper part of the sponge, often
+scarcely recognizable at its base. Very little spongin present.
+
+_Spicules._ Skeleton-spicules long, smooth, sharply pointed; the length
+on an average at least 20 times the greatest breadth, often more.
+Flesh-spicules slender, gradually pointed, nearly straight, covered with
+minute straight or nearly straight spines. Gemmule-spicules very
+similar, but usually a little stouter and often blunt at the ends; their
+spines rather longer than those on the flesh-spicules, usually more
+numerous near the ends than in the middle of the spicule, slightly
+retroverted, those at the extreme tips often so arranged as to suggest a
+rudimentary rotule.
+
+[Illustration: Fig. 9.--Gemmule of _Spongilla proliferens_ as seen in
+optical section (from Calcutta), x 140.]
+
+_Gemmules_ usually numerous, lying free near the base of the sponge,
+very variable in size, spherical, surrounded by a thick granular layer
+in which the spicules, which are always very numerous, are arranged
+tangentially, their position being more near the vertical than the
+horizontal; a few horizontal spicules usually present on the external
+surface of the gemmule, which frequently has a ragged appearance owing
+to some of the tangential spicules protruding further than others.
+Foraminal tubule stout, cylindrical, usually somewhat contorted; its
+orifice irregular in outline. Sometimes more than one foramen present.
+
+_S. proliferens_ can be distinguished from all forms of _S. lacustris_
+and _S. alba_ by the fact that its gemmules possess a foraminal tubule;
+from _S. cinerea_ it can be distinguished by its colour and its smooth
+skeleton-spicules, and from _S. travancorica_ by its free gemmules. I
+have been enabled by the kindness of Prof. Max Weber to examine
+specimens from Celebes and Java identified by him as _S. cinerea_,
+Carter, and have no doubt that they belong to my species.
+
+TYPE in the Indian Museum; a co-type in the British Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--All over Eastern India and Burma; also in
+Cochin on the west coast; Ceylon; W. China; Java, Flores and Celebes.
+_Localities_:--BENGAL, Calcutta and neighbourhood (_Annandale_);
+Berhampore, Murshidabad district (_R. E. Lloyd_): ASSAM, Mangal-dai near
+the Bhutan frontier (_S. W. Kemp_): MADRAS PRESIDENCY, Madras (town) and
+neighbourhood (_J. R. Henderson_); Rambha, Ganjam district
+(_Annandale_); Bangalore, Mysore (alt. _ca._ 3000 ft.) (_Annandale_);
+Ernakulam and Trichur, Cochin (_G. Mathai_): BURMA, Rangoon
+(_Annandale_, _J. Coggin Brown_); Prome, Upper Burma (_J. Coggin
+Brown_); Kawkareik, Amherst district, Tenasserim (_Annandale_): CEYLON,
+between Maradankawela and Galapita-Gala, North Central Province
+(_Willey_). Mr. J. Coggin Brown has recently brought back specimens from
+Yunnan.
+
+BIOLOGY.--_S. proliferens_ is usually found in ponds which never dry up;
+Prof. Max Weber found it in small streams in Malaysia. It is common in
+India on the leaves of _Vallisneria_ and _Limnanthemum_, on the roots of
+_Pistia stratiotes_ and on the stems of rushes and grass. So far as I
+have been able to discover, the life of the individual sponge is short,
+only lasting a few weeks.
+
+Sexual reproduction occurs seldom or never, but reproduction by means of
+buds and gemmules continues throughout the year. The former is a rare
+method of reproduction in most Spongillidae but in this species occurs
+normally and constantly, the buds being often very numerous on the
+external surface. They arise a short distance below the surface as
+thickenings in the strands of cells that accompany the radiating fibres
+of the skeleton. As they grow they push their way up the fibres, forcing
+the external membrane outwards. The membrane contracts gradually round
+their bases, cuts off communication between them and the parent sponge
+and finally sets them adrift. No hole remains when this takes place, for
+the membrane closes up both round the base of the bud and over the
+aperture whence it has emerged.
+
+The newly liberated bud already possesses numerous minute pores, but as
+yet no osculum; its shape exhibits considerable variation, but the end
+that was farthest from the parent-sponge before liberation is always
+more or less rounded, while the other end is flat. The size also varies
+considerably. Some of the buds float, others sink. Those that float do
+so either owing to their shape, which depends on the degree of
+development they have reached before liberation, or to the fact that a
+bubble of gas is produced in their interior. The latter phenomenon only
+occurs when the sun is shining on the sponge at the moment they are set
+free, and is due to the action of the chlorophyll of the green bodies so
+abundant in certain of the parenchyma cells of this species. If the
+liberation of the bud is delayed rather longer than usual, numbers of
+flesh-spicules are produced towards the ends of the primary
+skeleton-fibres and spread out in one plane so as to have a fan-like
+outline; in such buds the form is more flattened and the distal end less
+rounded than in others, and the superficial area is relatively great, so
+that they float more readily. Those buds that sink usually fall in such
+a way that their proximal, flattened end comes in contact with the
+bottom or some suspended object, to which it adheres. Sometimes,
+however, owing to irregularity of outline in the distal end, the
+proximal end is uppermost. In this case it is the distal end that
+adheres. Whichever end is uppermost, it is in the uppermost end, or as
+it may now be called, the upper surface, that the osculum is formed.
+Water is drawn into the young sponge through the pores and, finding no
+outlet, accumulates under the external membrane, the subdermal cavity
+being at this stage even larger than it is in the adult sponge.
+Immediately after adhesion the young sponge flattens itself out. This
+process apparently presses together the water in the subdermal cavity
+and causes a large part of it to accumulate at one point, which is
+usually situated near the centre of the upper surface. A transparent
+conical projection formed of the external membrane arises at this point,
+and at the tip of the cone a white spot appears. What is the exact cause
+of this spot I have not yet been able to ascertain, but it marks the
+point at which the imprisoned water breaks through the expanded
+membrane, thus forming the first osculum. Before the aperture is formed,
+it is already possible to distinguish on the surface of the parenchyma
+numerous channels radiating from the point at which the osculum will be
+formed to the periphery of the young sponge. These channels as a rule
+persist in the adult organism and result from the fact that the inhalent
+apertures are situated at the periphery, being absent from both the
+proximal and the distal ends of the bud. In the case of floating buds
+the course of development is the same, except that the osculum, as in
+the case of development from the gemmule in other species (see Zykoff,
+Biol. Centrbl. xii, p. 713, 1892), is usually formed before adhesion
+takes place.
+
+The sponge of _S. proliferens_ is usually too small to afford shelter to
+other animals, and I have not found in it any of those commonly
+associated with _S. carteri_ and _S. alba_.
+
+Owing to its small size _S. proliferens_ is more easily kept alive in an
+aquarium than most species, and its production of buds can be studied in
+captivity. In captivity a curious phenomenon is manifested, viz. the
+production of extra oscula, often in large numbers. This is due either
+to a feebleness in the currents of the sponge which makes it difficult
+to get rid of waste substances or to the fact that the canals get
+blocked. The effluent water collects in patches under the external
+membrane instead of making its way out of the existing oscula, and new
+oscula are formed over these patches in much the same way as the first
+osculum is formed in the bud.
+
+
+3. Spongilla alba*, _Carter_.
+
+     _Spongilla alba_, Carter, J. Bombay Asiat. Soc. iii, p. 32,
+     pl. i, fig. 4 & Ann. Nat. Hist. (2) iv, p. 83, pl. iii, fig.
+     4 (1849)
+
+     _Spongilla alba_, Bowerbank, P. Zool. Soc. London, 1863, p.
+     463 pl. xxxviii, fig. 15.
+
+     _Spongilla alba_, Carter, Ann. Nat. Hist. (5) vii, p. 88
+     (1881).
+
+     _Spongilla alba_, Petr, Rozp. Ceske Ak. Praze, Trida, ii,
+     pl. i, figs. 3-6 (1899) (text in Czech).
+
+     _Spongilla alba_, Annandale, Rec. Ind. Mus. i, p. 388, pl.
+     xiv, fig. 2 (1907).
+
+_Sponge_ forming masses of considerable area, but never of more than
+moderate depth or thickness. Surface smooth and undulating or with
+irregular or conical projections; sponge hard but brittle; colour white
+or whitish; oscula of moderate or large size, never very conspicuous;
+radiating furrows absent or very short; external membrane adhering to
+the substance of the sponge.
+
+_Skeleton_ forming a moderately dense network of slender radiating and
+transverse fibres feebly held together; little spongin present; the
+meshes much smaller than in _S. lacustris_ or _S. proliferens_.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, slender, feebly
+curved. Gemmule-spicules (fig. 8, p. 71) slender, cylindrical, blunt or
+abruptly pointed at the ends, feebly curved, bearing relatively long
+backwardly directed spines, which are usually more numerous at the ends
+than near the middle of the shaft. Flesh-spicules very numerous in the
+parenchyma and especially the external membrane, as a rule considerably
+more slender and more sharply pointed than the gemmule-spicules, covered
+with straight spines which are often longer at the middle of the shaft
+than at the ends.
+
+_Gemmules_ usually of large size, with a moderately thick granular
+layer; spicules never very numerous, often lying horizontally on the
+external surface of the gemmule as well as tangentially in the granular
+layer; no foraminal tubule; a foraminal cup sometimes present.
+
+
+3_a_. Var. cerebellata, _Bowerbank_.
+
+     _Spongilla cerebellata_, Bowerbank, P. Zool. Soc. London,
+     1863, p. 465, pl. xxxviii, fig. 16.
+
+     _Spongilla alba_ var. _cerebellata_, Carter, Ann. Nat. Hist.
+     (5) vii, p. 88 (1881).
+
+     _Spongilla cerebellata_, Weltner, Arch. Naturg. lxi (i), p.
+     117 (1895).
+
+     _Spongilla cerebellata_, Kirkpatrick, Ann. Nat. Hist. (7)
+     xx, p. 523 (1907).
+
+This variety is distinguished from the typical form by the total absence
+of flesh-spicules. The gemmule-spicules are also more numerous and cross
+one another more regularly.
+
+
+3_b_. Var. bengalensis*, _Annandale_. (Plate I, figs. 1-3.)
+
+     _Spongilla lacustris_ var. _bengalensis_, Annandale, J.
+     Asiat. Soc. Bengal, 1906, p. 56.
+
+     _Spongilla alba_ var. _marina_, _id._, Rec. Ind. Mus. i, p.
+     389 (1907).
+
+The sponge is either devoid of branches or produces irregular,
+compressed, and often digitate processes, sometimes of considerable
+length and delicacy. Flesh-spicules are usually present throughout the
+sponge, but are sometimes absent from one part of a specimen and present
+in others. Some of the gemmules are often much smaller than the others.
+Perhaps this form should be regarded as a phase rather than a true
+variety (see p. 18).
+
+All forms of _S. alba_ can be distinguished from all forms of _S.
+lacustris_ by the much closer network of the skeleton and by the
+consequent hardness of the sponge; also by the complete absence of green
+corpuscles.
+
+TYPES. The types of the species and of the var. _cerebellata_ are in the
+British Museum, with fragments of the former in the Indian Museum; that
+of var. _bengalensis_ is in the Indian Museum, with a co-type in London.
+
+GEOGRAPHICAL DISTRIBUTION.--India And Egypt. _Localities_:--BOMBAY
+PRESIDENCY, island of Bombay (_Carter_); Igatpuri, W. Ghats
+(_Annandale_): BENGAL, Calcutta; Port Canning, Ganges delta (var.
+_bengalensis_) (_Annandale_); Garia, Salt Lakes, nr. Calcutta (var.
+_bengalensis_) (_B. L. Chaudhuri_); Chilka Lake, Orissa (var.
+_bengalensis_) (_Gopal Chunder Chatterjee_): MADRAS PRESIDENCY, Rambha,
+Ganjam district (_Annandale_): NIZAM'S TERRITORY, Aurangabad
+(_Bowerbank_, var. _cerebellata_). The var. _cerebellata_ has also been
+taken near Cairo.
+
+BIOLOGY.--The typical form of the species is usually found growing on
+rocks or bricks at the edges of ponds, while the variety _bengalensis_
+abounds on grass-roots in pools and swamps of brackish water in the
+Ganges delta and has been found on mussel-shells (_Modiola jenkinsi_,
+Preston) in practically salt water in the Chilka Lake. Carter procured
+the typical form at Bombay on stones which were only covered for six
+months in the year, and "temporarily on floating objects." In Calcutta
+this form flourishes in the cold weather on artificial stonework in the
+"tanks" together with _S. carteri_, _S. fragilis_, _Ephydatia meyeni_,
+and _Trochospongilla latouchiana_.
+
+The variety _bengalensis_ is best known to me as it occurs in certain
+ponds of brackish water at Port Canning on the Mutlah River, which
+connects the Salt Lakes near Calcutta with the sea. It appears in these
+ponds in great luxuriance every year at the beginning of the cold
+weather and often coats the whole edge for a space of several hundred
+feet, growing in irregular masses which are more or less fused together
+on the roots and stems of a species of grass that flourishes in such
+situations. Apparently the tendency for the sponges to form branches is
+much more marked in some years than in others (see Pl. I, figs. 1-3).
+The gemmules germinate towards the end of the "rains," and large masses
+of sponge are not formed much before December. At this season, however,
+the level of the water in the ponds sinks considerably and many of the
+sponges become dry. If high winds occur, the dry sponges are broken up
+and often carried for considerable distances over the flat surrounding
+country. In January the gemmules floating on the surface of the ponds
+form a regular scum. _S. alba_ var. _bengalensis_ is the only sponge
+that occurs in these ponds at Port Canning, but _S. lacustris_, subsp.
+_reticulata_, is occasionally found with it on brickwork in the ditches
+that drain off the water from the neighbouring fields into the Mutlah
+estuary. The latter sponge, however, perishes as these ditches dry up,
+at an earlier period than that at which _S. alba_ reaches its maximum
+development.
+
+The larvae of _Sisyra indica_ are commonly found in the oscula of the
+typical form of _S. alba_ as well as in those of _S. lacustris_ subsp.
+_reticulata_, and _S. carteri_; but the compact structure of the sponge
+renders it a less suitable residence for other _incolae_ than _S.
+carteri_.
+
+In the variety _bengalensis_, as it grows in the ponds at Port Canning,
+a large number of arthropods, molluscs and other small animals take
+shelter. Apart from protozoa and rotifers, which have as yet been little
+studied, the following are some of the more abundant inhabitants of the
+sponge:--The sea-anemone, _Sagartia schilleriana_ subsp. _exul_ (see p.
+140), which frequently occurs in very large numbers in the broader
+canals; the free-living nematode, _Oncholaimus indicus_[W], which makes
+its way in and out of the oscula; molluscs belonging to several species
+of the genus _Corbula_, which conceal themselves in the canals but are
+sometimes engulfed in the growing sponge and so perish; young
+individuals of the crab _Varuna litterata_, which hide among the
+branches and ramifications of the larger sponges together with several
+small species of prawns and the schizopod _Macropsis orientalis_[X]; the
+peculiar amphipod _Quadrivisio bengalensis_[Y], only known from the
+ponds at Port Canning, which breeds in little communities inside the
+sponge; a small isopod[Z], allied to _Sphaeroma walkeri_, Stebbing; the
+larva of a may-fly, and those of at least two midges (Chironomidae).
+
+     [Footnote W: O. von Linstow, Rec. Ind. Mus. i, p. 45
+     (1907).]
+
+     [Footnote X: W. M. Tattersall, _ibid._, ii, p. 236 (1908).]
+
+     [Footnote Y: T. R. R. Stebbing, _ibid._, i, p. 160 (1907);
+     and N. Annandale, _ibid._, ii, p. 107 (1908).]
+
+     [Footnote Z: Mr. Stebbing has been kind enough to examine
+     specimens of this isopod, which he will shortly describe in
+     the Records of the Indian Museum. _S. walkeri_, its nearest
+     ally, was originally described from the Gulf of Manaar,
+     where it was taken in a tow-net gathering (see Stebbing in
+     Herdman's Report on the Ceylon Pearl Fisheries, pt. iv, p.
+     31 (1905)).]
+
+The peculiarly mixed nature (marine and lacustrine) of the fauna
+associated with _S. alba_ in the ponds at Port Canning is well
+illustrated by this list, and it only remains to be stated that little
+fish (_Gobius alcockii_, _Barbus stigma_, _Haplochilus melanostigma_,
+_H. panchax_, etc.) are very common and feed readily on injured sponges.
+They are apparently unable to attack a sponge so long as its external
+membrane is intact, but if this membrane is broken, they swarm round the
+sponge and devour the parenchyma greedily. In fresh water one of these
+fishes (_Gobius alcockii_, see p. 94) lays its eggs in sponges.
+
+The chief enemy of the sponges at Port Canning is, however, not an
+animal but a plant, viz., a green filamentous alga which grows inside
+the sponge, penetrating its substance, blocking up its canals and so
+causing it to die. Similar algae have been described as being beneficial
+to the sponges in which they grow[AA], but my experience is that they
+are deadly enemies, for the growth of such algae is one of the
+difficulties which must be fought in keeping sponges alive in an
+aquarium. The alga that grows in _S. alba_ often gives it a dark green
+colour, which is, however, quite different from the bright green caused
+by the presence of green corpuscles. The colour of healthy specimens of
+the variety _bengalensis_ is a rather dark grey, which appears to be due
+to minute inorganic particles taken into the cells of the parenchyma
+from the exceedingly muddy water in which this sponge usually grows. If
+the sponge is found in clean water, to whichever variety of the species
+it belongs, it is nearly white with a slight yellowish tinge. Even when
+the typical form is growing in close proximity to _S. proliferens_, as
+is often the case, no trace of green corpuscles is found in its cells.
+
+     [Footnote AA: See M. and A. Weber in M. Weber's Zool. Ergeb.
+     Niederl. Ost-Ind. vol. i, p. 48, pl. v (1890).]
+
+
+4. Spongilla cinerea*, _Carter_.
+
+     _Spongilla cinerea_, Carter, J. Bombay Soc. iii, p. 30, pl.
+     i, fig. 5, & Ann. Nat. Hist. (2) iv, p. 82, pl. iii, fig. 5
+     (1849).
+
+     _Spongilla cinerea_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 468, pl. xxxviii, fig. 19.
+
+     _Spongilla cinerea_, Carter, Ann. Nat. Hist. (5) vii, p. 263
+     (1881).
+
+_Sponge_ forming large, flat sheets, never more than a few millimetres
+in thickness, without a trace of branches, compact but very friable, of
+a dark greyish colour; oscula small and inconspicuous or moderately
+large, never prominent; membrane adhering closely to the sponge.
+
+_Skeleton_ with well-defined but slender radiating fibres, which contain
+very little spongin; transverse fibres close together but consisting for
+the most part of one or two spicules only.
+
+_Spicules._ Skeleton-spicules short, slender, sharply pointed, minutely
+serrated or irregular in outline, almost straight. Gemmule-spicules very
+small, rather stout, cylindrical, pointed, covered with relatively long
+and stout spines which are either straight or directed towards the ends
+of the spicule. Flesh-spicules fairly numerous in the external membrane
+but by no means abundant in the parenchyma, very slender, gradually
+pointed, covered uniformly with minute but distinct spines.
+
+_Gemmules_ very small, only visible to the naked eye as minute specks,
+as a rule numerous, free in the substance of the sponge, each provided
+with a slender foraminal tubule and covered with a thick granular coat
+in which the gemmule-spicules are arranged almost horizontally; a
+horizontal layer of spicules also present on the external surface of the
+gemmule; gemmule-spicules very numerous.
+
+[Illustration: Fig. 10.--Gemmules and fragment of the skeleton of
+_Spongilla cinerea_ (from type specimen), x 35.]
+
+This sponge is easily distinguished from its Indian allies by the form
+of its skeleton-spicules, which are, as Bowerbank expresses it,
+"subspined"; that it to say, under a high power of the microscope their
+outline appears to be very minutely serrated, although under a low power
+they seem to be quite smooth. The spicules also are smaller than those
+of _S. alba_, the only species with which _S. cinerea_ is likely to be
+confused, and the gemmule has a well-developed foraminal tubule; the
+skeleton is much closer than in _S. proliferens_.
+
+TYPE in the British Museum; a piece in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--_S. cinerea_ is only known from the Bombay
+Presidency. Carter obtained the original specimens at Bombay and the
+only ones I have found were collected at Nasik, which is situated on the
+eastern slopes of the Western Ghats, about 90 miles to the north-east.
+
+BIOLOGY.--Carter's specimens were growing on gravel, rocks and stones at
+the edge of "tanks," and were seldom covered for more than six months in
+the year. Mine were on the sides of a stone conduit built to facilitate
+bathing by conveying a part of the water of the Godaveri River under a
+bridge. They were accompanied by _Spongilla indica_ and _Corvospongilla
+lapidosa_ (the only other sponges I have found in running water in
+India) and in the month of November appeared to be in active growth.
+
+
+5. Spongilla travancorica*, _Annandale_.
+
+     _Spongilla travancorica_, Annandale, Rec. Ind. Mus. iii, p.
+     101, pl. xii, fig. 1 (1909).
+
+_Sponge_ small, encrusting, without branches, hard but brittle; its
+structure somewhat loose; colour dirty white. Dermal membrane in close
+contact with the skeleton; pores and oscula inconspicuous. Surface
+minutely hispid, smooth and rounded as a whole.
+
+_Skeleton_ consisting of moderately stout and coherent radiating fibres
+and well-defined transverse ones; a number of horizontal megascleres
+present at the base and surface, but not arranged in any definite order.
+No basal membrane.
+
+[Illustration: Fig. 11.--Microscleres of _Spongilla travancorica_.
+
+A=Gemmule-spicules; B=flesh-spicules (from type specimen), x 240.]
+
+_Spicules._ Skeleton-spicules smooth, pointed at either end, moderately
+stout, straight or curved, sometimes angularly bent; curvature usually
+slight. Free microscleres abundant in the dermal membrane, slender,
+nearly straight, gradually and sharply pointed, profusely ornamented
+with short straight spines, which are much more numerous and longer at
+the middle than near the ends. Gemmule-spicules stouter and rather
+longer, cylindrical, terminating at each end in a sharp spine,
+ornamented with shorter spines, which are more numerous and longer at
+the ends than at the middle; at the ends they are sometimes directed
+backwards, without, however, being curved.
+
+_Gemmules_ firmly adherent to the support of the sponge, at the base of
+which they form a layer one gemmule thick; each provided with at least
+one foraminal tubule, which is straight and conical: two tubules, one at
+the top and one at one side, usually present. Granular layer well
+developed. Spicules arranged irregularly in this layer, as a rule being
+more nearly vertical than horizontal but pointing in all directions, not
+confined externally by a membrane; no external layer of horizontal
+spicules.
+
+  _Measurements of Spicules and Gemmules._
+
+  Length of skeleton-spicules                 0.289-0.374 mm.
+  Greatest diameter of skeleton-spicules      0.012-0.016  "
+  Length of free microscleres                 0.08-0.096   "
+  Greatest diameter of free microscleres      0.002 mm.
+  Length of gemmule-spicules                  0.1-0.116    "
+  Diameter of gemmule-spicule                 0.008 mm.
+    "       " gemmule                         0.272-0.374  "
+
+This species is easily distinguished from its allies of the subgenus
+_Euspongilla_ by its adherent gemmules with their (usually) multiple
+apertures and rough external surface.
+
+TYPE in the collection of the Indian Museum.
+
+HABITAT. Backwater near Shasthancottah, Travancore, in slightly brackish
+water; on the roots of shrubs growing at the edge; November, 1908
+(_Annandale_).
+
+The specimens were dead when found.
+
+
+6. Spongilla hemephydatia*, _Annandale_.
+
+     _Spongilla hemephydatia_, Annandale, Rec. Ind. Mus. iii, p.
+     275 (1909).
+
+[Illustration: Fig. 12.--Gemmule and spicules of _Spongilla
+hemephydatia_ (from type specimen).]
+
+_Sponge_ soft, fragile, amorphous, of a dirty yellow colour, with large
+oscula, which are not conspicuously raised above the surface but open
+into very wide horizontal channels in the substance of the sponge. The
+oscular collars are fairly well developed, but the subepidermal space is
+not extensive.
+
+_Skeleton_ diffuse, consisting of very fine radiating fibres, which are
+crossed at wide and irregular intervals by still finer transverse ones;
+very little chitinoid substance present.
+
+_Spicules._ Skeleton-spicules smooth, slender, sharply pointed at both
+ends, nearly straight. No true flesh-spicules. Gemmule-spicules straight
+or nearly so, cylindrical, or constricted in the middle, obscurely
+pointed or blunt, clothed with short, sharp, straight spines, which are
+very numerous but not markedly longer at the two ends; these spicules
+frequently found free in the parenchyma.
+
+_Gemmules_ numerous, small, free, spherical, yellow, with a
+well-developed granular coat (in which the spicules are arranged almost
+horizontally) and external to it a fine membrane which in preserved
+specimens becomes puckered owing to unequal contraction; each gemmule
+with a single aperture provided with a straight, rather wide, but very
+delicate foraminal tubule.
+
+  _Measurements of Spicules and Gemmules._
+
+  Length of skeleton-spicule       0.313 mm.
+  Breadth of skeleton-spicule      0.012 "
+  Length of gemmule-spicule        0.062 "
+  Breadth of gemmule-spicule       0.004 "
+  Diameter of gemmule              0.313-0.365 mm.
+
+This sponge in its general structure bears a very close resemblance to
+_Spongilla crateriformis_.
+
+TYPE in the collection of the Indian Museum.
+
+HABITAT. Growing on weeds at the edge of the Sur Lake, Orissa, October
+1908. Only one specimen was taken, together with many examples of _S.
+lacustris_ subsp. _reticulata_, _S. carteri_ and _S. crassissima_.
+
+
+7. Spongilla crateriformis* (_Potts_).
+
+     _Meyenia crateriforma_, Potts, P. Ac. Philad. 1882, p. 12.
+
+     _Meyenia crateriformis, id., ibid._ 1887, p. 228, pl. v,
+     fig. 6, pl. x, fig. 5.
+
+     ? _Ephydatia crateriformis_, Hanitsch, Nature, ii, p. 511
+     (1895).
+
+     _Ephydatia crateriformis_, Weltner, Arch. Naturg. lxi (i),
+     pp. 122, 134 (1895).
+
+     ? _Ephydatia crateriformis_, Hanitsch, Irish Natural. iv, p.
+     125, pl. iv, fig. 5 (1895).
+
+     _Ephydatia indica_, Annandale, J. Asiat. Soc. Bengal, 1907,
+     p. 20 (figures poor).
+
+     _Ephydatia indica, id._, Rec. Ind. Mus. i, pp. 272, 279,
+     388, 391 (1907).
+
+     _Ephydatia crateriformis_, Scharff, European Animals, p. 34
+     (1907).
+
+     _Ephydatia crateriformis_, Annandale, P. U.S. Mus. xxxvii,
+     p. 402, fig. 1 (1909).
+
+_Sponge_ very fragile, forming soft irregular masses on the roots and
+stems of water-plants, between which it is sometimes stretched as a
+delicate film, or thin layers or cushions on flat surfaces. Oscula
+large, flat, circular, or of irregular shape, opening into broad
+horizontal canals, which at their distal end are superficial and often
+covered by the external membrane only. Colour white, yellowish, greyish,
+or blackish.
+
+_Skeleton_ very delicate; radiating fibres rarely consisting of more
+than two parallel spicules; transverse fibres far apart, frequently
+consisting of single spicules; very little spongin present.
+
+[Illustration: Fig 13.--Spicules of _Spongilla crateriformis_.
+
+A. From specimen taken in July in a tank on the Calcutta maidan. B. From
+type specimen of _Ephydatia indica_ taken in the Indian Museum tank in
+winter. Both figures x 240.]
+
+_Spicules._ Skeleton-spicules feebly curved, slender, as a rule
+irregular in outline, sometimes almost smooth; the ends as a rule
+sharply pointed, often constricted off and expanded so as to resemble
+spear-heads, occasionally blunt. No true flesh-spicules.
+Gemmule-spicules often free in the parenchyma, cylindrical, slender,
+very variable in length in different sponges, straight or nearly so, as
+a rule with an irregular circle of strong straight or recurved spines at
+either end resembling a rudimentary rotule, and with shorter straight
+spines scattered on the shaft, sometimes without the rudimentary rotule,
+either truncate at the ends or terminating in a sharp spine.
+
+_Gemmules_ small, free, each surrounded by a thick granular layer in
+which the spicules stand upright or nearly so, and covered externally by
+a delicate but very distinct chitinous membrane; no horizontal spicules;
+foramen situated at the base of a crater-like depression in the granular
+coat, which is sometimes raised round it so as to form a conspicuous
+rampart; a short, straight foraminal tubule.
+
+The shape of the spicules is extremely variable, and sponges in which
+they are very different occur in the same localities and even in the
+same ponds. It is possible that the differences are directly due to
+slight changes in the environment, for in one pond in Calcutta a form
+with _Spongilla_-like gemmule-spicules appears to replace the typical
+form, which is common in winter, during the hot weather and "rains." I
+have not, however, found this to be the case in other ponds. Perhaps _S.
+hemephydatia_ will ultimately prove to be a variety of this very
+variable species, but its smooth and regular skeleton-spicules and
+short-spined gemmule-spicules afford a ready method of distinguishing it
+from _S. crateriformis_. The two sponges are easily distinguished from
+all others in the subgenus _Euspongilla_ by the upright and regular
+arrangement of their gemmule-spicules, for although in _S. proliferens_
+and _S. travancorica_ some of the gemmule-spicules are nearly vertical,
+their arrangement is always irregular, a large proportion of the
+spicules make an acute angle with the inner coat of the gemmule and a
+few as a rule lie parallel to it. The systematic position of _S.
+crateriformis_ is almost exactly intermediate between _Euspongilla_ and
+_Ephydatia_, to which genus it has hitherto been assigned. I think,
+however, that taking into consideration its close relationship to _S.
+hemephydatia_, it is best to assign it to _Spongilla_, as its
+rudimentary rotules never form distinct disks. I have examined some of
+Potts's original specimens from different American localities and can
+detect no constant difference between them and Indian specimens.
+
+TYPES in the United States National Museum; co-types in Calcutta.
+
+GEOGRAPHICAL DISTRIBUTION.--This sponge was originally described from
+North America (in which continent it is widely distributed) and has been
+recorded from the west of Ireland with some doubt. In India and Burma it
+is widely distributed. BENGAL, Calcutta and neighbourhood (_Annandale_);
+Sonarpur, Gangetic delta (_Annandale_); BOMBAY PRESIDENCY, Igatpuri
+Lake, W. Ghats (altitude _ca._ 2,000 feet) (_Annandale_); MADRAS
+PRESIDENCY, neighbourhood of Madras town (_J. R. Henderson_); Museum
+compound, Egmore (Madras town) (_Annandale_); near Bangalore (alt. _ca._
+3,000 ft.), Mysore State (Annandale); Ernakulam, Cochin (_G. Mathai_):
+BURMA, Kawkareik, interior of Amherst district, Tenasserim, and the
+Moulmein waterworks in the same district (_Annandale_).[AB]
+
+     [Footnote AB: Mr. C. A. Paiva, Assistant in the Indian
+     Museum, has lately (March 31st, 1911) obtained specimens of
+     _S. crateriformis_ in a small pond of fresh water on Ross
+     Island in the Andaman group. The existence of this widely
+     distributed species on an oceanic island is noteworthy.]
+
+BIOLOGY.--_S. crateriformis_ flourishes in Calcutta throughout the year.
+Here it is usually found adhering to the roots of water-plants,
+especially _Pistia_ and _Limnanthemum_. In the case of the former it
+occurs at the surface, in that of the latter at the bottom. When growing
+near the surface or even if attached to a stone at the bottom in clear
+water, it is invariably of a pale yellowish or greyish colour. When
+growing on the roots of _Limnanthemum_ in the mud of the Gangetic
+alluvium, however, it is almost black, and when growing in the reddish
+muddy waters of the tanks round Bangalore of a reddish-brown colour.
+This appears to be due entirely to the absorption of minute particles of
+inorganic matter by the cells of the parenchyma. If black sponges of the
+species are kept alive in clean water, they turn pure white in less than
+a week, apparently because these particles are eliminated. When growing
+on stones the sponge, as found in India, often conforms exactly with
+Potts's description: "a filmy grey sponge, branching off here and there
+... yet with a curious lack of continuity...."
+
+The wide efferent canals of this sponge afford a convenient shelter to
+small crustacea, and the isopod _Tachaea spongillicola_, Stebbing (see p.
+94), is found in them more abundantly than in those of any other sponge.
+This is especially the case when the sponge is growing at the bottom. On
+the surface of the sponge I have found a peculiar protozoon which
+resembles the European _Trichodina spongillae_ in general structure but
+belongs, I think, to a distinct species, if not to a distinct genus.
+
+
+Subgenus B. EUNAPIUS, _J. E. Gray_.
+
+     _Eunapius_, J. E. Gray (_partim_), P. Zool. Soc. London,
+     1867, p. 552.
+
+     _Spongilla_ (_s. str._), Vejdovsky, in Potts's "Fresh-Water
+     Sponges," P. Ac. Philad. 1887, p. 172.
+
+     _Spongilla_ (_s. str._), Weltner, in Zacharias's Tier- und
+     Pflanzenwelt des Suesswassers, i, p. 214 (1891).
+
+     _Spongilla_ (_s. str._), Annandale, Zool. Jahrb., Syst.
+     xxvii, p. 559 (1909).
+
+TYPE, _Spongilla carteri_, Carter.
+
+Spongillae in which the gemmules are covered with layers of distinct
+polygonal air-spaces with chitinous walls.
+
+The gemmules are usually fastened together in groups, which may either
+be free in the sponge or adhere to its support as a "pavement layer";
+sometimes, however, they are not arranged in this manner, but are quite
+independent of one another. The skeleton is usually delicate, sometimes
+very stout (_e. g._, in _S. nitens_, Carter).
+
+The term _Eunapius_ here used is not quite in the original sense, for
+Gray included under it Bowerbank's _Spongilla paupercula_ which is now
+regarded as a form of _S. lacustris_. His description, nevertheless,
+fits the group of species here associated except in one particular,
+viz., the smoothness of the gemmule-spicules to which he refers, for
+this character, though a feature of _S. carteri_, is not  found in
+certain closely allied forms. The use of "_Spongilla_" in a double sense
+may be avoided by the adoption of Gray's name.
+
+The subgenus _Eunapius_ is, like _Euspongilla_, cosmopolitan. It is not,
+however, nearly so prolific in species. Four can be recognized in India,
+two of which range, in slightly different forms, as far north as Europe,
+one of them also being found in North America, Northern Asia, and
+Australia.
+
+
+8. Spongilla carteri* _Carter_ (_Bowerbank_, in litt.). (Plate II. fig.
+1.)
+
+     _Spongilla friabilis_?, Carter (_nec_ Lamarck), J. Bombay
+     Asiat. Soc. iii, p. 31, pl. i, fig. 3 (1849), & Ann. Nat.
+     Hist. (2) iv, p. 83, pl. ii. fig. 3 (1849).
+
+     _Spongilla carteri_, Carter, Ann. Nat. Hist. (3) iii, p.
+     334, pl. viii, figs. 1-7 (1859).
+
+     _Spongilla carteri_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 469, pl. xxxviii, fig. 20.
+
+     _Eunapius carteri_, J. E. Gray, _ibid._ 1867, p. 552.
+
+     _Spongilla carteri_, Carter, Ann. Nat. Hist. (5) vii, p. 86
+     (1881).
+
+     _Spongilla carteri_, _id._, _ibid._ x, p. 369 (1882).
+
+     _Spongilla carteri_, Potts, P. Ac. Philad. 1887, p. 194.
+
+     _Spongilla carteri_, Weltner, Arch. Naturg. lxi (i), pp.
+     117, 134 (1895).
+
+     _Spongilla carteri_, Kirkpatrick, P. Zool. Soc. London, 1906
+     (i), p. 219, pl. xv, figs. 3, 4 (? figs. 1, 2).
+
+     _Spongilla carteri_, Annandale, J. Asiat. Soc. Bengal, 1906,
+     p. 188, pl. i, fig. 1.
+
+     _Spongilla carteri_, Willey, Spolia Zeyl. iv, p. 184 (1907).
+
+     _Spongilla carteri_, Annandale, _ibid._ vii, p. 63, pl. 1,
+     fig. 1 (1910).
+
+[Illustration: Fig. 14.--Gemmule of _Spongilla carteri_ (from Calcutta),
+as seen in optical section, x 140.]
+
+_Sponge_ massive, as a rule with the surface smooth and rounded,
+occasionally bearing irregular ridges, which may even take the form of
+cockscombs; the oscula large, rounded, conspicuous but not raised above
+the surface of the sponge, leading into broad vertical canals; the
+lateral canals, except in the immediate vicinity of the central vertical
+ones, not very broad; the oscular collars extending for a considerable
+distance over the oscula in living or well-preserved specimens, never
+standing out from the surface; the oscula never surrounded by radiating
+furrows. The inhalent pores surrounded externally by unmodified cells of
+the external membrane. Colour greyish, sometimes with a flush of green
+on the external surface.
+
+The sponge has a peculiarly strong and offensive smell.
+
+_Skeleton_ fairly compact, with well-developed radiating fibres; the
+transverse fibres splayed out at either end so that they sometimes
+resemble a pair of fans joined together by the handles (fig. 3, p. 33).
+A moderate amount of spongin present.
+
+_Spicules._ Skeleton-spicules smooth, pointed, nearly straight, never
+very stout but somewhat variable in exact proportions. Gemmule-spicules
+similar but much smaller. (There are no true flesh-spicules, but
+immature skeleton-spicules may easily be mistaken for them.)
+
+_Gemmules_ as a rule numerous, spherical or flattened at the base,
+variable in size, each covered by a thick coat consisting of several
+layers of relatively large polygonal air-spaces. A single aperture
+surrounded by a crater-like depression in the cellular coat and provided
+with a foraminal tubule resembling an inverted bottle in shape. (This
+tubule, which does not extend beyond the surface of the cellular coat,
+is liable to be broken off in dried specimens.) The spicules variable in
+quantity, arranged irregularly among the spaces of the cellular coat and
+usually forming a sparse horizontal layer on its external surface. Each
+gemmule contained in a cage of skeleton-spicules, by the pressure of
+which it is frequently distorted.
+
+
+8_a._ Var. mollis*, nov.
+
+This variety is characterized by a paucity of skeleton-spicules. The
+sponge is therefore soft and so fragile that it usually breaks in pieces
+if lifted from the water by means of its support. Owing to the paucity
+of skeleton-spicules, which resemble those of the typical form
+individually, the radiating and transverse fibres are extremely
+delicate.
+
+Common in Calcutta.
+
+
+8_b._ Var. cava*, nov.
+
+This variety is characterized by the fact that the oscula open into
+broad horizontal canals, the roof of which is formed by a thin layer of
+parenchyma and skeleton or, in places, of the external membrane only.
+The skeleton is loose and fragile, and the living sponge has a peculiar
+glassy appearance. In spirit the colour is yellowish, during life it is
+greenish or white.
+
+Taken at Bombay; November, 1907.
+
+
+8_c._ Var. lobosa*, nov.
+
+The greater part of the sponge in this variety consists of a number of
+compressed but pointed vertical lobes, which arise from a relatively
+shallow, rounded base, in which the oscula occur. The dried sponge has a
+yellowish colour.
+
+Apparently common in Travancore.
+
+       *     *     *     *     *
+
+I cannot distinguish these three "varieties"[AC] from the typical form
+as distinct species; indeed, their status as varieties is a little
+doubtful in two cases out of the three. Var. _cava_ appears to be a
+variety in the strict sense of the word (see p. 18), for it was found on
+the island of Bombay, the original locality of the species, growing side
+by side with the typical form. Var. _lobosa_, however, should perhaps be
+regarded as a subspecies rather than a variety, for I have received
+specimens from two localities in the extreme south-west of India and
+have no evidence that the typical form occurs in that part of the
+country. Evidence, however, is rather scanty as regards the occurrence
+of freshwater sponges in S. India. Var. _mollis_, again, may be a phase
+directly due to environment. It is the common form in the ponds of
+certain parts (_e. g._ in the neighbourhood of the Maidan and at
+Alipore) of the Calcutta municipal area, but in ponds in other parts
+(_e. g._ about Belgatchia) of the same area, only the typical form is
+found. It is possible that the water in the former ponds may be
+deficient in silica or may possess some other peculiarity that renders
+the production of spicules difficult for _S. carteri_; but this seems
+hardly probable, for _S. crassissima_, a species with a rather dense
+siliceous skeleton, flourishes in the same ponds. I have noticed that in
+ponds in which the aquatic vegetation is luxuriant and such genera of
+plants as _Pistia_ and _Limnanthemum_ flourish, there is always a
+tendency for _S. carteri_ to be softer than in ponds in which the
+vegetation is mostly cryptogamic, and in Calcutta those parts of the
+town in which sponges of this species produce most spicules are those in
+which a slight infiltration of brackish water into the ponds may be
+suspected; but in the interior of India, in places where the water is
+absolutely fresh, hard specimens seem to be the rule rather than the
+exception.
+
+     [Footnote AC: The only complete European specimen of the
+     species I have seen differs considerably in outward form
+     from any Indian variety, consisting of a flat basal area
+     from which short, cylindrical turret-like branches arise.
+     This specimen is from Lake Balaton in Hungary and was sent
+     me by Prof. von Daday de Dees of Buda-Pesth.]
+
+_S. carteri_ is closely related to _S. nitens_, Carter (Africa, and
+possibly S. America), but differs from that species in its comparatively
+slender, sharp skeleton-spicules and smooth gemmule-spicules. It may
+readily be distinguished from all other Indian freshwater sponges by its
+large, deep, round oscula, but this feature is not so marked in var.
+_lobosa_ as in the other forms. The typical form and var. _mollis_ grow
+to a larger size than is recorded for any other species of the family. I
+possess a specimen of the typical form from the neighbourhood of
+Calcutta which measures 30 x 27 cm. in diameter and 19.5 cm. in depth,
+and weighs (dry) 24-3/4 oz. The base of this specimen, which is solid
+throughout, is nearly circular, and the general form is mound-shaped.
+Another large specimen from Calcutta is in the form of an irregular
+wreath, the greatest diameter of which is 34 cm. This specimen weighs
+(dry) 16-1/4 oz. Both these specimens probably represent the growth of
+several years.
+
+TYPES.--The types of the varieties _mollis_, _cava_ and _lobosa_ are in
+the collection of the Indian Museum. I regard as the type of the species
+the specimen sent by Carter to Bowerbank and by him named _S. carteri_,
+although, owing to some confusion, Carter's description under this name
+appeared some years before Bowerbank's. This specimen is in the British
+Museum, with a fragment in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--The range of the species extends westwards
+to Hungary, southwards to Mauritius and eastwards to the island of
+Madura in the Malay Archipelago; a specimen from Lake Victoria Nyanza in
+Central Africa has been referred to it by Kirkpatrick (P. Zool. Soc.
+London, 1906 (i), p. 219), but I doubt whether the identification is
+correct. In India _S. carteri_ is by far the most universally
+distributed and usually much the commonest freshwater sponge; it is one
+of the only two species as yet found in Ceylon. Specimens are known from
+the following localities:--PUNJAB, Lahore (_J. Stephenson_): BOMBAY
+PRESIDENCY, island of Bombay (_Carter_, _Kirkpatrick_, _Annandale_);
+Igatpuri, W. Ghats (alt. _ca._ 2,000 ft.) (_Annandale_): UNITED
+PROVINCES (plains), Agra (_Kirkpatrick_); Lucknow: HIMALAYAS, Bhim Tal,
+Kumaon (alt. 4,500 ft.) (_Annandale_); Tribeni, Nepal (_Hodgart_):
+BENGAL, Calcutta and neighbourhood; Rajshahi (Rampur Bhulia) on the R.
+Ganges about 150 miles N. of Calcutta (_Annandale_); Berhampur,
+Murshidabad district (_R. E. Lloyd_); Pusa, Darbbhanga district
+(_Bainbrigge Fletcher_); Siripur, Saran district, Tirhut (_M.
+Mackenzie_); Puri and the Sur Lake, Orissa (_Annandale_): MADRAS
+PRESIDENCY, near Madras town (_J. R. Henderson_); Madura district (_R.
+Bruce Foote_); Bangalore (_Annandale_) and Worgaum, Mysore State
+(2,500-3,000 ft.); Ernakulam and Trichur, Cochin (_G. Mathai_);
+Trivandrum and the neighbourhood of C. Comorin, Travancore (var.
+_lobosa_) (_R. S. N. Pillay_): BURMA, Kawkareik, interior of Amherst
+district, Tenasserim (_Annandale_); Rangoon (_Annandale_); Bhamo, Upper
+Burma (_J. Coggin Brown_): CEYLON, Peradeniya (_E. E. Green_); outlet of
+the Maha Rambaikulam between Vavuniya and Mamadu, Northern Province
+(_Willey_); Horowapotanana, between Trincomalee and Anuradihapura,
+North-Central Province (_Willey_).
+
+BIOLOGY.--_S. carteri_ usually grows in ponds and lakes; I have never
+seen it in running water. Mr. Mackenzie found it on the walls of old
+indigo wells in Tirhut.
+
+The exact form of the sponge depends to some extent on the forces acting
+on it during life. At Igatpuri, for instance, I found that specimens
+attached to the stems of shrubs growing in the lake and constantly
+swayed by the wind had their surface irregularly reticulated with high
+undulating ridges, while those growing on stones at the bottom of a
+neighbouring pond were smooth and rounded.
+
+Sponges of this species do not shun the light.
+
+In Calcutta _S. carteri_ flourishes during the cold weather (November to
+March). By the end of March many specimens that have attached themselves
+to delicate stems such as those of the leaves of _Limnanthemum_, or to
+the roots of _Pistia stratiotes_, have grown too heavy for their support
+and have sunk down into the mud at the bottom of the ponds, in which
+they are quickly smothered. Others fixed to the end of branches
+overhanging the water or to bricks at the edge have completely dried up.
+A large proportion, however, still remain under water; but even these
+begin to show signs of decay at this period. Their cells migrate to the
+extremities of the sponge, leaving a mass of gemmules in the centre, and
+finally perish.
+
+Few sponges exist in an active condition throughout the hot weather. The
+majority of those that do so exhibit a curious phenomenon. Their surface
+becomes smoothly rounded and they have a slightly pinkish colour; the
+majority of the cells of their parenchyma, if viewed under a high power
+of the microscope, can be seen to be gorged with very minute drops of
+liquid. This liquid is colourless in its natural condition, but if the
+sponge is plunged into alcohol the liquid turns of a dark brown colour
+which stains both the alcohol and the sponge almost instantaneously.
+Probably the liquid represents some kind of reserve food-material. Even
+in the hot weather a few living sponges of the species may be found that
+have not this peculiarity, but, in some ponds at any rate, the majority
+that survive assume the peculiar summer form, which I have also found at
+Lucknow.
+
+Reproduction takes place in _S. carteri_ in three distinct ways, two of
+which may be regarded as normal, while the third is apparently the
+result of accident. If a healthy sponge is torn into small pieces and
+these pieces are kept in a bowl of water, little masses of cells
+congregate at the tips of the radiating fibres of the skeleton and
+assume a globular form. At first these cells are homogeneous, having
+clear protoplasm full of minute globules of liquid. The masses differ
+considerably in size but never exceed a few millimetres in diameter. In
+about two days differentiation commences among the cells; then spicules
+are secreted, a central cavity and an external membrane formed, and an
+aperture, the first osculum, appears in the membrane. In about ten days
+a complete young sponge is produced, but the details of development have
+not been worked out.
+
+The most common normal form of reproduction is by means of gemmules,
+which are produced in great numbers towards the end of the cold weather.
+If small sponges are kept alive in an aquarium even at the beginning of
+the cold weather, they begin to produce gemmules almost immediately, but
+these gemmules although otherwise perfect, possess few or no
+gemmule-spicules. If the sponge becomes desiccated at the end of the
+cold weather and is protected in a sheltered place, some or all of the
+gemmules contained in the meshes of its skeleton germinate _in situ_ as
+soon as the water reaches it again during the "rains." It is by a
+continuous or rather periodical growth of this kind, reassumed season
+after season, that large masses of sponge are formed. In such masses it
+is often possible to distinguish the growth of the several years, but as
+a rule the layers become more or less intimately fused together, for no
+limiting membrane separates them. A large proportion of the gemmules
+are, however, set free and either float on the surface of the water that
+remains in the ponds or are dried up and carried about by the wind. In
+these circumstances they do not germinate until the succeeding cold
+weather, even if circumstances other than temperature are favourable;
+but as soon as the cold weather commences they begin to produce new
+sponges with great energy.
+
+Sexual reproduction, the second normal form, takes place in _S. carteri_
+mainly if not only at the approach of a change of season, that is to say
+about March, just before the hot weather commences, and about November,
+just as the average temperature begins to sink to a temperate level. At
+these seasons healthy sponges may often be found full of eggs and
+embryos, which lie in the natural cavities of the sponge without
+protecting membrane.
+
+In the ponds of Calcutta a large number of animals are found associated
+in a more or less definite manner with _Spongilla carteri_. Only one,
+however, can be described with any degree of certainty as being in
+normal circumstances an enemy, namely the larva of _Sisyra indica_,[AD]
+and even in the case of this little insect it is doubtful how far its
+attacks are actually injurious to the sponge. The larva is often found
+in considerable numbers clinging to the oscula and wide efferent canals
+of _S. carteri_, its proboscis inserted into the substance of the
+sponge. If the sponge dies and the water becomes foul the larvae swim or
+crawl away. If the sponge dries up, they leave its interior (in which,
+however, they sometimes remain for some days after it has become dry)
+and pupate in a silken cocoon on its surface. Hence they emerge as
+perfect insects after about a week.
+
+     [Footnote AD: Needham. Rec. Ind. Mus. iii, p. 206 (1909).]
+
+An animal that may be an enemy of _S. carteri_ is a flat-worm (an
+undescribed species of _Planaria_) common in its larger canals and
+remarkable for the small size of its pharynx. The same worm, however, is
+also found at the base of the leaves of bulrushes and in other like
+situations, and there is no evidence that it actually feeds on the
+sponge. Injured sponges are eaten by the prawn _Palaemon lamarrei_,
+which, however, only attacks them when the dermal membrane is broken. A
+_Tanypus_ larva (Chironomid Diptera) that makes its way though the
+substance of the sponge may also be an enemy; it is commoner in decaying
+than in vigorous sponges.
+
+The presence of another Chironomid larva (_Chironomus_, sp.) appears to
+be actually beneficial. In many cases it is clear that this larva and
+the sponge grow up together, and the larva is commoner in vigorous than
+in decayed sponges. Unlike the _Tanypus_ larva, it builds parchment-like
+tubes, in which it lives, on the surface of the sponge. The sponge,
+however, often grows very rapidly and the larva is soon in danger of
+being engulfed in its substance. The tube is therefore lengthened in a
+vertical direction to prevent this catastrophe and to maintain
+communication with the exterior. The process may continue until it is
+over an inch in length, the older part becoming closed up owing to the
+pressure of the growing sponge that surrounds it. Should the sponge die,
+the larva lives on in its tubes without suffering, and the ends of tubes
+containing larvae may sometimes be found projecting from the worn surface
+of dead sponges. The larva does not eat the sponge but captures small
+insects by means of a pair of legs on the first segment of its thorax.
+In so doing it thrusts the anterior part of its body out of the tube, to
+the inner surface of which it adheres by means of the pair of false legs
+at the tip of the abdomen. This insect, which is usually found in the
+variety _mollis_, appears to do good to the sponge in two ways--by
+capturing other insects that might injure it and by giving support to
+its very feeble skeleton.
+
+A precisely similar function, so far as the support of the sponge is
+concerned, is fulfilled by the tubular zooecia of a phase of the
+polyzoon _Plumatella fruticosa_ (see p. 218) which in India is more
+commonly found embedded in the substance of _S. carteri_ than in that of
+any other species, although in Great Britain it is generally found in
+that of _S. lacustris_, which is there the commonest species of
+freshwater sponge.
+
+Another animal that appears to play an active part in the oeconomy of
+the sponge is a peculiar little worm (_Chaetogaster spongillae_) also
+found among the zooecia of _Plumatella_ and belonging to a widely
+distributed genus of which several species are found in association with
+pond-snails. _Chaetogaster spongillae_ often occurs in enormous numbers in
+dead or dying sponges of _S. carteri_, apparently feeding on the
+decaying organic matter of the sponge and assisting by its movements in
+releasing numerous gemmules. In so doing it undoubtedly assists in the
+dissemination of the species.
+
+Major J. Stephenson (Rec. Ind. Mus. v, p. 233) has recently found two
+other species of oligochaetes inhabiting _S. carteri_ var. _lobosa_ from
+Travancore. Both these species, unlike _Chaetogaster spongillae_, belong
+to a genus that is vegetarian in habits. One of them, _Nais pectinata_,
+has not yet been found elsewhere, while the other, _Nais communis_, has
+a very wide distribution. The latter, however, occurs in the sponge in
+two forms--one with eyes, the other totally blind. The blind form (_N.
+communis_ var. _caeca_) has only been found in this situation, but the
+other (var. _punjabensis_) lives free as well as in association with the
+sponge, in which the blind form was the commoner of the two.
+
+The majority of the animals found in association with _S. carteri_ gain
+shelter without evident assistance to the sponge. This is the case as
+regards the little fish (_Gobius alcockii_), one of the smallest of the
+vertebrates (length about 1/2 inch), which lays its eggs in the patent
+oscula, thus securing for them a situation peculiarly favourable to
+their development owing to the constant current of water that passes
+over them. In the absence of sponges, however, this fish attaches its
+eggs to the floating roots of the water-plant _Pistia stratiotes_.
+Numerous small crustacea[AE] also take temporary or permanent refuge in
+the cavities of _S. carteri_, the most noteworthy among them being the
+Isopod _Tachaea spongillicola_[AF], the adults of which are found in the
+canal of this and other sponges, while the young cling to the external
+surface of the carapace of _Palaemon lamarrei_ and other small prawns.
+Many worms and insects of different kinds also enter the canals of _S.
+carteri_, especially when the sponge is becoming desiccated; from
+half-dry sponges numerous beetles and flies may be bred, notably the
+moth-fly _Psychoda nigripennis_[AG] of which enormous numbers sometimes
+hatch out from such sponges.
+
+     [Footnote AE: According to the late Rai Bahadur R. B.
+     Sanyal, freshwater sponges are called in Bengali "shrimps'
+     nests." From his description it is evident that he refers
+     mainly to _S. carteri_ (see Hours with Nature, p. 46;
+     Calcutta 1896).]
+
+     [Footnote AF: Stebbing, J. Linn. Soc. xxx, p. 40; Annandale,
+     Rec. Ind. Mus. i, p. 279.]
+
+     [Footnote AG: Brunetti, Rec. Ind. Mus. ii, p. 376 (1908).]
+
+As the sponge grows it frequently attaches itself to small molluscs such
+as the young of _Vivipara bengalensis_, which finally become buried in
+its substance and thus perish. Possibly their decaying bodies may afford
+it nourishment, but of the natural food of sponges we know little. _S.
+carteri_ flourishes best and reaches its largest size in ponds used for
+domestic purposes by natives of India, and thrives in water thick with
+soap-suds. It is possible, though direct proof is lacking, that the
+sponge does good in purifying water used for washing the clothes,
+utensils, and persons of those who drink the same water, by absorbing
+decaying animal and vegetable matter from it.
+
+Various minute algae are found associated with _S. carteri_, but of these
+little is yet known. The green flush sometimes seen on the surface of
+the typical form is due to the fact that the superficial cells of the
+parenchyma contain green corpuscles. These, however, are never very
+numerous and are not found in the inner parts of the sponge, perhaps
+owing to its massive form. It is noteworthy that these green bodies
+flourish in large numbers throughout the substance of sponges of _S.
+proliferens_, a species always far from massive, growing in the same
+ponds as _S. carteri_.
+
+
+9. Spongilla fragilis, _Leidy_.
+
+     _Spongilla fragilis_, Leidy, P. Ac. Philad. 1851, p. 278.
+
+     _Spongilla lordii_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 466, pl. xxxviii, fig. 17.
+
+     _Spongilla contecta_, Noll, Zool. Garten*, 1870, p. 173.
+
+     _Spongilla ottavaensis_, Dawson, Canad. Nat.* (new series)
+     viii, p. 5 (1878).
+
+     _Spongilla sibirica_, Dybowski, Zool. Anz., Jahr. i, p. 53
+     (1878).
+
+     _Spongilla morgiana_, Potts, P. Ac. Philad. 1880, p. 330.
+
+     _Spongilla lordii_, Carter, Ann. Nat. Hist. (5) vii, p. 89,
+     pl. vi, fig. 13 (1881).
+
+     _Spongilla sibirica_, Dybowski, Mem. Ac. St. Petersb. (7)
+     xxx, no. x, p. 10, fig. 12.
+
+     _Spongilla glomerata_, Noll, Zool. Anz., Jahr. ix, p. 682
+     (1886).
+
+     _Spongilla fragilis_, Vejdovsky, P. Ac. Philad. 1887, p.
+     176.
+
+     _Spongilla fragilis_, Potts, _ibid._ p. 197, pl. v, fig. 2;
+     pl. viii, figs. 1-4.
+
+     _Spongilla fragilis_, Weltner, Arch. Naturg. lix (1), p.
+     266, pl. ix, figs. 18-20 (1893).
+
+     _Spongilla fragilis_, _id._, Arch. Naturg. lxi (i), p. 117
+     (1895).
+
+     _Spongilla fragilis_, _id._, in Semon's Zool. Forsch. in
+     Austral. u. d. Malay. Arch. v, part v, p. 523.
+
+     _Spongilla fragilis_, Annandale, P. U.S. Mus. xxxvii, p. 402
+     (1909).
+
+     _Spongilla fragilis_, _id._, Annot. Zool. Japon. vii, part
+     ii, p. 106, pl. ii, fig. 1 (1909).
+
+_Sponge_ flat, lichenoid, never of great thickness, devoid of branches,
+dense in texture but very friable; colour brown, green, or whitish;
+oscula numerous, small, flat, distinctly star-shaped.
+
+_Skeleton_ with well defined radiating and transverse fibres, which are
+never strong but form a fairly dense network with a small amount of
+spongin.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, moderately stout,
+as a rule nearly straight. No flesh-spicules. Gemmule-spicules
+cylindrical, blunt or abruptly pointed, nearly straight, covered with
+relatively stout, straight, irregular spines, which are equally
+distributed all over the spicule.
+
+_Gemmules_ bound together in free groups of varying numbers and forming
+a flat layer at the base of the sponge; each gemmule small in size,
+surrounded by a thick cellular coat of several layers; with a relatively
+long and stout foraminal tubule, which projects outwards through the
+cellular coat at the sides of the group or at the top of the basal layer
+of gemmules, is usually curved, and is not thickened at the tip; more
+than one foraminal tubule sometimes present on a single gemmule;
+gemmule-spicules arranged horizontally or at the base of the cellular
+coat.
+
+The species as a species is easily distinguished from all others, its
+nearest ally being the N. American _S. ingloriformis_ with sparsely
+spined skeleton-spicules which are very few in number, and gemmule
+groups in which the foraminal tubules all open downwards.
+
+Several varieties of _S. fragilis_ have been described in Europe and
+America.
+
+TYPE.--Potts refers to the type as being in the Academy of Natural
+Sciences at Philadelphia.
+
+GEOGRAPHICAL DISTRIBUTION.--All over Europe and N. America; also in
+Siberia, Australia, and S. America. The species is included in this work
+in order that its Asiatic local races may be fitly described.
+
+
+9 _a._ Subsp. calcuttana*, nov.
+
+     ? _Spongilla decipiens_, Weltner (_partim_), Arch. Naturg.
+     lxi (i), pp. 117, 134 (1895).
+
+     _Spongilla decipiens_, Annandale, Journ. As. Soc. Beng.
+     1906, p. 57.
+
+     _Spongilla fragilis_, _id._, Rec. Ind. Mus. i, p. 390
+     (1907).
+
+[Illustration: Fig. 15.--_Spongilla fragilis_ subsp. _calcuttana_.
+A=group of gemmules, x 70; B=spicules, x 240. From type specimen.]
+
+This local race, which is common in Calcutta, is distinguished from the
+typical form mainly by the shape of its skeleton-spicules, most of which
+are abruptly pointed or almost rounded at the tips, sometimes bearing a
+minute conical projection at each end. The gemmule-spicules, which are
+usually numerous, are slender. The foraminal tubules are usually long
+and bent, but are sometimes very short and quite straight. The colour is
+usually greyish, occasionally brown.
+
+I have not found this race except in Calcutta, in the ponds of which it
+grows on bricks or, very commonly, on the stems of bulrushes, often
+covering a considerable area.
+
+TYPE in the Indian Museum.
+
+
+9 _b._ Subsp. decipiens*, _Weber_.
+
+     _Spongilla decipiens_, Weber, Zool. Ergeb. Niederlaend.
+     Ost-Ind. i, p. 40, pl. iv, figs. 1-5 (1890).
+
+This (?) local race is distinguished by the fact that the foraminal
+tubules are invariably short and straight and thickened at the tips, and
+that gemmule-spicules do not occur on the external surface of the
+cellular coat of the gemmules.
+
+I include Weber's _Spongilla decipiens_ in the Indian fauna on the
+authority of Weltner, who identified specimens from the Museum "tank,"
+Calcutta, as belonging to this form. All, however, that I have examined
+from our "tank" belong to the subspecies _calcuttana_, most of the
+skeleton-spicules of which are much less sharp than those of
+_decipiens_. By the kindness of Prof. Max Weber I have been able to
+examine a co-type of his species, which is probably a local race
+peculiar to the Malay Archipelago.
+
+TYPE in the Amsterdam Museum; a co-type in Calcutta.
+
+Perhaps the Japanese form, which has spindle-shaped gemmule-spicules
+with comparatively short and regular spines, should be regarded as a
+third subspecies, and the Siberian form as a fourth.
+
+
+10. Spongilla gemina*, sp. nov.
+
+_Sponge_ forming small, shallow, slightly dome-shaped patches of a more
+or less circular or oval outline, minutely hispid on the surface,
+friable but moderately hard. Oscula numerous but minute and
+inconspicuous, never star-shaped. Dermal membrane adhering closely to
+the sponge. Colour grey or brown.
+
+_Skeleton_ forming a close and regular network at the base of the
+sponge, becoming rather more diffuse towards the external surface; the
+radiating and the transverse fibres both well developed, of almost equal
+diameter. Little spongin present.
+
+_Spicules._ Skeleton-spicules slender, smooth, sharply pointed. No
+flesh-spicules. Gemmule-spicules long, slender, cylindrical, blunt or
+bluntly pointed, somewhat irregularly covered with minute straight
+spines.
+
+_Gemmules_ small, bound together in pairs, as a rule free in the
+parenchyma but sometimes lightly attached at the base of the sponge.
+Each gemmule flattened on the surface by which it is attached to its
+twin, covered with a thin coat of polygonal air-spaces which contains
+two layers of gemmule-spicules crossing one another irregularly in a
+horizontal plane. One or two foraminal tubules present on the surface
+opposite the flat one, bending towards the latter, often of considerable
+length, cylindrical and moderately stout.
+
+TYPE in the Indian Museum.
+
+This species is closely allied to _S. fragilis_, from which it may be
+distinguished by the curious twinned arrangement of its gemmules. It
+also differs from _S. fragilis_ in having extremely small and
+inconspicuous oscula.
+
+_Locality._ I only know this sponge from the neighbourhood of Bangalore,
+where Dr. Morris Travers and I found it in October, 1910 growing on
+stones and on the leaves of branches that dipped into the water at the
+edge of a large tank.
+
+
+11. Spongilla crassissima*, _Annandale_.
+
+     _Spongilla crassissima_, Annandale, J. Asiat. Soc. Bengal,
+     1907, p. 17, figs. 2, 3.
+
+     _Spongilla crassissima_, _id._, _ibid._ p. 88.
+
+     _Spongilla crassissima_, _id._, Rec. Ind. Mus. i. p. 390,
+     pl. xiv, fig. 4 (1907).
+
+_Sponge_ very hard and strong, nearly black in colour, sometimes with a
+greenish tinge, forming spherical, spindle-shaped or irregular masses
+without branches but often several inches in diameter. Oscula circular
+or star-shaped, usually surrounded by radiating furrows; pores normally
+contained in single cells. External membrane closely adherent to the
+sponge except immediately round the oscula.
+
+_Skeleton_ dense, compact and only to be broken by the exercise of
+considerable force; radiating and transverse fibres not very stout but
+firmly bound together by spongin (fig. 6, p. 38), which occasionally
+extends between them as a delicate film; their network close and almost
+regular.
+
+_Spicules._ Skeleton-spicules smooth, feebly curved, sausage-shaped but
+by no means short, as a rule bearing at each end a minute conical
+projection which contains the extremity of the axial filament. No
+flesh-spicules. Gemmule-spicules closely resembling those of _S.
+fragilis_ subsp. _calcuttana_, but as a rule even more obtuse at the
+ends.
+
+_Gemmules_ as in _S. fragilis_ subsp. _calcuttana_; a basal layer of
+gemmules rarely formed.
+
+
+11 _a._ Var. crassior*, _Annandale_.
+
+     _Spongilla crassior_, Annandale, Rec. Ind. Mus. i, p. 389,
+     pl. xiv, fig. 3 (1907).
+
+This variety differs from the typical form chiefly in its even stronger
+skeleton (fig. 3, p. 33) and its stouter skeleton-spicules, which do not
+so often possess a terminal projection. The sponge is of a brownish
+colour and forms flat masses of little thickness but of considerable
+area on sticks and on the stems of water-plants.
+
+TYPES.--The types of both forms are in the Indian Museum. Co-types have
+been sent to London.
+
+GEOGRAPHICAL DISTRIBUTION.--This sponge is only known from Bengal. The
+variety _crassior_ was found at Rajshahi (Rampur Bhulia) on the Ganges,
+about 150 miles N. of Calcutta, while the typical form is fairly common
+in the "tanks" of Calcutta and very abundant in the Sur Lake near Puri
+in Orissa.
+
+[Illustration: Fig. 16.--Spicules of _Spongilla crassissima_ var.
+_crassior_ (from type specimen), x 240.]
+
+BIOLOGY.--_S. crassissima_ is usually found near the surface in shallow
+water. Attached to the roots of the floating water-plant _Pistia
+stratiotes_ it assumes a spherical form, while on sticks or like objects
+it is spindle-shaped. Sometimes it is found growing on the same stick or
+reed-stem as _S. carteri_, the two species being in close contact and
+_S. carteri_ always overlapping _S. crassissima_. The dark colour is due
+to minute masses of blackish pigment in the cells of the parenchyma. The
+dense structure of the sponge is not favourable to the presence of
+_incolae_, but young colonies of the polyzoon _Plumatella fruticosa_ are
+sometimes overgrown by it. Although they may persist for a time by
+elongating their tubular zooecia through the substance of the sponge,
+they do not in these circumstances reach the same development as when
+they are overgrown by the much softer _S. carteri_.
+
+_S. crassissima_ is found during the "rains" and the cold weather. In
+Calcutta it attains its maximum size towards the end of the latter
+season. In spite of its hard and compact skeleton, the sponge does not
+persist from one cold weather to another.
+
+A curious phenomenon has been noticed in this species, but only in the
+case of sponges living in an aquarium, viz. the cessation during the
+heat of the day of the currents produced by its flagella.
+
+
+Subgenus C. STRATOSPONGILLA, _Annandale_.
+
+     _Stratospongilla_, Annandale, Zool. Jahrb., Syst. xxvii, p.
+     561 (1909).
+
+TYPE, _Spongilla bombayensis_, Carter.
+
+Spongillae in the gemmules of which the pneumatic layer is absent or
+irregularly developed, its place being sometimes taken by air-spaces
+between the stout chitinous membranes that cover the gemmule. At least
+one of these membranes is always present.
+
+The gemmule-spicules lie in the membrane or membranes parallel to the
+surface of the gemmule, and are often so arranged as to resemble a
+mosaic. The gemmules themselves are usually adherent to the support of
+the sponge. The chitinous membrane or membranes are often in continuity
+with a membrane that underlies the base of the sponge. The skeleton is
+usually stout, though often almost amorphous, and the skeleton-spicules
+are sometimes sausage-shaped.
+
+Sponges of this subgenus form crusts or sheets on solid submerged
+objects.
+
+_Stratospongilla_ is essentially a tropical subgenus, having its
+head-quarters in Central Africa and Western India. One of its species,
+however, (_S. sumatrana_*, Weber) occurs both in Africa and the Malay
+Archipelago, while another has only been found in S. America (_S.
+navicella_, Carter).
+
+Aberrant species occur in China (_S. sinensis_*, _S. coggini_*) and the
+Philippines (_S. clementis_*). Three species have been found in the
+Bombay Presidency and Travancore, one of which (_S. bombayensis_*)
+extends its range eastwards to Mysore and westwards across the Indian
+Ocean to Natal.
+
+
+12. Spongilla indica*, _Annandale_.
+
+     _Spongilla indica_, Annandale, Rec. Ind. Mus. ii, p. 25,
+     figs. 1, 2 (1908).
+
+_Sponge_ forming a very thin layer, of a bright green or pale grey
+colour; surface smooth, minutely hispid; pores and oscula inconspicuous,
+the latter approached in some instances by radiating furrows; subdermal
+cavity small; texture compact, rather hard.
+
+_Skeleton_ incoherent, somewhat massive owing to the large number of
+spicules present. Spicules forming triangular meshes and occasionally
+arranged in vertical lines several spicules broad but without spongin.
+
+_Spicules._ Skeleton-spicules straight or nearly straight, slender,
+cylindrical, amphistrongylous, uniformly covered with minute, sharp
+spines; flesh-spicules slender, sharply pointed, straight or curved,
+irregularly covered with relatively long, straight sharp spines,
+abundant in the dermal membrane, scarce in the substance of the sponge.
+Gemmule-spicules short, stout, sausage-shaped, covered with minute
+spines, which are sometimes absent from the extremities.
+
+_Gemmules_ spherical, somewhat variable in size, with a single aperture,
+which is provided with a trumpet-shaped foraminal tubule and is situated
+at one side of the gemmule in its natural position; the inner chitinous
+coat devoid of spicules, closely covered by an outer coat composed of a
+darkly coloured chitinoid substance in which the gemmule-spicules are
+embedded, lying parallel or almost parallel to the inner coat. The outer
+coat forms a kind of mantle by means of the skirts of which the gemmule
+is fastened to the support of the sponge. This coat is pierced by the
+foraminal tubule.  The gemmules are distinct from one another.
+
+[Illustration: Fig. 17.--Gemmule of _Spongilla indica_ seen from the
+side (from type specimen), magnified.]
+
+  Average length of skeleton-spicules       0.2046 mm.
+     "   breadth of skeleton-spicules       0.0172  "
+     "   length of flesh-spicules           0.053   "
+     "   breadth of flesh-spicules          0.0053  "
+     "   length of gemmule-spicules         0.044   "
+     "   breadth of gemmule-spicules        0.0079  "
+
+_S. indica_ is closely allied to _S. sumatrana_*, Weber, which has been
+found both in the Malay Archipelago and in East Africa. It may be
+distinguished by its blunt, almost truncated megascleres and
+comparatively slender gemmule-spicules.
+
+TYPE in the Indian Museum.
+
+HABITAT, etc.--Growing, together with _S. cinerea_ and _Corvospongilla
+lapidosa_, on the stone sides of an artificial conduit in the R.
+Godaveri at Nasik on the eastern side of the Western Ghats in the Bombay
+Presidency. The water was extremely dirty and was used for bathing
+purposes. The sponge was green where the light fell upon it, grey where
+it was in the shadow of the bridge under which the conduit ran. The only
+specimens I have seen were taken in November, 1907.
+
+
+13. Spongilla bombayensis*, _Carter_. (Plate II, fig. 2.)
+
+     _Spongilla bombayensis_, Carter, Ann. Nat. Hist. (5) x, p.
+     369, pl. xvi, figs. 1-6 (1882).
+
+     _Spongilla bombayensis_, Annandale, Zool. Jahrb., Syst.
+     xxvii, p. 562, figs. B, C (1909).
+
+_Sponge_ hard but friable, forming thin layers or cushions; its surface
+often irregular but without a trace of branches; its area never very
+great; oscula inconspicuous; external membrane adhering closely to the
+sponge; colour brownish or greyish.
+
+[Illustration: Fig. 18.--Gemmule of _Spongilla bombayensis_ as seen from
+above (from type specimen), magnified.]
+
+_Skeleton_ almost amorphous, very dense, consisting of large numbers of
+spicules arranged irregularly; radiating fibres occasionally visible in
+sections, but almost devoid of spongin; a more or less definite
+reticulation of horizontal spicules lying immediately under the external
+membrane.
+
+_Spicules._ Skeleton-spicules slender, pointed, feebly curved,
+irregularly roughened or minutely spined all over the surface.
+Flesh-spicules straight, narrowly rhomboidal in outline, sharply
+pointed, slender, covered with minute, irregular, straight spines,
+scanty in the parenchyma, abundant in the external membrane.
+Gemmule-spicules sausage-shaped or bluntly pointed, variable in length
+but usually rather stout, covered with minute spines, as a rule
+distinctly curved.
+
+_Gemmules_ round or oval, firmly adherent[AH] to the base of the sponge,
+as a rule rather shallowly dome-shaped, covered by two thick chitinous
+membranes, in each of which there is a dense horizontal layer of
+spicules; no granular or cellular covering; the two chitinous coats
+separated by an empty space; the aperture or apertures on the side of
+the gemmule in its natural position, provided with foraminal tubules,
+which may be either straight or curved, project through the outer
+chitinous membrane and often bend down towards the base of the gemmule.
+The spicules of the outer layer often more irregular in outline and less
+blunt than those of the inner layer.
+
+     [Footnote AH: The outer covering by means of which the
+     gemmule is fixed is not formed until the other structures
+     are complete. In young sponges, therefore, free gemmules may
+     often be found.]
+
+This sponge is allied to _S. indica_, but is distinguished among other
+characters by its sharp skeleton-spicules and by the fact that the
+gemmule is covered by two chitinous membranes instead of one.
+
+TYPE in the British Museum; a fragment in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--S. and W. India and S. Africa. Carter's type
+was found in the island of Bombay, my own specimens in Igatpuri Lake in
+the Western Ghats. I have recently (October 1910) found sponges and bare
+gemmules attached to stones at the end of a tank about 10 miles from
+Bangalore (Mysore State) in the centre of the Madras Presidency. Prof.
+Max Weber obtained specimens in Natal.
+
+BIOLOGY.--The specimens collected by Prof. Weber in Natal and those
+collected by myself in the Bombay Presidency were both obtained in the
+month of November. It is therefore very interesting to compare them from
+a biological point of view. In so doing, it must be remembered that
+while in S. Africa November is near the beginning of summer, in India it
+is at the beginning of the "cold weather," that is to say, both the
+coolest and the driest season of the year. The lake in which my
+specimens were obtained had, at the time when they were collected,
+already sunk some inches below its highest level, leaving bare a gently
+sloping bank of small stones. Adhering to the lower surface of these
+stones I found many small patches of _Spongilla bombayensis_, quite dry
+but complete so far as their harder parts were concerned and with the
+gemmules fully formed at their base. From the shallow water at the edge
+of the lake I took many similar stones which still remained submerged.
+It was evident that the sponge had been just as abundant on their lower
+surface as on that of the stones which were now dry; but only the
+gemmules remained, sometimes with a few skeleton-spicules adhering to
+them (Pl. II, fig. 2). The bulk of the skeleton had fallen away and the
+parenchyma had wholly perished. In a few instances a small sponge, one
+or two millimetres in diameter, had already been formed among the
+gemmules; but these young sponges appeared to belong to some other
+species, possibly _Spongilla indica_, which was also common in the lake.
+
+Carter's specimen of _S. bombayensis_, which was evidently in much the
+same condition as those I found still submerged a month later, was taken
+in October in a disused quarry. It was surrounded by a mass of _S.
+carteri_ three inches in diameter, and was attached to a herbaceous
+annual. The point on the edge of the quarry at which this plant grew was
+not reached by the water until July. It is therefore necessary to assume
+that the gemmules of _S. bombayensis_ had been formed between July and
+October. Probably the larva of the sponge had settled down on the plant
+during the "rains"--which commence in Bombay about the beginning of
+June--and had grown rapidly. The production of gemmules may have been
+brought about owing to the sponge being choked by the more vigorous
+growth of _S. carteri_, a species which grows to a considerable size in
+a comparatively short time, while _S. bombayensis_ apparently never
+reaches a thickness of more than a few millimetres.
+
+The manner in which the gemmules of _S. bombayensis_ are fastened to the
+solid support of the sponge must be particularly useful in enabling them
+to sprout in a convenient environment as soon as the water reaches them.
+The fact that the gemmules remained fixed without support renders it
+unnecessary for the skeleton to persist as a cage containing them (or at
+any rate a proportion of them) during the period of rest.
+
+Prof. Weber's specimens of _S. bombayensis_ were collected in a river,
+apparently on stones or rocks, towards the beginning of the S. African
+summer. They contain comparatively few gemmules and were evidently in a
+vigorous condition as regards vegetative growth. Unfortunately we know
+nothing of the seasonal changes which take place in freshwater sponges
+in S. Africa, but the difference between these changes in Europe and in
+India shows that they are dependent on environment as well as the
+idiosyncrasy of the species. It is very interesting, therefore, to see
+that the condition of sponges taken in S. Africa differs so widely from
+that of other individuals of the same species taken in India at the same
+season.
+
+In Prof. Weber's specimens I have found numerous small tubules of
+inorganic debris. These appear to be the work of Chironomid larvae, of
+which there are several specimens loose in the bottle containing the
+sponges. Other tubules of a very similar appearance but with a delicate
+chitinoid foundation appear to be the remains of a species of
+_Plumatella_ of which they occasionally contain a statoblast.
+
+
+14. Spongilla ultima*, _Annandale_. (Plate II, fig. 3.)
+
+     _Spongilla ultima_, Annandale, Rec. Ind. Mus. v, p. 31 (1910).
+
+_Sponge_ hard and strong, forming a thin layer on solid objects, of a
+pale green colour (dry); the oscula small but rendered conspicuous by
+the deep radiating furrows that surround them; external surface of the
+sponge rough but not spiny.
+
+_Skeleton_ forming a compact but somewhat irregular reticulation in
+which the radiating fibres are not very much more distinct than the
+transverse ones; a considerable amount of almost colourless spongin
+present.
+
+_Spicules._ Skeleton-spicules smooth, stout, amphioxous, as a rule
+straight or nearly straight, not infrequently inflated in the middle or
+otherwise irregular. No flesh-spicules. Gemmule-spicules variable in
+size, belonging to practically every type and exhibiting practically
+every abnormality possible in the genus, the majority being more or less
+sausage-shaped and having a roughened surface, but others being
+cruciform, spherical, subspherical, rosette-like, needle-like, bifid or
+even trifid at one extremity.
+
+[Illustration: Fig. 19.--Spicules of _Spongilla ultima_ (from type
+specimen), x 120.]
+
+_Gemmules_ adherent, spherical, large, each covered by two distinct
+layers of horizontal spicules; the outer layer intermixed with
+skeleton-spicules and often containing relatively large siliceous
+spheres, a large proportion of the spicules being irregular in shape;
+the spicules of the inner layer much more regular and as a rule
+sausage-shaped. The outer layer is contained in a chitinous membrane
+which spreads out over the base of the sponge. The foraminal tubules are
+short and straight.
+
+This sponge is allied to _S. bombayensis_, from which it is
+distinguished not only by the abnormal characters of its
+gemmule-spicules and the absence of flesh-spicules, but also by the form
+of its skeleton-spicules and the structure of its skeleton. I have
+examined several specimens dry and in spirit; but _S. ultima_ is the
+only Indian freshwater sponge, except _Corvospongilla burmanica_, I have
+not seen in a fresh condition.
+
+TYPES in the Indian Museum; co-types at Trivandrum.
+
+HABITAT. Discovered by Mr. R. Shunkara Narayana Pillay, of the
+Trivandrum Museum, in a tank near Cape Comorin, the southernmost point
+of the Indian Peninsula.
+
+
+Genus 2. PECTISPONGILLA, _Annandale_.
+
+     _Pectispongilla_, Annandale, Rec. Ind. Mus. iii, p. 103 (1909).
+
+TYPE, _Pectispongilla aurea_, Annandale.
+
+The structure of the sponge resembling that of _Euspongilla_ or
+_Ephydatia_; but the gemmule-spicules bear at either end, at one side
+only, a double vertical row of spines, so that they appear when viewed
+in profile like a couple of combs joined together by a smooth bar.
+
+[Illustration: Fig. 20.--Gemmule and spicules of _Pectispongilla aurea_
+(type specimen). _a_, Skeleton-spicules; _b_, gemmule-spicules; _b'_, a
+single gemmule-spicule more highly magnified.]
+
+GEOGRAPHICAL DISTRIBUTION.--The genus is monotypic and is only known
+from Travancore and Cochin in the south-west of the Indian Peninsula.
+
+
+15. Pectispongilla aurea*, _Annandale_.
+
+     _Pectispongilla aurea_, Annandale, _op. cit._, p. 103, pl.
+     xii, fig. 2.
+
+_Sponge_ forming minute, soft, cushion-like masses of a deep golden
+colour (dull yellow in spirit); the surface smooth, minutely hispid. One
+relatively large depressed osculum usually present in each sponge; pores
+inconspicuous; dermal membrane in close contact with the parenchyma.
+
+_Skeleton_ consisting of slender and feebly coherent radiating fibres as
+a rule two or three spicules thick, with single spicules or ill-defined
+transverse fibres running horizontally. Towards the  external surface
+transverse spicules are numerous, but they do not form any very regular
+structure.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, straight or
+nearly so. Gemmule-spicules minute, with the stem smooth and
+cylindrical, relatively stout and much longer than the comb at either
+end; the two combs equal, with a number of minute, irregularly scattered
+spines between the two outer rows of stouter ones. No free microscleres.
+
+_Gemmules_ minute, spherical, with a single aperture, which is provided
+with a very short foraminal tubule; the granular coat well developed;
+the spicules arranged in a slanting position, but more nearly vertically
+than horizontally, with the combs pointing in all directions; no
+external chitinous membrane.
+
+  Length of skeleton-spicule                     0.2859 mm.
+  Greatest diameter of skeleton-spicule          0.014  "
+  Length of gemmule-spicule                      0.032-0.036 mm.
+  Length of comb of gemmule-spicule              0.008 mm.
+  Greatest diameter of shaft of gemmule-spicule  0.004  "
+  Diameter of gemmule                            0.204-0.221 mm.
+
+The gemmule-spicules first appear as minute, smooth, needle-like bodies,
+which later become roughened on one side at either end and so finally
+assume the mature form. There are no bubble-cells in the parenchyma.
+
+
+15_a._ Var. subspinosa*, nov.
+
+This variety differs from the typical form in having its skeleton
+spicules covered with minute irregular spines or conical projections.
+
+TYPES of both the typical form and the variety in the Indian Museum;
+co-types of the typical form in the Trivandrum Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--The same as that of the genus.
+_Localities_:--Tenmalai, at the base of the western slopes of the W.
+Ghats in Travancore (typical form) (_Annandale_); Ernakulam and Trichur
+in Cochin (var. _subspinosa_) (_G. Mathai_).
+
+BIOLOGY.--My specimens, which were taken in November, were growing on
+the roots of trees at the edge of an artificial pool by the roadside.
+They were in rather dense shade, but their brilliant golden colour made
+them conspicuous objects in spite of their small size. Mr. Mathai's
+specimens from Cochin were attached to water-weeds and to the husk of a
+cocoanut that had fallen or been thrown into the water.
+
+
+Genus 3. EPHYDATIA, _Lamouroux_.
+
+     _Ephydatia_, Lamouroux, Hist. des Polyp. corall. flex.* p. 6
+     (_fide_ Weltner) (1816).
+
+     _Ephydatia_, J. E. Gray, P. Zool. Soc. London. 1867, p. 550.
+
+     _Trachyspongilla_, Dybowsky (_partim_), Zool. Anz. i, p. 53
+     (1874).
+
+     _Meyenia_, Carter (_partim_), Ann. Nat. Hist. (5) vii, p. 90
+     (1881).
+
+     _Carterella_, Potts & Mills (_partim_), P. Ac. Philad. 1881,
+     p. 150.
+
+     _Ephydatia_, Vejdovsky, Abh. Boehm. Ges. xii, p. 23 (1883).
+
+     _Meyenia_, Potts (_partim_), _ibid._ 1887, p. 210.
+
+     _Carterella_, _id._ (_partim_), _ibid._ 1887, p. 260.
+
+     _Ephydatia_, Weltner (_partim_), Arch. Naturg. lxi (i), p.
+     121 (1895).
+
+     _Ephydatia_, Annandale, P. U.S. Mus. xxxvii, p. 404 (1909).
+
+TYPE, (?) _Spongilla fluviatilis_, auctorum.
+
+This genus is separated from _Spongilla_ by the structure of the
+gemmule-spicules, which bear at either end a transverse disk with
+serrated or deeply notched edges, or at any rate with edges that are
+distinctly undulated. The disks are equal and similar. True
+flesh-spicules are usually absent, but more or less perfect birotulates
+exactly similar to those associated with the gemmules are often found
+free in the parenchyma. The skeleton is never very stout and the
+skeleton-spicules are usually slender.
+
+As has been already stated, some authors consider _Ephydatia_ as the
+type-genus of a subfamily distinguished from the subfamily of which
+_Spongilla_ is the type-genus by having rotulate gemmule-spicules. The
+transition between the two genera, however, is a very easy one. Many
+species of the subgenus _Euspongilla_, the typical subgenus of
+_Spongilla_ (including _S. lacustris_, the type-species of the genus),
+have the spines at the ends of the gemmule-spicules arranged in such a
+way as to suggest rudimentary rotules, while in the typical form of _S.
+crateriformis_ this formation is so distinct that the species has
+hitherto been placed in the genus _Ephydatia_ (_Meyenia_), although in
+some sponges that agree otherwise with the typical form of the species
+the gemmule-spicules are certainly not rotulate and in none do these
+spicules bear definite disks.
+
+GEOGRAPHICAL DISTRIBUTION.--_Ephydatia_, except _Spongilla_, is the most
+generally distributed genus of the Spongillidae, but in most countries it
+is not prolific in species. In Japan, however, it appears to predominate
+over _Spongilla_. Only one species is known from India, but another (_E.
+blembingia_*, Evans) has been described from the Malay Peninsula, while
+Weber found both the Indian species and a third (_E. bogorensis_*) in
+the Malay Archipelago.
+
+
+16. Ephydatia meyeni* (_Carter_).
+
+     _Spongilla meyeni_, Carter, J. Bomb. Asiat. Soc. iii, p. 33,
+     pl. i, fig. 1, & Ann. Nat. Hist. (2) iv, p. 84, pl. iii,
+     fig. 1 (1849).
+
+     _Spongilla meyeni_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 448, pl. xxxviii, fig. 4.
+
+     _Spongilla meyeni_, Carter, Ann. Nat. Hist. (5) vii, p. 93
+     (1881).
+
+     _Ephydatia fluviatilis_, Weber, Zool. Ergeb. Niederlaend.
+     Ost-Ind. i. pp. 32, 46 (1890).
+
+     _Ephydatia muelleri_, Weltner (_partim_), Arch. Naturg. lxi
+     (i), p. 125 (1895).
+
+     _Ephydatia robusta_, Annandale, J. Asiat. Soc. Bengal, 1907,
+     p. 24, fig. 7.
+
+     _Ephydatia muelleri_ subsp. _meyeni_, _id._, Rec. Ind. Mus.
+     ii, p. 306 (1908).
+
+_Sponge_ hard and firm but easily torn, usually of a clear white,
+sometimes tinged with green, forming irregular sheets or masses never of
+great thickness, without branches but often with stout subquadrate
+projections, the summits of which are marked with radiating grooves; the
+whole surface often irregularly nodulose and deeply pitted; the oscula
+inconspicuous; the membrane adhering closely to the parenchyma. _The
+parenchyma contains numerous bubble-cells_ (see p. 31, fig. 2).
+
+_Skeleton_ dense but by no means regular; the radiating fibres distinct
+and containing a considerable amount of spongin, at any rate in the
+outer part of the sponge; transverse fibres hardly distinguishable,
+single spicules and irregular bundles of spicules taking their place.
+
+[Illustration: Fig. 21.--Gemmule and spicules of _Ephydatia meyeni_
+(from Calcutta). _a_, Skeleton-spicules; _b_, gemmule-spicules.]
+
+_Spicules._ Skeleton-spicules entirely smooth, moderately stout, feebly
+curved, sharply pointed. No flesh-spicules. Gemmule-spicules with the
+shaft as a rule moderately stout, much longer than the diameter of one
+disk, smooth or with a few stout, straight horizontal spines, which are
+frequently bifid or trifid; the disks flat, of considerable size, with
+their margins cleanly and deeply divided into a comparatively small
+number of deep, slender, triangular processes of different sizes; the
+shaft extending not at all or very little beyond the disks.
+
+_Gemmules_ spherical, usually numerous and of rather large size; each
+covered by a thick layer of minute air-spaces, among which the
+gemmule-spicules are arranged vertically, often in two or even three
+concentric series; a single short foraminal tubule; the pneumatic coat
+confined externally by a delicate membrane, with small funnel-shaped
+pits over the spicules of the outer series.
+
+I think that the gemmules found by me in Bhim Tal and assigned to
+Potts's _Meyenia robusta_ belong to this species, but some of the
+spicules are barely as long as the diameter of the disks. In any case
+Potts's description is so short that the status of his species is
+doubtful. His specimens were from N. America.
+
+_E. meyeni_ is closely related to the two commonest Holarctic species of
+the genus, _E. fluviatilis_ and _E. muelleri_, which have been confused
+by several authors including Potts. From _E. fluviatilis_ it is
+distinguished by the possession of bubble-cells in the parenchyma, and
+from _E. muelleri_ by its invariably smooth skeleton-spicules and the
+relatively long shafts of its gemmule-spicules. The latter character is
+a marked feature of the specimens from the Malay Archipelago assigned by
+Prof. Max Weber to _E. fluviatilis_; I am indebted to his kindness for
+an opportunity of examining some of them.
+
+TYPE in the British Museum; a fragment in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--India and Sumatra. _Localities_:--BENGAL,
+Calcutta and neighbourhood (_Annandale_); MADRAS PRESIDENCY, Cape
+Comorin, Travancore (_Trivandrum Mus._): BOMBAY PRESIDENCY, Island of
+Bombay (_Carter_): HIMALAYAS, Bhim Tal, Kumaon (alt. 4,500 feet)
+(_Annandale_).
+
+BIOLOGY.--My experience agrees with Carter's, that this species is never
+found on floating objects but always on stones or brickwork. It grows in
+the Calcutta "tanks" on artificial stonework at the edge of the water,
+together with _Spongilla carteri_, _S. alba_, _S. fragilis_ subsp.
+_calcuttana_, and _Trochospongilla latouchiana_. It flourishes during
+the cold weather and often occupies the same position in succeeding
+years. In this event the sponge usually consists of a dead base, which
+is of a dark brownish colour and contains no cells, and a living upper
+layer of a whitish colour.
+
+The larva of _Sisyra indica_ is sometimes found in the canals, but the
+close texture of the sponge does not encourage the visits of other
+_incolae_.
+
+
+Genus 4. DOSILIA, _Gray_.
+
+     _Dosilia_, J. E. Gray, P. Zool. Soc. London, 1867, p. 550.
+
+TYPE, _Spongilla plumosa_, Carter.
+
+This genus is distinguished from _Ephydatia_ by the nature of the free
+microscleres, the microscleres of the gemmule being similar in the two
+genera. The free microscleres consist as a rule of several or many
+shafts meeting together in several or many planes at a common centre,
+which is usually nodular. The free ends of these shafts often possess
+rudimentary rotulae. Occasionally a free microsclere may be found that is
+a true monaxon and sometimes such spicules are more or less distinctly
+birotulate. The skeleton is also characteristic. It consists mainly of
+radiating fibres which bifurcate frequently in such a way that a
+bush-like structure is produced. Transverse fibres are very feebly
+developed and are invisible to the naked eye. Owing to the structure of
+the skeleton the sponge has a feathery appearance.
+
+Gray originally applied the name _Dosilia_ to this species and to
+_"Spongilla" baileyi_, Bowerbank. It is doubtful how far his generic
+description applies to the latter, which I have not seen; but although
+the position of _"Spongilla" baileyi_ need not be discussed here, I may
+say that I do not regard it as a congener of _Dosilia plumosa_, the free
+microscleres of which are of a nature rare but not unique in the family.
+With _Dosilia plumosa_ we must, in any case, associate in one genus the
+two forms that have been described as varieties, viz., _palmeri_*, Potts
+from Texas and Mexico, and _brouini_*, Kirkpatrick from the White Nile.
+By the kindness of the authorities of the Smithsonian Institution and
+the British Museum I have been able to examine specimens of all three
+forms, in each case identified by the author of the name, and I am
+inclined to regard them as three very closely allied but distinct
+species. Species with free microscleres similar to those of these three
+forms but with heterogeneous or tubelliform gemmule-spicules will
+probably need the creation of a new genus or new genera for their
+reception.
+
+GEOGRAPHICAL DISTRIBUTION.--The typical species occurs in Bombay and
+Madras; _D. palmeri_ has probably an extensive range in the drier parts
+of Mexico and the neighbouring States, while _D. brouini_ has only been
+found on the banks of the White Nile above Khartoum, in Tropical Africa.
+
+
+17. Dosilia plumosa* (_Carter_).
+
+     _Spongilla plumosa_, Carter, J. Bomb. Asiat. Soc. iii, p.
+     34, pl. i, fig. 2, & Ann. Nat. Hist. (2) iv, p. 85, pl. iii,
+     fig. 2 (1849).
+
+     _Spongilla plumosa_, Bowerbank, P. Zool. Soc. London, 1863,
+     p. 449, pl. xxxviii, fig. 5.
+
+     _Dosilia plumosa_, J. E. Gray, _ibid._ 1867, p. 551.
+
+     _Meyenia plumosa_, Carter, Ann. Nat. Hist. (5) vii, p. 94,
+     pl. v, fig. 6 (1881).
+
+     _Meyenia plumosa_, Potts, P. Ac. Philad. 1887, p. 233.
+
+     _Ephydatia plumosa_, Weltner, Arch. Naturg. lxi (i), p. 126
+     (1895).
+
+     _Ephydatia plumosa_, Petr, Rozp. Ceske Ak. Praze, Trida ii,
+     pl. ii, figs. 29, 30 (text in Czech) (1899).
+
+_Sponge_ forming soft irregular masses which are sometimes as much as 14
+cm. in diameter, of a pale brown or brilliant green colour; no branches
+developed but the surface covered with irregular projections usually of
+a lobe-like nature.
+
+_Skeleton_ delicate, with the branches diverging widely, exhibiting the
+characteristic structure of the genus in a marked degree, containing a
+considerable amount of chitin, which renders it resistant in spite of
+its delicacy.
+
+_Spicules._ Skeleton-spicules smooth, sharply pointed, nearly straight,
+moderately slender, about twenty times as long as their greatest
+transverse diameter. Flesh-spicules occasionally amphioxous or
+birotulate and with a single shaft, more frequently consisting of many
+shafts meeting in a distinct central nodule, which is itself smooth; the
+shafts irregularly spiny, usually more or less nodular at the tip, which
+often bears a distinct circle of recurved spines that give it a rotulate
+appearance. Gemmule-spicules with long, slender, straight shafts, which
+bear short, slender, straight, horizontal spines sparsely and
+irregularly scattered over their surface; the rotulae distinctly convex
+when seen in profile; their edge irregularly and by no means deeply
+notched; the shafts not extending beyond their surface but clearly seen
+from above as circular umbones.
+
+[Illustration: Fig. 22.--_Dosilia plumosa._
+
+A=microscleres, x 240; B=gemmule as seen in optical section from
+below, x 75. (From Rambha.)]
+
+_Gemmules._ Somewhat depressed, covered with a thick granular pneumatic
+coat, in which the spicules stand erect; the single aperture depressed.
+Each gemmule surrounded more or less distinctly by a circle or several
+circles of flesh-spicules.
+
+TYPE in the British Museum; some fragments in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--Bombay and Madras. Carter's specimens were
+taken in the island of Bombay, mine at Rambha in the north-east of the
+Madras Presidency. I have been unable to discover this species in the
+neighbourhood of Calcutta, but it is apparently rare wherever it occurs.
+
+BIOLOGY.--Carter writes as regards this species:--"This is the coarsest
+and most resistant of all the species. As yet I have only found three or
+four specimens of it, and these only in two tanks. I have never seen it
+fixed on any solid body, but always floating on the surface of the
+water, about a month after the first heavy rains of the S.W. monsoon
+have fallen. Having made its appearance in that position, and having
+remained there for upwards of a month, it then sinks to the bottom. That
+it grows like the rest, adherent to the sides of the tank, must be
+inferred from the first specimen which I found (which exceeds two feet
+in circumference) having had a free and a fixed surface, the latter
+coloured by the red gravel on which it had grown. I have noticed it
+growing, for two successive years in the month of July, on the surface
+of the water of one of the two tanks in which I have found it, and would
+account for its temporary appearance in that position, in the following
+way, viz., that soon after the first rains have fallen, and the tanks
+have become filled, all the sponges in them appear to undergo a partial
+state of putrescency, during which gas is generated in them, and
+accumulates in globules in their structure, through which it must burst,
+or tear them from their attachments and force them to the surface of the
+water. Since then the coarse structure of _plumosa_ would appear to
+offer greater resistance to the escape of this air, than that of any of
+the other species, it is probable that this is the reason of my having
+hitherto only found it in the position mentioned."
+
+It seems to me more probable that the sponges are actually broken away
+from their supports by the violence of the rain and retain air
+mechanically in their cavities. The only specimens of _D. plumosa_ that
+I have seen alive were attached very loosely to their support. In
+writing of the "coarse structure" of this species, Carter evidently
+alludes to the wide interspaces between the component branches of the
+skeleton.
+
+My specimens were attached to the stem of a water-lily growing in a pool
+of slightly brackish water and were of a brilliant green colour. I
+mistook them at first for specimens of _S. lacustris_ subsp.
+_reticulata_ in which the branches had not developed normally. They were
+taken in March and were full of gemmules. The pool in which they were
+growing had already begun to dry up.
+
+
+Genus 5. TROCHOSPONGILLA, _Vejdovsky_.
+
+     _Trochospongilla_, Vejdovsky, Abh. K. Boehm. Ges. Wiss. xii,
+     p. 31 (1883).
+
+     _Trochospongilla_, Wierzejski, Arch. Slaves de Biologie, i,
+     p. 44 (1886).
+
+     _Trochospongilla_, Vejdovsky, P. Ac. Philad. 1887, p. 176.
+
+     _Meyenia_, Potts (_partim_), _ibid._ p. 210.
+
+     _Tubella_, _id._ (_partim_), _ibid._, p. 248.
+
+     _Meyenia_, Carter (_partim_), Ann. Nat. Hist. (5) vii, p. 90
+     (1881).
+
+     _Trochospongilla_, Weltner, in Zacharias's Tier- und
+     Pflanzenwelt, i, p. 215 (1891).
+
+     _Trochospongilla_, _id._, Arch. Naturg. lxi (i), p. 120
+     (1895).
+
+     _Tubella_, _id._ (_partim_), _ibid._ p. 128.
+
+TYPE, _Spongilla erinaceus_, Ehrenberg.
+
+The characteristic feature of this genus is that the rotulae of the
+gemmule-spicules, which are homogeneous, have smooth instead of serrated
+edges. Their stem is always short and they are usually embedded in a
+granular pneumatic coat. The sponge is small in most of the species as
+yet known; in some species microscleres without rotulae are associated
+with the gemmules.
+
+[Illustration: Fig. 23.--A=skeleton-spicule of _Trochospongilla
+latouchiana_; A'=gemmule-spicule of the same species; B=gemmule of _T.
+phillottiana_ as seen in optical section from above; B'=skeleton-spicule
+of same species: A, A', B' x 240; B x 75. All specimens from Calcutta.]
+
+I think it best to include in this genus, as the original diagnosis
+would suggest, all those species in which all the gemmule-spicules are
+definitely birotulate and have smooth edges to their disks, confining
+the name _Tubella_ to those in which the upper rotula is reduced to a
+mere knob. Even in those species in which the two disks are normally
+equal, individual spicules may be found in which the equality is only
+approximate, while, on the other hand, it is by no means uncommon for
+individual spicules in such species as _"Tubella" pennsylvanica_, which
+is here included in _Trochospongilla_, to have the two disks nearly
+equal, although normally the upper one is much smaller than the lower.
+There is very rarely any difficulty, however, in seeing at a glance
+whether the edge of the disk is smooth or serrated, the only species in
+which this difficulty would arise being, so far as I am aware, the
+Australian _Ephydatia capewelli_* (Haswell), the disks of which are
+undulated and nodulose rather than serrated.
+
+GEOGRAPHICAL DISTRIBUTION.--The genus includes so large a proportion of
+small, inconspicuous species that its distribution is probably known but
+imperfectly. It would seem to have its headquarters in N. America but
+also occurs in Europe and Asia. In India three species have been found,
+one of which (_T. pennsylvanica_) has an extraordinarily wide and
+apparently discontinuous range, being common in N. America, and having
+been found in the west of Ireland, the Inner Hebrides, and near the west
+coast of S. India. The other two Indian species are apparently of not
+uncommon occurrence in eastern India and Burma.
+
+
+  _Key to the Indian Species of_ Trochospongilla.
+
+   I. Rotules of the gemmule-spicules equal
+      or nearly so.
+      A. Skeleton-spicules smooth, usually
+         pointed                             _latouchiana_, p. 115.
+      B. Skeleton-spicules spiny, blunt      _phillottiana_, p. 117.
+  II. Upper rotule of the gemmule-spicules
+      distinctly smaller than the lower.
+      Skeleton-spicules spiny, pointed       _pennsylvanica_, p. 118.
+
+
+18. Trochospongilla latouchiana*, _Annandale_.
+
+     _Trochospongilla latouchiana_, Annandale, J. Asiat. Soc.
+     Bengal, 1907, p. 21, fig. 5.
+
+     _Trochospongilla latouchiana_, _id._, Rec. Ind. Mus. ii, p.
+     157 (1908).
+
+     _Trochospongilla leidyi_, _id._ (_nec_ Bowerbank), _ibid._
+     iii, p. 103 (1909).
+
+[Illustration: Fig. 24.--_Trochospongilla latouchiana._
+
+Vertical section of part of skeleton with gemmules _in situ_, x 30; also
+a single gemmule, x 70. (From Calcutta).]
+
+_Sponge_ forming cushion-shaped masses rarely more than a few
+centimetres in diameter or thickness and of a brown or yellow colour,
+hard but rather brittle; surface evenly rounded, minutely hispid; oscula
+inconspicuous, small, circular, depressed, very few in number; external
+membrane adhering closely to the parenchyma; a chitinous membrane at the
+base of the sponge. Larger sponges divided into several layers by
+similar membranes.
+
+_Skeleton_ dense, forming a close reticulation; radiating fibres slender
+but quite distinct, running up right through the sponge, crossed at
+frequent intervals by single spicules or groups of spicules.
+
+_Spicules._ Skeleton-spicules smooth, about twenty times as long as the
+greatest transverse diameter, as a rule sharply pointed; smooth
+amphistrongyli, which are often inflated in the middle, sometimes mixed
+with them but never in large numbers. No flesh-spicules.
+Gemmule-spicules with the rotulae circular or slightly asymmetrical, flat
+or nearly flat, marked with a distinct double circle as seen from above,
+sometimes not quite equal; the shaft not projecting beyond them; the
+diameter of the rotule 4-1/2 to 5 times that of the shaft, which is
+about 2-2/3 times as long as broad.
+
+_Gemmules_ small (0.2 x 0.18 mm.), as a rule very numerous and scattered
+throughout the sponge, flask-shaped, clothed when mature with a thin
+microcell coat in which the birotulates are arranged with overlapping
+rotulae, their outer rotulae level with the surface; foraminal aperture
+circular, situated on an eminence.
+
+
+  _Average Measurements._
+
+  Diameter of gemmule                0.2 x 0.18 mm.
+  Length of skeleton-spicule               0.28  "
+  Length of birotulate-spicule             0.175 "
+  Diameter of rotula                       0.02  "
+
+_T. latouchiana_ is closely related to _T. leidyi_ (Bowerbank) from N.
+America, but is distinguished by its much more slender
+skeleton-spicules, by the fact that the gemmules are not enclosed in
+cages of megascleres or confined to the base of the sponge, and by
+differences in the structure of the skeleton.
+
+TYPE in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--Lower Bengal and Lower Burma.
+_Localities_:--BENGAL, Calcutta and neighbourhood (_Annandale_): BURMA,
+Kawkareik, Amherst district, Tenasserim (_Annandale_).
+
+BIOLOGY.--This species, which is common in the Museum tank, Calcutta, is
+apparently one of those that can grow at any time of year, provided that
+it is well covered with water. Like _T. leidyi_ it is capable of
+producing fresh layers of living sponge on the top of old ones, from
+which they are separated by a chitinous membrane. These layers are not,
+however, necessarily produced in different seasons, for it is often
+clear from the nature of the object to which the sponge is attached that
+they must all have been produced in a short space of time. What appears
+to happen in most cases is this:--A young sponge grows on a brick, the
+stem of a reed or some other object at or near the edge of a pond, the
+water in which commences to dry up. As the sponge becomes desiccated its
+cells perish. Its gemmules are, however, retained in the close-meshed
+skeleton, which persists without change of form. A heavy shower of rain
+then falls, and the water rises again over the dried sponge. The
+gemmules germinate immediately and their contents spread out over the
+old skeleton, secrete a chitinous membrane and begin to build up a new
+sponge. The process may be repeated several times at the change of the
+seasons or even during the hot weather, or after a "break in the rains."
+If, however, the dried sponge remains exposed to wind and rain for more
+than a few months, it begins to disintegrate and its gemmules are
+carried away to other places. Owing to their thin pneumatic coat and
+relatively heavy spicules they are not very buoyant. Even in the most
+favourable circumstances the sponge of _T. latouchiana_ never forms
+sheets of great area. In spite of its rapid growth it is frequently
+overgrown by _Spongilla carteri_.
+
+
+19. Trochospongilla phillottiana*, _Annandale_.
+
+     _Trochospongilla phillottiana_, Annandale, J. Asiat. Soc.
+     Bengal, 1907, p. 22, fig. 6.
+
+     _Trochospongilla phillottiana_, _id._, Rec. Ind. Mus. i, p.
+     269 (1907).
+
+     _Trochospongilla phillottiana_, _id._, _ibid._ ii, p. 157
+     (1908).
+
+_Sponge_ hard but friable, forming sheets or patches often of great
+extent but never more than about 5 mm. thick; the surface minutely
+hispid, flat; colour pale yellow, the golden-yellow gemmules shining
+through the sponge in a very conspicuous manner; oscula inconspicuous;
+external membrane adherent; no basal chitinous membrane.
+
+_Skeleton_ dense but by no means strong; the reticulation close but
+produced mainly by single spicules, which form triangular meshes;
+radiating fibres never very distinct, only persisting for a short
+distance in a vertical direction; each gemmule enclosed in an open,
+irregular cage of skeleton-spicules.
+
+_Spicules._ Skeleton-spicules short, slender, blunt, more or less
+regularly and strongly spiny, straight or feebly curved. No
+flesh-spicules. Gemmule-spicules with the rotulae circular, very wide as
+compared with the shaft, concave on the surface, with the shaft
+projecting as an umbo on the surface; the lower rotula often a little
+larger than the upper.
+
+_Gemmules_ numerous, situated at the base of the sponge in irregular,
+one-layered patches, small (0.32 x 0.264 mm.), of a brilliant golden
+colour, distinctly wider than high, with a single aperture situated on
+an eminence on the apex, each clothed (when mature) with a pneumatic
+coat that contains relatively large but irregular air-spaces among which
+the spicules stand with the rotulae overlapping alternately, a
+funnel-shaped pit in the coat descending from the surface to the upper
+rotula of each of them; the surface of the gemmule covered with
+irregular projections.
+
+  Diameter of gemmule          0.32 x 0.264 mm.
+  Length of skeleton-spicule          0.177  "
+  Length of gemmule-spicule           0.015  "
+  Diameter of rotule                  0.022  "
+
+This species appears to be related to _T. pennsylvanica_, from which it
+differs mainly in the form of its gemmule-spicules and the structure of
+its gemmule. My original description was based on specimens in which the
+gemmule-spicules were not quite mature.
+
+TYPE in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--Lower Bengal and Lower Burma.
+_Localities_:--BENGAL, Calcutta (_Annandale_): BURMA, jungle pool near
+Kawkareik, Amherst district, Tenasserim (_Annandale_).
+
+BIOLOGY.--This species covers a brick wall at the edge of the Museum
+tank in Calcutta every year during the "rains." In the cold weather the
+wall is left dry, but it is usually submerged to a depth of several feet
+before the middle of July. It is then rapidly covered by a thin layer of
+the sponge, which dies down as soon as the water begins to sink when the
+"rains" are over. For some months the gemmules adhere to the wall on
+account of the cage of spicules in which each of them is enclosed, but
+long before the water rises again the cages disintegrate and the
+gemmules are set free. Many of them fall or are carried by the wind into
+the water, on the surface of which, owing to their thick pneumatic coat,
+they float buoyantly. Others are lodged in cavities in the wall. On the
+water the force of gravity attracts them to one another and to the edge
+of the pond, and as the water rises they are carried against the wall
+and germinate. In thick jungle at the base of the Dawna Hills near
+Kawkareik[AI] in the interior of Tenasserim, I found the leaves of
+shrubs which grew round a small pool, covered with little dry patches of
+the sponge, which had evidently grown upon them when the bushes were
+submerged. This was in March, during an unusually severe drought.
+
+     [Footnote AI: This locality is often referred to in
+     zoological literature as Kawkare_et_ or Kawkari_t_, or even
+     K_o_kari_t_.]
+
+
+20. Trochospongilla pennsylvanica* (_Potts_).
+
+     _Tubella pennsylvanica_, Potts, P. Ac. Philad. 1882, p. 14.
+
+     _Tubella pennsylvanica_, _id._, _ibid._ 1887, p. 251, pl.
+     vi, fig. 2, pl. xii, figs. 1-3.
+
+     _Tubella pennsylvanica_, Mackay, Trans. Roy. Soc. Canada,
+     1889, Sec. iv, p. 95.
+
+     _Tubella pennsylvanica_, Hanitsch, Nature, li, p. 511
+     (1895).
+
+     _Tubella pennsylvanica_, Weltner, Arch. Naturg. lxi (i), p.
+     128 (1895).
+
+     _Tubella pennsylvanica_, Hanitsch, Irish Natural. iv, p. 129
+     (1895).
+
+     _Tubella pennsylvanica_, Annandale, J. Linn. Soc., Zool.,
+     xxx, p. 248 (1908).
+
+     _Tubella pennsylvanica_, _id._, Rec. Ind. Mus. iii, p. 102
+     (1909).
+
+     _Tubella_ _pennsylvanica_, _id._, P. U.S. Mus. xxxvii, p.
+     403, fig. 2 (1909).
+
+_Sponge_ soft, fragile, forming small cushion-shaped masses, grey or
+green; oscula few in number, often raised on sloping eminences
+surrounded by radiating furrows below the external membrane; external
+membrane adhering to the parenchyma.
+
+_Skeleton_ close, almost structureless. "Surface of mature specimens
+often found covered with parallel skeleton spicules, not yet arranged to
+form cell-like interspaces" (_Potts_).
+
+_Spicules._ Skeleton-spicules slender, cylindrical, almost straight,
+sharp or blunt, minutely, uniformly or almost uniformly spined; spines
+sometimes absent at the tips. No flesh-spicules. Gemmule-spicules with
+the lower rotula invariably larger than the upper; both rotulae flat or
+somewhat sinuous in profile, usually circular but sometimes asymmetrical
+or subquadrate in outline, varying considerably in size.
+
+_Gemmules_ small, numerous or altogether absent, covered with a granular
+pneumatic coat of variable thickness; the rotulae of the gemmule-spicules
+overlapping and sometimes projecting out of the granular coat.
+
+The measurements of the spicules and gemmules of an Indian specimen and
+of one from Lehigh Gap, Pennsylvania, are given for comparison:--
+
+                                   Travancore.          Pennsylvania.
+  Length of skeleton-spicules    0.189-0.242 mm.        0.16-0.21 mm.
+                              (average 0.205 mm.)   (average 0.195 mm.)
+  Breadth      "        "       0.0084-0.0155 mm.        0.0084 mm.
+  Length of birotulate                 0.0126  "         0.0099  "
+  Diameter of upper rotula             0.0084  "         0.0084  "
+       "      lower   "                0.0169  "         0.0168  "
+       "      gemmule                  0.243-0.348 mm.   0.174-0.435 mm.
+
+The spicules of the Travancore specimen are, therefore, a trifle larger
+than those of the American one, but the proportions are closely similar.
+
+The difference between the gemmule-spicules of this species and those of
+such a form as _T. phillottiana_ is merely one of degree and can hardly
+be regarded as a sufficient justification for placing the two species in
+different genera. If, as I have proposed, we confine the generic name
+_Tubella_ to those species in which the gemmule-spicules are really like
+"little trumpets," the arrangement is a much more natural one, for these
+species have much in common apart from the gemmule-spicules. _T.
+pennsylvanica_ does not appear to be very closely related to any other
+known species except _T. phillottiana_.
+
+TYPE in the U.S. National Museum, from which specimens that appear to be
+co-types have been sent to the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--Very wide and apparently discontinuous:--N.
+America (widely distributed), Ireland (_Hanitsch_), Hebrides of Scotland
+(_Annandale_), Travancore, S. India (_Annandale_). The only Indian
+locality whence I have obtained specimens is Shasthancottah Lake near
+Quilon in Travancore.
+
+BIOLOGY.--In Shasthancottah Lake _T. pennsylvanica_ is found on the
+roots of water-plants that are matted together to form floating islands.
+It appears to avoid light and can only be obtained from roots that have
+been pulled out from under the islands. In Scotland I found it on the
+lower surface of stones near the edge of Loch Baa, Isle of Mull. In such
+circumstances the sponge is of a greyish colour, but specimens of the
+variety _minima_ taken by Potts on rocks and boulders in Bear Lake,
+Pennsylvania, were of a bright green.
+
+Sponges taken in Travancore in November were full of gemmules; in my
+Scottish specimens (taken in October) I can find no traces of these
+bodies, but embryos are numerous.
+
+
+Genus 6. TUBELLA, _Carter_.
+
+     _Tubella_, Carter, Ann. Nat. Hist. (5) vii, p. 96 (1881).
+
+     _Tubella_, Potts (_partim_), P. Ac. Philad. 1887, p. 248.
+
+     _Tubella_, Weltner (_partim_), Arch. Naturg. lxi (i), p. 128
+     (1895).
+
+TYPE, _Spongilla paulula_, Bowerbank.
+
+This genus is distinguished from _Ephydatia_ and _Trochospongilla_ by
+the fact that the two ends of the gemmule-spicules are unlike not only
+in size but also in form. It sometimes happens that this unlikeness is
+not so marked in some spicules as in others, but in some if not in all
+the upper end of the shaft (that is to say the end furthest removed from
+the inner coat of the gemmule in the natural position) is reduced to a
+rounded knob, while the lower end expands into a flat transverse disk
+with a smooth or denticulated edge. The spicule thus resembles a little
+trumpet resting on its mouth. The shaft of the spicule is generally
+slender and of considerable length. The skeleton of the sponge is as a
+rule distinctly reticulate and often hard; the skeleton-spicules are
+either slender or stout and sometimes change considerably in proportions
+and outline as they approach the gemmules.
+
+GEOGRAPHICAL DISTRIBUTION.--The genus is widely distributed in the
+tropics of both Hemispheres, its headquarters apparently being in S.
+America; but it is nowhere rich in species. Only two are known from the
+Oriental Region, namely _T. vesparium_* from Borneo, and _T.
+vesparioides_* from Burma.
+
+
+21. Tubella vesparioides*, _Annandale_. (Plate II, fig. 4.)
+
+     _Tubella vesparioides_, Annandale, Rec. Ind. Mus. ii, p. 157
+     (1908).
+
+_Sponge_ forming rather thick sheets of considerable size, hard but
+brittle, almost black in colour; oscula inconspicuous; external membrane
+supported on a reticulate horizontal skeleton.
+
+_Skeleton._ The surface covered with a network of stout spicule-fibres,
+the interstices of which are more or less deeply sunk, with sharp fibres
+projecting vertically upwards at the nodes; the whole mass pervaded by a
+similar network, which is composed of a considerable number of spicules
+lying parallel to one another, overlapping at the ends and bound
+together by a profuse secretion of spongin.
+
+[Illustration: Fig. 25.--Spicules of _Tubella vesparioides_ (from type
+specimen). x 240.]
+
+_Spicules._ Skeleton-spicules slender, smooth, amphioxous, bent in a
+wide arc or, not infrequently, at an angle. No true flesh-spicules.
+Gemmule-spicules terminating above in a rounded, knob-like structure and
+below in a relatively broad, flat rotula, which is very deeply and
+irregularly indented round the edge when mature, the spicules at an
+earlier stage of development having the form of a sharp pin with a round
+head; shaft of adult spicules projecting slightly below the rotula,
+long, slender, generally armed with a few stout conical spines, which
+stand out at right angles to it.
+
+_Gemmules_ numerous throughout the sponge, spherical, provided with a
+short, straight foraminal tubule, surrounded by one row of spicules,
+which are embedded in a rather thin granular coat.
+
+  Average length of skeleton-spicule          0.316 mm.
+    "     breadth of skeleton-spicule         0.0135 "
+    "     length of gemmule-spicule           0.046  "
+    "     diameter of rotula                  0.0162 "
+    "         "       gemmule                 0.446  "
+
+This sponge is closely related to _Tubella vesparium_ (v. Martens) from
+Borneo, from which it may be distinguished by its smooth
+skeleton-spicules and the deeply indented disk of its gemmule-spicules.
+The skeleton-fibres are also rather less stout. By the kindness of Dr.
+Weltner, I have been able to compare types of the two species.
+
+TYPE in the Indian Museum.
+
+HABITAT.--Taken at the edge of the Kanghyi ("great pond") at Mudon near
+Moulmein in the Amherst district of Tenasserim. The specimens were
+obtained in March in a dry state and had grown on logs and branches
+which had evidently been submerged earlier in the year. The name
+_vesparium_ given to the allied species on account of its resemblance to
+a wasps' nest applies with almost equal force to this Burmese form.
+
+
+Genus 7. CORVOSPONGILLA, nov.
+
+TYPE[AJ], _Spongilla loricata_, Weltner.
+
+     [Footnote AJ: Potts's _Spongilla novae-terrae_ from
+     Newfoundland and N. America cannot belong to this genus
+     although it has similar flesh-spicules, for, as Weltner has
+     pointed out (_op. cit. supra_ p. 126), the gemmule-spicules
+     are abortive rotulae. This is shown very clearly in the
+     figure published by Petr (Rozp. Ceske Ak. Praze, Trida, ii,
+     pl. ii, figs. 27, 28, 1899), who assigns the species to
+     _Heteromeyenia_. Weltner places it in _Ephydatia_, and it
+     seems to be a connecting link between the two genera. It has
+     been suggested that it is a hybrid (Traxler, Termes.
+     Fuzetek, xxi, p. 314, 1898).]
+
+Spongillidae in which the gemmule-spicules are without a trace of rotulae
+and the flesh-spicules have slender cylindrical shafts that bear at or
+near either end a circle of strong recurved spines. The gemmule-spicules
+are usually stout and sausage-shaped, and the gemmules resemble those of
+_Stratospongilla_ in structure. The skeleton is strong and the
+skeleton-spicules stout, both resembling those of the "genus"
+_Potamolepis_, Marshall.
+
+As in all other genera of Spongillidae the structure of the skeleton is
+somewhat variable, the spicule-fibres of which it is composed being much
+more distinct in some species than in others. The skeleton-spicules are
+often very numerous and in some cases the skeleton is so compact and
+rigid that the sponge may be described as stony. The flesh-spicules
+closely resemble the gemmule-spicules of some species of _Ephydatia_ and
+_Heteromeyenia_.
+
+GEOGRAPHICAL DISTRIBUTION.--The species of this genus are probably
+confined to Africa (whence at least four are known) and the Oriental
+Region. One has been recorded from Burma and another from the Bombay
+Presidency.
+
+
+  _Key to the Indian Species of_ Corvospongilla.
+
+  I. Gemmule with two layers of gemmule-spicules;
+  those of the inner layer not
+  markedly smaller than those of the outer.       _burmanica_, p. 123.
+
+  II. Gemmule with two layers of gemmule-spicules,
+  the outer of which contains
+  spicules of much greater size than the
+  inner.                                          _lapidosa_, p. 124.
+
+
+22. Corvospongilla burmanica* (_Kirkpatrick_). (Plate II, fig. 5.)
+
+     _Spongilla loricata_ var. _burmanica_, Kirkpatrick, Rec.
+     Ind. Mus. ii, p. 97, pl. ix (1908).
+
+_Sponge_ forming a shallow sheet, hard, not very strong, of a pale
+brownish colour; the surface irregularly spiny; the oscula small but
+conspicuous, circular, raised on little turret-like eminences; the
+external membrane adhering closely to the sponge.
+
+_Skeleton_ dense but by no means regular; the network composed largely
+of single spines; thick radiating fibres distinguishable in the upper
+part of the sponge.
+
+_Spicules._ Skeleton-spicules smooth, not very stout, amphistrongylous,
+occasionally a little swollen at the ends, often with one or more
+fusiform swellings, measuring on an average about 0.27 x 0.0195 mm.
+Flesh-spicules with distinct rotules, the recurved spines numbering 4 to
+6, measuring about 1/7 the length of the spicules; the shaft by no means
+strongly curved; their length from 0.03-0.045 mm. Gemmule-spicules
+amphioxous, as a rule distinctly curved, sometimes swollen at the ends,
+covered regularly but somewhat sparsely with fine spines, not measuring
+more than 0.49 x 0.078 mm.
+
+_Gemmules_ strongly adherent, arranged in small groups, either single or
+double; when single spherical, when double oval; each gemmule or pair of
+gemmules covered by two layers of gemmule-spicules bound together in
+chitinous substance; the inner layer on the inner coat of the gemmule,
+the outer one separated from it by a space and in contact with the outer
+cage of skeleton-spicules; the size of the gemmule-spicules variable in
+both layers; external to the outer layer a dense cage of
+skeleton-spicules; foraminal tubule short, cylindrical.
+
+This sponge is closely related to _S. loricata_, Weltner, of which
+Kirkpatrick regards it as a variety. "The main difference," he writes,
+"between the typical African form and the Burmese variety consists in
+the former having much larger microstrongyles (83 x 15.7  mu [0.83 x 0.157
+mm.]) with larger and coarser spines;... Judging from Prof. Weltner's
+sections of gemmules, these bodies lack the definite outer shell of
+smooth macrostrongyles [blunt skeleton-spicules], though this may not
+improbably be due to the breaking down and removal of this layer. A
+further difference consists in the presence, in the African specimen, of
+slender, finely spined strongyles [amphistrongyli], these being absent
+in the Burmese form, though perhaps this fact is not of much
+importance."
+
+TYPE in the British Museum; a piece in the Indian Museum.
+
+HABITAT.--Myitkyo, head of the Pegu-Sittang canal, Lower Burma (_E. W.
+Oates_).
+
+BIOLOGY.--The sponge had grown over a sheet of the polyzoon _Hislopia
+lacustris_, Carter (see p. 204), remains of which can be detected on its
+lower surface.
+
+"Mr. E. W. Oates, who collected and presented the sponge, writes that
+the specimen was found encrusting the vertical and horizontal surfaces
+of the bottom beam of a lock gate, where it covered an area of six
+square feet. The beam had been tarred several times before the sponge
+was discovered. The portion of the gate on which the sponge was growing
+was submerged from November to May for eight hours a day at spring
+tides, but was entirely dry during the six days of neap tides. From May
+to October it was constantly submerged. The sponge was found in April.
+Although the canal is subject to the tides, the water at the lock is
+always fresh. The colour of the sponge during life was the same as in
+its present condition."
+
+
+23. Corvospongilla lapidosa* (_Annandale_).
+
+     _Spongilla lapidosa_ Annandale, Rec. Ind. Mus. ii, pp. 25,
+     26, figs. 3, 4, 5 (1908).
+
+The _sponge_ forms a thin but extremely hard and resistant crust the
+surface of which is either level, slightly concave, or distinctly
+corrugated; occasional groups of spicules project from it, but their
+arrangement is neither so regular nor so close as is the case in _C.
+burmanica_. The dermal membrane adheres closely to the sponge. The
+oscula are small; some of them are raised above the general surface but
+not on regular turret-shaped eminences. The colour is grey or black.
+There is a thick chitinous membrane at the base of the sponge.
+
+[Illustration: Fig. 26.--Spicules of _Corvospongilla lapidosa_ (from
+type specimen), x 240.]
+
+The _skeleton_ is extremely dense owing to the large number of spicules
+it contains, but almost structureless; broad vertical groups of spicules
+occur but lack spongin and only traverse a small part of the thickness
+of the sponge; their position is irregular. The firmness of the skeleton
+is due almost entirely to the interlocking of individual spicules. At
+the base of the sponge the direction of a large proportion of the
+spicules is horizontal or nearly horizontal, the number arranged
+vertically being much greater in the upper part.
+
+_Spicules._ The skeleton-spicules are sausage-shaped and often a little
+swollen at the ends or constricted in the middle. A large proportion are
+twisted or bent in various ways, and a few bear irregular projections or
+swellings. The majority, however, are quite smooth. Among them a few
+more or less slender, smooth amphioxi occur, but these are probably
+immature spicules. The length and curvature of the amphistrongyli varies
+considerably, but the average measurements are about 0.28 x 0.024 mm.
+The flesh-spicules also vary greatly in length and in the degree to
+which their shafts are curved. At first sight it seems to be possible to
+separate them into two categories, one in which the shaft is about 0.159
+mm. long, and another in which it is only 0.05 mm. or even less; and
+groups of birotulates of approximately the same length often occur in
+the interstices of the skeleton. Spicules of all intermediate lengths
+can, however, be found. The average diameter of the shaft is 0.0026 mm.
+and of the rotula 0.0106 mm., and the rotula consists of from 6 to 8
+spines. The gemmule-spicules vary greatly in size, the longest measuring
+about 0.08 x 0.014 and the smallest about 0.034 x 0.007 or even less.
+There appears to be in their case an even more distinct separation as
+regards size than there is in that of the flesh-spicules; but here again
+intermediate forms occur. They are all stout, more or less blunt, and
+more or less regularly covered with very short spines; most of them are
+distinctly curved, but some are quite straight.
+
+_Gemmules._ The gemmules are firmly adherent to the support of the
+sponge, at the base of which they are congregated in groups of four or
+more. They vary considerably in size and shape, many of them being
+asymmetrical and some elongate and sausage-shaped. The latter consist of
+single gemmules and not of a pair in one case. Extreme forms measure
+0.38 x 0.29 and 0.55 x 0.25. Each gemmule is covered with a thick
+chitinous membrane in close contact with its wall and surrounding it
+completely. This membrane is full of spicules arranged as in a mosaic;
+most or all of them belong to the smaller type, and as a rule they are
+fairly uniform in size. Separated from this layer by a considerable
+interval is another layer of spicules embedded in a chitinous membrane
+which is in continuity with the basal membrane of the sponge. The
+spicules in this membrane mostly belong to the larger type and are very
+variable in size; mingled with them are often a certain number of
+birotulate flesh-spicules. The membrane is in close contact with a dense
+cage of skeleton-spicules arranged parallel to it and bound together by
+chitinous substance. The walls of this cage, when they are in contact
+with those of the cages of other gemmules, are coterminous with them.
+There is a single depressed aperture in the gemmules, as a rule situated
+on one of the longer sides.
+
+This sponge is distinguished from _C. burmanica_ not only by differences
+in external form, in the proportions of the spicules and the structure
+of the skeleton, but also by the peculiar nature of the armature of the
+gemmule. The fact that birotulate spicules are often found in close
+association with them, is particularly noteworthy.
+
+TYPE in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--This sponge has only been found in the
+Western Ghats of the Bombay Presidency. _Localities_:--Igatpuri Lake and
+the R. Godaveri at Nasik.
+
+BIOLOGY.--There is a remarkable difference in external form between the
+specimens taken in Igatpuri and those from Nasik, and this difference is
+apparently due directly to environment. In the lake, the waters of which
+are free from mud, the sponges were growing on the lower surface of
+stones near the edge. They formed small crusts not more than about 5 cm.
+(2 inches) in diameter and of a pale greyish colour. Their surface was
+flat or undulated gently, except round the oscula where it was raised
+into sharply conical eminences with furrowed sides. The specimens from
+Nasik, which is about 30 miles from Igatpuri, were attached, together
+with specimens of _Spongilla cinerea_ and _S. indica_, to the sides of a
+stone conduit full of very muddy running water. They were black in
+colour, formed broad sheets and were markedly corrugated on the surface.
+Their oscula were not raised on conical eminences and were altogether
+most inconspicuous. The skeleton was also harder than that of sponges
+from the lake.
+
+In the lake _C. lapidosa_ was accompanied by the gemmules of _Spongilla
+bombayensis_, but it is interesting that whereas the latter sponge was
+entirely in a resting condition, the former was in full vegetative
+vigour, a fact which proves, if proof were necessary, that the similar
+conditions of environment do not invariably have the same effect on
+different species of Spongillidae.
+
+
+  APPENDIX TO PART I.
+
+  FORM OF UNCERTAIN POSITION.
+
+  (Plate I, fig. 4.)
+
+On more than one occasion I have found in my aquarium in Calcutta small
+sponges of a peculiar type which I am unable to refer with certainty to
+any of the species described above. Fig. 4, pl. I, represents one of
+these sponges. They are never more than about a quarter of an inch in
+diameter and never possess more than one osculum. They are
+cushion-shaped, colourless and soft. The skeleton-spicules are smooth,
+sharply pointed, moderately slender and relatively large. They are
+arranged in definite vertical groups, which project through the dermal
+membrane, and in irregular transverse formation. Small spherical
+gemmules are present but have only a thin chitinous covering without
+spicules or foramen.
+
+These sponges probably represent an abnormal form of some well-known
+species, possibly of _Spongilla carteri_. I have seen nothing like them
+in natural conditions.
+
+
+
+
+  PART II.
+
+  FRESHWATER POLYPS
+
+  (HYDRIDA).
+
+
+
+
+INTRODUCTION TO PART II.
+
+
+I.
+
+THE PHYLUM COELENTERATA AND THE CLASS HYDROZOA.
+
+
+The second of the great groups or phyla into which the metazoa are
+divided is the Coelenterata, in which are included most of the animals
+commonly known as zoophytes, and also the corals, sea-anemones and
+jelly-fish. These animals are distinguished from the sponges on the one
+hand and from the worms, molluscs, arthropods, vertebrates, etc., on the
+other by possessing a central cavity (the coelenteron or "hollow
+inside") the walls of which are the walls of the body and consist of
+_two_ layers of cells separated by a structureless, or apparently
+structureless, jelly. This cavity has as a main function that of a
+digestive cavity.
+
+An ideally simple coelenterate would not differ much in general
+appearance from an olynthus (p. 27), but it would have no pores in the
+body-wall and its upper orifice would probably be surrounded by
+prolongations of the body-wall in the form of tentacles. There would be
+no collar-cells, and the cells of the body generally would have a much
+more fixed and definite position and more regular functions than those
+of any sponge. The most characteristic of them would be the so-called
+cnidoblasts. Each of these cells contains a capsule[AK] from which a
+long thread-like body can be suddenly uncoiled and shot out.
+
+     [Footnote AK: Similar capsules are found in the tissues of
+     certain worms and molluscs, but there is the strongest
+     evidence that these animals, which habitually devour
+     coelenterates, are able to swallow the capsules uninjured
+     and to use them as weapons of defence (see Martin, Q. J.
+     Micro. Sci. London, lii, p. 261, 1908, and Grosvenor, Proc.
+     Roy. Soc. London, lxxii, p. 462, 1903). The "trichocysts" of
+     certain protozoa bear a certain resemblance to the
+     nettle-cells of coelenterates and probably have similar
+     functions.]
+
+The simplest in structure of the coelenterates are those that constitute
+the class Hydrozoa. In this class the primitive central cavity is not
+divided up by muscular partitions and there is no folding in of the
+anterior part of the body to form an oesophagus or stomatodaeum such as
+is found in the sea-anemones and coral polyps. In many species and
+genera the life-history is complex, illustrating what is called the
+alternation of generations. That is to say, only alternate generations
+attain sexual maturity, those that do so being produced as buds from a
+sexless generation, which itself arises from the fertilized eggs of a
+previous sexual generation. The sexual forms as a rule differ
+considerably in structure from the sexless ones; many medusae are the
+sexual individuals in a life-cycle in which those of the sexless
+generation are sedentary.
+
+An excellent general account of the coelenterates will be found in the
+Cambridge Natural History, vol. i (by Prof. Hickson).
+
+
+STRUCTURE OF HYDRA.
+
+_Hydra_, the freshwater polyp, is one of the simplest of the Hydrozoa
+both as regards structure and as regards life-history. Indeed, it
+differs little as regards structure from the ideally simple coelenterate
+sketched in a former paragraph, while its descent is direct from one
+polyp to another, every generation laying its own eggs[AL]. The animal
+may be described as consisting of the following parts:--(1) an upright
+(or potentially upright) column or body, (2) a circle of contractile
+tentacles at the upper extremity of the column, (3) an oral disk or
+peristome surrounding the mouth and surrounded by the tentacles, and (4)
+a basal or aboral disk at the opposite extremity. The whole animal is
+soft and naked. The column, when the animal is at rest, is almost
+cylindrical in some forms but in others has the basal part distinctly
+narrower than the upper part. It is highly contractile and when
+contracted sometimes assumes an annulate appearance; but as a rule the
+external surface is smooth.
+
+     [Footnote AL: The statement is not strictly accurate as
+     regards the Calcutta phase of _H. vulgaris_, for the summer
+     brood apparently does not lay eggs but reproduces its
+     species by means of buds only. This state of affairs,
+     however, is probably an abnormality directly due to
+     environment.]
+
+The tentacles vary in number, but are never very numerous. They are
+disposed in a single circle round the oral disk and are hollow, each
+containing a prolongation of the central cavity of the column. Like the
+column but to an even greater degree they are contractile, and in some
+forms they are capable of great elongation. They cannot seize any object
+between them, but are able to move in all directions.
+
+The disk that surrounds the mouth, which is a circular aperture, is
+narrow and can to some extent assume the form of a conical proboscis,
+although this feature is never so marked as it is in some hydroids. The
+basal disk is even narrower and is not splayed out round the edges.
+
+[Illustration: Fig. 27.--Nettle-cells of _Hydra_.
+
+A=capsules from nettle-cells of a single specimen of the summer phase of
+_H. vulgaris_ from Calcutta, x 480: figures marked with a dash represent
+capsules with barbed threads. B=a capsule with the thread discharged,
+from the same specimen, x 480. C=capsule with barbed thread, from a
+specimen of _H. oligactis_ from Lahore. D=undischarged nettle-cell of
+_H. vulgaris_ from Europe (after Nussbaum, highly magnified).
+E=discharged capsule of the same (after the same author).
+_a_=cnidoblast; _b_=capsule; _c_=thread; _d_=cnidocil. Only the base of
+the thread is shown in E.]
+
+A section through the body-wall shows it to consist of the three typical
+layers of the coelenterates, viz., (i) an outer cellular layer of
+comparatively small cells, the ectoderm; (ii) an intermediate,
+structureless or apparently structureless layer, the mesogloea or
+"central jelly"; and (iii) an internal layer or endoderm consisting of
+relatively large cells. The cells of the ectoderm are not homogeneous.
+Some of them possess at their base narrow and highly contractile
+prolongations that exercise the functions of muscles. Others are
+gland-cells and secrete mucus; others have round their margins delicate
+ramifying prolongations and act as nerve-cells. Sense-cells, each of
+which bears on its external surface a minute projecting bristle, are
+found in connection with the nerve-cells, and also nettle-cells of more
+than one type.
+
+The mesogloea is very thin.
+
+The endoderm consists mainly of comparatively large cells with polygonal
+bases which can be seen from the external surface of the column in
+colourless individuals. Their inner surface is amoeboid and in certain
+conditions bears one or more vibratile cilia or protoplasmic lashes.
+Nettle-cells are occasionally found in the endoderm, but apparently do
+not originate in this layer.
+
+The walls of the tentacles do not differ in general structure from those
+of the column, but the cells of the endoderm are smaller and the
+nematocysts of the ectoderm more numerous, and there are other minor
+differences.
+
+A more detailed account of the anatomy of _Hydra_ will be found in any
+biological text-book, for instance in Parker's Elementary Biology; but
+it is necessary here to say something more as regards the nettle-cells,
+which are of great biological and systematic importance.
+
+A nettle-cell of the most perfect type and the structures necessary to
+it consist of the following parts:--
+
+     (1) A true cell (the cnidoblast), which contains--
+     (2) a delicate capsule full of liquid;
+     (3) a long thread coiled up in the capsule; and
+     (4) a cnidocil or sensory bristle, which projects from the
+         external surface of the cnidoblast.
+
+A nerve-cell is associated with each cnidoblast.
+
+In _Hydra_ the nettle-cells are of two distinct types, in one of which
+the thread is barbed at the base, whereas in the other it is simple.
+Both types have often two or more varieties and intermediate forms
+occur, but generally speaking the capsules with simple threads are much
+smaller than those with barbed ones. The arrangement of the nettle-cells
+is not the same in all species of _Hydra_, but as a rule they are much
+more numerous in the tentacles than elsewhere on the body, each large
+cell being surrounded by several small ones. The latter are always much
+more numerous than the former.
+
+
+CAPTURE AND INGESTION OF PREY: DIGESTION.
+
+The usual food of _Hydra_ consists of small insect larvae, worms, and
+crustacea, but the eggs of fish are also devoured. The method in which
+prey is captured and ingested has been much disputed, but the following
+facts appear to be well established.
+
+If a small animal comes in contact with the tentacles of the polyp, it
+instantly becomes paralysed. If it adheres to the tentacle, it perishes;
+but if, as is often the case, it does not do so, it soon recovers the
+power of movement. Animals which do not adhere are generally those (such
+as ostracod crustacea) which have a hard integument without weak spots.
+Nematocysts of both kinds shoot out their threads against prey with
+considerable violence, the discharge being effected, apparently in
+response to a chemical stimulus, by the sudden uncoiling of the thread
+and its eversion from the capsule. Apparently the two kinds of threads
+have different functions to perform, for whereas there is no doubt that
+the barbed threads penetrate the more tender parts of the body against
+which they are hurled, there is evidence that the simple threads do not
+do so but wrap themselves round the more slender parts. Nussbaum (Arch.
+mikr. Anat. xxix, pl. xx, fig. 108) figures the tail of a _Cyclops_
+attacked by _Hydra vulgaris_ and shows several simple threads wrapped
+round the hairs and a single barbed thread that has penetrated the
+integument. Sometimes the cyst adheres to the thread and remains
+attached to its cnidoblast and to the polyp, but sometimes the thread
+breaks loose. Owing to the large mass of threads that sometimes
+congregate at the weaker spots in the external covering of an animal
+attacked (_e. g._, at the little sensory pits in the integument of the
+dorsal surface of certain water-mites) it is often difficult to trace
+out the whole length of any one thread, and as a thread still attached
+to its capsule is frequently buried in the body of the prey, right up to
+the barbs, while another thread that has broken loose from its capsule
+appears immediately behind the fixed one, it seems as though the barbs,
+which naturally point towards the capsule, had become reversed. This
+appearance, however, is deceptive. The barbs are probably connected with
+the discharge of the thread and do not function at all in the same way
+as those on a spear- or arrow-head, never penetrating the object against
+which the projectile is hurled. Indeed, their position as regards the
+thread resembles that of the feathers on the shaft of an arrow rather
+than that of the barb of the head.
+
+Adhesion between the tentacles and the prey is effected partly by the
+gummy secretion of the glands of the ectoderm, which is perhaps
+poisonous as well as adhesive, and partly by the threads. Once the prey
+is fast and has ceased to struggle, it is brought to the mouth, which
+opens wide to receive it, by the contraction and the contortions of the
+tentacles, the column, and the peristome. At the same time a mass of
+transparent mucus from the gastral cavity envelops it and assists in
+dragging it in. There is some dispute as to the part played by the
+tentacles in conveying food into the mouth. My own observations lead me
+to think that, at any rate so far as _H. vulgaris_ is concerned, they do
+not push it in, but sometimes in their contortions they even enter the
+cavity accidentally.
+
+When the food has once been engulfed some digestive fluid is apparently
+poured out upon it. In _H. vulgaris_ it is retained in the upper part of
+the cavity and the soluble parts are here dissolved out, the insoluble
+parts such as the chitin of insect larvae or crustacea being ejected from
+the mouth. Digestion is, however, to a considerable extent
+intracellular, for the cells of the endoderm have the power of thrusting
+out from their surface lobular masses of their cell-substance in which
+minute nutritive particles are enveloped and dissolved. The movements of
+the cilia which can also be thrust out from and retracted into these
+cells, keep the food in the gastral cavity in motion and probably turn
+it round so as to expose all parts in turn to digestive action. Complete
+digestion, at any rate in the Calcutta form, takes several days to
+accomplish, and after the process is finished a flocculent mass of
+colourless excreta is emitted from the mouth.
+
+
+COLOUR.
+
+In _Hydra viridis_, a species that has not yet been found in India, the
+green colour is due to the presence in the cells of green corpuscles
+which closely resemble those of the cells of certain freshwater sponges.
+They represent a stage in the life-cycle of _Chlorella vulgaris_,
+Beyerinck[AM], an alga which has been cultivated independently.
+
+     [Footnote AM: Bot. Zeitung, xlviii (1890): see p. 49, _antea_.]
+
+In other species of the genus colour is largely dependent on food,
+although minute corpuscles of a _dark_ green shade are sometimes found
+in the cells of _H. oligactis_. In the Calcutta phase of _H. vulgaris_
+colour is due entirely to amorphous particles situated mainly in the
+cells of the endoderm. If the polyp is starved or exposed to a high
+temperature, these particles disappear and it becomes practically
+colourless. They probably form, therefore, some kind of food-reserve,
+and it is noteworthy that a polyp kept in the unnatural conditions that
+prevail in a small aquarium invariably becomes pale, and that its
+excreta are not white and flocculent but contain dark granules
+apparently identical with those found in the cells of coloured
+individuals (p. 154).
+
+Berninger[AN] has just published observations on the effect of
+long-continued starvation on _Hydra_ carried out in Germany. He finds
+that the tentacles, mouth, and central jelly disappear, and that a
+closed "bladder" consisting of two cellular layers remains; but, to
+judge from his figures, the colour does not disappear in these
+circumstances.
+
+     [Footnote AN: Zool. Anz. xxxvi, pp. 271-279, figs., Oct.
+     1910.]
+
+
+BEHAVIOUR.
+
+_Hydra viridis_ is a more sluggish animal than the other species of its
+genus and does not possess the same power of elongating its column and
+tentacles. It is, nevertheless, obliged to feed more frequently. Wagner
+(Quart. J. Micr. Sci. xlviii, p. 586, 1905) found it impossible to use
+this species in his physiological experiments because it died of
+starvation more rapidly than other forms. This fact is interesting in
+view of the theory that the green corpuscles in the cells of _H.
+viridis_ elaborate nutritive substances for its benefit. _H. vulgaris_,
+at any rate in Calcutta, does not ordinarily capture prey more often
+than about once in three days.
+
+All _Hydrae_ (except possibly the problematical _H. rubra_ of Roux, p.
+160) spend the greater part of their time attached by the basal disk to
+some solid object, but, especially in early life, _H. vulgaris_ is often
+found floating free in the water, and all the species possess powers of
+progression. They do not, however, all move in the same way. _H.
+viridis_ progresses by "looping" like a geometrid caterpillar. During
+each forward movement the column is arched downwards so that the
+peristome is in contact with the surface along which the animal is
+moving. The basal disk is then detached and the column is twisted round
+until the basal disk again comes in contact with the surface at a point
+some distance in advance of its previous point of attachment. The
+manoeuvre is then repeated. _H. vulgaris_, when about to move, bends
+down its column so that it lies almost prone, stretches out its
+tentacles, which adhere near the tips to the surface (p. 153), detaches
+its basal disk, and then contracts the tentacles. The column is dragged
+forward, still lying almost prone, the basal disk is bent downwards and
+again attached, and the whole movement is repeated. Probably _H.
+oligactis_ moves in the same way.
+
+When _H. viridis_ is at rest the tentacles and column, according to
+Wagner, exhibit rhythmical contractions in which those of the buds act
+in sympathy with those of the parent. In _H. vulgaris_ no such movements
+have been observed. This species, however, when it is waiting for prey
+(p. 154) changes the direction of its tentacles about once in half an
+hour.
+
+All species of _Hydra_ react to chemical and physical stimuli by
+contraction and by movements of the column and tentacles, but if the
+stimuli are constantly repeated, they lose the power to some extent. All
+species are attracted by light and move towards the point whence it
+reaches them. _H. vulgaris_, however, at any rate in India, is more
+strongly repelled by heat. Consequently, if it is placed in a glass
+vessel of water, on one side of which the sun is shining directly, it
+moves away from the source of the light[AO]. But if the vessel be
+protected from the direct rays of the sun and only a subdued light falls
+on one side of it, the polyp moves towards that side. No species of the
+genus is able to move in a straight line. Wilson (Amer. Natural. xxv, p.
+426, 1891) and Wagner (_op. cit. supra_) have published charts showing
+the elaborately erratic course pursued by a polyp in moving from one
+point to another and the effect of light as regards its movements.
+
+     [Footnote AO: Mr. F. H. Gravely tells me that this is also
+     the case as regards _H. viridis_ in England, at any rate if
+     freshly captured specimens are placed overnight in a bottle
+     in a window in such a position that the early morning
+     sunlight falls upon one side of the bottle.]
+
+If an individual of _H. vulgaris_ that contains half digested food in
+its gastral cavity is violently removed from its natural surroundings
+and placed in a glass of water, the column and tentacles contract
+strongly for a few minutes. The body then becomes greatly elongated and
+the tentacles moderately so; the tentacles writhe in all directions
+(their tips being sometimes thrust into the mouth), and the food is
+ejected.
+
+
+REPRODUCTION.
+
+Reproduction takes place in _Hydra_ (i) by means of buds, (ii) by means
+of eggs, and (iii) occasionally by fission.
+
+
+(a) _Sexual Reproduction._
+
+The sexual organs consist of ovaries (female) and spermaries (male).
+Sometimes the two kinds of organs are borne by the same individual
+either simultaneously or in succession, but some individuals or races
+appear to be exclusively of one sex. There is much evidence that in
+unfavourable conditions the larger proportion of individuals develop
+only male organs.
+
+In temperate climates most forms of _Hydra_ breed at the approach of
+winter, but starvation undoubtedly induces a precocious sexual activity,
+and the same is probably the case as regards other unfavourable
+conditions such as lack of oxygen in the water and either too high or
+too low a temperature.
+
+Downing states that in N. America (Chicago) _H. vulgaris_ breeds in
+spring and sometimes as late as December; in Calcutta it has only been
+found breeding in February and March. Except during the breeding-season
+sexual organs are absent; they do not appear in the same position on the
+column in all species.
+
+The spermaries take the form of small mound-shaped projections on the
+surface of the column. Each consists of a mass of sperm-mother cells, in
+which the spermatozoa originate in large numbers. The spermatozoa
+resemble those of other animals, each possessing a head, which is shaped
+like an acorn, and a long vibratile tail by means of which it moves
+through the water. In the cells of the spermary the spermatozoa are
+closely packed together, with their heads pointing outwards towards the
+summit of the mound through which they finally make their way into the
+water. The aperture is formed by their own movements. Downing (Zool.
+Jahrb. (Anat.) xxi, p. 379, 1905) and other authors have studied the
+origin of the spermatozoa in great detail.
+
+[Illustration: Fig. 28.--Eggs of _Hydra_ (magnified).
+
+A=egg of _H. vulgaris_ (after Chun). B=vertical section through egg of
+_H. oligactis_, form A (after Brauer). C=vertical section through egg of
+_H. oligactis_, form B (after Brauer).]
+
+The ovaries consist of rounded masses of cells lying at the base of the
+ectoderm. One of these cells, the future egg, grows more rapidly than
+the others, some or all of which it finally absorbs by means of lobose
+pseudopodia extruded from its margin. It then makes its way by amoeboid
+movements between the cells of the ectoderm until it reaches the
+surface. In _H. vulgaris_ (Mem. Asiat. Soc. Beng. i, p. 350, 1906) the
+egg is first visible with the aid of a lens as a minute star-shaped body
+of an intense white colour lying at the base of the ectoderm cells. It
+increases in size rapidly, gradually draws in its pseudopodia (the rays
+of the star) and makes its way through the ectoderm to the exterior. The
+process occupies not more than two hours. The issuing ovum does not
+destroy the ectoderm cells as it passes out, but squeezes them together
+round the aperture it makes. Owing to the pressure it exerts upon them,
+they become much elongated and form a cup, in which the embryo rests on
+the surface of the parent. By the time that the egg has become globular,
+organic connection has ceased to exist. The embryo is held in position
+partly by means of the cup of elongated ectoderm cells and partly by a
+delicate film of mucus secreted by the parent. The most recent account
+of the oogenesis ("ovogenesis") is by Downing (Zool. Jahrb. (Anat.)
+xxvii, p. 295, 1909).
+
+
+(b) _Budding._
+
+The buds of _Hydra_ arise as hollow outgrowths from the wall of the
+column, probably in a definite order and position in each species. The
+tentacles are formed on the buds much as the buds themselves arise on
+the column. There is much dispute as to the order in which these
+structures appear on the bud, and Haacke (Jenaische Zeitschr. Naturwiss.
+xiv, p. 133, 1880) has proposed to distinguish two species, _H.
+trembleyi_ and _H. roeselii_, in accordance with the manner in which the
+phenomenon is manifested. It seems probable, however, that the number of
+tentacles that are developed in the first instance is due, at any rate
+to some extent, to circumstances, for in the summer brood of _H.
+vulgaris_ in Calcutta five usually appear simultaneously, while in the
+winter brood of the same form four as a rule do so. Sometimes buds
+remain attached to their parents sufficiently long to develop buds
+themselves, so that temporary colonies of some complexity arise, but I
+have not known this to occur in the case of Indian individuals.
+
+
+(c) _Fission._
+
+Reproduction by fission occurs naturally but not habitually in all
+species of _Hydra_. It may take place either by a horizontal or by a
+vertical division of the column. In the latter case it may be either
+equal or unequal. If equal, it usually commences by an elongation in one
+direction of the circumoral disk, which assumes a narrowly oval form;
+the tentacles increase in number, and a notch appears at either side of
+the disk and finally separates the column into two equal halves, each of
+which is a complete polyp. The division sometimes commences at the base
+of the column, but this is very rare. Transverse fission can be induced
+artificially and is said to occur sometimes in natural conditions. It
+commences by a constriction of the column which finally separates the
+animal into two parts, the lower of which develops tentacles and a
+mouth, while the upper part develops a basal disk. Unequal vertical
+division occurs when the column is divided vertically in such a way that
+the two resulting polyps are unequal in size. It is apparently not
+accompanied by any great increase in the number of the tentacles, but
+probably starts by one of the tentacles becoming forked and finally
+splitting down the middle.
+
+The question of the regeneration of lost parts in _Hydra_ cannot well be
+separated from that of reproduction by fission. Over a hundred and fifty
+years ago Trembley found that if a polyp were cut into several pieces,
+each piece produced those structures necessary to render it a perfect
+polyp. He also believed that he had induced a polyp that had been turned
+inside out to adapt itself to circumstances and to reverse the functions
+and structure of the two cellular layers of its body. In this, however,
+he was probably mistaken, for there can be little doubt that his polyp
+turned right side out while not under his immediate observation. Many
+investigators have repeated some of his other experiments with success
+in Europe, but the Calcutta _Hydra_ is too delicate an animal to survive
+vivisection and invariably dies if lacerated. It appears that, even in
+favourable circumstances, for a fresh polyp to be formed by artificial
+fission it is necessary for the piece to contain cells of both
+cell-layers.
+
+
+DEVELOPMENT OF THE EGG.
+
+The egg of _Hydra_ is said to be fertilized as it lies at the base of
+the ectoderm, through which the fertilizing spermatozoon bores its way.
+As soon as the egg has emerged from the cells of its parent it begins to
+split up in such a manner as to form a hollow mass of comparatively
+large equal cells. Smaller cells are separated off from these and soon
+fill the central cavity. Before segmentation begins a delicate film of
+mucus is secreted over the egg, and within this film the larger cells
+secrete first a thick chitinous or horny egg-shell and within it a
+delicate membrane. Development in some cases is delayed for a
+considerable period, but sooner or later, by repeated division of the
+cells, an oval hollow embryo is formed and escapes into the water by the
+disintegration of the egg-shell and the subsequent rupture of the inner
+membrane. Tentacles soon sprout out from one end of the embryo's body
+and a mouth is formed; the column becomes more slender and attaches
+itself by the aboral pole to some solid object.
+
+
+ENEMIES.
+
+_Hydra_ seems to have few natural enemies. Martin (Q. J. Micr. Sci.
+London, lii, p. 261, 1908) has, however, described how the minute worm
+_Microstoma lineare_ attacks _Hydra "rubra"_ in Scottish lochs, while
+the larva of a midge devours _H. vulgaris_ in considerable numbers in
+Calcutta tanks (p. 156).
+
+
+COELENTERATES OF BRACKISH WATER.
+
+Marine coelenterates of different orders not infrequently make their way
+or are carried by the tide up the estuaries of rivers into brackish
+water, and several species have been found living in isolated lagoons
+and pools of which the water was distinctly salt or brackish. Among the
+most remarkable instances of such isolation is the occurrence in Lake
+Qurun in the Fayum of Egypt of _Cordylophora lacustris_ and of the
+peculiar little hydroid recently described by Mr. C. L. Boulenger as
+_Moerisia lyonsi_ (Q. J. Micr. Sci. London, lii, p. 357, pls. xxii,
+xxiii, 1908). In the delta of the Ganges there are numerous ponds which
+have at one time been connected with estuaries or creeks of brackish
+water and have become isolated either naturally or by the hand of man
+without the marine element in their fauna by any means disappearing (p.
+14). The following species have been found in such ponds:--
+
+(_a_) _Hydrozoa._
+
+(1) _Bimeria vestita_, Wright (1859).
+
+Hincks, Hist. Brit. Hydr. Zooph. p. 103, pl. xv, fig. 2 (1868);
+Annandale, Rec. Ind. Mus. i, p. 141, fig. 3 (1907).
+
+This is a European species which has also been found off S. America. It
+occurs not uncommonly in the creeks that penetrate into the Ganges delta
+and has been found in pools of brackish water at Port Canning. The
+Indian form is perhaps sufficiently distinct to be regarded as a
+subspecies. The medusoid generation is suppressed in this genus.
+
+(2) _Syncoryne filamentata_, Annandale (1907).
+
+Annandale, Rec. Ind. Mus. i, p. 139, figs. 1, 2 (1907).
+
+Both hydroid and medusae were found in a small pool of brackish water at
+Port Canning. The specific name refers to the fact that the ends of the
+rhizomes from which the polyps arise are frequently free and elongate,
+for the young polyp at the tip apparently takes some time to assume its
+adult form.
+
+(3) _Irene ceylonensis_, Browne (1905).
+
+     Browne, in Herdman's Report on the Pearl Fisheries of
+     Ceylon, iv, p. 140, pl. iii, figs. 9-11 (1905); Annandale,
+     Rec. Ind. Mus. i, p. 142, fig. 4 (1907).
+
+The medusa was originally taken off the coast of Ceylon, while the
+hydroid was discovered in ponds of brackish water at Port Canning. It is
+almost microscopic in size.
+
+The first two of these species belong to the order Gymnoblastea
+(Anthomedusae) and the third to the Calyptoblastea (Leptomedusae).
+
+(b) _Actinozoa._
+
+(4) _Sagartia schilleriana_, Stoliczka (1869).
+
+     _S. schilleriana_, Stoliczka, Journ. As. Soc. Beng. (2)
+     xxxviii, p. 28, pls. x, xi (1869); _Metridium
+     schillerianum_, Annandale, Rec. Ind. Mus. i, p. 47, pl. iii
+     (1907).
+
+This sea-anemone, which has only been found in the delta of the Ganges,
+offers a most remarkable instance of what appears to be rapid adaptation
+of a species to its environment. The typical form, which was described
+in 1869 by Stoliczka from specimens taken in tidal creeks and estuaries
+in the Gangetic area and in the ponds at Port Canning, is found attached
+to solid objects by its basal disk. The race (subsp. _exul_), however,
+that is now found in the same ponds has become elongate in form and has
+adopted a burrowing habit, apparently owing to the fact that the bottom
+of the ponds in which it lives is soft and muddy.
+
+In addition to these four species a minute hydroid belonging to the
+order Gymnoblastea and now being described by Mr. J. Ritchie has been
+taken in the ponds at Port Canning. It is a very aberrant form.
+
+
+FRESHWATER COELENTERATES OTHER THAN HYDRA.
+
+_Hydra_ is the only genus of coelenterates as yet found in fresh water
+in India, but several others have been discovered in other countries.
+They are:--
+
+(1) _Cordylophora lacustris_, Allman (1843).
+
+     Hincks, Hist. Brit. Hydr. Zooph. p. 16, pl. iii, fig. 2
+     (1868).
+
+This is a branching hydroid that does not produce free medusae. It forms
+bushy masses somewhat resembling those formed by a luxuriant growth of
+_Plumatella fruticosa_ (pl. iii, fig. 1) in general appearance. _C.
+lacustris_ is abundant in canals, rivers, and estuaries in many parts of
+Europe and has recently been found in the isolated salt lake
+Birket-el-Qurun in the Fayum of Egypt.
+
+(2) _Cordylophora whiteleggei_, v. Lendenfeld (1887).
+
+     Zool. Jahrb. ii, p. 97 (1887).
+
+A species or race of much feebler growth; as yet imperfectly known and
+only recorded from fresh water in Australia.
+
+_Cordylophora_ is a normal genus of the class Hydrozoa and the order
+Gymnoblastea; the next four genera are certainly Hydrozoa, but their
+affinities are very doubtful.
+
+(3) _Microhydra ryderi_, Potts (1885).
+
+     Potts, Q. J. Micr. Sci. London, l, p. 623, pls. xxxv, xxxvi;
+     Browne, _ibid._ p. 635, pl. xxxvii (1906).
+
+This animal, which has been found in N. America and in Germany,
+possesses both an asexual hydroid and a sexual medusoid generation. The
+former reproduces its species by direct budding as well as by giving
+rise, also by a form of budding, to medusae that become sexually mature.
+The hydroid has no tentacles.
+
+(4) _Limnocodium sowerbii_, Lankester (1880).
+
+     Lankester, Q. J. Micr. Sci. London, xx, p. 351, pls. xxx,
+     xxxi (1880); Fowler, _ibid._ xxx, p. 507, pl. xxxii (1890).
+
+There is some doubt as to the different stages in the life-cycle of this
+species. The medusa has been found in tanks in hot-houses in England,
+France and Germany, and a minute hydroid closely resembling that of
+_Microhydra ryderi_ has been associated with it provisionally.
+
+(5) _Limnocodium kawaii_, Oka (1907).
+
+     Oka, Annot. Zool. Japon. vi, p. 219, pl. viii (1907).
+
+Only the medusa, which was taken in the R. Yang-tze-kiang, is as yet
+known.
+
+(6) _Limnocnida tanganyikae_, Bohm (1889).
+
+     R. T. Guenther, Ann. Nat. Hist. (6) xi, p. 269, pls. xiii,
+     xiv (1893).
+
+Only the medusa, which is found in Lake Tanganyika, Lake Victoria Nyanza
+and the R. Niger, has been found and it is doubtful whether a hydroid
+generation exists.
+
+(7) _Polypodium hydriforme_, Ussow (1885).
+
+     Morph. Jahrb. xii, p. 137 (1887).
+
+Two stages in this peculiar hydroid, which is found in the R. Volga, are
+known, (_a_) a spiral ribbon-like form parasitic on the eggs of the
+sterlet (_Acipenser ruthenus_), and (_b_) a small _Hydra_-like form with
+both filamentous and club-shaped tentacles. The life-history has not yet
+been worked out[AP].
+
+     [Footnote AP: Since this was written, Lippen has described a
+     third stage in the life-history of _Polypodium_ (Zool. Anz.
+     Leipzig, xxxvii, Nr. 5, p. 97 (1911)).]
+
+
+II.
+
+HISTORY OF THE STUDY OF HYDRA.
+
+Hydra was discovered by Leeuwenhoek at the beginning of the eighteenth
+century and had attracted the attention of several skilful and accurate
+observers before that century was half accomplished. Among them the
+chief was Trembley, whose "Memoires pour servir a l'histoire d'un genre
+de Polype d'eau douce"* was published at Paris 1744, and is remarkable
+not only for the extent and accuracy of the observations it enshrines
+but also for the beauty of its plates. Baker in his work entitled "An
+attempt towards a natural history of the Polyp"* (London, 1743) and
+Roesel von Rosenhof in the third part of his "Insecten-Belustigung"
+(Nurenberg, 1755) also made important contributions to the study of the
+physiology and structure of _Hydra_ about the same period. Linne
+invented the name _Hydra_, and in his "Fauna Sueica" and in the various
+editions of his "Systema Naturae" described several forms in a manner
+that permits some of them to be recognized; but Linne did not
+distinguish between the true _Hydra_ and other soft sessile
+Coelenterates, and it is to Pallas ("Elenchus Zoophytorum," 1766) that
+the credit properly belongs of reducing the genus to order. It is a
+tribute to his insight that three of the four species he described are
+still accepted as "good" by practically all students of the
+Coelenterates, while the fourth was a form that he had not himself seen.
+
+In the nineteenth century the freshwater polyp became a favourite object
+of biological observation and was watched and examined by a host of
+observers, among the more noteworthy of whom were Kleinenberg, Nussbaum,
+and Brauer, who has since the beginning of the present century made an
+important contribution to the taxonomy of the genus.
+
+
+BIBLIOGRAPHY OF HYDRA.
+
+_Hydra_ has been examined by thousands of students in biological
+laboratories all over the civilized world, and the literature upon it is
+hardly surpassed in magnitude by that on any other genus but _Homo_. The
+following is a list of a few of the more important general memoirs and
+of the papers that refer directly to Asiatic material. A systematic
+bibliography is given by Bedot in his "Materiaux pour servir a
+l'Histoire des Hydroides," Rev. Suisse Zool. xviii, fasc. 2 (1910).
+
+(a) _General._
+
+1743. BAKER, "An attempt towards a natural history of the Polyp"*
+(London).
+
+1744. TREMBLEY, "Memoires pour servir a l'histoire d'un genre de polypes
+d'eau douce"* (Paris).
+
+1755. ROESEL VON ROSENHOF, "Insecten-Belustigung: iii, Hist. Polyporum."
+
+1766. PALLAS, "Elenchus Zoophytorum."
+
+1844. LAURENT, "Rech. sur l'Hydre et l'Eponge d'eau douce" ("Voy. de la
+Bonite, Zoophytologie").
+
+1847. JOHNSTON, "A History of the British Zoophytes" (2nd edition).
+
+1868. HINCKS, "History of British Hydroid Zoophytes."
+
+1872. KLEINENBERG, "Hydra. Eine Anatomisch Entwicklungsgeschichtliche
+Untersuchung."
+
+1882. JICKELI, "Der Bau der Hydroidpolypen," Morph. Jahrb. viii, p. 373.
+
+1887. NUSSBAUM, "Ueber die Theilbarkeit der lebendigen Materie. II.
+Mittheilung. Beitraege zur Naturgeschichte des Genus Hydra," Arch. mikr.
+Anat. Bonn, xxix, p. 265.
+
+1891. BRAUER, "Ueber die Entwicklung von Hydra," Zeitschr. wiss. Zool.
+Leipzig, lii, p. 169.
+
+1892. CHUN, "Coelenterata (Hohlthiere)," in Bronn's Thier-Reichs II (2).
+
+1905. DOWNING, "The spermatogenesis of Hydra," Zool. Jahrb. (Anat.) xxi,
+p. 379.
+
+1908. BRAUER, "Die Benennung und Unterscheidung der Hydra-Arten," Zool.
+Ann. xxxiii, p. 790.
+
+1909. FRISCHHOLZ, "Biologie und Systematik im Genus Hydra," Braun's
+Annal. Zool. (Wuerzburg) iii, p. 105.
+
+1910. BERNINGER, "Ueber Einwirkung des Hungers auf Hydra," Zool. Anz.
+xxxvi, p. 271.
+
+(b) _Asiatic References._
+
+1894. RICHARD, "Sur quelques Animaux inferieurs des eaux douces du
+Tonkin (Protozoaires, Rotiferes, Entomostraces)," Mem. Soc. zool.
+France, vii, p. 237.
+
+1904. VON DADAY, "Mikroskopische Suesswasserthiere aus Turkestan," Zool.
+Jahrb. (Syst.) xix, p. 469.
+
+1906. ANNANDALE, "Notes on the Freshwater Fauna of India. No. IV. _Hydra
+orientalis_ and its bionomical relations with other Invertebrates," J.
+Asiat. Soc. Bengal (new series), ii, p. 109.
+
+1906. ANNANDALE, "The Common _Hydra_ of Bengal: its Systematic Position
+and Life History," Mem. As. Soc. Bengal, i, p. 339.
+
+1907. ANNANDALE, "Notes on the Freshwater Fauna of India. No. X. _Hydra
+orientalis_ during the Rains," J. Asiat. Soc. Bengal (new series), iii,
+p. 27.
+
+1907. ANNANDALE, "Notes on the Freshwater Fauna of India. No. XI.
+Preliminary Note on the occurrence of a Medusa (_Irene ceylonensis_,
+Browne) in a brackish pool in the Ganges Delta and on the Hydroid Stage
+of the species," J. Asiat. Soc. Bengal (new series), iii, p. 79.
+
+1907. WILLEY, "Freshwater Sponge and Hydra in Ceylon," Spolia Zeylan.
+Colombo, iv, p. 184.
+
+1908. ANNANDALE, "Observations on specimens of _Hydra_ from Tibet, with
+notes on the distribution of the genus in Asia," Rec. Ind. Mus. ii, p.
+311.
+
+1910. POWELL, "Lessons in Practical Biology for Indian Students"
+(Bombay).
+
+1910. LLOYD, "An Introduction to Biology for Students in India"
+(London).
+
+
+
+
+GLOSSARY OF TECHNICAL TERMS USED IN PART II.
+
+
+  _Aboral_ (or _basal_)       The disk by means of which a free polyp
+  _disk_                      attaches itself to external objects.
+
+  _Cnidoblast_                The living cell of the nematocyst or
+                              nettle-cell (_q. v._).
+
+  _Cnidocil_                  A minute bristle that projects on the
+                              surface in connection with a nettle-cell
+                              (_q. v._).
+
+  _Column_                    The upright or potentially upright
+                              part of a polyp (_q. v._).
+
+  _Ectoderm_                  The external cell-layer of the body-wall.
+
+  _Endoderm_                  The internal cell-layer of the body-wall.
+
+  _Green (chlorophyll)        Minute green bodies contained in cells
+   corpuscles_                of polyps or other animals and
+                              representing a stage in the life-history
+                              of an alga (_Chlorella_).
+
+  _Mesogloea_                 The intermediate, gelatinous layer of
+                              the body-wall.
+
+  _Nettle-cell (nematocyst)_  A cell capsule full of liquid in which
+                              an eversible thread is coiled up.
+
+  _Oral disk_                 The eminence that surrounds the mouth
+                              and is surrounded by tentacles.
+
+  _Peristome_                 See "oral disk."
+
+  _Polyp_                     An individual coelenterate of simple
+                              structure that is fixed temporarily or
+                              permanently by one end of a more
+                              or less cylindrical body and possesses
+                              a mouth at the other end.
+
+  _Tentacles_                 Filamentous outgrowths (in _Hydra_
+                              hollow) of the body-wall round the
+                              mouth.
+
+
+
+
+  LIST OF THE INDIAN HYDRIDA.
+
+
+  Class HYDROZOA.
+
+  Order ELEUTHEROBLASTEA.
+
+  Family HYDRIDAE.
+
+  Genus HYDRA, _Linne_ (1746).
+
+  24. _H. vulgaris_, Pallas (1766).
+
+  25. _H. oligactis_, Pallas (1766).
+
+
+Order ELEUTHEROBLASTEA.
+
+Naked hydrozoa which reproduce their kind by means of buds or eggs, or
+by fission, without exhibiting the phenomena of alternation of
+generations.
+
+
+Family HYDRIDAE.
+
+     HYDRAIDAE, Johnston, Hist. Brit. Zooph. (ed. 2) i, p. 120
+     (1847).
+     HYDRIDAE, Hincks, Hist. Brit. Hydroid. Zooph. p. 309 (1868).
+
+Small Eleutheroblastea in which the mouth is surrounded by hollow
+tentacles. Permanent colonies are not formed, but reproduction by
+budding commonly takes place.
+
+
+Genus HYDRA, _Linne_.
+
+TYPE, _Hydra viridis_, Linne.
+
+Freshwater polyps which produce eggs with hard chitinous shells.
+Although habitually anchored by the end of the body furthest from the
+mouth to extraneous objects, they possess considerable powers of
+locomotion. They are extremely contractile and change greatly from time
+to time in both form and size.
+
+Only three well-established species of the genus, which is universally
+distributed and occurs only in fresh or brackish[AQ] water, can be
+recognized, namely, _H. viridis_, Linne (=_H. viridissima_, Pallas), _H.
+vulgaris_, Pallas (=_H. grisea_, Linne), and _H. oligactis_, Pallas
+(=_H. fusca_, Linne). The two latter occur in India, but _H. viridis_
+does not appear to have been found as yet anywhere in the Oriental
+Region, although it is common all over Europe and N. America and also in
+Japan. The distribution of _H. vulgaris_ is probably cosmopolitan, but
+there is some evidence that _H. oligactis_ avoids tropical districts,
+although, under the name _Hydra fusca_, it has been doubtfully recorded
+as occurring in Tonquin[AR].
+
+     [Footnote AQ: A small form of _H. viridis_ (var. _bakeri_,
+     Marshall) is found in brackish water in England.]
+
+     [Footnote AR: Richard, Mem. Soc. zool. France, vii, p. 237
+     (1894).]
+
+The three species may be distinguished from one another by the following
+key:--
+
+  [I. Colour leaf-green; the cells contain green
+       (chlorophyll) corpuscles of definite form.
+     A. Tentacles comparatively stout, habitually
+        shorter than the column, which is cylindrical.
+        Egg-shell without spines, ornamented
+        with a reticulate pattern                    _viridis_.]
+  II. Colour never leaf-green; no chlorophyll
+       corpuscles present in the cells.
+     A. Tentacles capable of great elongation but
+        when the animal is at rest never very much
+        longer than the column, which is cylindrical
+        when the gastral cavity is empty.
+        Largest nettle-cells almost as broad as
+        long. Egg-shell bearing long spines most
+        of which are divided at the tips             _vulgaris_, p. 148.
+     B. Tentacles, even when the animal is at rest,
+        much longer than the column, the basal
+        part of which, even when the gastral
+        cavity is empty, is constricted. Largest
+        nettle-cells considerably longer than
+        broad.  Egg-shell smooth or bearing
+        short, simple spines                         _oligactis_, p. 158.
+
+
+24. Hydra vulgaris, _Pallas_.
+
+     Polypes de la seconde espece, Trembley, Mem. pour servir a
+     l'histoire d'un genre de polypes d'eau douce*, pl. i, figs.
+     2, 5; pl. vi, figs. 2, 8; pl. viii, figs. 1-7; pl. xi, figs.
+     11-13 (1744).
+
+     Roesel von Rosenhof, Insecten-Belustigung, iii, Hist.
+     Polyporum, pls. lxxvi, lxxvii, lxxix-lxxxiii (1755).
+
+     ? _Hydra polypus_, Linne, Fauna Suecica, p. 542 (1761).
+
+     _Hydra vulgaris_, Pallas, Elenchus Zoophytorum, p. 30
+     (1766).
+
+     ? _Hydra attenuata_, _id_., _ibid_. p. 32.
+
+     _Hydra grisea_, Linne (Gmelin), Systema Naturae (ed. 13), p.
+     3870 (1782).
+
+     _Hydra pallens_, _id_., _ibid_. p. 3871.
+
+     _Hydra vulgaris_, Ehrenberg, Abhandl. Akad. Wiss. Berlin,
+     1836, p. 134, taf. ii.
+
+     _Hydra brunnea_, Templeton, London's Mag. Nat. Hist. ix, p.
+     417 (1836).
+
+     _Hydra vulgaris_, Laurent, Rech. sur l'Hydre at l'Eponge
+     d'eau douce (Voy. de la Bonite, Zoophytologie), p. 11, pl.
+     i, pl. ii, figs. 2, 2'' (1844).
+
+     _Hydra vulgaris_, Johnston, Hist. British Zoophytes (ed. 2),
+     i, p. 122, pl. xxix, fig. 2 (1847).
+
+     _Hydra vulgaris_, Hincks, Hist. British Hydroid Zoophytes,
+     i, p. 314, fig. 41 (1868).
+
+     _Hydra aurantiaca_, Kleinenberg, Hydra, p. 70, pl. i, fig.
+     1, pl. iii, fig. 10 (1872).
+
+     _Hydra trembleyi_, Haacke, Zool. Anz. Leipzig, ii, p. 622
+     (1879).
+
+     _Hydra grisea_, Jickeli, Morph. Jahrb. viii, p. 391, pl.
+     xviii, fig. 2 (1883).
+
+     _Hydra grisea_, Nussbaum, Arch. mikr. Anat. Bonn, xxix, p.
+     272, pl. xiii, pl. xiv, figs. 33, 37, 47 (1887).
+
+     ? _Hydra hexactinella_, v. Lendenfeld, Zool. Jahrb. Jena,
+     ii, p. 96, pl. vi, figs. 13, 14 (1887).
+
+     ? _Hydra hexactinella_, _id_., Proc. Linn. Soc. N. S. Wales,
+     x, p. 678, p. xlviii, figs. 1-4 (1887).
+
+     _Hydra grisea_, Brauer, Zeit. wiss. Zool. Leipzig, lii, p.
+     169 (1891).
+
+     _Hydra grisea_, Chun, in Broenn's Thier-Reichs, ii (2), pl.
+     ii, figs. 2_b_, 2_c_, 5 (1892).
+
+     _Hydra grisea_, Downing, Zool. Jahrb. (Anat.) Jena, xxi, p.
+     381 (1905).
+
+     _Hydra orientalis_, Annandale, J. Asiat. Soc. Bengal, (new
+     series) i, 1905, p. 72.
+
+     _Hydra orientalis_, _id._, _ibid._ (new series) ii, 1906, p.
+     109.
+
+     _Hydra orientalis_, _id._, Mem. Asiat. Soc. Bengal, i, p.
+     340 (1906).
+
+     ? _Hydra orientalis_, Willey, Spol. Zeylan. Colombo, iv, p.
+     185 (1907).
+
+     _Hydra grisea_, Weltner, Arch. Naturg. Berlin, lxxiii, i, p.
+     475 (1907).
+
+     _Hydra vulgaris_, Brauer, Zool. Anz. xxxiii, p. 792, fig. 1
+     (1908).
+
+     _Hydra orientalis_, Annandale, Rec. Ind. Mus. ii, p. 312
+     (1908).
+
+     _Hydra grisea_, Frischholz, Braun's Zool. Annal. (Wuerzburg),
+     iii, pp. 107, 134, &c., figs. 1 and 10-17 (1909).
+
+     _Hydra grisea_, _id._, Biol. Centralbl. Berlin, xxix, p. 184
+     (1909).
+
+     _Hydra vulgaris_, Brauer, Die Suesswasserfauna Deutschlands,
+     xix, p. 192, figs. 336-338 (1909).
+
+     _Hydra pentactinella_, Powell, Lessons in Practical Biology
+     for Indian Students, p. 24 (Bombay, 1910).
+
+
+Phase _orientalis*_, Annandale.
+
+_Colour_ variable; in summer usually pale, in winter either deep orange,
+dull brown, or dark green. The cells do not contain spherical or oval
+coloured bodies.
+
+[Illustration: Fig. 29.--_Hydra vulgaris_, from Calcutta (phase
+_orientalis_).
+
+A=winter brood; B=summer brood, the same individual in an expanded and a
+contracted condition. B is more highly magnified than A.]
+
+_Column_ slender and capable of great elongation, normally almost
+cylindrical, but when containing food often shaped like a wine-glass.
+The surface is thickly set with nettle-cells the cnidocils of which give
+it an almost hirsute appearance under the microscope. When extended to
+the utmost the column is sometimes nearly 30 mm. (1-1/5 inches) long,
+but more commonly it is about half that length or even shorter.
+
+_Tentacles_ usually 4-6, occasionally 8. They are always slender except
+when they are contracted, then becoming swollen at the base and slightly
+globular at the tip. If the animal is at rest they are not very much
+longer than the body, but if it is hungry or about to move from one
+place to another they are capable of very great extension, often
+becoming like a string of minute beads (the groups of nettle-cells)
+strung on an invisible wire.
+
+_Nettle-cells._ The capsules with barbed threads (fig. 27, p. 131) are
+very variable in size, but they are invariably broad in proportion to
+their length and as a rule nearly spherical. In a _Hydra_ taken in
+Calcutta during the winter the largest capsules measured (unexploded)
+0.0189 mm. in breadth and 0.019 in length, but in summer they are
+smaller (about 0.012 mm. in breadth). Smaller capsules with barbed
+threads always occur. The barbed threads are very long and slender. At
+their base they bear a circle of stout and prominent spines, usually 4
+in number; above these there are a number of very small spines, but the
+small spines are usually obscure. Malformed corpuscles are common. The
+capsules with unbarbed threads are very nearly as broad at the distal as
+at the proximal end; they are broadly oval with rounded ends.
+
+_Reproductive organs._ The reproductive organs are confined to the upper
+part of the body. In India eggs (fig. 28, p. 137) are seldom produced.
+They sometimes appear, however, at the beginning of the hot weather. In
+form they are spherical, and their shell bears relatively long spines,
+which are expanded, flattened and more or less divided at the tip. The
+part of the egg that is in contact with the parent-polyp is bare.
+Spermaries are produced more readily than ovaries; they are mammillate
+in form and number from 4 to 24. Ovaries and spermaries have not been
+found on the same individual.
+
+_Buds_ are confined to a narrow zone nearer the base than the apex of
+the column. Rarely more than 2 are produced at a time, and I have never
+seen an attached bud budding. In winter 5 tentacles are as a rule
+produced simultaneously, and in summer 4. In the former case a fifth
+often makes its appearance before the bud is liberated.
+
+In Calcutta two broods can be distinguished, a cold-weather brood, which
+is larger, stouter, and more deeply coloured, produces buds more freely,
+has larger nematocysts, and as a rule possesses 6 tentacles; and a
+hot-weather brood, which is smaller, more slender and paler, produces
+buds very sparingly, has smaller nematocysts, and as a rule possesses
+only 4 or 5 tentacles. Only the cold-weather form is known to become
+sexually mature. There is evidence, however, that in those parts of
+India which enjoy a more uniform tropical climate than Lower Bengal,
+polyps found at all times of year resemble those found in the hot
+weather in Calcutta, and sometimes produce spermatozoa or eggs.
+
+I have recently had an opportunity of comparing specimens of the
+Calcutta hot-weather form with well-preserved examples of _H. vulgaris_,
+Pallas (=_H. grisea_, Linn.), from England. They differ from these
+polyps in very much the same way as, but to a greater degree than they
+do from the winter phase of their own race, and I have therefore no
+doubt that _H. orientalis_ is merely a tropical phase of Pallas's
+species. My description is based on Indian specimens, which seem to
+differ, so far as anatomy is concerned, from European ones in the
+following points:--
+
+     (1) The sexes are invariably distinct;
+     (2) the nematocysts are invariably smaller.
+
+I have seen in Burma an abnormal individual with no tentacles. Its buds,
+however, possessed these organs.
+
+TYPE. None of the older types of _Hydra_ are now in existence. That of
+_H. orientalis_ is, however, in the collection of the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--_H. vulgaris_ is common in Europe and N.
+America and is probably found all over tropical Asia. The following are
+Indian and Ceylon localities:--BENGAL, Calcutta and neighbourhood
+(_Annandale_, _Lloyd_); Adra, Manbhum district (_Paiva_), Rampur Bhulia
+on the R. Ganges (_Annandale_); Chakradharpur, Chota Nagpur
+(_Annandale_); Pusa, Bihar (_Annandale_); Puri, Orissa (_Annandale_):
+MADRAS, sea-beach near Madras town (_Henderson_): BOMBAY, island of
+Bombay (_Powell_): BURMA, Mandalay, Upper Burma, and Moulmein, N.
+Tenasserim (_Annandale_): CEYLON, Colombo and Peradeniya (_Willey_,
+_Green_). Dr. A. D. Imms tells me that he has obtained specimens that
+probably belong to this species in the Jumna at Allahabad.
+
+BIOLOGY.--In India _H. vulgaris_ is usually found, so far as my
+experience goes, in stagnant water. In Calcutta it is most abundant in
+ponds containing plenty of aquatic vegetation, and seems to be
+especially partial to the plant _Limnanthemum_, which has floating
+leaves attached to thin stalks that spring up from the bottom, and to
+_Lemna_ (duckweed). Dr. Henderson, however, found specimens in a pool of
+rain-water on the sea-shore near Madras.
+
+There is evidence that each of the two broods which occur in Lower
+Bengal represents at least one generation; probably it represents more
+than one, for tentacles are rarely if ever produced after the animal has
+obtained its full size, and never (or only owing to accident) decrease
+in number after they have once appeared. The winter form is found
+chiefly near the surface of the water, especially on the roots of
+duckweed and on the lower surface of the leaves of _Limnanthemum_; but
+the summer form affects deeper water in shady places, and as a rule
+attaches itself to wholly submerged plants. The latter form is to be met
+with between March and October, the cold-weather form between October
+and March, both being sometimes found together at the periods of
+transition. In the unnatural environment of an aquarium, however,
+individuals of the winter form lose their colour and become attenuated,
+in these features resembling the summer form, even in the cooler months.
+Buds produced in these conditions rarely have more than five tentacles
+or themselves produce buds freely after liberation.
+
+The buds appear in a fixed order and position, at any rate on
+individuals examined in winter; in specimens of the summer form the
+position is fixed, but the order is irregular. Each quadrant of the
+column has apparently the power of producing, in a definite zone nearer
+the aboral pole than the mouth, a single bud; but the buds of the
+different quadrants are not produced simultaneously. If we imagine that
+the quadrants face north, south, east, and west, and that the first bud
+is produced in the north quadrant, the second will be produced in the
+east quadrant, the third in the south, and the fourth in the west. It is
+doubtful whether more than four buds are produced in the lifetime of an
+individual, and apparently attached buds never bud in this race. The
+second bud usually appears before the first is liberated, and this is
+also the case occasionally as regards the third, but it is exceptional
+for four buds to be present at one time. About three weeks usually
+elapse between the date at which the bud first appears as a minute
+conical projection on the surface of the parent and that at which it
+liberates itself. This it does by bending down, fixing itself to some
+solid object by means of the tips of its tentacles, the gland-cells of
+which secrete a gummy fluid, and then tearing itself free.
+
+Although it is rare for more than two buds to be produced
+simultaneously, budding is apparently a more usual form of reproduction
+than sexual reproduction. Individuals that bear eggs have not yet been
+found in India in natural conditions, although males with functional
+spermaries are not uncommon at the approach of the hot weather. The few
+eggs that I have seen were produced in my aquarium towards the end of
+the cold weather. Starvation, lack of oxygen, and too high a temperature
+(perhaps also lack of light) appear to stimulate the growth of the male
+organs in ordinary cases, but perhaps they induce the development of
+ovaries in the case of individuals that are unusually well nourished.
+
+The spines that cover the egg retain debris of various kinds upon its
+surface, so that it becomes more or less completely concealed by a
+covering of fragments of dead leaves and the like even before it is
+separated from the polyp. Its separation is brought about by its falling
+off the column of the parent. Nothing is known of its subsequent fate,
+but probably it lies dormant in the mud through the hot weather. Eggs
+are sometimes produced that have no shells. This is probably due to the
+fact that they have not been fertilized.
+
+Reproduction by fission occurs rarely in the Indian _Hydra_, but both
+equal and unequal vertical fission have been observed. In the case of
+equal fission the circumoral area lengthens in a horizontal direction,
+and as many extra tentacles as those the polyp already possesses make
+their appearance. The mouth then becomes constricted in the middle and
+notches corresponding to its constriction appear at either side of the
+upper part of the column. Finally the whole animal divides into two
+equal halves in a vertical direction. I have only seen one instance of
+what appeared to be unequal vertical fission--that of a polyp consisting
+of two individuals still joined together by the basal disk, but one
+about half the size of the other. Each had three well-developed
+tentacles, and in addition a minute fourth tentacle. This was situated
+on the side opposed to that of the other individual which bore a similar
+tentacle. Transverse fission has not been observed. The Indian _Hydra_
+is a very delicate animal as compared with such a form as _H. viridis_,
+and all attempts to produce artificial fission without killing the polyp
+have as yet failed.
+
+Young individuals are often, and adults occasionally, found floating
+free in the water, either with the mouth uppermost and the tentacles
+extended so as to cover as large an area as possible or with the aboral
+pole at the surface. In the former case they float in mid-water, being
+of nearly the same specific gravity as the water, and are carried about
+by any movement set up in it. In the latter case, however, the base of
+the column is actually attached to some small object such as the cast
+skin of a water-flea or to a minute drop of mucus originally given out
+by the polyp's own mouth; the tentacles either hang downwards or are
+spread out round the mouth, and the animal is carried about by wind or
+other agencies acting on the surface.
+
+In addition to this passive method of progression the polyp can crawl
+with considerable rapidity. In doing so it bends its column down to the
+object along which it is about to move in such a way that it lies almost
+parallel to the surface, the basal disk, however, being still attached.
+The tentacles are then extended and attach themselves near the tips to
+the surface a considerable distance away. Attachment is effected by the
+secretion of minute drops of adhesive substance from gland-cells. The
+basal disk is liberated and the tentacles contract, dragging the column,
+which still lies prone, along as they do so. The basal disk again
+affixes itself, the tentacles wrench themselves free, the surface of
+their cells being often drawn out in the process into pseudopodia-like
+projections, which of course are not true pseudopodia[AS] but merely
+projections produced by the mechanical strain. The whole action is then
+repeated. The polyp can also pull itself across a space such as that
+between two stems or leaves by stretching out one of its tentacles,
+fixing the tip to the object it desires to reach, pulling itself free
+from its former point of attachment, and dragging itself across by
+contracting the fixed tentacle. The basal disk is then turned round and
+fixed to the new support.
+
+     [Footnote AS: See Zykoff, Biol. Centralbl. xviii, p. 272
+     (1898), and Annandale, Rec. Ind. Mus. i, p. 67 (1907).]
+
+The Indian polyp, like all its congeners, is attracted by light, but it
+is more strongly repelled by heat. Probably it never moves in a straight
+line, but if direct sunlight falls on one side of a glass aquarium, the
+polyps move away from that side in a much less erratic course than is
+usually the case. If conditions are favourable, they often remain in one
+spot for weeks at a time, their buds congregating round them as they are
+set free. In a natural environment it seems that regular migrations take
+place in accordance with changes in temperature, for whereas in cool
+weather many individuals are found adhering to the lower surface of the
+floating leaves of _Limnanthemum_, few are found in this position
+immediately after a rise in the thermometer. If the rise is only a small
+one, they merely crawl down the stems to the end of which the leaves are
+attached, but as soon as the hot weather begins in earnest, the few that
+survive make their way to the deepest and most shady part of the pond.
+In captivity the polyps seek the bottom of any vessel in which they are
+contained, if sunlight falls on the surface of the water.
+
+The chief function of the tentacles is that of capturing prey. The
+Indian polyp feeds as a rule in the early morning, before the day has
+become hot. In an aquarium at any rate, the tentacles are never more
+than moderately extended during the night. If the polyp is hungry, they
+are extended to their greatest length in the early morning, and if prey
+is not captured, they sometimes remain in this condition throughout the
+day. In these circumstances they hang down or stand up in the water
+closely parallel to one another, and often curved in the middle as if a
+current were directed against them. Prey that comes in contact with one
+of them has little chance of escape, for nematocysts from all the
+tentacles can be readily discharged against it. Approximately once in
+half an hour the direction of the tentacles is changed, but I have been
+unable to observe any regular rhythmical movements of the tentacles or
+any correlation between those of a parent polyp and the buds still
+attached to it.
+
+The prey consists chiefly of the young larvae of midges (Chironomidae) and
+may-flies, but small copepod and phyllopod crustacea are also captured.
+
+As soon as the prey adheres firmly to the tentacles and has become
+paralysed it is brought to the mouth by their contracting strongly and
+is involved in a mass of colourless mucus extruded from the digestive
+cavity. Partly by the contraction of muscle-fibres in the body-wall and
+partly by movements of the mouth itself assisted by the mucus, which
+apparently remains attached to the walls of the cavity, the food is
+brought into the mouth. If it is at all bulky, it remains in the upper
+part of the cavity, the gland-cells pouring out a digestive fluid upon
+it and so dissolving out soluble substances. A large share of the
+substances thus prepared falls down to the bottom of the cavity and are
+there digested by the endoderm cells. The insoluble parts of the food
+are, however, ejected from the mouth without ever reaching the base of
+the cavity.
+
+The colour of the polyp appears to be due mainly to the results of
+digestion. Brown or orange individuals recently captured in a pond and
+kept in favourable conditions take three or four days to digest their
+food, and the excreta ejected from the mouth then take the form of a
+white flocculent mass. If, however, the same individuals are kept for
+long in a glass aquarium, they lose their colour, even though they feed
+readily. Digestion is then a much more rapid process, and the excreta
+contain minute, irregular, coloured granules, which appear to be
+identical with those contained in the endoderm cells of individuals that
+have recently digested a meal fully. Starved individuals are always
+nearly colourless. It seems, therefore, that in this species colour is
+due directly to the products of digestion, and that digestion does not
+take place so fully in unfavourable conditions or at a high temperature
+as it does in more healthy circumstances. The dark green colour of some
+polyps is, however, less easily explained. I have noticed that all the
+individuals which have produced eggs in my aquarium have been of this
+colour, which they have retained in spite of captivity; whereas
+individuals that produced spermatozoa often lost their colour completely
+before doing so, sometimes becoming of a milky white owing to the
+accumulation of minute drops of liquid in their endoderm cells. Even in
+green individuals there is never any trace in the cells of coloured
+bodies of a definite form.
+
+The Indian polyp, unlike European representatives of its species, is a
+very delicate little animal. In captivity at any rate, three
+circumstances are most inimical to its life: firstly, a sudden rise in
+the temperature, which may either kill the polyp directly or cause it to
+hasten its decease by becoming sexually mature; secondly, the lack of a
+free current of air on the surface of the aquarium; and thirdly, the
+growth of a bacterium, which forms a scum on the top of the water and
+clogs up the interstices between the leaves and stems of the
+water-plants, soon killing them. If adult polyps are kept even in a
+shallow opaque vessel which is shut up in a room with closed shutters
+they generally die in a single night; indeed, they rarely survive for
+more than a few days unless the vessel is placed in such a position that
+air is moving almost continuously over its surface. The bacterium to
+which I allude often almost seals up the aquarium, especially in March
+and April, in which months its growth is very rapid. Strands of slime
+produced by it surround the polyp and even enter its mouth. In this
+event the polyp retracts its tentacles until they become mere
+prominences on its disk, and shrinks greatly in size. The colouring
+matter in its body becomes broken up into irregular patches owing to
+degeneracy of the endoderm cells, and it dies within a few hours.
+
+_Hydra_ in Calcutta is often devoured by the larva of a small midge
+(_Chironomus fasciatipennis_, Kieffer) common in the tanks from November
+to February. In the early stages of its larval life this insect wanders
+free among communities of protozoa (_Vorticella_, _Epistylis_, &c.) and
+rotifers on which it feeds, but as maturity approaches begins to build
+for itself a temporary shelter of one of two kinds, either a delicate
+silken tunnel the base of which is formed by some smooth natural
+surface, or a regular tube the base of which is fixed by a stalk
+situated near the middle of its length to some solid object, while the
+whole surface is covered with little projections. The nature of the
+covering appears to depend partly on that of the food-supply and partly
+on whether the larva is about to change its skin.
+
+I had frequently noticed that tunnels brought from the tank on the under
+surface of _Limnanthemum_ leaves had a _Hydra_ fixed to them. This
+occurred in about a third of the occupied shelters examined. The _Hydra_
+was always in a contracted condition and often more or less mutilated.
+By keeping a larva together with a free polyp in a glass of clean water,
+I have been able to observe the manner in which the polyp is captured
+and entangled. The larva settles down near the base of its column and
+commences to spin a tunnel. When this is partially completed, it passes
+a thread round the polyp's body to which it gives a sharp bite. This
+causes the polyp to bend down its tentacles, which the larva entangles
+with threads of silk, doing so by means of rapid, darting movements; for
+the nettle-cells would prove fatal should they be shot out against its
+body, which is soft. Its head is probably too thickly coated with chitin
+to excite their discharge. Indeed, small larvae of this very species form
+no inconsiderable part of the food of the polyp, and, so far as my
+observations go, a larva is always attacked in the body and swallowed in
+a doubled-up position.
+
+When the _Hydra_ has been firmly built into the wall of the shelters and
+its tentacles fastened down by their bases on the roof, the larva
+proceeds, sometimes after an interval of some hours, to eat the body,
+which it does very rapidly, leaving the tentacles attached to its
+shelter. The meal only lasts for a few minutes; after it the larva
+enjoys several hours' repose, protected by remains of its victim, which
+retain a kind of vitality for some time. During this period it remains
+still, except for certain undulatory movements of the posterior part of
+the body which probably aid in respiration. Then it leaves the shelter
+and goes in search of further prey. Its food, even when living in a
+tunnel, does not consist entirely of _Hydra_. I have watched a larva
+building its shelter near a number of rotifers, some of which it
+devoured and some of which it plastered on to its tunnel.
+
+The tubular shelters occasionally found are very much stouter structures
+than the tunnels, but are apparently made fundamentally of the same
+materials; and structures intermediate between them and the tunnels are
+sometimes produced. The larva as a rule fastens to them branches
+detached from living colonies of Vorticellid protozoa such as
+_Epistylis_[AT].
+
+     [Footnote AT: Further particulars regarding the life-history
+     of this larva will be found on pp. 114 and 115, J. Asiat.
+     Soc. Bengal, ii (n. s.) 1906.]
+
+Of animals living in more or less intimate relations with the polyp, I
+have found two very distinct species of protozoa, neither of which is
+identical with either of the two commonly found in association with
+_Hydra_ in Europe, _Trichodina pediculus_ and _Kerona polyporum_. On two
+occasions, one in January and the other at the beginning of February, I
+have seen a minute colourless flagellate on the tentacles of the
+Calcutta polyp. On the first occasion the tentacles were completely
+covered with this protozoon, so that they appeared at first sight as
+though encased in flagellated epithelium. The minute organism was
+colourless, transparent, considerably larger than the spermatozoa of
+_Hydra_, slightly constricted in the middle and rounded at each end. It
+bore a long flagellum at the end furthest from its point of attachment,
+the method of which I could not ascertain. When separated from the polyp
+little groups clung together in rosettes and gyrated in the water. On
+the other occasion only a few individuals were observed. Possibly this
+flagellate was a parasite rather than a commensal, as the individual on
+which it swarmed was unusually emaciated and colourless, and bore
+neither gonads nor buds. The larger stinging cells were completely
+covered by groups of the organism, and possibly this may have interfered
+with the discharge of stinging threads.
+
+The other protozoon was _Vorticella monilata_, Tatem, which has been
+found, not in association with _Hydra_, in Europe and S. America. In
+Calcutta I have only seen it attached to the column of the polyp, but
+probably it would also be found, if carefully looked for, attached to
+water-weeds.
+
+Especially in the four-rayed stage, the polyp not infrequently attaches
+itself to shells of _Vivipara_, and, more rarely, to those of other
+molluscs. It is doubtful whether this temporary association between
+_Hydra_ and the mollusc is of any importance to the latter. Even when
+the polyp settles on its body and not on its shell (as is sometimes the
+case) the _Vivipara_ appears to suffer no inconvenience, and makes no
+attempt to get rid of its burden. It is possible, on the other hand,
+that the _Hydra_ may protect it by devouring would-be parasites; but of
+this there is no evidence[AU].
+
+     [Footnote AU: In the Calcutta tanks operculate molluscs such
+     as _Vivipara_ are certainly more free from visible attack
+     than non-operculate species. This is the case for instance,
+     as regards the common aquatic glowworm (_Luciola_ sp.),
+     which destroys large numbers of individuals of _Limnophysa_,
+     _Limnaeus_, &c. If it has been starved for several days in an
+     aquarium it will attack an operculate form, but rarely with
+     success. Similarly _Chaetogaster bengalensis_ attaches itself
+     exclusively to non-operculate forms. In the one case the
+     polyp could do very little against an adversary with so
+     stout an integument as the insect, while, in the other, it
+     is doubtful whether the worm does any harm to its host. The
+     polyp would afford very little protection against the
+     snail's vertebrate enemies or against what appears to be its
+     chief foe, namely, drought. As the water sinks in the tank
+     non-operculate species migrate to the deeper parts, but
+     _Vivipara_ and _Ampullaria_ close their shells, remain where
+     they are, and so often perish, being left high and dry,
+     exposed to the heat of the sun.]
+
+The association, however, is undoubtedly useful to _Hydra_. The mud on
+the shells of _Vivipara_ taken on floating objects shows that in cool
+weather the snail comes up from the bottom to the surface, and it
+probably goes in the opposite direction in hot weather. Moreover, the
+common Calcutta species (_V. bengalensis_) feeds very largely, if not
+exclusively, on minute green algae. It therefore naturally moves towards
+spots where smaller forms of animal and vegetable life abound and
+conditions are favourable for the polyp. The polyp's means of
+progression are limited, and the use of a beast of burden is most
+advantageous to it, for it can detach itself when it arrives at a
+favourable habitat. If specimens are kept in water which is allowed to
+become foul, a very large proportion of them will attach themselves to
+any snails confined with them. Under natural conditions they would thus
+in all probability be rapidly conveyed to a more suitable environment.
+In the tanks it is far commoner to find young four-rayed polyps on
+_Vivipara_ than individuals with five or six rays; but the adults of the
+species are far less prone to change their position than are the young.
+
+The Calcutta _Hydra_, especially in spring, exhibits a distinct tendency
+to frequent the neighbourhood of sponges and polyzoa, such as _Spongilla
+carteri_ and the denser forms of _Plumatella_. Possibly this is owing to
+the shade these organisms provide.
+
+
+25. Hydra oligactis, _Pallas_.
+
+     Polypes de la troisieme espece, Trembley, Mem. hist.
+     Polypes,* pl. i, figs. 3, 4, 6; pl. ii, figs. 1-4; pl. iii,
+     fig. 11; pl. v, figs. 1-4; pl. vi, figs. 3-7, 9, 10; pl.
+     viii, figs. 8, 11; pl. ix (1744).
+
+     Roesel von Rosenhof, Insekt.-Belustigung, iii, Hist. Polyp.,
+     pls. lxxxiv-lxxxvi (1755).
+
+     _Hydra socialis_, Linne, Fauna Sueica, p. 542 (1761).
+
+     _Hydra oligactis_, Pallas, Elench. Zooph. p. 29 (1766).
+
+     ? _Hydra attenuata_, _id._, _ibid._ p. 32.
+
+     _Hydra fusca_, Linne, Syst. Nat. (ed. 13), p. 3870 (1782).
+
+     _Hydra oligactis_, Johnston, Brit. Zooph. i, p. 124, fig. 27
+     (p. 120) (1847).
+
+     _Hydra oligactis_, Hincks, Hist. Brit. Hydr. Zooph. i, p.
+     315, fig. 42 (1868).
+
+     _Hydra roeselii_, Haacke, Jena Zeitschr. Naturwiss. xiv, p.
+     135 (1880).
+
+     ? _Hydra rhaetica_, Asper, Zool. Anz. 1880, p. 204, figs.
+     1-3.
+
+     _Hydra vulgaris_, Jickeli (_nec_ Pallas), Morph. Jahrb.
+     viii, p. 391, pl. xviii, fig. 3 (1882).
+
+     _Hydra fusca_, Nussbaum, Arch. mikr. Anat. Bonn, xxix, p.
+     273, pl. xiv, figs. 34-36, pl. xv, figs. 48-51, &c. (1887).
+
+     _Hydra fusca_, Brauer, Zeit. wiss. Zool. Leipzig, lii, p.
+     177, pl. xi, figs. 2, 5, 6; pl. xii, fig. 6 (1891).
+
+     _Hydra_ sp. ? _id._, _ibid._ pl. xi, figs. 3, 3a, 4, 7, 8;
+     pl. xii, figs. 1, 2, 5-13.
+
+     _Hydra fusca_, Chun in Broenn's Thier-Reichs, ii (2), pl. ii,
+     figs. 2(_a_), 4, 6 (1892).
+
+     _Hydra monoecia_, Downing, Science* (5) xii, p. 228.
+
+     _Hydra fusca_, _id._, Zool. Jahrb. (Anat.) xxi, p. 382
+     (1905).
+
+     _Hydra dioecia_, _id._, _ibid._ pl. xxiii, figs. 6, 7, &c.
+
+     _Hydra fusca_, Hertwig, Biol. Centralbl. xxvi, p. 489
+     (1906).
+
+     _Hydra oligactis_, Brauer, Zool. Anz. xxxiii, p. 792, fig. 2
+     (1908).
+
+     _Hydra polypus_, _id._, _ibid._
+
+     _Hydra fusca_, Frischholz, Ann. Zool. (Wuerzburg), iii, p.
+     114, figs. 2-9 (1909).
+
+     _Hydra oligactis_, Brauer, Suesswasserfauna Deutschl. xix, p.
+          193, figs. 339-341 (1909).
+
+     _Hydra polypus_, _id._, _ibid._ figs. 342-344.
+
+This species differs from _H. vulgaris_ in the following characters:--
+
+     (1) Even when the gastral cavity is empty, the basal part of
+     the column is distinctly more slender than the upper part;
+     (2) even when the animal is at rest, the tentacles are much
+     longer than the column;
+     (3) the nettle-cells of both types are usually smaller and
+     more uniform in size than in the other species; those with
+     barbed threads (fig. 27, p. 131) are always flask-shaped and
+     somewhat narrower in proportion to their length, while those
+     with simple threads are pointed or almost pointed at their
+     distal end;
+     (4) the stinging threads of the more complex form are
+     comparatively stout and short;
+     (5) there are comparatively few nettle-cells in the column;
+     (6) the egg-shell is nearly smooth or covered more or less
+     completely with short, simple spines (fig. 28, p. 137).
+
+_H. oligactis_ is usually a more vigorous form than _H. vulgaris_ and,
+in spite of its name, has often a considerable number of tentacles. The
+few Indian specimens examined have, however, been small and have not had
+more than six tentacles. I have not seen an Indian specimen with more
+than two buds, but European specimens sometimes produce a great many,
+and as the daughter buds do not always separate from the parent until
+they have themselves produced buds, temporary colonies of some
+complexity arise; Chun figures a specimen with nineteen daughter and
+granddaughter buds[AV].
+
+     [Footnote AV: Pallas writes as regards this "pulcherrime
+     vegetantem varietatem" with his usual critical insight, "Vix
+     tamen peculiaris speciei nomine salutanda videtur." It is
+     probably the _Hydra socialis_ of Linne.]
+
+In Europe and N. America there appear to be two races or phases of the
+species. To avoid ambiguity they may be called form A and form B and
+described as follows:--
+
+   Form A is of vigorous growth. It is as a rule dioecious, and
+     its reproductive organs may be borne practically at any
+     level on the surface of the column. Its eggs are spherical
+     and as a rule covered almost uniformly with spines.
+
+   Form B is smaller and has smaller and more variable
+     nettle-cells. Its reproductive organs are borne only on the
+     distal third or at the base of its column and it is often
+     monoecious. The lower surface of its egg is flattened,
+     adherent, and devoid of spines.
+
+The larger form (A) was originally named _Hydra monoecia_ by Downing,
+who in 1904 expressed a wish to substitute for the specific name, which
+had been given through inadvertence, the more appropriate one _dioecia_.
+As, however, it appears to be the commoner of the two in northern
+Europe, we may regard it as probably being the one named _Hydra
+oligactis_ by Pallas and therefore may accept it as the _forma typica_
+of that species. According to Brauer (1908) the smaller form is Linne's
+_Hydra polypus_; but the original description of the "species" hardly
+bears out this view. As reproductive organs have not yet been found in
+Indian specimens, it is impossible to say to which of the two forms they
+belong.
+
+A red form of _H. oligactis_ occurs in Tibet in the lake Rham-tso, at an
+altitude of about 15,000 feet and has been reported from various small
+lakes in mountainous parts of Europe. It is probably the form called
+_Hydra rhaetica_ by Asper, but his figures are lacking in detail and
+appear to have been drawn from specimens in a state of partial
+contraction. _H. rubra_, Lewes (Ann. Mag. Nat. Hist. (3) v, p. 71,
+1860), may also be identical with this form. Roux, indeed, states that
+_H. rubra_ is only found living unattached at considerable depths (Ann.
+Biol. lacustre ii, p. 266, 1907); but this statement does not accord
+with the fact that Lewes's specimens were found in ponds on Wimbledon
+Common.
+
+TYPE not in existence.
+
+GEOGRAPHICAL DISTRIBUTION.--_H. oligactis_ is widely distributed in
+Europe and N. America, but in India has only been found in and near the
+city of Lahore in the Punjab.
+
+BIOLOGY.--This species was found by Major J. Stephenson, I.M.S., in the
+basin of a fountain at Lahore and in an ornamental canal in the Shalimar
+Gardens on the outskirts of the same city. Nothing is known as regards
+its habits in this country. In N. America, according to Downing, form B
+breeds in September and October and form A from October to December. The
+eggs of form B remain attached to the parent until the two cellular
+layers are formed and then drop off, whereas those of form A are fixed
+by the parent to some extraneous object, its column contracting until
+they are in a favourable position for attachment.
+
+The colour of Indian examples of _H. oligactis_ apparently resembles
+that of the Calcutta winter brood of _H. vulgaris_ so far as visual
+effect is concerned, but I have noticed in specimens from Lahore and the
+neighbourhood that very minute spherical bodies of a dark green colour
+are present in the endoderm cells.
+
+
+
+
+  PART III.
+
+  FRESHWATER POLYZOA
+
+  (CTENOSTOMATA & PHYLACTOLAEMATA).
+
+
+
+
+INTRODUCTION TO PART III.
+
+
+I.
+
+STATUS AND STRUCTURE OF THE POLYZOA.
+
+The Polyzoa constitute a class in the third great division of the animal
+kingdom, the so-called Triploblastea. In this division are included also
+the worms, molluscs, insects, crustacea, spiders, vertebrates, etc.; for
+heterogeneous as its elements appear, all these animals may be
+considered to have essential features in common, in particular a body
+consisting primarily of three cellular layers. Most of them also possess
+a body cavity distinct from the alimentary canal. Some authors regard
+the position of the polyzoa as near that of the higher worms, but the
+group is an isolated one.
+
+In considering the anatomy of simple forms of animal life such as the
+sponges it is necessary to pay attention mainly to individual cells, but
+in discussing more complicated forms our notice is first attracted to
+tissues and organs, for the cells of which these tissues and organs are
+composed have each a definite position, a definite structure, and a
+definite function. The most characteristic feature of the polyzoa,
+considered from this point of view, is the fact that most of their
+organs fall into one of two categories and are connected either with
+what is called the "zooecium" or with what is known as the "polypide."
+The zooecium is a cage in which the polypide is enclosed, but it is a
+living cage, differing from the shell of a snail or the tubes in which
+many worms encase themselves in being part of the animal itself. The
+polypide consists mainly of the organs connected directly and indirectly
+with nutrition and of part of the muscular system; its name is derived
+from the fact that it bears a superficial resemblance to a polyp such as
+_Hydra_.
+
+The shape and structure of the zooecium differs greatly in different
+groups of polyzoa. In its simplest form it is merely a cylindrical tube
+of living matter which secretes an outer horny or gelatinous covering.
+It is open at the end furthest from its base, at which it is attached
+either to another zooecium or to some kind of supporting structure.
+Certain parts of the polypide can always be extruded from the aperture,
+which is known technically as the "orifice," or withdrawn through it
+into the zooecium. When the polypide is retracted it draws in with it a
+portion of the zooecium. The dead outer layer or ectocyst lines part of
+the portion thus invaginated and forms the walls of a cavity within the
+orifice. The base of this cavity consists in many forms of a transverse
+partition pierced in the middle by a circular hole and known as the
+"diaphragm." The diaphragm, however, does not constitute the limit of
+the invaginated portion of the zooecium, for the living inner wall or
+endocyst is dragged in still further and forms a sheath round the
+retracted tentacles. When the tentacles are protruded they emerge
+through the hole in the diaphragm, carrying with them their sheath of
+endocyst. The invagination above the diaphragm, consisting of both
+endocyst and ectocyst, is then everted.
+
+The tentacles are a characteristic feature of the polypide. Together
+with the base to which they are attached they are known as the
+"lophophore"; they surround the mouth, usually in a circle. They differ
+widely from the tentacles of _Hydra_ in both structure and function,
+although they too serve as organs for the capture of prey; they are not
+highly contractile and are not provided with nettle-cells but are
+covered with cilia, which are in constant motion. When extruded they
+form a conspicuous calix-like crown to the zooecium, but in the
+retracted condition they are closely pressed together and lie parallel
+to one another. They are capable individually of motion in all
+directions but, although they usually move in concert, they cannot as a
+rule seize objects between them.
+
+The mouth is a hole situated in the midst of the tentacles. It leads
+directly into a funnel-shaped oesophagus, the upper part of which is
+lined with cilia and is sometimes distinguished as the "pharynx," while
+the lower part, the oesophagus proper, is a thin-walled tube that
+connects the pharynx with the stomach, which it enters on the dorsal
+side. The stomach is a bulky organ that differs markedly in form and
+structure in different groups of polyzoa. It is lined internally with
+glandular cells and the inner wall is sometimes thrown into folds or
+"rugae." The part with which the oesophagus communicates is known as the
+"cardiac" portion, while the part whence the intestine originates is
+called the "pylorus" or "pyloric" portion. The intestine commences on
+the ventral side opposite the entrance of the oesophagus and nearly on a
+level with it, the bulk of the stomach depending between the two tubes.
+This part of the stomach is often produced into a blind tube, the fundus
+or caecum. The alimentary canal may therefore be described as distinctly
+Y-shaped. The proximal part of the intestine is in some forms lined with
+cilia, and the tube as a whole is usually divided into two parts--the
+intestine proper, which is nearest the stomach, and the rectum, which
+opens by the anus not far from the mouth.
+
+The nervous system consists of a central ganglion or brain, which is
+situated at the base of the tentacles on the side nearest the anus and
+gives out radiating nerves in all directions. Close to the brain and
+providing a communication between the cavity of the zooecium and the
+cavity in which the tentacles are contained (or, in the case of an
+expanded polyp, the external world) is a ciliated tube known as the
+"intertentacular organ." Apparently it acts as a passage through which
+the genital products are expelled; but contradictory statements have
+been made regarding it, and perhaps it is present only at certain
+seasons or in certain conditions of the polypide.
+
+[Illustration: Fig. 30.--Vertical section through a polypide of
+_Alcyonidium_ with the polypide retracted (after Prouho).
+
+A=orifice; B=contracted collar; C=diaphragm; D=parieto-vaginal muscles;
+E=tentacles; F=pharynx; G=oesophagus; H=stomach; J=intestine; K=rectum;
+L=intertentacular organ; M=retractor muscle; N=testes; O=ovary;
+P=funiculus; Q=parietal muscles; R=ectocyst; S=endocyst.]
+
+The muscular system is often of a complicated nature, but three sets of
+muscles may be distinguished as being of peculiar importance, viz., (i)
+the retractor muscles, which are fixed to the base of the lophophore at
+one end and to the base of the zooecium at the other, and by contracting
+pull the former back into the zooecium; (ii) the parieto-vaginal
+muscles, which connect the upper part of the invaginated portion of the
+zooecium with the main wall thereof; and (iii) the parietal muscles,
+which run round the inner wall of the zooecium and compress the zooecium
+as a whole. The parietal muscles are not developed in the
+Phylactolaemata, the most highly specialized group of freshwater polyzoa.
+
+The cavity between the polypide and the zooecium contains a reticulate
+tissue of cells known as the "funicular" tissue, and this tissue is
+usually concentrated to form a hollow strand or strands ("funiculi")
+that connect the outer wall of the alimentary canal with the endocyst.
+
+This rapid sketch of the general anatomy of a simple polyzoon will be
+the best understood by comparing it with fig. 30, which represents, in a
+somewhat diagrammatic fashion, a vertical section through a single
+zooecium and polypide of the order Ctenostomata, to which some of the
+freshwater species belong. The polypide is represented in a retracted
+condition in which the Y-shaped disposition of the alimentary canal is
+somewhat obscured.
+
+In the great majority of cases the polyzoa form permanent colonies or
+polyparia, each of which consists of a number of individual zooecia and
+polypides connected together by threads of living tissue. These colonies
+are formed by budding, not by independent individuals becoming
+associated together. In a few cases compound colonies are formed owing
+to the fact that separate simple colonies congregate and secrete a
+common investment; but in these cases there is no organic connection
+between the constituent colonies. It is only in the small subclass
+Entoprocta, the polypides and zooecia of which are not nearly so
+distinct from one another as they are in other polyzoa (the Ectoprocta),
+that mature solitary individuals occur.
+
+As representatives of both subclasses of polyzoa and of more than one
+order of Ectoprocta occur in fresh water, I have prefaced my description
+of the Indian species with a synopsis of the more conspicuous characters
+of the different groups (pp. 183-186).
+
+
+CAPTURE AND DIGESTION OF FOOD: ELIMINATION OF WASTE PRODUCTS.
+
+The food of all polyzoa consists of minute living organisms, but its
+exact nature has been little studied as regards individual species and
+genera. In _Victorella bengalensis_ it consists largely of diatoms,
+while the species of _Hislopia_ and _Arachnoidea_ possess an alimentary
+canal modified for the purpose of retaining flagellate organisms until
+they become encysted. Similar organisms form a large part of the food of
+the phylactolaemata.
+
+Although the tentacles may be correctly described as organs used in
+capturing prey, they do not themselves seize it but waft it by means of
+the currents set up by their cilia to the mouth, into which it is swept
+by the currents produced by the cilia lining the pharynx. The tentacles
+are also able in some species to interlace themselves in order to
+prevent the escape of prey. Apparently they have the power of rejecting
+unsuitable food, for they may often be observed to bend backwards and
+forwards and thrust particles that have approached them away, and if the
+water contains anything of a noxious nature in solution the lophophore
+is immediately retracted, unless it has been completely paralysed. In
+the phylactolaemata the peculiar organ known as the epistome is capable
+of closing the mouth completely, and probably acts as an additional
+safeguard in preventing the ingestion of anything of an injurious
+nature.
+
+In many genera and larger groups the food commonly passes down the
+pharynx into the stomach without interruption, although it is probable
+that in all species the oesophagus can be closed off from the stomach by
+a valve at its base. In some forms, however, a "gizzard" is interposed
+between the oesophagus and the stomach. This gizzard has not the same
+function in all cases, for whereas in some forms (_e. g._, in
+_Bowerbankia_) it is lined with horny projections and is a powerful
+crushing organ, in others (_e. g._, in _Hislopia_ or _Victorella_) it
+acts as an antechamber in which food can be preserved without being
+crushed until it is required for digestion, or rough indigestible
+particles can be retained which would injure the delicate walls of the
+stomach.
+
+Digestion takes place mainly in the stomach, the walls of which are of a
+glandular nature. The excreta are formed into oval masses in the rectum
+and are extruded from the anus in this condition.
+
+Although the gross non-nutritious parts of the food are passed _per
+anum_, the waste products of the vital processes are not eliminated so
+easily, and a remarkable process known as the formation of brown bodies
+frequently takes place. This process cannot be described more clearly
+and succinctly than by quoting Dr. Harmer's description of it from pp.
+471 and 472 of vol. ii. of the Cambridge Natural History, a volume to
+which I have been much indebted in the preparation of this introduction.
+The description is based very largely on Dr. Harmer's own
+observations[AW].
+
+     [Footnote AW: Q. J. Micr. Sci. xxxiii, p. 123 (1892).]
+
+"The tentacles, alimentary canal, and nervous system break down, and the
+tentacles cease to be capable of being protruded. The degenerating
+organs become compacted into a rounded mass, known from its colour as
+the 'brown body.' This structure may readily be seen in a large
+proportion of the zooecia of transparent species. In active parts of the
+colony of the body-wall next develops an internal bud-like structure,
+which rapidly acquires the form of a new polypide. This takes the place
+originally occupied by the old polypide, while the latter may either
+remain in the zooecium in the permanent form of a 'brown body,' or pass
+to the exterior. In _Flustra_ the young polypide-bud becomes connected
+with the 'brown body' by a funiculus. The apex of the blind pouch or
+'caecum' of the young stomach is guided by this strand to the 'brown
+body,' which it partially surrounds. The 'brown body' then breaks up,
+and its fragments pass into the cavity of the stomach, from which they
+reach the exterior by means of the anus."
+
+Brown bodies are rarely if ever found in the phylactolaemata, in which
+the life of the colony is always short; but they are not uncommon in
+_Hislopia_ and _Victorella_, although in the case of the former they may
+easily escape notice on account of the fact that they are much paler in
+colour than is usually the case. When they are found in a ctenostome the
+collar-like membrane characteristic of the suborder is extruded from the
+orifice (which then disappears) and remains as a conspicuous external
+addition to the zooecium, the ectocyst of which, at any rate in
+_Bowerbankia_ and _Victorella_, sometimes becomes thickened and dark in
+colour.
+
+It is noteworthy that the colouring matter of the brown bodies is
+practically the only colouring matter found in the polypides of most
+polyzoa. Young polypides are practically colourless in almost all cases.
+
+
+REPRODUCTION: BUDDING.
+
+Polyzoa reproduce their species in three ways--(i) by means of eggs,
+(ii) by budding, and (iii) by means of bodies developed asexually and
+capable of lying dormant in unfavourable conditions without losing their
+vitality.
+
+Most, if not all species are hermaphrodite, eggs and spermatozoa being
+produced either simultaneously or in succession by each individual, or
+by certain individuals in each zoarium. The reproductive organs are
+borne on the inner surface of the endocyst, as a rule in a definite
+position, and often in connection with the funiculus or funiculi. It is
+doubtful to what extent eggs are habitually fertilized by spermatozoa of
+the individual that has borne them, but in some cases this is
+practically impossible and spermatozoa from other individuals must be
+introduced into the zooecium.
+
+Budding as a rule does not result in the formation of independent
+organisms, but is rather comparable to the proliferation that has become
+the normal method of growth in sponges, except of course that
+individuality is much more marked in the component parts of a polyzoon
+colony than it is in a sponge. In the genera described in this volume
+budding takes place by the outgrowth of a part of the body-wall and the
+formation therein of a new polypide, but the order in which the buds
+appear and their arrangement in reference to the parent zooecium is
+different in the different groups. In the freshwater ctenostomes three
+buds are typically produced from each zooecium, one at the anterior end
+and one at either side, the two latter being exactly opposite one
+another. The parent zooecium in this formation arises from another
+zooecium situated immediately behind it, so that each zooecium, except
+at the extremities of the zoarium, is connected with four other zooecia,
+the five together forming a cross. The two lateral buds are, however,
+frequently suppressed, or only one of them is developed, and a linear
+series of zooecia with occasional lateral branches is formed instead of
+a series of crosses. In the phylactolaemata, on the other hand, the
+linear method of budding is the typical one, but granddaughter-buds are
+produced long before the daughter-buds are mature, so that the zooecia
+are frequently pressed together, and lateral buds are produced
+irregularly. In _Victorella_ additional adventitious buds are produced
+freely near the tip of the zooecium.
+
+Reproduction by spontaneous fission sometimes occurs, especially in the
+Lophopinae, but the process differs from that which takes place when a
+_Hydra_ divides into two, for there is no division of individual zooecia
+or polypides but merely one of the whole zoarium.
+
+The production of reproductive bodies analogous to the gemmules of
+sponges appears to be confined in the polyzoa to the species that
+inhabit fresh or brackish water, nor does it occur in all of these.
+
+All the phylactolaemata produce, within their zooecia, the bodies known
+as statoblasts. These bodies consist essentially of masses of cells
+containing abundant food-material and enclosed in a capsule with thick
+horny walls. In many cases the capsule is surrounded by a "swim-ring"
+composed of a mass of horny-walled chambers filled with air, which
+renders the statoblast extremely light and enables it to float on the
+surface of the water; while in some genera the margin of the swim-ring
+bears peculiar hooked processes, the function of which is obscure. The
+whole structure first becomes visible as a mass of cells (the origin of
+all of which is not the same) formed in connection with the funiculus,
+and the statoblast may be regarded as an internal bud. Its origin and
+development in different genera has been studied by several authors,
+notably by Oka[AX] in _Pectinatella_, and by Braem[AY] in _Cristatella_.
+
+     [Footnote AX: Journ. Coll. Sci. Tokyo, iv, p. 124 (1891).]
+
+     [Footnote AY: Bibliotheca Zoologica, ii, pt. 6, p. 17
+     (1890).]
+
+The external form of the statoblasts is very important in the
+classification of the phylactolaemata, to which these structures are
+confined. In all the genera that occur in India they are flattened and
+have an oval, circular, or approximately oval outline.
+
+In temperate climates statoblasts are produced in great profusion at the
+approach of winter, but in India they occur, in most species, in
+greatest numbers at the approach of the hot weather.
+
+[Illustration: Fig. 31.--Part of the zoarium of _Victorella bengalensis_
+entirely transformed into resting buds, x 25. (From an aquarium in
+Calcutta.)]
+
+In the family Paludicellidae (ctenostomata) external buds which resemble
+the statoblasts in many respects are produced at the approach of
+unfavourable climatic conditions, but no such buds are known in the
+family Hislopiidae, the zoaria of which appear to be practically
+perennial. The buds consist of masses of cells formed at the points at
+which ordinary buds would naturally be produced, but packed with
+food-material and protected like statoblasts by a thick horny coat. It
+seems also that old zooecia and polypides are sometimes transformed into
+buds of the kind (fig. 31), and it is possible that there is some
+connection between the formation of brown bodies and their production.
+Like the statoblasts of the phylactolaemata the resting buds of the
+Paludicellidae are produced in Europe at the approach of winter, and in
+India at that of the hot weather.
+
+
+DEVELOPMENT.
+
+(a) _From the Egg._
+
+Some polyzoa are oviparous, while in others a larva is formed within the
+zooecium and does not escape until it has attained some complexity of
+structure. Both the ctenostomatous genera that are found in fresh water
+in India are oviparous, but whereas in _Victorella_ the egg is small and
+appears to be extruded soon after its fertilization, in _Hislopia_ it
+remains in the zooecium for a considerable time, increases to a
+relatively large size, and in some unknown manner accumulates a
+considerable amount of food-material before escaping. Unfortunately the
+development is unknown in both genera.
+
+In the phylactolaemata the life-history is much better known, having been
+studied by several authors, notably by Allman, by Kraepelin, and by
+Braem (1908). The egg is contained in a thin membrane, and while still
+enclosed in the zooecium, forms by regular division a hollow sphere
+composed of similar cells. This sphere then assumes an ovoid form,
+becomes covered with cilia externally, and breaks its way through the
+egg-membrane into the cavity of the zooecium. Inside the embryo, by a
+process analogous to budding, a polypide or a pair of polypides is
+formed. Meanwhile the embryo has become distinctly pear-shaped, the
+polypide or polypides being situated at its narrow end, in which a pore
+makes its appearance. The walls are hollow in the region occupied by the
+polypide, the cavity contained in them being bridged by slender threads
+of tissue. The larva thus composed makes its way out of the zooecium,
+according to Kraepelin through the orifice of a degenerate bud formed
+for its reception, and swims about for a short time by means of the
+cilia with which it is covered. Its broad end then affixes itself to
+some solid object, the polypide is everted through the pore at the
+narrow end and the whole of that part of the larva which formerly
+enclosed it is turned completely inside out. A zoarium with its included
+polypides is finally produced from the young polypide by the rapid
+development of buds.
+
+(b) _From the Statoblast and Resting Buds._
+
+There is little information available as regards the development of the
+young polyzoon in the resting buds of the freshwater ctenostomes. In
+_Paludicella_ and _Pottsiella_ the capsule of the bud splits
+longitudinally into two valves and the polypide emerges between them;
+but in _Victorella bengalensis_ one of the projections on the margin of
+the bud appears to be transformed directly into the tip of a new
+zooecium and the capsule is gradually absorbed.
+
+Contradictory statements have been made as regards several important
+points in the development of the statoblast and it is probable that
+considerable differences exist in different species. The following facts
+appear to be of general application. The cellular contents of the
+capsule consist mainly of a mass of cells packed with food-material in a
+granular form, the whole enclosed in a delicate membrane formed of flat
+cells. When conditions become favourable for development a cavity
+appears near one end of the mass and the cells that form its walls
+assume a columnar form in vertical section. The cavity increases rapidly
+in size, and, as it does so, a young polypide is budded off from its
+walls. Another bud may then appear in a similar fashion, and the
+zooecium of the first bud assumes its characteristic features. The
+capsule then splits longitudinally into two disk-like valves and the
+young polypide, in some cases already possessing a daughter bud, emerges
+in its zooecium, adheres by its base to some external object and
+produces a new polyparium by budding. The two valves of the statoblast
+often remain attached to the zoarium that has emerged from between them
+until it attains considerable dimensions (see Plate IV, fig. 3 _a_).
+
+What conditions favour development is a question that cannot yet be
+answered in a satisfactory manner. Statoblasts can lie dormant for
+months and even for years without losing their power of germinating, and
+it is known that in Europe they germinate more readily after being
+subjected to a low temperature. In tropical India this is, of course, an
+impossible condition, but perhaps an abnormally high temperature has the
+same effect. At any rate it is an established fact that whereas the
+gemmules of most species germinate in Europe in spring, in Bengal they
+germinate either at the beginning of the "rains" or at that of our mild
+Indian winter.
+
+
+MOVEMENTS.
+
+[Illustration: Fig. 32.--Zoarium of _Lophopodella carteri_ moving along
+the stem of a water plant, x 4. (From Igatpuri Lake.)]
+
+In the vast majority of the polyzoa, marine as well as freshwater,
+movement is practically confined to the polypide, the external walls of
+the zooecium being rigid, the zooecia being closely linked together and
+the whole zoarium permanently fixed to some extraneous object. In a few
+freshwater species belonging to the genera _Cristatella_, _Lophopus_,
+_Lophopodella_ and _Pectinatella_, the whole zoarium has the power of
+progression. This power is best developed in _Cristatella_, which glides
+along with considerable rapidity on a highly specialized "sole" provided
+with abundant mucus and representing all that remains of the ectocyst.
+It is by no means clear how the zoaria of the other genera move from one
+place to another, for the base is not modified, so far as can be seen,
+for the purpose, and the motion is extremely slow. It is probable,
+however, that progression is effected by alternate expansions and
+contractions of the base, and in _Lophopodella_ (fig. 32), which moves
+rather less slowly than its allies, the anterior part of the base is
+raised at times from the surface along which it is moving. The whole
+zoarium can be released in this way and occasionally drops through the
+water, and is perhaps carried by currents from one place to another in
+so doing.
+
+So far as the polypides are concerned, the most important movements are
+those which enable the lophophore and the adjacent parts to be extruded
+from and withdrawn into the zooecium. The latter movement is executed by
+means of the retractor muscles, which by contracting drag the extruded
+parts back towards the posterior end of the endocyst, but it is not by
+any means certain how the extrusion of the lophophore is brought about.
+In most ctenostomes the action of the parietal muscles doubtless assists
+in squeezing it out when the retractor and parieto-vaginal muscles
+relax, but Oka states that protrusion can be effected in the
+phylactolaemata even after the zooecium has been cut open. Possibly some
+hydrostatic action takes place, however, and allowance must always be
+made for the natural resilience of the inverted portion of the ectocyst.
+
+Even when the polypide is retracted, muscular action does not cease, for
+frequent movements, in some cases apparently rhythmical, of the
+alimentary canal may be observed, and in _Hislopia_ contraction of the
+gizzard takes place at irregular intervals.
+
+When the lophophore is expanded, the tentacles in favourable
+circumstances remain almost still, except for the movements of their
+cilia; but if a particle of matter too large for the mouth to swallow or
+otherwise unsuitable is brought by the currents of the cilia towards it,
+individual tentacles can be bent down to wave it away and similar
+movements are often observed without apparent cause.
+
+In the cheilostomes certain individuals of each zoarium are often
+profoundly modified in shape and function and exhibit almost constant
+rhythmical or convulsive movements, some ("avicularia") being shaped
+like a bird's beak and snapping together, others ("vibracula") being
+more or less thread-like and having a waving motion.
+
+
+DISTRIBUTION OF THE FRESHWATER POLYZOA.
+
+Fifteen genera of freshwater Polyzoa are now recognized, one
+entoproctous and fourteen ectoproctous; five of the latter are
+ctenostomatous and nine phylactolaematous. Of the fourteen ectoproctous
+genera seven are known to occur in India, viz., _Victorella_,
+_Hislopia_, _Fredericella_, _Plumatella_, _Stolella_, _Lophopodella_,
+and _Pectinatella_. Except _Stolella_, which is only known from northern
+India, these genera have an extremely wide geographical range;
+_Victorella_ occurs in Europe, India, Africa, and Australia; _Hislopia_
+in India, Indo-China, China, and Siberia; _Fredericella_ in Europe, N.
+America, Africa, India, and Australia; _Plumatella_ in all geographical
+regions; _Lophopodella_ in E. and S. Africa, India, and Japan;
+_Pectinatella_ in Europe, N. America, Japan, and India.
+
+Two genera, _Paludicella_ and _Lophopus_, have been stated on
+insufficient grounds to occur in India. The former is known from Europe
+and N. America, and is said to have been found in Australia, while the
+latter is common in Europe and N. America and also occurs in Brazil.
+
+Of the genera that have not been found in this country the most
+remarkable are _Urnatella_ and _Cristatella_. The former is the only
+representative in fresh water of the Entoprocta and has only been found
+in N. America. Each individual is borne upon a segmented stalk the
+segments of which are enclosed in strong horny coverings and are
+believed to act as resting buds. _Cristatella_, which is common in
+Europe and N. America, is a phylactolaematous genus of highly specialized
+structure. It possesses a creeping "sole" or organ of progression at the
+base of the zoarium.
+
+The other phylactolaematous genera that do not occur in India appear to
+be of limited distribution, for _Australella_ is only known from N. S.
+Wales, and _Stephanella_ from Japan. The ctenostomatous _Arachnoidea_
+has only been reported from Lake Tanganyika, and _Pottsiella_ only from
+a single locality in N. America.
+
+As regards the exotic distribution of the Indian species little need be
+said. The majority of the _Plumatellae_ are identical with European
+species, while the only species of _Fredericella_ that has been
+discovered is closely allied to the European one. The Indian species of
+_Lophopodella_ occurs also in E. Africa and Japan, while that of
+_Pectinatella_ is apparently confined to India, Burma and Ceylon, but is
+closely allied to a Japanese form.
+
+
+POLYZOA OF BRACKISH WATER.
+
+With the exception of _Victorella_, which occurs more commonly in
+brackish than in fresh water and has been found in the sea, the genera
+that occur in fresh water are confined or practically confined to that
+medium; but certain marine ctenostomes and cheilostomes not uncommonly
+make their way, both in Europe and in India, into brackish water, and in
+the delta of the Ganges an entoproctous genus also does so. The
+ctenostomatous genera that are found occasionally in brackish water
+belong to two divisions of the suborder, the Vesicularina and the
+Alcyonellea. To the former division belongs _Bowerbankia_, a form of
+which (_B. caudata_ subsp. _bengalensis_, p. 187) is often found in the
+Ganges delta with _Victorella bengalensis_. No species of Alcyonellea
+has, however, as yet been found in Indian brackish waters. The two
+Indian cheilostomes of brackish water belong to a genus (_Membranipora_)
+also found in similar situations in Europe. One of them (_M.
+lacroixii_[AZ]) is, indeed, identical with a European form that occurs
+in England both in the sea and in ditches of brackish water. I have
+found it in the Cochin backwaters, in ponds of brackish water at the
+south end of the Chilka Lake (Ganjam, Madras), on the shore at Puri in
+Orissa, and in the Mutlah River at Port Canning. The second species (_M.
+bengalensis_, Stoliczka) is peculiar to the delta of the Ganges[BA] and
+has not as yet been found in the open sea. The two species are easily
+recognized from one another, for whereas the lip of _M. bengalensis_
+(fig. 33) bears a pair of long forked spines, there are no such
+structures on that of _M. lacroixii_, the dorsal surface of which is
+remarkably transparent. _M. lacroixii_ forms a flat zoarium, the only
+part visible to the naked eye being often the beaded margin of the
+zooecia, which appears as a delicate reticulation on bricks, logs of
+wood, the stems of rushes and of hydroids, etc.; but the zoarium of _M.
+bengalensis_ is as a rule distinctly foliaceous and has a peculiar
+silvery lustre.
+
+     [Footnote AZ: There is some doubt as to the proper name of
+     this species, which may not be the one originally described
+     as _Membranipora lacroixii_ by Andouin. I follow Busk and
+     Hincks in my identification (see Cat. Polyzoa Brit. Mus. ii,
+     p. 60, and Hist. Brit. Polyzoa, p. 129). Levinsen calls it
+     _M. hippopus_, sp. nov. (see Morphological and Systematic
+     Studies on the Cheilostomatous Bryozoa, p. 144; Copenhagen,
+     1909).]
+
+     [Footnote BA: Miss Thornely (Rec. Ind. Mus. i, p. 186, 1907)
+     records it from Mergui, but this is an error due to an
+     almost illegible label. The specimens she examined were the
+     types of the species from Port Canning. Since this was
+     written I have obtained specimens from Bombay--_April_,
+     1911.]
+
+[Illustration: Fig. 33.--Outline of four zooecia of _Membranipora
+bengalensis_, Stoliczka (from type specimen, after Thornely). In the
+left upper zooecium the lip is shown open.]
+
+_Loxosomatoides_[BB] (fig. 34), the Indian entoproctous genus found in
+brackish water, has not as yet been obtained from the open sea, but has
+recently been introduced, apparently from a tidal creek, into isolated
+ponds of brackish water at Port Canning. It is easily recognized by the
+chitinous shield attached to the ventral (posterior) surface.
+
+     [Footnote BB: Annandale, Rec. Ind. Mus. ii, p. 14 (1908).]
+
+[Illustration: Fig. 34.--_Loxosomatoides colonialis_, Annandale.
+
+A and B, a single individual of form A, as seen (A) in lateral, and (B)
+in ventral view; C, outline of a similar individual with the tentacles
+retracted, as seen from in front (dorsal view); D, ventral view of an
+individual and bud of form B. All the figures are from the type
+specimens and are multiplied by about 70.]
+
+
+II.
+
+HISTORY OF THE STUDY OF THE FRESHWATER POLYZOA.
+
+The naturalists of the eighteenth century were acquainted with more than
+one species of freshwater polyzoon, but they did not distinguish these
+species from the hydroids. Trembley discovered _Cristatella_, which he
+called "Polype a Panache," in 1741, and Linne described a species of
+_Plumatella_ under the name _Tubipora repens_ in 1758, while ten years
+later Pallas gave a much fuller description (under the name _Tubularia
+fungosa_) of the form now known as _Plumatella fungosa_ or _P. repens_
+var. _fungosa_. Although Trembley, Baker, and other early writers on the
+fauna of fresh water published valuable biological notes, the first
+really important work of a comprehensive nature was that of Dumortier
+and van Beneden, published in 1848. All previous memoirs were, however,
+superseded by Allman's Monograph of the Fresh-Water Polyzoa, which was
+issued in 1857, and this memoir remains in certain respects the most
+satisfactory that has yet been produced. In 1885 Jullien published a
+revision of the phylactolaemata and freshwater ctenostomes which is
+unfortunately vitiated by some curious lapses in observation, but it is
+to Jullien that the recognition of the proper position of _Hislopia_ is
+due. The next comprehensive monograph was that of Kraepelin, which
+appeared in two parts (1887 and 1892) in the Abhandlungen des Naturwiss.
+Vereins of Hamburg. In its detailed information and carefully executed
+histological plates this work is superior to any that preceded it or has
+since appeared, but the system of classification adopted is perhaps less
+liable to criticism than that followed by Braem in his "Untersuchungen,"
+published in the Bibliotheca Zoologica in 1888.
+
+During the second half of the nineteenth century and the first decade of
+the twentieth several authors wrote important works on the embryology
+and anatomy of the phylactolaemata, notably Kraepelin, Braem, and Oka;
+but as yet the ctenostomes of fresh water have received comparatively
+little attention from anything but a systematic point of view.
+
+From all points of view both the phylactolaemata and the ctenostomes of
+Asia have been generally neglected, except in the case of the Japanese
+phylactolaemata, which have been studied by Oka. Although Carter made
+some important discoveries as regards the Indian forms, he did not
+devote to them the same attention as he did to the sponges. In the case
+of the only new genus he described he introduced a serious error into
+the study of the two groups by placing _Hislopia_ among the
+cheilostomes, instead of in its true position as the type genus of a
+highly specialized family of ctenostomes.
+
+For fuller details as to the history of the study of the freshwater
+Polyzoa the student may refer to Allman's and to Kraepelin's monographs.
+An excellent summary is given by Harmer in his chapter on the freshwater
+Polyzoa in vol. ii. of the Cambridge Natural History; and Loppens has
+recently (1908) published in the Annales de Biologie lacustre a concise
+survey of the systematic work that has recently been undertaken.
+Unfortunately he perpetuates Carter's error as regards the position of
+_Hislopia_.
+
+
+BIBLIOGRAPHY OF THE FRESHWATER POLYZOA.
+
+A very full bibliography of the freshwater Polyzoa will be found in pt.
+i. of Kraepelin's "Die Deutschen Suesswasserbryozoen" (1887), while
+Loppens, in his survey of the known species (Ann. Biol. lacustre, ii,
+1908), gives some recent references. The following list contains the
+titles of some of the more important works of reference, of memoirs on
+special points such as reproduction and of papers that have a special
+reference to Asiatic species. Only the last section is in any way
+complete.
+
+(a) _Works of Reference._
+
+1847. VAN BENEDEN, "Recherches sur les Bryozoaires fluviatiles de
+Belgique," Mem. Ac. Roy. Belgique, xxi.
+
+1850. DUMORTIER and VAN BENEDEN, "Histoire Naturelle des Polypes
+composes d'eau douce," 2^e partie, Mem. Ac. Roy. Bruxelles, xvi
+(complement).
+
+1856. ALLMAN, "A Monograph of the Fresh-Water Polyzoa" (London).
+
+1866-1868. HYATT, "Observations on Polyzoa, suborder Phylactolaemata,"
+Comm. Essex Inst. iv, p. 197, v, p. 97.
+
+1880. HINCKS, "A History of the British Marine Polyzoa."
+
+1885. JULLIEN, "Monographie des Bryozoaires d'eau douce," Bull. Soc.
+zool. France, x, p. 91.
+
+1887 & 1892. KRAEPELIN, "Die deutschen Suesswasserbryozoen," Abhandl.
+Nat. Vereins Hamburg, x & xii.
+
+1890. BRAEM, "Untersuchungen des Bryozoen des suessen Wassers," Bibl.
+Zool. ii, Heft 6 (Cassel).
+
+1896. HARMER, Cambridge Natural History, ii, Polyzoa, chap. xviii.
+
+1899. KORSCHELT and HEIDER, "Embryology of Invertebrates," vol. ii,
+chap. xvi. (English edition by Bernard and Woodward, 1899.)
+
+1908. LOPPENS, "Les Bryozoaires d'eau douce," Ann. Biol. lacustre, iii.
+p. 141.
+
+(b) _Special Works on Embryology, etc._
+
+1875. NITSCHE, "Beitraege zur Kenntniss der Bryozoen," Zeitschr. f. wiss.
+Zool. xxv (supplement), p. 343.
+
+1880. REINHARD, "Zur Kenntniss der Suesswasser-Bryozoen," Zool. Anz. iii,
+p. 208.
+
+1888. BRAEM, "Untersuchungen ueber die Bryozoen des suessen Wassers,"
+Zool. Anz. xi, pp. 503, 533.
+
+1891. OKA, "Observations on Freshwater Polyzoa," J. Coll. Sci. Tokyo,
+iv, p. 89.
+
+1906. WILCOX, "Locomotion in young colonies of _Pectinatella
+magnifica_," Biol. Bull. Wood's Hole, ii.
+
+1908. BRAEM, "Die geschlechtliche Entwickelung von Fredericella sultana
+nebst Beobachtungen ueber die weitere Lebensgeschichte der Kolonien,"
+Bibl. Zool. xx, Heft 52.
+
+(c) _Papers that refer specifically to Asiatic species._
+
+1851. LEIDY described _Plumatella diffusa_ in Proc. Ac. Philad. v, p.
+261 (1851).
+
+1858. CARTER, "Description of a Lacustrine Bryozoon allied to
+_Flustra_," Ann. Nat. Hist. (3) i, p. 169.
+
+1859. CARTER, "On the Identify in Structure and Composition of the
+so-called Seed-like Body of _Spongilla_ with the Winter-egg of the
+Bryozoa: and the presence of Starch-granules in each," Ann. Nat. Hist.
+(3) iii, p. 331. (Statoblast of _Lophopodella_ described and figured.)
+
+1862. MITCHELL, "Freshwater Polyzoa," Q. J. Micr. Sci. (new series) ii,
+p. 61. ("_Lophopus_" recorded from Madras.)
+
+1866. HYATT, "Observations on Polyzoa, suborder Phylactolaemata," Comm.
+Essex Inst. iv, p. 197. ("_Pectinatella carteri_" named.)
+
+1869. STOLICZKA, "On the Anatomy of _Sagartia schilleriana_ and
+_Membranipora bengalensis_, a new coral and a bryozoon living in
+brackish water at Port Canning," J. As. Soc. Bengal, xxxviii, ii, p. 28.
+
+1880. JULLIEN, "Description d'un nouveau genre de Bryozoaire
+Cheilostomien des eaux douces de la Chine et du Cambodge et de deux
+especes nouvelles," Bull. Soc. zool. France, v, p. 77. ("_Norodonia_"
+described.)
+
+1885. JULLIEN, "Monographie des Bryozoaires d'eau douce," Bull. Soc.
+zool. France, x, p. 91. (_Hislopia_ assigned to the ctenostomes.)
+
+1887. KRAEPELIN, "Die deutschen Suesswasserbryozoen," Abh. Ver. Hamburg,
+x. (_Plumatella philippinensis._)
+
+1891. OKA, "Observations on Freshwater Polyzoa," J. Coll. Sci. Tokyo,
+iv, p. 89.
+
+1898. MEISSNER, "Die Moosthiere Ost-Afrikas," in Mobius's
+Deutsch-Ost-Afrika, iv. (_Lophopodella carteri_ recorded from E.
+Africa.)
+
+1901. KOROTNEFF, "Faunistische Studien am Baikalsee," Biol. Centrbl.
+xxi, p. 305. ("_Echinella_" described.)
+
+1904-1906. ROUSSELET, "On a new Freshwater Polyzoon from Rhodesia,
+_Lophopodella thomasi_, gen. et sp. nov.", J. Quekett Club (2) ix, p.
+45. (Genus _Lophopodella_ described.)
+
+1906. ANNANDALE, "Notes on the Freshwater Fauna of India. No. II. The
+Affinities of _Hislopia_," J. As. Soc. Bengal (new series) ii, p. 59.
+
+1906. KRAEPELIN, "Eine Suesswasser-bryozoe (_Plumatella_) aus Java,"
+Mitth. Mus. Hamburg, xxiii, p. 143.
+
+1907. ANNANDALE, "Notes on the Freshwater Fauna of India. No. XII. The
+Polyzoa occurring in Indian Fresh and Brackish Pools," J. As. Soc. Bengal
+(new series) iii, p. 83.
+
+1907. ANNANDALE, "Statoblasts from the surface of a Himalayan Pond,"
+Rec. Ind. Mus. i, p. 177.
+
+1907. ANNANDALE, "The Fauna of Brackish Ponds at Port Canning, Lower
+Bengal: I.--Introduction and Preliminary Account of the Fauna," Rec.
+Ind. Mus. i, p. 35.
+
+1907. ANNANDALE, "The Fauna of Brackish Ponds at Port Canning, Lower
+Bengal: VI.--Observations on the Polyzoa, with further notes on the
+Ponds," Rec. Ind. Mus. i, p. 197.
+
+1907. ANNANDALE, "Further Note on a Polyzoon from the Himalayas," Rec.
+Ind. Mus. i, p. 145.
+
+1907. ROUSSELET, "Zoological Results of the Third Tanganyika Expedition,
+conducted by Dr. W. A. Cunnington, 1904-1905.--Report on the Polyzoa,"
+P. Z. Soc. London, i, p. 250. (_Plumatella tanganyikae._)
+
+1907. OKA, "Eine dritte Art von _Pectinatella_ (_P. davenporti_, n.
+sp.)," Zool. Anz. xxxi, p. 716.
+
+1907. APSTEIN, "Das Plancton im Colombo-See auf Ceylon," Zool. Jahrb.
+(Syst.) xxv, p. 201. (_Plumatella_ recorded.)
+
+1907. WALTON, "Notes on _Hislopia lacustris_, Carter," Rec. Ind. Mus. i,
+p. 177.
+
+1907-1908. OKA, "Zur Kenntnis der Suesswasser-Bryozoenfauna von Japan,"
+Annot. Zool. Japon, vi, p. 117.
+
+1907-1908. OKA, "Ueber eine neue Gattung von Suesserwasserbryozoen,"
+Annot. Zool. Japon, vi, p. 277.
+
+1908. ANNANDALE, "The Fauna of Brackish Ponds at Port Canning, Lower
+Bengal: VII.--Further Observations on the Polyzoa with the description
+of a new genus of Entoprocta," Rec. Ind. Mus. ii, p. 11.
+
+1908. ANNANDALE, "Corrections as to the Identity of Indian
+Phylactolaemata," Rec. Ind. Mus. ii, p. 110.
+
+1908. ANNANDALE, "Three Indian Phylactolaemata," Rec. Ind. Mus. ii, p.
+169.
+
+1908. KIRKPATRICK, "Description of a new variety of _Spongilla
+loricata_, Weltner," Rec. Ind. Mus. ii, p. 97. (_Hislopia_ recorded from
+Burma.)
+
+1909. ANNANDALE, "Preliminary Note on a new genus of Phylactolaematous
+Polyzoa," Rec. Ind. Mus. iii, p. 279.
+
+1909. ANNANDALE, "A new species of _Fredericella_ from Indian Lakes,"
+Rec. Ind. Mus. iii. p. 373.
+
+1909. WALTON, "Large Colonies of _Hislopia lacustris_," Rec. Ind. Mus.
+iii, p. 295.
+
+1910. ANNANDALE, "Materials for a Revision of the Phylactolaematous
+Polyzoa of India," Rec. Ind. Mus. v, p. 37.
+
+1911. WEST and ANNANDALE, "Descriptions of Three Species of Algae
+associated with Indian Freshwater Polyzoa," J. As. Soc. Bengal
+(_ined._).
+
+
+
+
+GLOSSARY OF TECHNICAL TERMS USED IN PART III.
+
+
+  _Brown body_            A body formed in a zooecium by the degeneration
+                          of a polypide as a preparation
+                          for its regeneration.
+
+  _Cardiac portion_ (of   That part which communicates with the
+   the stomach).          oesophagus.
+
+  _Collar_                A longitudinally pleated circular membrane
+                          capable of being thrust out of the orifice
+                          in advance of the lophophore and of
+                          closing together inside the zooecium above
+                          the tentacles when they are retracted.
+
+  _Dorsal surface_        (_Of zooecium_ or _polypide_) the surface
+                          nearest the mouth; (_of statoblast_) the
+                          surface furthest from that by which the
+                          statoblast is attached to the funiculus
+                          during development.
+
+  _Ectocyst_              The outer, structureless layer of the zooecium.
+
+  _Emarginate_            Having a thin or defective triangular area
+  (of a zooecium)         in the ectocyst at the tip.
+
+  _Endocyst_              The inner, living (cellular) layer of the
+                          zooecium.
+
+  _Epistome_              A leaf-like ciliated organ that projects
+                          upwards and forwards over the mouth
+                          between it and the anus.
+
+  _Funiculus_             A strand of tissue joining the alimentary
+                          canal to the endocyst.
+
+  _Furrowed_              Having a thin or defective longitudinal
+  (of a zooecium)         linear streak in the ectocyst on the dorsal
+                          surface.
+
+  _Gizzard_               A chamber of the alimentary canal situated
+                          at the cardiac end of the stomach and
+                          provided internally with a structureless
+                          lining.
+
+  _Intertentacular organ_ A ciliated tube running between the cavity
+                          of the zooecium and the external base of
+                          the lophophore.
+
+  _Keeled_                Having a longitudinal ridge on the dorsal
+  (of a zooecium)         surface.
+
+  _Lophophore_            The tentacles with the base to which they
+                          are attached.
+
+  _Marginal processes_    Chitinous hooked processes on the margin
+  (of statoblast).        of the swim-ring (_q. v._).
+
+  _OEsophagus_            That part of the alimentary canal which
+                          joins the mouth to the stomach.
+
+  _Orifice_               The aperture through which the lophophore
+                          can be protruded from or retracted into
+                          the zooecium.
+
+  _Parietal muscles_      Transverse muscles running round the inner
+                          wall of the zooecium.
+
+  _Parieto-vaginal_       Muscles that surround the orifice, running
+  _muscles_               between the folds of the zooecium in an
+                          oblique direction.
+
+  _Polyparium_            The whole body of zooecia and polypides
+                          which are in organic connection.
+
+  _Polypide_              The tentacular crown, alimentary canal,
+                          and retractor muscles of a polyzoon-individual.
+
+  _Pyloric portion_       That part which communicates with the
+  (of the stomach).       intestine.
+
+  _Resting bud_           An external bud provided with food-material
+                          in its cells, with a horny external
+                          coat and capable of lying dormant in
+                          unfavourable conditions.
+
+  _Retractor muscles_     The muscles by the action of which the
+                          lophophore can be pulled back into the
+                          zooecium.
+
+  _Statoblast_            An internal bud arising from the funiculus,
+                          containing food-material in its cells,
+                          covered with a horny coat and capable
+                          of lying dormant in unfavourable conditions.
+
+  _Swim-ring_             A ring of polygonal air-spaces surrounding
+                          the statoblast.
+
+  _Ventral surface_       (_Of zooecium_ or _polypide_) the surface
+                          nearest the anus; (_of statoblast_) the surface
+                          by which the statoblast is attached
+                          to the funiculus during development.
+
+  _Zoarium_               The whole body of zooecia which are in
+                          organic connection.
+
+  _Zooecium_              Those parts of the polyzoon-individual
+                          which constitute a case or "house" for
+                          the polypide.
+
+
+
+
+SYNOPSIS OF THE CLASSIFICATION OF THE POLYZOA.
+
+
+
+
+I.
+
+SYNOPSIS OF THE SUBCLASSES, ORDERS, AND SUBORDERS.
+
+Class POLYZOA.
+
+Small coelomate animals, each individual of which consists of a
+polyp-like organism or polypide enclosed in a "house" or zooecium
+composed partly of living tissues. The mouth is surrounded by a circle
+of ciliated tentacles that can be retracted within the zooecium; the
+alimentary canal, which is suspended in the zooecium, is Y-shaped and
+consists of three parts, the oesophagus, the stomach, and the intestine.
+
+
+Subclass ENTOPROCTA.
+
+The anus as well as the mouth is enclosed in the circle of tentacles and
+the zooecium is not very distinctly separated from the polypide. Some
+forms are solitary or form temporary colonies by budding.
+
+Most Entoprocta are marine, but a freshwater genus (_Urnatella_) occurs
+in N. America, while the Indian genus _Loxosomatoides_ (fig. 34, p. 176)
+is only known from brackish water.
+
+
+Subclass ECTOPROCTA.
+
+The anus is outside the circle of tentacles and the zooecium can always
+be distinguished from the polypide. All species form by budding
+permanent communities the individuals in which remain connected together
+by living tissue.
+
+
+Order I. GYMNOLAEMATA.
+
+Ectoproctous polyzoa the polypides of which have no epistome; the
+zooecia are in nearly all cases distinctly separated from one another by
+transverse perforated plates.
+
+Most of the Gymnolaemata are marine, but species belonging to two of the
+three suborders into which they are divided often stray into brackish
+water, while a few genera that belong to one of these two suborders are
+practically confined to fresh water. The three suborders are
+distinguished as follows:--
+
+
+Suborder A. _CHEILOSTOMATA._
+
+The zooecia are provided with a "lip" or lid hinged to the posterior
+margin of the orifice (see fig. 33, p. 175). This lid closes
+automatically outside the zooecium or in a special chamber on the
+external surface (the "peristome") when the polypide retracts and is
+pushed open by the tentacles as they expand. The majority of the zooecia
+in each zoarium are more or less distinctly flattened, but some of them
+are often modified to form "vibracula" and "avicularia."
+
+The Cheilostomata are essentially a marine group, but some species are
+found in estuaries and even in pools and ditches of brackish water (fig.
+33).
+
+
+Suborder B. _CTENOSTOMATA._
+
+The zooecia are provided with a collar-like membrane which is pleated
+vertically and closes together above the polypide inside the zooecium
+when the former is retracted; it is thrust out of the zooecium and
+expands into a ring-shaped form just before the tentacles are extruded.
+The zooecia are usually more or less tubular, but in some genera and
+species are flattened.
+
+The majority of the Ctenostomata are marine, but some genera are found
+in estuaries, while those of one section of the suborder live almost
+exclusively in fresh water.
+
+
+Suborder C. _CYCLOSTOMATA._
+
+The zooecia are provided neither with a lip nor with a collar-like
+membrane. They are tubular and usually have circular orifices.
+
+The Cyclostomata are exclusively marine.
+
+
+Order II. PHYLACTOLAEMATA.
+
+Ectoproctous polyzoa the polypides of which have a leaf-shaped organ
+called an epistome projecting upwards and forwards within the circle of
+tentacles and between the mouth and the anus. The zooecia are not
+distinct from one another, but in dendritic forms the zoarium is divided
+irregularly by chitinous partitions.
+
+The Phylactolaemata are, without exception, freshwater species.
+
+
+
+
+II.
+
+SYNOPSIS OF THE LEADING CHARACTERS OF THE DIVISIONS OF THE SUBORDER
+CTENOSTOMATA.
+
+
+Suborder B. _CTENOSTOMATA._
+
+The suborder has been subdivided in various ways by different authors.
+The system here adopted is essentially the same as that proposed in a
+recent paper by Waters (Journ. Linn. Soc. London, Zool. xxi, p. 231,
+1910), but I have thought it necessary to add a fourth division to the
+three adopted by that author, namely, the Alcyonellea, Stolonifera, and
+Vesicularina. This new division includes all the freshwater genera and
+may be known as the Paludicellina. In none of these divisions are the
+tentacles webbed at the base.
+
+The four divisions may be recognized from the following synopsis of
+their characteristic features:--
+
+
+Division I. ALCYONELLEA.
+
+The zooecia arise directly from one another in a fleshy or gelatinous
+mass. The polypide has no gizzard. The species are essentially marine,
+but a few are found in brackish water in estuaries.
+
+
+Division II. STOLONIFERA.
+
+The zooecia arise from expansions in a delicate creeping rhizome or
+root-like structure, the order in which they are connected together
+being more or less irregular. As a rule (perhaps always) there is no
+gizzard. The species are marine.
+
+
+Division III. VESICULARINA.
+
+The zooecia grow directly from a tubular stem which is usually free and
+vertical, their arrangement being alternate, spiral or irregular. There
+is a stout gizzard which bears internal chitinous projections and is
+tightly compressed when the polypide is retracted. The species are
+essentially marine, but a few are found in brackish water.
+
+
+Division IV. PALUDICELLINA, nov.
+
+The zooecia are arranged in a regular cruciform manner and arise either
+directly one from another or with the intervention of tubular processes.
+If the polypide has a gizzard it does not bear internal chitinous
+projections. Most of the species are confined to fresh water, but a few
+are found in brackish water or even in the sea.
+
+Although all true freshwater Ctenostomes belong to the fourth of these
+divisions, species of a genus (_Bowerbankia_) included in the third are
+so frequently found in brackish water and in association with one
+belonging to the fourth, and are so easily confounded with the latter,
+that I think it necessary to include a brief description of the said
+genus and of the form that represents it in ponds of brackish water in
+India.
+
+
+
+
+SYSTEMATIC LIST OF THE INDIAN FRESHWATER POLYZOA.
+
+[The types have been examined in the case of all species, etc., whose
+names are marked thus, *.]
+
+
+  Order I. GYMNOLAEMATA.
+
+  Suborder I. _CTENOSTOMATA._
+
+  [Division III. Vesicularina.]
+
+  [Genus BOWERBANKIA, Farre (1837).]
+
+  [_B. caudata_ subsp. _bengalensis_*, Annandale (1907).
+  (Brackish water).]
+
+
+  Division IV. Paludicellina, nov.
+
+  Family I. PALUDICELLIDAE.
+
+  Genus 1. PALUDICELLA, Gervais (1836).
+
+  ? _Paludicella_ sp. (_fide_ Carter).
+
+  Genus 2. VICTORELLA, Kent (1870).
+
+  26._V. bengalensis_*, Annandale (1907).
+
+
+  Family II. HISLOPIIDAE.
+
+  Genus HISLOPIA, Carter (1858).
+
+  27. _H. lacustris_, Carter (1858).
+  27 _a._ _H. lacustris_ subsp. _moniliformis_*, nov.
+
+
+  Order II. PHYLACTOLAEMATA.
+
+  Division I. Plumatellina.
+
+  Family 1. FREDERICELLIDAE.
+
+  Genus FREDERICELLA, Gervais (1836).
+
+  28. _F. indica_*, Annandale (1909).
+
+
+  Family 2. PLUMATELLIDAE.
+
+  Subfamily A. PLUMATELLINAE.
+
+  Genus 1. PLUMATELLA, Lamarck (1816).
+
+  29. _P. fruticosa_, Allman (1844).
+  30. _P. emarginata_, Allman (1844).
+  31. _P. javanica_*, Kraepelin (1905).
+  32. _P. diffusa_, Leidy (1851).
+  33. _P. allmani_, Hancock (1850).
+  34. _P. tanganyikae_*, Rousselet (1907).
+  35. _P. punctata_, Hancock (1850).
+
+  Genus 2. STOLELLA, Annandale (1909).
+
+  36. _S. indica_*, Annandale (1909).
+
+
+  Subfamily B. LOPHOPINAE.
+
+  Genus 1. LOPHOPODELLA, Rousselet (1904).
+
+  37. _L. carteri_* (Hyatt) (1865).
+  37 _a._ _L. carteri_ var. _himalayana_* (Annandale) (1907).
+
+  Genus 2. PECTINATELLA, Leidy (1851).
+
+  38. _P. burmanica_*, Annandale (1908).
+
+
+  Order CTENOSTOMATA.
+
+  [Division VESICULARINA.
+
+  Family VESICULARIDAE.
+
+  VESICULARIDAE, Hincks, Brit. Marine Polyzoa, p. 512 (1880).
+
+Zooecia constricted at the base, deciduous, attached to a stem that is
+either recumbent or vertical.
+
+
+Genus BOWERBANKIA, _Farre_.
+
+     _Bowerbankia_, Farre, Phil. Trans. Roy. Soc. cxxvii, p. 391 (1837).
+
+     _Bowerbankia_, Hincks, _op. cit._ p. 518.
+
+_Zoarium_ vertical or recumbent. _Zooecia_ ovate or almost cylindrical,
+arranged on the stem singly, in clusters or in a subspiral line.
+_Polypide_ with 8 or 10 tentacles.
+
+
+Bowerbankia caudata, _Hincks_.
+
+     _Bowerbankia caudata_, Hincks, _op. cit._ p. 521, pl. lxxv,
+     figs. 7, 8.
+
+This species is easily distinguished from all others by the fact that
+mature zooecia have always the appearance of being fixed to the sides of
+a creeping, adherent stem and are produced, below the point at which
+they are thus fixed, into a pointed "tail."
+
+
+Subsp. bengalensis, _Annandale_.
+
+     _Bowerbankia caudata_, Thornely, Rec. Ind. Mus. i, p. 196
+       (1907).
+
+     _Bowerbankia caudata_, Annandale, _ibid._ p. 203.
+
+     _Bowerbankia caudata_ race _bengalensis_, _id._, _ibid._
+       ii. p. 13 (1908).
+
+The Indian race is only distinguished from the typical form by its
+greater luxuriance of growth and by the fact that the "tail" of the
+zooecia is often of relatively great length, sometimes equaling or
+exceeding the rest of the zooecium. The stem, which is divided at
+irregular intervals by partitions, often crosses and recrosses its own
+course and even anastomoses, and a fur-like structure is formed in which
+the zooecia representing the hairs become much elongated; but upright
+branches are never formed. The zoarium has a greenish or greyish tinge.
+
+TYPE in the Indian Museum.
+
+GEOGRAPHICAL DISTRIBUTION.--_B. caudata_ subsp. _bengalensis_ is common
+in brackish water in the Ganges delta, where it often occurs in close
+association with _Victorella bengalensis_, and also at the south end of
+the Chilka Lake in the north-east of the Madras Presidency. Although it
+has not yet been found elsewhere, it probably occurs all round the
+Indian coasts.]
+
+
+Division PALUDICELLINA, nov.
+
+This division consists of two very distinct families, the species of
+which are easily distinguished at a glance by the fact that in one (the
+Paludicellidae) the zooecia are tubular, while in the other (the
+Hislopiidae) they are broad and flattened. The anatomical and
+physiological differences between the two families are important, and
+they are associated together mainly on account of the method of budding
+by means of which their zoaria are produced.
+
+[Illustration: Fig. 35.--Single zooecia of _Victorella_ and _Hislopia_
+(magnified).
+
+A, zooecium of _Victorella pavida_, Kent, with the polypide retracted
+(after Kraepelin).
+
+B, zooecium of _Hislopia lacustris_, Carter (typical form from the
+United Provinces), with the collar completely and the tentacles partly
+protruded.
+
+A=collar; B=orifice; C=tentacles; D=pharynx; E=oesophagus proper;
+F=gizzard; G=stomach; G'=cardiac portion of stomach; H=intestine;
+J=rectum; K=anus; L=young egg; M=green cysts in gizzard; N=testes;
+O=ovary; O'=funiculus.
+
+The muscles are omitted except in fig. B.]
+
+
+Family PALUDICELLIDAE.
+
+     PALUDICELLIDAE, Allman, Mon. Fresh-Water Polyzoa, p. 113
+     (1857).
+
+     HOMODIAETIDAE, Kent, Q. J. Micr. Sci. x, p. 35 (1870).
+
+     VICTORELLIDAE, Hincks, Brit. Marine Polyzoa, p. 558 (1880).
+
+     PALUDICELLIDEES, Jullien, Bull. Soc. zool. France, x, p. 174
+     (1885).
+
+     PALUDICELLIDES, Loppens, Ann. Biol. lacustre, iii, p. 170
+     (1908).
+
+     VICTORELLIDES, _id._, _ibid._ p. 171.
+
+_Zoarium._ The zoarium is recumbent or erect, and is formed typically
+either of zooecia arising directly in cruciform formation from one
+another, or of zooecia joined together in similar formation with the
+intervention of tubules arising from their own bases. Complications
+often arise, however, either on account of the suppression of the
+lateral buds of a zooecium, so that the formation becomes linear instead
+of cruciform, or by the production in an irregular manner of additional
+tubules and buds from the upper part of the zooecia. A confused and
+tangled zoarium may thus be formed, the true nature of which can only be
+recognized by the examination of its terminal parts.
+
+_Zooecia._ The zooecia are tubular and have a terminal or subterminal
+orifice, which is angulate or subangulate as seen from above. Owing to
+this fact, to the stiff nature of the external ectocyst, to the action
+of circular muscles that surround the tentacular sheath, and to the
+cylindrical form of the soft inverted part, the orifice, as seen from
+above, appears to form four flaps or valves, thus [illustration: sketch,
+similar to a cloverleaf inside a square with rounded corners].
+
+_Polypide._ The alimentary canal is elongate and slender as a whole, the
+oesophagus (including the pharynx) being of considerable length. In
+_Paludicella_ and _Pottsiella_ the oesophagus opens directly into the
+cardiac limb of the stomach, which is distinctly constricted at its
+base; but in _Victorella_ the base of the oesophagus is constricted off
+from the remainder to form an elongate oval sac the walls of which are
+lined with a delicate structureless membrane. _Victorella_ may therefore
+be said to possess a gizzard, but the structure that must be so
+designated has not the function (that of crushing food) commonly
+associated with the name, acting merely as a chamber for the retention
+of solid particles. In this genus the cardiac limb of the stomach is
+produced and vertical but not constricted at the base. The tentacles in
+most species number 8, but in _Paludicella_ there are 16.
+
+_Resting buds._ The peculiar structures known in Europe as "hibernacula"
+are only found in this family. The name hibernacula, however, is
+inappropriate to the only known Indian species as they are formed in
+this country at the approach of summer instead of, as in Europe and N.
+America, at that of winter. It is best, therefore, to call them "resting
+buds." They consist of masses of cells congregated at the base of the
+zooecia, gorged with food material and covered with a resistant horny
+covering.
+
+The family Paludicellidae consists of three genera which may be
+distinguished as follows:--
+
+   I. Orifice terminal; main axis of the zooecium
+      vertical; zooecia separated from one another
+      by tubules.
+    [A. Base of the zooecia not swollen; no
+        adventitious buds                          POTTSIELLA.]
+     B. Base of the zooecium swollen; adventitious
+        buds produced near the tip                 VICTORELLA, p. 194.
+  II. Orifice subterminal, distinctly on the dorsal
+      surface; main axis of the zooecium horizontal
+      (the zoarium being viewed from the dorsal
+      surface); buds not produced at the tip of the
+      zooecia                                      PALUDICELLA, p. 192.
+
+Of these three genera, _Pottsiella_ has not yet been found in India and
+is only known to occur in N. America. It consists of one species, _P.
+erecta_ (Potts) from the neighbourhood of Philadelphia in the United
+States.
+
+_Victorella_ includes four species, _V. pavida_ known from England and
+Germany and said to occur in Australia, _V. muelleri_ from Germany
+(distinguished by possessing parietal muscles at the tip of the
+zooecia), _V. symbiotica_ from African lakes and _V. bengalensis_ from
+India. These species are closely related.
+
+_Paludicella_ is stated by Carter to have been found in Bombay, but
+probably what he really found was the young stage of _V. bengalensis_. A
+single species is known in Europe and N. America, namely _P.
+ehrenbergi_, van Beneden (=_Alcyonella articulata_, Ehrenberg).
+
+I have examined specimens of all the species of this family as yet
+known.
+
+
+Genus 1. PALUDICELLA, _Gervais_.
+
+     _Paludicella_, Gervais, Compt. Rend. iii, p. 797 (1836).
+
+     _Paludicella_, Allman, Mon. Fresh-Water Polyzoa, p. 113
+     (1857).
+
+     ? _Paludicella_, Carter, Ann. Nat. Hist. (3) iii, p. 333
+     (1859).
+
+     _Paludicella_, Jullien, Bull. Soc. zool. France, x, p. 174
+     (1885).
+
+     _Paludicella_, Kraepelin, Deutsch. Suesswasserbryozoen, i, p.
+     96 (1887).
+
+     _Paludicella_, Loppens, Ann. Biol. lacustre, iv, p. 14
+     (1910).
+
+_Zoarium._ The nature of the zoarium in this genus is well expressed by
+Ehrenberg's specific name "_articulata_," although the name was given
+under a false impression. The zooecia arise directly from one another in
+linear series with occasional side-branches. The side-branches are,
+however, often suppressed. The zoarium as a whole is either recumbent
+and adherent or at least partly vertical.
+
+_Zooecia._ Although the zooecia are distinctly tubular as a whole, two
+longitudinal axes may be distinguished in each, for the tip is bent
+upwards in a slanting direction, bearing the orifice at its extremity.
+The main axis is, however, at right angles to the dorso-ventral axis,
+and the dorsal surface, owing to the position of the aperture, can
+always be readily distinguished from the ventral, even when the position
+of the zooecium is vertical. Each zooecium tapers towards the posterior
+extremity. Parietal muscles are always present.
+
+[Illustration: Fig. 36.--Structure of _Paludicella ehrenbergi_ (A and B
+after Allman).
+
+A=a single zooecium with the polypide retracted. B=the base of the
+lophophore as seen from above with the tentacles removed. C=the orifice
+of a polypide with the collar expanded and the tentacles partly
+retracted. _a_=tentacles; _c_=collar; _d_=mouth; _e_=oesophagus;
+_f_=stomach; _g_=intestine; _k_=parieto-vaginal muscles; _p_=parietal
+muscles; _o_=cardiac part of the stomach; _r_=retractor muscle;
+_s_=funiculus.]
+
+_Polypide._ The most striking features of the polypide are the absence
+of any trace of a gizzard and the highly specialized form assumed by the
+cardiac part of the stomach. There are two funiculi, both connecting the
+pyloric part of the stomach with the endocyst. The ovary develops at the
+end of the upper, the testis at that of the lower funiculus.
+
+_Resting buds._ The resting buds are spindle-shaped.
+
+Kraepelin recognized two species in the genus mainly by their method of
+growth and the number of tentacles. In his _P. muelleri_ the zoarium is
+always recumbent and the polypide has 8 tentacles, whereas in _P.
+articulata_ or _ehrenbergi_ the tentacles number 16 and upright branches
+are usually developed. It is probable, however, that the former species
+should be assigned to _Victorella_, for it is often difficult to
+distinguish _Paludicella_ from young specimens of _Victorella_ unless
+the latter bear adventitious terminal buds. The gizzard of _Victorella_
+can be detected in well-preserved material even under a fairly low power
+of the microscope, and I have examined specimens of what I believe to be
+the adult of _muelleri_ which certainly belong to that genus.
+
+It is always difficult to see the collar of _Paludicella_, because of
+its transparency and because of the fact that its pleats are apparently
+not strengthened by chitinous rods as is usually the case. Allman
+neither mentions it in his description of the genus nor shows it in his
+figures, and Loppens denies its existence, but it is figured by
+Kraepelin and can always be detected in well-preserved specimens, if
+they are examined carefully. If the collar were actually absent, its
+absence would separate _Paludicella_ not only from _Victorella_ and
+_Pottsiella_, but also from all other ctenostomes. In any case,
+_Victorella_ is distinguished from _Paludicella_ and _Pottsiella_ by
+anatomical peculiarities (_e. g._, the possession of a gizzard and the
+absence of a second funiculus) that may ultimately be considered
+sufficiently great to justify its recognition as the type and only genus
+of a separate family or subfamily.
+
+The description of _Paludicella_ is included here on account of Carter's
+identification of the specimens he found at Bombay; but its occurrence
+in India is very doubtful.
+
+
+Genus 2. _VICTORELLA_, _Kent_.
+
+     _Victorella_, Kent, Q. J. Micr. Sci. x, p. 34 (1870).
+
+     _Victorella_, Hincks, Brit. Marine Polyzoa, p. 559 (1880).
+
+     _Victorella_, Kraepelin, Deutsch. Suesswasserbryozoen, i, p.
+     93 (1887).
+
+TYPE, _Victorella pavida_, Kent.
+
+_Zoarium._ The zoarium consists primarily of a number of erect or
+semi-erect tubular zooecia joined together at the base in a cruciform
+manner by slender tubules, but complications are introduced by the fact
+that adventitious buds and tubules are produced, often in large numbers,
+round the terminal region of the zooecia, and that these buds are often
+separated from their parent zooecium by a tubule of considerable length,
+and take root among other zooecia at a distance from their point of
+origin. A tangled mass may thus be formed in which it is difficult to
+recognize the regular arrangement of the zooecia that can be readily
+detached at the growing points of the zoarium.
+
+_Zooecia._ The zooecia when young closely resemble those of
+_Paludicella_, but as they grow the terminal upturned part increases
+rapidly, while the horizontal basal part remains almost stationary and
+finally appears as a mere swelling at the base of an almost vertical
+tube, in which by far the greater part, if not the whole, of the
+polypide is contained. Round the terminal part of this tube adventitious
+buds and tubules are arranged more or less regularly. There are no
+parietal muscles.
+
+_Polypide._ The polypide has 8 slender tentacles, which are thickly
+covered with short hairs. The basal part of the oesophagus forms a
+thin-walled sac (the "gizzard") constricted off from the upper portion
+and bearing internally a thin structureless membrane. Circular muscles
+exist in its wall but are not strongly developed on its upper part.
+There is a single funiculus, which connects the posterior end of the
+stomach with the base of the zooecium. The ovaries and testes are borne
+on the endocyst, not in connection with the funiculus.
+
+_Resting buds._ The resting buds are flattened or resemble young zooecia
+in external form.
+
+_Victorella_, although found in fresh water, occurs more commonly in
+brackish water and is known to exist in the littoral zone of the sea.
+
+
+26. Victorella bengalensis, _Annandale_.
+
+     _Victorella pavida_, Annandale (_nec_ Kent), Rec. Ind. Mus.
+     i, p. 200, figs. 1-4 (1907).
+
+     _Victorella bengalensis_, _id._, _ibid._ ii, p. 12, fig. 1
+     (1908).
+
+_Zoarium._ _The mature zoarium resembles a thick fur_, the hairs of
+which are represented by elongate, erect, slender tubules (the zooecia),
+the arrangement of the whole being very complicated and irregular. The
+base of the zoarium often consists of an irregular membrane formed of
+matted tubules, which are sometimes agglutinated together by a gummy
+secretion. The zoarium as a whole has a faint yellowish tinge.
+
+_Zooecia._ The zooecia when young are practically recumbent, each being
+of an ovoid form and having a stout, distinctly quadrate orificial
+tubule projecting upwards and slightly forwards near the anterior margin
+of the dorsal surface. At this stage a single tubule, often of great
+relative length, is often given off near the orifice, bearing a bud at
+its free extremity. As the zooecium grows the tubular part becomes much
+elongated as compared with the basal part and assumes a vertical
+position. Its quadrate form sometimes persists but more often
+disappears, so that it becomes almost circular in cross-section
+throughout its length. Buds are produced near the tip in considerable
+profusion. As a rule, if they appear at this stage, the tubule
+connecting them with the parent zooecium is short or obsolete; sometimes
+they are produced only on one side of the zooecium, sometimes on two.
+The buds themselves produce granddaughter and great-granddaughter buds,
+often connected together by short tubules, while still small and
+imperfectly developed. The swelling at the base of the zooecium, when
+the latter is fully formed, is small.
+
+_Polypide._ The polypide has the features characteristic of the genus.
+The base of the gizzard is surrounded by a strong circular muscle.
+
+[Illustration: Fig. 37.--_Victorella bengalensis_ (type specimens).
+
+A=single zooecium without adventitious buds but with a young resting bud
+(_b_), x 70 (dorsal view); B=lateral view of a smaller zooecium without
+buds, x 70; C=upper part of a zooecium with a single adventitious bud, x
+70; D=outline of the upper part of a zooecium with adventitious buds of
+several generations, x 35; E=remains of a zooecium with two resting buds
+(_b_) attached. All the specimens figured are from Port Canning and,
+except D, are represented as they appear when stained with borax carmine
+and mounted in canada balsam.]
+
+_Resting buds._ The resting buds (fig. 31, p. 170) are somewhat variable
+in shape but are always flat with irregular cylindrical or
+subcylindrical projections round the margin, on which the horny coat is
+thinner than it is on the upper surface. This surface is either smooth
+or longitudinally ridged.
+
+TYPE in the Indian Museum.
+
+This species differs from the European _V. pavida_ in very much the same
+way as, but to a greater extent than, the Indian race of _Bowerbankia
+caudata_ does from the typical English one (see p. 189). The growth of
+the zoarium is much more luxuriant, and the form of the resting buds is
+different.
+
+GEOGRAPHICAL DISTRIBUTION.--_V. bengalensis_ is abundant in pools of
+brackish water in the Ganges delta and in the Salt Lakes near Calcutta;
+it also occurs in ponds of fresh water near the latter. I have received
+specimens from Madras from Dr. J. R. Henderson, and it is probable that
+the form from Bombay referred by Carter to _Paludicella_ belonged to
+this species.
+
+BIOLOGY.--In the Ganges delta _V. bengalensis_ is usually found coating
+the roots and stems of a species of grass that grows in and near
+brackish water, and on sticks that have fallen into the water. It also
+spreads over the surface of bricks, and I have found a specimen on a
+living shell of the common mollusc _Melania tuberculata_. Dr. Henderson
+obtained specimens at Madras from the surface of a freshwater shrimp,
+_Palaemon malcolmsonii_. In the ponds at Port Canning the zoaria grow
+side by side with, and even entangled with those of _Bowerbankia
+caudata_ subsp. _bengalensis_, to the zooecia of which their zooecia
+bear a very strong external resemblance so far as their distal extremity
+is concerned. This resemblance, however, disappears in the case of
+zooecia that bear terminal buds, for no such buds are borne by _B.
+caudata_; and the yellowish tint of the zoaria of _V. bengalensis_ is
+characteristic. Zoaria of the entoproct _Loxosomatoides colonialis_ and
+colonies of the hydroid _Irene ceylonensis_ are also found entangled
+with the zoaria of _V. bengalensis_, the zooecia of which are often
+covered with various species of Vorticellid protozoa and small rotifers.
+The growth of _V. bengalensis_ is more vigorous than that of the other
+polyzoa found with it, and patches of _B. caudata_ are frequently
+surrounded by large areas of _V. bengalensis_.
+
+The food of _V. bengalensis_ consists largely of diatoms, the siliceous
+shells of which often form the greater part of its excreta. Minute
+particles of silt are sometimes retained in the gizzard, being
+apparently swallowed by accident.
+
+There are still many points to be elucidated as regards the production
+and development of the resting buds in _V. bengalensis_, but two facts
+are now quite clear as regards them: firstly, that these buds are
+produced at the approach of the hot weather and germinate in November or
+December; and secondly, that the whole zoarium may be transformed at the
+former season into a layer of resting buds closely pressed together but
+sometimes exhibiting in their arrangement the typical cruciform
+formation. Resting buds may often be found in vigorous colonies as late
+as the beginning of December; these buds have not been recently formed
+but have persisted since the previous spring and have not yet
+germinated. Sometimes only one or two buds are formed at the base of an
+existing zooecium (fig. 37 _a_), but apparently it is possible not only
+for a zooecium to be transformed into a resting bud but for it to
+produce four other buds round its base before undergoing the change.
+Young polypides are formed inside the buds and a single zooecium sprouts
+out of each, as a rule by the growth of one of the basal projections,
+when conditions are favourable.
+
+Polypides of _V. bengalensis_ are often transformed into brown bodies.
+When this occurs the orifice closes together, with the collar expanded
+outside the zooecium. I have occasionally noticed that the ectocyst of
+such zooecia was distinctly thicker and darker in colour than that of
+normal zooecia.
+
+Eggs and spermatozoa are produced in great numbers, as a rule
+simultaneously in the same zooecia, but individuals kept in captivity
+often produce spermatozoa only. The eggs are small and are set free as
+eggs. Nothing is known as regards their development.
+
+Polypides are as a rule found in an active condition only in the cold
+weather, but I have on one occasion seen them in this condition in
+August, in a small zoarium attached to a shell of _Melania tuberculata_
+taken in a canal of brackish water near Calcutta.
+
+
+Family HISLOPIIDAE.
+
+     HISLOPIDEES, Jullien, Bull. Soc. zool. France, x, p. 180
+     (1885).
+
+     HISLOPIIDAE, Annandale, Rec. Ind. Mus. i, p. 200 (1907).
+
+_Zoarium_ recumbent, often forming an almost uniform layer on solid
+subjects.
+
+_Zooecia_ flattened, adherent; the orifice dorsal, either surrounded by
+a chitinous rim or situated at the tip of an erect chitinous tubule; no
+parietal muscles.
+
+_Polypide_ with an ample gizzard which possesses a uniform chitinous
+lining and does not close together when the polypide is retracted.
+
+_Resting bud_, not produced.
+
+Only two genera can be recognized in this family, _Arachnoidea_, Moore,
+from Central Africa, and _Hislopia_, Carter, which is widely distributed
+in Eastern Asia. The former genus possesses an upright orificial tubule
+and has zooecia separated by basal tubules. Its anatomy is imperfectly
+known, but it certainly possesses a gizzard of similar structure to that
+of _Hislopia_, between which and _Victorella_ its zooecium is
+intermediate in form.
+
+
+Genus HISLOPIA, _Carter_.
+
+     _Hislopia_, Carter, Ann. Nat. Hist. (3) i, p. 169 (1858).
+
+     _Hislopia_, Stolickza, J. As. Soc. Bengal, xxxviii (2), p.
+     61 (1869).
+
+     _Norodonia_, Jullien, Bull. Soc. zool. France, v, p. 77
+     (1880).
+
+     _Hislopia_, _id._, _ibid._ x, p. 183 (1885).
+
+     _Norodonia_, _id._, _ibid._ p. 180.
+
+     _Echinella_, Korotneff, Biol. Centrbl. xxi, p. 311 (1901).
+
+     _Hislopia_, Annandale, J. As. Soc. Bengal (new series) ii,
+     p. 59 (1906).
+
+     _Hislopia_, Loppens, Ann. Biol. lacustre, iii, p. 175
+     (1908).
+
+TYPE, _Hislopia lacustris_, Carter.
+
+_Zoarium._ The zoarium consists primarily of a main axis running in a
+straight line, with lateral branches that point forwards and outwards.
+Further proliferation, however, often compacts the structure into an
+almost uniform flat area.
+
+_Zooecia._ The zooecia (fig. 35 B, p. 190) are flat and have the orifice
+surrounded by a chitinous rim but not much raised above the dorsal
+surface. They arise directly one from another.
+
+_Polypide._ The polypide possesses from 12 to 20 tentacles. Its
+funiculus is rudimentary or absent. Neither the ovaries nor the testes
+have any fixed position on the lateral walls of the zooecium to which
+they are confined.
+
+The position of this genus has been misunderstood by several zoologists.
+Carter originally described _Hislopia_ as a cheilostome allied to
+_Flustra_; in 1880 Jullien perpetuated the error in describing his
+_Norodonia_, which was founded on dried specimens of Carter's genus;
+while Loppens in 1908 still regarded the two "genera" as distinct and
+placed them both among the cheilostomes. In 1885, however, Jullien
+retracted his statement that _Norodonia_ was a cheilostome and placed
+it, together with _Hislopia_, in a family of which he recognized the
+latter as the eponymic genus. Carter's mistake arose from the fact that
+he had only examined preserved specimens, in which the thickened rim of
+the orifice is strongly reminiscent of the "peristome" of certain
+cheilostomes, while the posterior of the four folds into which the
+tentacle sheath naturally falls (as in all ctenostomes, _cf._ the
+diagram on p. 191) is in certain conditions rather larger than the other
+three and suggests the "lip" characteristic of the cheilostomes. If
+living specimens are examined, however, it is seen at once that the
+posterior fold, like the two lateral folds and the anterior one, changes
+its form and size from time to time and has no real resemblance to a
+"lip."
+
+That there is a remarkable, if superficial, resemblance both as regards
+the form of the zooecium and as regards the method of growth between
+_Hislopia_ and certain cheilostomes cannot be denied, but the structure
+of the orifice and indeed of the whole organism is that of a ctenostome
+and the resemblance must be regarded as an instance of convergence
+rather than of genetic relationship.
+
+The most striking feature of the polypide of _Hislopia_ is its gizzard
+(fig. 38, p. 201) which is perhaps unique (except for that of
+_Arachnoidea_) both in structure and function. In structure its
+peculiarities reside mainly in three particulars: (i), it is not
+constricted off directly from the thin-walled oesophageal tube, but
+possesses at its upper extremity a thick-walled tubular portion which
+can be entirely closed from the oesophagus at its upper end but always
+remains in communication with the spherical part of the gizzard; (ii),
+this spherical part of the gizzard is uniformly lined with a thick
+chitinous or horny layer which in optical section has the appearance of
+a pair of ridges; and (iii), there is a ring of long and very powerful
+cilia round the passage from the gizzard to the stomach. The cardiac
+limb of the stomach, which is large and heart-shaped, is obsolete. The
+wall of the spherical part of the gizzard consists of two layers of
+cells, an outer muscular layer consisting of powerful circular muscles
+and an inner glandular layer, which secretes the chitinous lining. The
+inner walls of the tubular part consist of non-ciliated columnar cells,
+and when the polypide is retracted it lies almost at right angles to the
+main axis of the zooecium.
+
+The spherical part of the gizzard invariably contains a number of green
+cells, which lie free in the liquid it holds and are kept in motion by
+the cilia at its lower aperture. The majority of these cells can be seen
+with the aid of a high power of the microscope to consist of a hard
+spherical coat or cyst containing green protoplasm in which a spherical
+mass of denser substance (the nucleus) and a number of minute
+transparent granules can sometimes be detected. The external surface of
+many of the cysts is covered with similar granules, but some are quite
+clean.
+
+There can be no doubt that these cysts represent a stage in the
+life-history of some minute unicellular plant or animal. Indeed,
+although it has not yet been found possible to work out this
+life-history in detail, I have been able to obtain much evidence that
+they are the resting stage of a flagellate organism allied to _Euglena_
+which is swallowed by the polyzoon and becomes encysted in its gizzard,
+extruding in so doing from its external surface a large proportion of
+the food-material that it has stored up within itself in the form of
+transparent granules. It may also be stated that some of the organisms
+die and disintegrate on being received into the gizzard, instead of
+encysting themselves.
+
+So long as the gizzard retains its spherical form the green cells and
+its other contents are prevented from entering the stomach by the
+movements of the cilia that surround its lower aperture, but every now
+and then, at irregular intervals, the muscles that form its outer wall
+contract. The chitinous lining although resilient and not inflexible is
+too stiff to prevent the lumen of the gizzard being obliterated, but the
+action of the muscles changes its contents from a spherical to an ovoid
+form and in so doing presses a considerable part of them down into the
+stomach, through the ring of the cilia.
+
+[Illustration: Fig. 38.--Optical section of gizzard of _Hislopia
+lacustris_, with contained green cysts, x 240.]
+
+The contraction of the gizzard is momentary, and on its re-expansion
+some of the green cysts that have entered the stomach are often
+regurgitated into it. Some, however, remain in the stomach, in which
+they are turned round and round by the action of the cilia at both
+apertures. They are apparently able to retain their form for some hours
+in these circumstances but finally disintegrate and disappear, being
+doubtless digested by the juices poured out upon them by the glandular
+lining of the stomach. In polypides kept under observation in clean
+tap-water all the cysts finally disappear, and the faeces assume a green
+colour. In preserved specimens apparently unaltered cysts are sometimes
+found in the rectum, but this is exceptional: I have observed nothing of
+the kind in living polypides. Cysts often remain for several days
+unaltered in the gizzard.
+
+Imperfect as these observations are, they throw considerable light on
+the functions of the gizzard in _Hislopia_. Primarily it appears to act
+as a food-reservoir in which the green cysts and other minute organisms
+can be kept until they are required for digestion. When in the gizzard
+certain organisms surrender a large proportion of the food-material
+stored up for their own uses, and this food-material doubtless aids in
+nourishing the polyzoon. Although the cysts in the gizzard are
+frequently accompanied by diatoms, the latter are not invariably
+present. The cysts, moreover, are to be found in the zooecia of
+polypides that have formed brown bodies, often being actually enclosed
+in the substance of the brown body. The gizzards of the specimens of
+_Arachnoidea_ I have examined contain cysts that resemble those found in
+the same position in _Hislopia_.
+
+_Hislopia_ is widely distributed in the southern part of the Oriental
+Region, and, if I am right in regarding _Echinella_, Korotneff as a
+synonym, extends its range northwards to Lake Baikal. It appears to be a
+highly specialized form but is perhaps related, through _Arachnoidea_,
+to _Victorella_.
+
+
+27. Hislopia lacustris, _Carter_.
+
+     _Hislopia lacustris_, Carter, Ann. Nat. Hist. (3) i, p. 170,
+     pl. vii, figs. 1-3 (1858).
+
+     _Norodonia cambodgiensis_, Jullien, Bull. Soc. zool. France,
+     v, p. 77, figs. 1-3 (1880).
+
+     _Norodonia sinensis_, _id._, _ibid._ p. 78, figs. 1-3.
+
+     _Norodonia cambodgiensis_, _id._, _ibid._ x, p. 181, figs.
+     244, 245 (1885).
+
+     _Norodonia sinensis_, _id._, _ibid._ p. 182, figs. 246, 247.
+
+     _Hislopia lacustris_, Annandale, J. As. Soc. Bengal (new
+     series) iii, p. 85 (1907).
+
+     _Hislopia lacustris_, Walton, Rec. Ind. Mus. i, p. 177
+     (1907).
+
+     _Hislopia lacustris_, Kirkpatrick, _ibid._ ii, p. 98 (1908).
+
+     _Hislopia lacustris_, Walton, _ibid._ iii, p. 295 (1909).
+
+_Zoarium._ The zoarium forms a flat, more or less solid layer and is
+closely adherent to foreign objects. As a rule it covers a considerable
+area, with radiating branches at the edges; but when growing on slender
+twigs or the stems of water-plants it forms narrow, closely compressed
+masses. One zooecium, however, never grows over another.
+
+_Zooecia._ The zooecia are variable in shape. In zoaria which have space
+for free expansion they are as a rule irregularly oval, the posterior
+extremity being often narrower than the anterior; but small triangular
+zooecia and others that are almost square may often be found. When
+growing on a support of limited area the zooecia are smaller and as a
+rule more elongate. The orifice is situated on a slight eminence nearer
+the anterior than the posterior margin of the dorsal surface. It is
+surrounded by a strong chitinous rim, which is usually square or
+subquadrate but not infrequently circular or subcircular. Sometimes a
+prominent spine is borne at each corner of the rim, but these spines are
+often vestigial or absent; they are rarely as long as the transverse
+diameter of the orifice. The zooecium is usually surrounded by a
+chitinous margin, and outside this margin there is often a greater or
+less extent of adherent membrane. In some zooecia the margin is obsolete
+or obsolescent. The dorsal surface is of a glassy transparency but by no
+means soft.
+
+[Illustration: Fig. 39.--_Hislopia lacustris._
+
+A=part of a zoarium of the subspecies _moniliformis_ (type specimen,
+from Calcutta), x 15; A=green cysts in gizzard; E=eggs.
+
+B=outline of part of a zoarium of the typical form of the species from
+the United Provinces, showing variation in the form of the zooecia and
+of the orifice, x 15.]
+
+_Polypide._ The polypide has from 12 to 20 tentacles, 16 being a common
+number.
+
+TYPE probably not in existence. It is not in the British Museum and
+Prof. Dendy, who has been kind enough to examine the specimens from
+Carter's collection now in his possession, tells me that there are none
+of _Hislopia_ among them.
+
+
+27 _a._ Subsp. moniliformis, nov.
+
+     _Hislopia lacustris_, Annandale, J. As. Soc. Bengal (new
+     series) ii, p. 59, fig. 1 (1906).
+
+In this race, which is common in Calcutta, the zooecia are almost
+circular but truncate or concave anteriorly and posteriorly. They form
+linear series with few lateral branches. I have found specimens
+occasionally on the shell of _Vivipara bengalensis_, but they are much
+more common on the leaves of _Vallisneria spiralis_.
+
+TYPE in the Indian Museum.
+
+The exact status of the forms described by Jullien as _Norodonia
+cambodgiensis_ and _N. sinensis_ is doubtful, but I see no reason to
+regard them as specifically distinct from _H. lacustris_, Carter, of
+which they may be provisionally regarded as varieties. The variety
+_cambodgiensis_ is very like my subspecies _moniliformis_ but has the
+zooecia constricted posteriorly, while var. _sinensis_, although the
+types were found on _Anodonta_ shells on which there was plenty of room
+for growth, resemble the confined phase of _H. lacustris_ so far as the
+form of their zooecia and of the orifice is concerned.
+
+GEOGRAPHICAL DISTRIBUTION.--The typical form is common in northern India
+and occurs also in Lower Burma; the subspecies _moniliformis_ appears to
+be confined to Lower Bengal, while the varieties _cambodgiensis_ and
+_sinensis_ both occur in China, the former having been found also in
+Cambodia and Siam. Indian and Burmese localities are:--BENGAL, Calcutta
+(subsp. _moniliformis_); Berhampur, Murshidabad district (_J. Robertson
+Milne_): CENTRAL PROVINCES, Nagpur (_Carter_): UNITED PROVINCES,
+Bulandshahr (_H. J. Walton_): BURMA, Pegu-Sittang Canal (_Kirkpatrick_).
+
+BIOLOGY.--Regarding the typical form of the species Major Walton writes
+(Rec. Ind. Mus. iii, p. 296):--"In volume i (page 177) of the Records of
+the Indian Museum, I described the two forms of colonies of _Hislopia_
+that I had found in the United Provinces (Bulandshahr). Of these, one
+was a more or less linear arrangement of the zooecia on leaves and
+twigs, and the other, and more common, form was an encrusting sheath on
+the outer surface of the shells of _Paludina_. During the present
+'rains' (July 1908) I have found many examples of what may be considered
+a much exaggerated extension of the latter form. These colonies have
+been on bricks, tiles, and other submerged objects. The largest colony
+that I have seen so far was on a tile; one side of the tile was exposed
+above the mud of the bottom of the tank, and its area measured about 120
+square inches; the entire surface was almost completely covered by a
+continuous growth of _Hislopia_. Another large colony was on a piece of
+bark which measured 7 inches by 3 inches; both sides were practically
+everywhere covered by _Hislopia_."
+
+Major Walton also notes that in the United Provinces the growth of
+_Hislopia_ is at its maximum during "rains," and that at that time of
+year almost every adult _Paludina_ in a certain tank at Bulandshahr had
+its shell covered with the zooecia. The Calcutta race flourishes all the
+year round but never forms large or closely compacted zoaria, those on
+shells of _Vivipara_ exactly resembling those on leaves of
+_Vallisneria_.
+
+In Calcutta both eggs and spermatozoa are produced at all times of the
+year simultaneously in the same zooecia, but the eggs in one zooecium
+often vary greatly in size. When mature they reach relatively
+considerable dimensions and contain a large amount of food material; but
+they are set free from the zooecium as eggs. They lie loose in the
+zooecium at a comparatively small size and grow in this position.
+Nothing is known as regards the development of _Hislopia_.
+
+Both forms of the species appear to be confined to water that is free
+from all traces of contamination with brine.
+
+
+Order PHYLACTOLAEMATA.
+
+The polypide in this order possesses a leaf-like ciliated organ (the
+epistome) which arises within the lophophore between the mouth and the
+anus and projects upwards and forwards over the mouth, which it can be
+used to close. The zooecia are never distinct from one another, but in
+dendritic forms such as _Plumatella_ the zoarium is divided at irregular
+intervals by chitinous partitions. The lophophore in most genera is
+horseshoe-shaped instead of circular, the part opposite the anus being
+deeply indented. There are no parietal muscles. The orifice of the
+zooecium is always circular, and there is no trace of any structure
+corresponding to the collar of the ctenostomes. The tentacles are always
+webbed at the base.
+
+All the phylactolaemata produce the peculiar reproductive bodies known as
+statoblasts.
+
+The phylactolaemata, which are probably descended from ctenostomatous
+ancestors, are confined to fresh or slightly brackish water. Most of the
+genera have a wide geographical distribution, but (with the exception of
+a few statoblasts of almost recent date) only one fossil form
+(_Plumatellites_, Fric. from the chalk of Bohemia) has been referred to
+the order, and that with some doubt.
+
+It is convenient to recognize two main divisions of the phylactolaemata,
+but these divisions hardly merit the distinction of being regarded as
+suborders. They may be called Cristatellina and Plumatellina and
+distinguished as follows:--
+
+Division I, PLUMATELLINA, nov.--Ectocyst well developed; zoaria without
+a special organ of progression; polypides contained in tubes.
+
+Division II, CRISTATELLINA, nov.--Ectocyst absent except at the base of
+the zoarium which is modified to form a creeping "sole"; polypides
+embedded in a common synoecium of reticulate structure.
+
+The Cristatellina consist of a single genus and probably of a single
+species (_Cristatella mucedo_, Cuvier), which is widely distributed in
+Europe and N. America, but has not been found in the Oriental Region.
+Eight genera of Plumatellina are known, and five (possibly six) of these
+genera occur in India.
+
+
+Division PLUMATELLINA, nov.
+
+The structure of the species included in this division is very uniform
+as regards the internal organs (see fig. 40 opposite and fig. 47 _a_, p.
+236). The alimentary canal is simpler than that of the Paludicellidae. A
+short oesophagus leads directly into the stomach, the cardiac portion of
+which is produced as a vertical limb almost cylindrical in form and not
+constricted at the base. This limb is as a rule of greater length than
+the oesophagus. The pyloric part of the stomach is elongated and narrow,
+and the intestine short, straight, and of ovoid form. There are no cilia
+at the pyloric opening. A single funiculus joins the posterior end of
+the stomach to the wall of the zooecium, bearing the statoblasts. Sexual
+organs are often absent.
+
+[Illustration: Fig. 40.--Structure of the Plumatellina (after Allman).
+
+A=a zooecium of _Fredericella_ with the polypide extruded. B=the
+lophophore of _Lophopus_ (tentacles removed) as seen obliquely from the
+right side. C=larva of _Plumatella_ as seen in optical section.
+_a_=tentacles; _b_=velum; _c_=epistome; _d_=mouth; _e_=oesophagus;
+_f_=stomach; _g_=intestine; _h_=anus; _j_=retractor muscle;
+_k_=parieto-vaginal muscles; _l_=funiculus.]
+
+Two families may be recognized as constituting the division, _viz._,
+(_a_) the Fredericellidae, which have a circular or oval lophophore and
+simple statoblast without a swim-ring, and (_b_) the Plumatellidae, in
+which the lophophore is shaped like a horseshoe and some or all of the
+statoblasts are provided with a ring of air-spaces.
+
+
+Family 1. FREDERICELLIDAE.
+
+     FREDERICELLIDAE, Kraepelin, Deutsch. Suesswasserbryozoen, i,
+     p. 168 (1887).
+
+_Zoaria_ dendritic; _zooecia_ distinctly tubular, with the ectocyst well
+developed; _statoblasts_ of one kind only, each surrounded by a
+chitinous ring devoid of air-spaces; _polypides_ with the lophophore
+circular or oval when expanded.
+
+The Fredericellidae consist of a single genus (_Fredericella_) which
+includes several closely-allied forms and has a wide geographical
+distribution.
+
+
+Genus FREDERICELLA, _Gervais_ (1838).
+
+     _Fredericella_, Allman, Mon. Fresh-Water Polyzoa, p. 11
+     (1857).
+
+     _Plumatella_, ("arret de developpement") Jullien, Bull. Soc.
+     zool. France, x, p. 121 (1885).
+
+       _Fredericella_, Kraepelin, Deutsch. Suesswasserbryozoen,
+     i, p. 99 (1887).
+
+     _Fredericella_, Goddard, Proc. Linn. Soc. N. S. Wales,
+     xxxiv, p. 489 (1909).
+
+This genus has the characters of the family. Its status has been much
+disputed, some authors regarding the shape of the lophophore as of great
+morphological importance, while Jullien believed that _Fredericella_ was
+merely an abnormal or monstrous form of _Plumatella_. The latter belief
+was doubtless due to the fact that the zoaria of the two genera bear a
+very close external resemblance to one another and are sometimes found
+entangled together. The importance of the shape of the lophophore may,
+however, easily be exaggerated, for, as both Jullien and Goddard have
+pointed out, it assumes an emarginate form when retracted.
+
+The best known species is the European and N. American _F. sultana_
+(Blumenbach), of which several varieties or phases have been described
+as distinct. This form is stated to occur also in S. Africa. _F.
+australiensis_, Goddard[BC] from N. S. Wales is said to differ from this
+species in having an oval instead of a circular lophophore and in other
+small anatomical characters; but it is doubtful how far these characters
+are valid, for the lophophore appears to be capable of changing its
+shape to some slight extent and has been stated by Jullien to be
+habitually oval in specimens from France. _F. cunningtoni_,
+Rousselet[BD] from Lake Tanganyika has stout zooecia encrusted with
+relatively large sand-grains.
+
+     [Footnote BC: Proc. Linn. Soc. N. S. Wales, xxxiv, p. 489
+     (1909).]
+
+     [Footnote BD: Rousselet, Proc. Zool. Soc. London, 1907 (1),
+     p. 254.]
+
+The zoaria of _Fredericella_ are usually found attached to solid objects
+in shallow water, but a form described as _F. duplessisi_, Ford has been
+found at a depth of 40 fathoms embedded in mud at the bottom of the Lake
+of Geneva. _F. cunningtoni_ was dredged from depths of about 10 and
+about 25 fathoms.
+
+The statoblasts of this genus do not float and often germinate in the
+parent zooecium after its polypides have died. They are produced in
+smaller numbers than is usually the case in other genera of the order.
+The polypides sometimes undergo a process of regeneration, but without
+the formation of brown bodies.
+
+[Illustration: Fig. 41.--_Fredericella indica._
+
+A=statoblast, x 120. B=outline of expanded lophophore and adjacent
+parts, x 75; a=anus, r=rectum. C=outline of zoarium on leaf of
+water-plant, x 3.
+
+(A and B are from specimens from Igatpuri, C from specimen from
+Shasthancottah).]
+
+
+28. Fredericella indica, _Annandale_.
+
+     _Fredericella indica_, Annandale, Rec. Ind. Mus. iii, p. 373,
+     fig. (1909).
+
+     _Fredericella indica_, _id._, _ibid._ v, p. 39 (1910).
+
+_Zoarium._ The zoarium is of delicate appearance and branches sparingly.
+It is often entirely recumbent but sometimes produces short, lax
+branches that consist of two or three zooecia only.
+
+_Zooecia._ The zooecia are very slender and almost cylindrical; they are
+slightly emarginate and furrowed, the keel in which the furrow runs
+being sometimes prominent. The external surface is minutely roughened
+and apparently soft, for small grains of sand and other debris cling to
+it, but never thickly. The ectocyst is practically colourless but not
+transparent.
+
+_Statoblasts._ The statoblasts are variable in size and form but most
+commonly have a regular broad oval outline; sometimes they are
+kidney-shaped. The dorsal surface is covered with minute star-shaped
+prominences, which sometimes cover it almost uniformly and are sometimes
+more numerous in the centre than towards the periphery. The ventral
+surface is smooth.
+
+_Polypide._ The lophophore bears about 20-25 tentacles, which are very
+slender and of moderate length; the velum at their base is narrow; as a
+rule the lophophore is accurately circular.
+
+TYPE in the Indian Museum.
+
+The most definite character in which this species differs from _F.
+sultana_ and _F. australiensis_ is the ornamentation of one surface of
+the statoblast, both surfaces of which are smooth in the two latter
+species. From _F. cunningtoni_, the statoblasts of which are unknown, it
+differs in having almost cylindrical instead of depressed zooecia and in
+not having the zooecia densely covered with sand-grains.
+
+GEOGRAPHICAL DISTRIBUTION.--Western India (the Malabar Zone): Igatpuri
+Lake, W. Ghats (alt. ca. 2,000 feet), Bombay Presidency, and
+Shasthancottah Lake near Quilon, Travancore.
+
+BIOLOGY.--In both the lakes in which the species has yet been found it
+was collected in November. The specimens obtained in Travancore were
+found to be undergoing a process of regeneration due at least partly to
+the fact that most of the polypides had perished and that statoblasts
+were germinating in the old zooecia. Specimens from the Bombay
+Presidency, which were obtained a little later in the month, were in a
+more vigorous condition, although even they contained many young
+polypides that were not yet fully formed. It seems, therefore, not
+improbable that _F. indica_ dies down at the beginning of the hot
+weather and is regenerated by the germination of its statoblasts at the
+beginning of the cold weather.
+
+At Shasthancottah zoaria were found entangled with zoaria of a delicate
+form of _Plumatella fruticosa_ to which they bore a very close external
+resemblance.
+
+
+Family 2. PLUMATELLIDAE.
+
+     PLUMATELLIDAE, Allman (_partim_), Mon. Fresh-Water Polyzoa,
+     pp. 76, 81 (1857).
+
+Phylactolaemata which have horseshoe-shaped lophophores and a
+well-developed ectocyst not specialized to form an organ of progression.
+Some or all of the statoblasts are provided with a "swim-ring"
+consisting of symmetrically disposed, polygonal chitinous chambers
+containing air.
+
+It is convenient to divide the Plumatellidae as thus defined into
+subfamilies (the Plumatellinae and the Lophopinae), which may be defined
+as follows:--
+
+
+Subfamily A. PLUMATELLINAE.
+
+Zoarium dendritic or linear, firmly fixed to extraneous objects; zooecia
+tubular, not fused together to form a gelatinous mass.
+
+
+Subfamily B. LOPHOPINAE.
+
+Zoarium forming a gelatinous mass in which the tubular nature of the
+zooecia almost disappears, capable to a limited extent of progression
+along a smooth surface.
+
+Both these subfamilies are represented in the Indian fauna, the
+Plumatellinae by two of the three genera known to exist, and the
+Lophopinae by two (or possibly three) of the four that have been
+described. The following key includes all the known genera, but the
+names of those that have not been recorded from India are enclosed in
+square brackets.
+
+
+_Key to the Genera of_ Plumatellidae.
+
+  I.  Statoblasts without marginal processes.
+    A. Zooecia cylindrical, not embedded in a gelatinous
+       investment (Plumatellinae).
+      _a_.  Zooecia arising directly from one another;
+            no stolon; free statoblast oval          PLUMATELLA, p. 212.
+      _a'_. Zooecia arising singly or in groups from
+            an adherent stolon; free statoblasts oval. STOLELLA, p. 229.
+    B. Zooecia cylindrical, embedded in a structureless
+       gelatinous investment.
+       Zooecia arising from a ramifying stolon;
+       statoblasts circular                               [STEPHANELLA.]
+    C. Polypides embedded in a hyaline synoecium
+       that conceals the cylindrical form of the
+       zooecia (Lophopinae).
+      _c_.  Polypides upright, their base far removed
+            from that of the zoarium when they are
+            expanded                                   LOPHOPUS, p. 231.
+      _c'_. Polypides recumbent for the greater
+            part of their length at the base of
+            the zoarium                               [AUSTRALELLA[BE].]
+  II. Statoblasts armed (normally) with hooked
+      processes (Lophopinae).
+     A. Processes confined to the extremities of
+        the statoblast; zoaria remaining separate
+        throughout life                            LOPHOPODELLA, p. 231.
+     B. Processes entirely surrounding the
+        statoblast; many zoaria embedded in a
+        common gelatinous investment so as to
+        form large compound colonies               PECTINATELLA, p. 235.
+
+     [Footnote BE: See Rec. Ind. Mus. v, p. 40, footnote (1910).]
+
+
+Subfamily A. PLUMATELLINAE.
+
+Of the two Indian genera of this subfamily, one (_Plumatella_) is almost
+universally distributed, while the other (_Stolella_) has only been
+found in the valley of the Ganges. The third genus of the subfamily
+(_Stephanella_) is only known from Japan.
+
+It should be noted that zoaria of different species and genera of this
+subfamily are often found in close proximity to one another and to
+zoaria of _Fredericella_, and that the branches of the different species
+are sometimes entangled together in such a way that they appear, unless
+carefully separated, to belong to the same zoarium.
+
+
+Genus 1. PLUMATELLA, _Lamarck_.
+
+     _Plumatella_, Lamarck, Animaux sans Vert. (ed. 1re) ii, p.
+     106 (1816).
+
+     _Alcyonella_, _id_., _ibid_. p. 100.
+
+     _Plumatella_, Allman, Mon. Fresh-Water Polyzoa, p. 92
+     (1857).
+
+     _Alcyonella_, _id_., _ibid_. p. 86.
+
+     _Plumatella_, Hyatt, Comm. Essex Inst. iv, p. 207, pl. viii
+     (1866).
+
+     _Plumatella_, Jullien (_partim_), Bull. Soc. zool. France,
+     x, p. 100 (1885).
+
+     _Hyalinella_, _id_., _ibid_. p. 133.
+
+     _Plumatella_, Kraepelin, Deutsch. Suesswass. Bryozoen, i, p.
+     104 (1887).
+
+     _Plumatella_, Braem, Unter. ue. Bryozoen des suessen Wassers,
+     p. 2 (Bibliotheca Zoologica, ii, 1890).
+
+_Zoarium_ dendritic, recumbent, erect, or partly recumbent and partly
+erect.
+
+_Zooecia_ tubular, not confined in a gelatinous synoecium; the ectocyst
+usually horny.
+
+_Statoblasts_ often of two kinds, free and stationary, the latter
+without air-cells and as a rule adherent by one surface, the former
+provided with a well-developed ring of air-cells but without marginal
+processes, oval in form, never more than about 0.6 mm. in length.
+
+_Polypide_ with less than 65 tentacles.
+
+[Illustration: Fig. 42.--Outlines of free statoblasts of _Plumatella_
+(enlarged).
+
+A, of _P. fruticosa_ (Calcutta); B, of _P. emarginata_ (Calcutta); C, of
+_P. javanica_ (Travancore); D, of _P. diffusa_ (Sikhim); E, of _P.
+allmani_ (Bhim Tal); F, of _P. diffusa_ (Rajshahi, Bengal); G, G', of
+_P. punctata_ (Calcutta); H, of _P. diffusa_ (Sikhim), statoblast
+further enlarged: A=outline of capsule; B=limit of swim-ring on
+ventral surface; C=limit of swim-ring on dorsal surface. [The dark
+area represents the capsule of the statoblast.]]
+
+Certain forms of this genus are liable to become compacted together in
+such a way as to constitute solid masses consisting of elongate vertical
+zooecia closely parallel to one another and sometimes agglutinated by
+means of a gummy substance. These forms were given by Lamarck in 1816
+the name _Alcyonella_, and there has been much dispute as to whether
+they represent a distinct genus, distinct species, or merely varieties
+or phases of more typical forms. It appears to be the case that all
+species which produce vertical branches are liable to have these
+branches closely packed together and the individual zooecia of which
+they are composed more or less greatly elongated. It is in this way that
+the form known to Allman as _Alcyonella benedeni_ is produced from the
+typical _Plumatella emarginata_. Other forms go further and secrete a
+gummy substance that glues the upright zooecia together and forces them
+to elongate themselves without branching. In these conditions the
+zooecia become polygonal in cross-section. It is probable that such
+forms (_e. g._, _Plumatella fungosa_ (Pallas)) should rank as distinct
+species, for the gummy secretion is present in great profusion even in
+young zoaria in which the zooecia have not yet assumed a vertical
+position. No such form, however, has as yet been found in India, and in
+any case it is impossible to regard _Alcyonella_ as a distinct genus.
+
+
+  _Key to the Indian Species of_ Plumatella.
+
+   I.  Ectocyst more or less stiff, capable of
+       transverse wrinkling only near the tips of
+       the zooecia, never contractile or greatly
+       swollen; zooecia rounded[BF] at the tip when
+       the polypide is retracted. Free statoblasts
+       elongate; the free portion of their swim-ring
+       distinctly narrower at the sides than at
+       the ends.
+      A. Ectocyst by no means rigid, of a uniform
+         pale colour; zooecia never emarginate or
+         furrowed, straight, curved or sinuous,
+         elongate, cylindrical                      _fruticosa_, p. 217.
+      B. Ectocyst rigid; zooecia (or at any rate
+         some of the zooecia) emarginate and furrowed.
+       _b_.   Ectocyst darkly pigmented over the
+              greater part of each zooecium, white
+              at the tip; branching of the zoarium
+              practically dichotomous, profuse, as
+              a rule both horizontal and vertical;
+              zooecia straight or slightly curved
+              or sinuous                           _emarginata_, p. 220.
+       _b'_.  Ectocyst colourless and hyaline;
+              branching of the zoarium sparse,
+              lateral, irregular, horizontal;
+              zooecia nearly straight, strongly
+              emarginate and furrowed                _javanica_, p. 221.
+       _b''_. The majority of the zooecia distinctly
+              L-shaped, one limb being as a rule
+              adherent; ectocyst never densely
+              pigmented.
+          beta.  Zooecia cylindrical, their furrowed
+                 keel never prominent                 _diffusa_, p. 223.
+          beta'. Zooecia (or at any rate some of the
+                 zooecia) constricted or tapering at
+                 the base, their emargination and
+                 furrow conspicuous                   _allmani_, p. 224.
+
+   II. Ectocyst stiff; zooecia truncated when the
+       polypide is retracted. Surface of zooecia
+       minutely roughened, distinctly annulate on
+       the distal part                            _tanganyikae_, p. 225.
+  III. Ectocyst swollen and contractile, capable
+       of transverse wrinkling all over the
+       zooecium; zooecia never emarginate            _punctata_, p. 227.
+
+     [Footnote BF: In specimens preserved in spirit they are apt
+     to collapse and therefore to become somewhat concave.]
+
+There has always been much difficulty in separating the species of
+_Plumatella_, and even now there is no general consensus of opinion as
+to the number that should be recognized. The difficulty, however, is
+much reduced if the following precautions are observed:--
+
+     (1) If the zoarium appears to be tangled, if the branches
+     intertwine or overlap, or if the zooecia are closely pressed
+     together, the whole mass should be carefully dissected out.
+     This is necessary not only because zoaria belonging to
+     different species are sometimes found entangled together but
+     also because it is often difficult to recognize the
+     characteristic method of branching and shape of the zooecia
+     unless it is done.
+
+     (2) As large a part as possible of each zoarium should be
+     examined, preferably with a binocular microscope, and
+     allowance should be made for irregularities and
+     abnormalities of all kinds. What must be observed is the
+     rule rather than the exceptions.
+
+     (3) When the statoblasts are being examined, care must be
+     taken that they lie flat and that their surface is parallel
+     to that of the nose-piece of the microscope. If they are
+     viewed obliquely it is impossible to see their true outlines
+     and proportions.
+
+     (4) In order to see the relative proportions of the capsule
+     and the swim-ring it is necessary that the statoblast should
+     be rendered transparent. This is often difficult owing to
+     the presence of air in the air-cells, but strong nitric acid
+     applied judiciously will render it possible (p. 240).
+
+In supervising the preparation of the plates that illustrate this genus
+I have impressed upon the artist the importance of representing what he
+saw rather than what he thought he ought to see, and the figures are
+very close copies of actual specimens. I have deliberately chosen for
+representation specimens of _Plumatella_ preserved by the simple methods
+which are often the only ones that it is possible for a traveller to
+adopt, for the great majority of naturalists will probably have no
+opportunity of examining living specimens or specimens preserved by
+special methods, and the main object, I take it, of this series is to
+enable naturalists first to distinguish the species described and then
+to learn something of their habitat and habits.
+
+GEOGRAPHICAL DISTRIBUTION.--Of the seven species included in this key
+five have been found in Europe (namely _P. fruticosa_, _P. emarginata_,
+_P. diffusa_, _P. allmani_, and _P. punctata_), while of these five all
+but _P. allmani_ are known to occur in N. America also. _P. javanica_ is
+apparently peculiar to the Oriental Region, while _P. tanganyikae_ has
+only been taken in Central Africa and in the Bombay Presidency.
+
+TYPES.--Very few of the type-specimens of the older species of
+_Plumatella_ are in existence. Allman's are neither in Edinburgh nor in
+London, and Mr. E. Leonard Gill, who has been kind enough to go through
+the Hancock Collection at Newcastle-on-Tyne, tells me that he cannot
+trace Hancock's. Those of the forms described by Kraepelin are in
+Hamburg and that of _P. tanganyikae_ in the British Museum, and there are
+schizotypes or paratypes of this species and of _P. javanica_ in
+Calcutta. The types of Leidy's species were at one time in the
+collection of the Philadelphia Academy of Science.
+
+BIOLOGY.--The zoaria of the species of _Plumatella_ are found firmly
+attached to stones, bricks, logs of wood, sticks, floating seeds, the
+stems and roots of water-plants, and occasionally to the shells of
+molluscs such as _Vivipara_ and _Unio_. Some species shun the light, but
+all are apparently confined to shallow water.
+
+Various small oligochaete worms (e. g., _Chaetogaster spongillae_,[BG]
+_Nais obtusa_, _Nais elinguis_, _Slavina appendiculata_ and _Pristina
+longiseta_[BH]), take shelter amongst them; dipterous larvae of the genus
+_Chironomus_ often build their protective tubes at the base of the
+zoaria, and the surface of the zooecia commonly bears a more or less
+profuse growth of such protozoa as _Vorticella_ and _Epistylis_. I have
+seen a worm of the genus _Chaetogaster_ devouring the tentacles of a
+polypide that had been accidentally injured, but as a rule the movements
+of the lophophore are too quick to permit attacks of the kind, and I
+know of no active enemy of the genus. The growth of sponges at the base
+of the zoaria probably chokes some species, but one form (_F.
+fruticosa_) is able to surmount this difficulty by elongating its
+zooecia (p. 219). A small worm (_Aulophorus tonkinensis_) which is
+common in ponds in Burma and the east of India as far west as Lucknow,
+often builds the tube in which it lives mainly of the free statoblasts
+of this genus. It apparently makes no selection in so doing but merely
+gathers the commonest and lightest objects it can find, for small seeds
+and minute fragments of wood as well as sponge gemmules and statoblasts
+of other genera are also collected by it. I know of no better way of
+obtaining a general idea as to what sponges and phylactolaemata are
+present in a pond than to examine the tubes of _Aulophorus tonkinensis_.
+
+     [Footnote BG: Annandale, J. As. Soc. Bengal (n. s.) ii, p.
+     188, pl. i (1906).]
+
+     [Footnote BH: See Michaelsen, Mem. Ind. Mus. i, pp. 131-135
+     (1908).]
+
+I am indebted to Mr. F. H. Gravely, Assistant Superintendent in the
+Indian Museum, for an interesting note regarding the food of
+_Plumatella_. His observations, which were made in Northamptonshire,
+were unfortunately interrupted at a critical moment, but I have
+reproduced them with his consent in order that other observers may
+investigate the phenomena he saw. Mr. Gravely noted that a small green
+flagellate which was abundant in water in which _Plumatella repens_ was
+growing luxuriantly, was swallowed by the polypides, and that if the
+polyparium was kept in a shallow dish of water, living flagellata of the
+same species congregated in a little pile under the anus of each
+polypide. His preparations show very clearly that the flagellates were
+passing through the alimentary canal without apparent change, but the
+method of preservation does not permit the retractile granules, which
+were present in large numbers in the cell-substance of the flagellates,
+to be displayed and it is possible that these granules had disappeared
+from those flagellates which are present in the recta of his specimens.
+It is clear, therefore, either that certain flagellates must pass
+through the alimentary canal of _Plumatella_ unchanged, or that the
+polyzoon must have the power of absorbing the stored food material the
+flagellates contain without doing them any other injury.
+
+The free statoblasts of _Plumatella_ are as a rule set free before the
+cells they contain become differentiated, and float on the surface of
+the water for some time before they germinate; but occasionally a small
+polypide is formed inside the capsule while it is still in its parent
+zooecium. I have, however, seen only one instance of this premature
+development, in a single statoblast contained in a small zoarium of _P.
+fruticosa_ found in Lower Burma in March. The fixed statoblasts usually
+remain fixed to the support of the zoarium, even when their
+parent-zooecium decays, and germinate _in situ_.
+
+The larva (fig. 40 C, p. 207) that originates from the egg of
+_Plumatella_ is a minute pear-shaped, bladder-like body covered
+externally with fine vibratile threads (cilia) and having a pore at the
+narrow end. At the period at which it is set free from the parent
+zooecium it already contains a fully formed polypide or pair of
+polypides with the tentacles directed towards the narrow end. After a
+brief period of active life, during which it moves through the water by
+means of its cilia, it settles down on its broad end, which becomes
+adhesive; the polypide or pair of polypides is everted through the pore
+at the narrow end, the whole of this end is turned inside out, and a
+fresh polyparium is rapidly formed by budding.
+
+
+29. Plumatella fruticosa, _Allman_. (Plate III, fig. 1; plate IV, fig.
+4; plate V, fig. 1.)
+
+     _Plumatella fruticosa_, Allman, Ann. Nat. Hist. xiii, p. 331
+     (1844).
+
+     _Plumatella repens_, van Beneden (? _nec_ Linne), Mem. Acad.
+     Roy. Belg. 1847, p. 21, pl. i, figs. 1-4.
+
+     _Plumatella fruticosa_, Johnston, Brit. Zooph. (ed. 2), p.
+     404 (1847).
+
+     _Plumatella coralloides_, Allman, Rep. Brit. Assoc. 1850, p.
+     335.
+
+     _Plumatella stricta_, _id._, Mon. Fresh-Water Polyzoa, p.
+     99, fig. 14 (1857).
+
+     _Plumatella fruticosa_, _id._, _ibid._ p. 102, pl. vi, figs.
+     3-5.
+
+     _Plumatella coralloides_, _id._, _ibid._ p. 103, pl. vii,
+     figs. 1-4.
+
+     _Plumatella repens_ and _P. stricta_, Carter, Ann. Nat.
+     Hist. (3) iii, p. 341 (1859).
+
+     _Plumatella lucifuga_, Jullien (_partim_), Bull. Soc. zool.
+     France, x, p. 114 (1885).
+
+     _Plumatella princeps_ var. _fruticosa_, Kraepelin, Deutsch.
+     Suesswasserbryozoen, i, p. 120, pl. vii, fig. 148 (1887).
+
+     _Plumatella fruticosa_, Braem, Unter. ii. Bryozoen des
+     suessen Wassers, p. 9, pl. i, fig. 15 (Bibl. Zool. ii)
+     (1890).
+
+     _Plumatella repens_, Annandale, J. As. Soc. Bengal (new
+     series) iii, 1907, p. 88.
+
+     _Plumatella emarginata_, Loppens (_partim_), Ann. Biol.
+     lacustre, iii, p. 161 (1908).
+
+     _Plumatella fruticosa_, Annandale, Rec. Ind. Mus. v, p. 45
+     (1910).
+
+_Zoarium._ The zoarium in the typical form has a loose appearance due to
+the fact that the branches are far apart and the ectocyst by no means
+rigid. When young the zoarium is adherent, but in well-grown polyparia
+vertical branches, often an inch or more in length, are freely produced.
+As a rule they have not the strength to stand upright if removed from
+the water. Branching is ordinarily lateral and as a rule occurs chiefly
+on one side of a main branch or trunk. In certain circumstances upright
+zooecia are pressed together and reach a great length without branching,
+and in this form (_P. coralloides_, Allman) daughter-zooecia are often
+produced at the tip of an elongated mother-zooecium in fan-like
+formation. A depauperated form (_P. stricta_, Allman), occurs in which
+the vertical branches are absent or very short. In all forms internal
+partitions are numerous and stout.
+
+_Zooecia._ The zooecia are cylindrical and bear a simple keel on their
+dorsal surface. They are never emarginate or furrowed. In the typical
+form their diameter is more than half a millimetre, and they are always
+of considerable length. The ectocyst is thin and never very rigid or
+deeply pigmented, the colour usually being an almost uniform pale
+pinkish brown and fading little towards the tip of the zooecium.
+
+_Statoblasts._ Both free and stationary statoblasts are formed, but the
+latter are rare and do not always adhere. They resemble the free
+statoblasts in general form but have a solid margin instead of a
+swim-ring and are often minutely serrated round the edge. The free
+statoblasts are at least considerably, sometimes very elongate; in all
+zoaria it is possible to find specimens that are more than twice as long
+as broad. The capsule is relatively large and resembles the swim-ring in
+outline, so that the free portion of the latter is not much narrower at
+the sides than at the ends. The sides are distinctly convex and the ends
+rounded; the swim-ring encroaches little on the surface of the capsule.
+
+_Polypide._ The tentacles number between 40 and 50 and are not festooned
+at the base. The stomach is slender and elongate.
+
+TYPE not in existence.
+
+SYSTEMATIC REMARKS.--_P. fruticosa_ is closely allied to _P. repens_
+(European and N. American) but always has much longer statoblasts. Three
+phases of the species may be distinguished as follows:--
+
+     A. (_Forma typica_). Zooecia stout in form, not greatly
+     elongate; free branches produced in profusion.
+
+     B. (_P. stricta_, Allman, _P. repens_, van Beneden). Zooecia
+     slender; free branches absent or consisting of two or three
+     zooecia only.
+
+     C. (_P. coralloides_, Allman). Vertical zooecia pressed
+     together and greatly elongated.
+
+Indian specimens of the typical form agree well with German specimens
+labelled by Prof. Kraepelin _P. princeps_ var. _fruticosa_, and
+specimens of the _coralloides_ phase could hardly be distinguished from
+similar specimens from Scotland.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. fruticosa_ is widely distributed in
+Europe and probably in N. America. I have seen Indian specimens from the
+Punjab (Lahore, _Stephenson_), from Bombay, from Travancore, from
+Calcutta and other places in the Ganges delta, from Rajshahi (Rampur
+Bhoolia) on the R. Ganges, from Kurseong in the E. Himalayas (alt. 4,500
+feet), and from Kawkareik in Tenasserim. Statoblasts found on the
+surface of a pond near Simla in the W. Himalayas (alt. _ca._ 8,000
+feet), probably belong to this species.
+
+BIOLOGY.--Allman states that in England _P. fruticosa_ is fond of still
+and slowly-running water. The typical form and the _coralloides_ phase
+grow abundantly in the Calcutta tanks, the former often attaining an
+extraordinary luxuriance. I have found the var. _stricta_ only in water
+in which there was reason to suspect a lack of minute life (and
+therefore of food), viz. in Shasthancottah Lake in Travancore, in a
+swamp in Lower Burma, and in a small jungle stream near the base of the
+Western Ghats in Travancore. The species is the only one that I have
+seen in running water in India, and the specimens obtained in the jungle
+stream in Travancore are the only specimens I have taken in these
+circumstances. _P. fruticosa_ always grows near the surface or near the
+edge of water; it is found attached to the stems of bulrushes and other
+aquatic plants, to floating seeds and logs and (rarely) to stones and
+bricks. So far as my experience goes it is only found, at any rate in
+Calcutta, in the cold weather and does not make its appearance earlier
+than October.
+
+The form Allman called _P. coralloides_ was found by him, "attached to
+floating logs of wood, together with _P. repens_ and _Cordylophora
+lacustris_, and generally immersed in masses of _Spongilla
+fluviatilis_." I have always found it immersed in sponges (_S.
+lacustris_, _S. alba_, _S. carteri_, and _S. crassissima_), except when
+the sponge in which it had been immersed had decayed. Indeed, the
+peculiar form it has assumed appears to be directly due to the pressure
+of the growing sponge exerted on the zooecia, for it is often possible
+to find a zoarium that has been partially overgrown by a sponge and has
+retained its typical form so long as it was free but has assumed the
+_coralloides_ form where immersed.[BI] In Shasthancottah Lake,
+Travancore, I found specimens of the _stricta_ phase embedded in the
+gelatinous mass formed by a social rotifer and to some extent
+assimilated to the _coralloides_ form.
+
+     [Footnote BI: Braem (_op. cit._, p. 3, pl. i, fig. 1), has
+     described and figured under the name _P. fungosa_ var.
+     _coralloides_, Allman, a dense form that somewhat resembles
+     this phase of _P. fruticosa_ but has become compacted
+     without external pressure. It is, however, probably a form
+     of _P. repens_ rather than _P. fungosa_ and differs in its
+     broad statoblasts from any form of _P. fruticosa_. I have
+     examined specimens of the same form from England.]
+
+
+30. Plumatella emarginata, _Allman_. (Plate III, fig. 2; plate IV, figs.
+1, 1 _a._)
+
+     _Plumatella emarginata_, Allman, Ann. Nat. Hist. xiii, p.
+     330 (1844).
+
+     _Plumatella emarginata_, Johnston, Brit. Zooph. (ed. 2), p.
+     404 (1847).
+
+     _Alcyonella benedeni_, Allman, Mon. Fresh-Water Polyzoa, p.
+     89, pl. iv, figs. 5-11 (1857).
+
+     _Plumatella emarginata_, _id._, _ibid._ p. 104, pl. vii,
+     figs. 5-10.
+
+     _Plumatella lucifuga_, Jullien, Bull. Soc. zool. France, x,
+     figs. 89, 90, p. 114 (1885).
+
+     _Plumatella princeps_ var. _emarginata_, Kraepelin
+     (_partim_), Deutsch. Suesswasserbryoz. p. 120, pl. iv, fig.
+     108, pl. v, fig. 123 (1887).
+
+     _Plumatella emarginata_, Braem, Unter. ii. Bryoz. suessen
+     Wassers, p. 9, pl. i, figs. 12, 14 (Bibl. Zool. ii) (1890).
+
+     _Plumatella emarginata_, Annandale (_partim_), J. As. Soc.
+     Bengal, (new series) iii, 1907, p. 89.
+
+     _Plumatella princeps_, Loppens (_partim_), Ann. Biol.
+     lacustre, iii, p. 162, fig. 7 (1908).
+
+     _Plumatella emarginata_, Annandale, Rec. Ind. Mus. v, p. 47
+     (1910).
+
+_Zoarium._ The zoarium often covers a considerable area on flat surfaces
+and is sometimes entirely recumbent. More usually, however, the younger
+part is vertical. In either case the branching is practically
+dichotomous, two young zooecia arising almost simultaneously at the tip
+of a mother-zooecium and diverging from one another at a small angle.
+When the zoarium becomes vertical, rigid branches of as much as an inch
+in length are sometimes produced in this way and, arising parallel to
+one another, are pressed together to form an almost solid mass
+(=_Alcyonella benedeni_, Allman). In such cases the basal zooecium or at
+any rate the basal part of each upright branch is considerably
+elongated. In recumbent zooecia the main branches often radiate outwards
+from a common centre.
+
+_Zooecia._ The zooecia are of almost equal width throughout, slender,
+and moderately elongate when recumbent. Their ectocyst is stiff; they
+are emarginate at the tip and more or less distinctly furrowed on the
+dorsal surface, the keel in which the furrow runs not being prominent.
+The orifice is often on the dorsal surface even in upright branches.
+Each zooecium is of a dark brown or almost black colour for the greater
+part of its length but has a conspicuous white tip which is extended
+down the dorsal surface in the form of a triangle, its limits being
+rather more extensive than and parallel to those of the emargination.
+
+_Statoblast._ The majority of the free statoblasts are elongate and
+truncate or subtruncate at the extremities, the sides being as a rule
+straight and parallel. In every polyparium specimens will be found that
+are between twice and thrice as long as broad. The capsule is, however,
+relatively much broader than the swim-ring, often being nearly circular,
+and there is therefore at either end a considerable extent of free
+air-cells, while the extent of these cells at the sides of the capsule
+is small. The air-cells cover a considerable part of the dorsal surface
+of the capsule. Fixed statoblasts are usually found in old colonies,
+especially at the approach of the hot weather. They have an oval form
+and are surrounded by a membranous margin on which traces of
+reticulation can often be detected. As a rule statoblasts of both types
+are produced in considerable but not in excessive numbers.
+
+_Polypide._ There are about 40 tentacles, the velum at the base of which
+extends upwards for a considerable distance without being festooned. The
+stomach is elongate and slender and narrowly rounded at the base.
+
+The method of branching, the coloration of the zooecia and the form of
+the free statoblast are all characteristic. Luxuriant or closely
+compressed zoaria of _P. diffusa_ often bear a superficial resemblance
+to those of _P. emarginata_, but the resemblance disappears if they are
+carefully dissected out. Indian specimens of _P. emarginata_ agree
+closely with European ones.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. emarginata_ is a common species in
+Europe, N. America, and southern Asia and probably also occurs in Africa
+and Australia. I have examined specimens from Calcutta, Rangoon, and
+Mandalay in Indian territory, and also from Jalor in the Patani States
+(Malay Peninsula) and the Tale Noi, Lakon Sitamarat, Lower Siam.
+Gemmules found by Apstein (Zool. Jahrb. (Syst.) xxv, 1907, p. 201) in
+plankton from the Colombo lake may belong to this species or to any of
+the others included by Kraepelin in his _P. princeps_.
+
+BIOLOGY.--In Ireland Allan found _P. emarginata_ in streams and
+rivulets, but it also occurs in European lakes. In India I have only
+found it in ponds. It prefers to adhere to the surface of stones or
+bricks, but when these are not available is found on the stems of
+water-plants. In the latter position the form called _Alcyonella
+benedeni_ by Allman is usually produced, owing to the fact that the
+upright branches are crowded together through lack of space, very much
+in the same way (although owing to a different cause) as those of _P.
+fruticosa_ are crowded together in the _coralloides_ phase, to which the
+_benedeni_ phase of _P. emarginata_ is in many respects analogous.
+
+Although it is essentially a cold-weather species in Calcutta, _P.
+emarginata_ is sometimes found in a living condition during the "rains."
+Zoaria examined at this season, however, contains few living polypides,
+the majority of the zooecia having rotted away and left fixed
+statoblasts only to mark their former position.
+
+
+31. Plumatella javanica, _Kraepelin_.
+
+     _Plumatella javanica_, Kraepelin, Mitt. Nat. Mus. Hamb.
+     xxiii, p. 143, figs. 1-3 (1903).
+
+     _Plumatella emarginata_ var. _javanica_, Loppens, Ann. Biol.
+     lacustre, iii, p. 162 (1908).
+
+     _Plumatella javanica_, Annandale, Rec. Ind. Mus. v, p. 50
+     (1910).
+
+     _Plumatella allmani_ var. _dumortieri_, _id._ (_partim_)
+     (_nec_ Allman), _ibid._ p. 49.
+
+This species is related to _P. emarginata_, from which it may be
+distinguished by the following characters:--
+
+_Zoarium._ The zoarium is always entirely recumbent and branches
+sparingly; its method of branching does not approach the dichotomous
+type but is lateral and irregular. Linear series of zooecia without
+lateral branches are often formed.
+
+_Zooecia._ The zooecia are slender and often very long; they are
+strongly emarginate and furrowed, and the keel that contains the furrow
+is conspicuous. The ectocyst is hyaline and as a rule absolutely
+colourless.
+
+_Statoblasts._ The free statoblasts are variable in length, sometimes
+distinctly elongate, sometimes elongate only to a moderate degree; they
+are rounded at the extremities and have the sides slightly or distinctly
+convex outwards. The capsule is relatively large, and the free portion
+of the swim-ring is not much broader at the ends than at the sides. The
+fixed statoblasts are elongate and surrounded by an irregularly shaped
+chitinous membrane, which is often of considerable extent. The whole of
+the dorsal surface is covered with what appear to be rudimentary
+air-spaces some of which even contain air.
+
+The transparent glassy ectocyst and strong furrowed keel of this species
+are very characteristic, but the former character is apt to be obscured
+by staining due to external causes, especially when the zoarium is
+attached to dead wood. The shape of the free statoblasts is too variable
+to be regarded as a good diagnostic character, but the fixed
+statoblasts, when they are to be found, are very characteristic in
+appearance. _P. javanica_ appears to be closely related to Allman's _P.
+dumortieri_, with which stained zoaria are apt to be confused. The
+character of the ectocyst is, however, different, and the free part of
+the swim-ring is distinctly narrower at the sides of the free
+statoblasts. Dr. Kraepelin has been kind enough to send me one of the
+types.
+
+TYPES in the Hamburg and Indian Museums.
+
+GEOGRAPHICAL DISTRIBUTION.--Java, Penang, India. Indian localities
+are:--BENGAL, Calcutta; Berhampore, Murshidabad; R. Jharai, Siripur,
+Saran district, Tirhut: E. HIMALAYAS, Kurseong, Darjiling district (alt.
+4,500 feet): MADRAS PRESIDENCY, canal near Srayikaad, Travancore. Mr. C.
+W. Beebe has recently sent me a specimen taken by him in the Botanical
+Gardens at Penang.
+
+BIOLOGY.--Very little is known about the biology of this species.
+Kraepelin took it in Java on the leaves of water-lilies. It is not
+uncommon during the cold weather in the Calcutta Zoological Gardens on
+floating seeds and sticks and on the stems of bulrushes; in Travancore I
+took it in November on the submerged leaves of _Pandani_ growing at the
+edge of a canal of slightly brackish water. Mr. Hodgart, the collector
+of the Indian Museum, found it in the R. Jharai on the stems of
+water-plants at a time of flood in the "rains." In Calcutta it is often
+found entangled with _P. fruticosa_ and _P. emarginata_.
+
+
+32. Plumatella diffusa, _Leidy_. (Plate IV, fig. 2.)
+
+     _Plumatella diffusa_, Leidy, P. Ac. Philad. v, p. 261
+     (1852).
+
+     _Plumatella diffusa_, Allman, Mon. Fresh-Water Polyzoa, p.
+     105 (1857).
+
+     _Plumatella diffusa_, Hyatt, Comm. Essex Inst. iv, pl. viii,
+     figs. 11, 12 (1866).
+
+     _Plumatella diffusa_, _id._, _ibid._ v, p. 107, fig. 12
+     (1868).
+
+     _Plumatella repens_, Jullien, Bull. Soc. zool. France, x,
+     fig. 37 (_lapsus_ for 73), p. 110 (1885).
+
+     _Plumatella diffusa_, _id._, _ibid._ figs. 155, 157, pp.
+     130, 131.
+
+     _Plumatella allmani_ var. _diffusa_, Annandale, Rec. Ind.
+     Mus. v, p. 49 (1910).
+
+_Zoarium._ The zoarium often covers a considerable area on flat surfaces
+and is sometimes found crowded together on the stems of plants. In the
+latter case the arrangement of the main branches is distinctly radiate.
+Upright branches occur rarely and never consist of more than three
+zooecia. The characteristic method of branching is best represented by
+the following diagram:--
+
+[Illustration: Fig. 43.]
+
+The partitions are stout and numerous.
+
+_Zooecia._ The great majority of the zooecia in each zoarium are
+distinctly L-shaped, the long limb being usually adherent. The vital
+organs of the polypide are contained in the vertical limb, while the
+horizontal one, in mature polyparia, is packed full of free statoblasts.
+The zooecia are cylindrical and as a rule obscurely emarginate and
+furrowed. The ectocyst is stiff; it is never deeply pigmented but is
+usually of a transparent horn-colour at the base of each zooecium and
+colourless at the tip, the contrast between the two portions never being
+very strong. The basal portion is rough on the surface, the distal
+portion smooth.
+
+_Statoblasts._ Free statoblasts are produced in very great profusion and
+fixed statoblasts are also to be found as a rule. The latter resemble
+those of _P. emarginata_. The free statoblasts are never very large or
+relatively broad, but they vary considerably as regards size and
+outline. The capsule is large, the sides convex outwards and the
+extremity more or less broadly rounded. The air-cells are unusually
+large and extend over a great part of the dorsal surface of the
+statoblast.
+
+_Polypide._ The polypide is shorter and stouter than that of _P.
+emarginata_ and as a rule has fewer tentacles.
+
+The most characteristic feature of this species is the form of the
+zooecia, which differ greatly from those of any other Indian species but
+_P. allmani_. In the latter they are distinctly "keg-shaped" (_i. e._,
+constricted at the base and swollen in the middle), and the zoarium
+never spreads out over large surfaces in the way in which that of _P.
+diffusa_ does.
+
+TYPE--? in the Philadelphia Academy of Sciences.
+
+GEOGRAPHICAL DISTRIBUTION.--This species was originally described from
+North America (in which it is apparently common) and occurs also in
+Europe. I have seen Indian specimens from the following
+localities:--BENGAL, Calcutta and neighbourhood; Rajshahi (Rampur
+Bhulia): E. HIMALAYAS, Gangtok, Native Sikhim (alt. 6,150 feet)
+(_Kirkpatrick_, _Stewart_): PUNJAB, Lahore (_Stephenson_).
+
+BIOLOGY.--_P. diffusa_ in Lower Bengal is a cold-weather species. It is
+remarkable for the enormous number of gemmules it produces and is
+usually found either on floating objects such as the stems of certain
+water-plants, or on stones or bricks at the edge of ponds.
+
+
+33. Plumatella allmani, _Hancock_. (Plate IV, figs. 3, 3 _a_.)
+
+     _Plumatella allmani_, Hancock, Ann. Nat. Hist. (2) v, p.
+     200, pl. v, fig. 3-4, pl. iii, fig. 2-3 (1850).
+
+     _Plumatella allmani_, Allman, Mon. Fresh-Water Polyzoa, p.
+     106, fig. 16 (1857).
+
+     _Plumatella elegans_, _id._, _ibid._ p. 107, pl. viii, figs.
+     6-10.
+
+     _Plumatella lucifuga_ ("forme rampante") Jullien, Bull. Soc.
+     zool. France, x, p. 114 (1885).
+
+This species is closely allied to _P. diffusa_, from which it differs in
+the following characters:--
+
+     (1) The zoarium never covers a large area and as a rule
+     grows sparingly and mainly in two directions.
+
+     (2) The zooecia are more irregular in shape, not so
+     distinctly elbowed, smaller; they have a much more
+     prominently keeled ridge. The great majority of them are
+     constricted at the base and taper towards the orifice. In
+     young zoaria they are almost colourless but in older ones
+     there is a band of not very dense pigment round the base of
+     the vertical limb.
+
+     (3) The free statoblasts are comparatively large and usually
+     show a tendency to taper at the extremities, often being
+     almost rhomboidal in form. The swim-ring does not extend so
+     far over the dorsal surface as it does in those of _P.
+     diffusa_; the "cells" of which it is composed are small.
+
+TYPE not in existence.
+
+I have seen every gradation between this form and Allman's _P. elegans_.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. allmani_ is apparently a rare species to
+which there are few references in literature. It was originally
+described from England and is stated by Jullien to occur in France. I
+have found specimens only in the lake Bhim Tal (alt. 4,500 feet) in the
+W. Himalayas.
+
+BIOLOGY.--The original specimens were found by Hancock on stones. My own
+were growing on the leaves of water-plants, usually on the under side.
+When the zooecia were forced to stretch across from one leaflet to
+another they assumed the sinuous form characteristic of Allman's _P.
+elegans_.
+
+
+34. Plumatella tanganyikae, _Rousselet_.
+
+     _Plumatella tanganyikae_, Rousselet, Proc. Zool. Soc. London,
+     1907 (i), p. 252, pl. xiv, figs. 1-4.
+
+     _Plumatella bombayensis_, Annandale, Rec. Ind. Mus. ii, p.
+     169, figs. 1, 2 (1908).
+
+     _Plumatella bombayensis_, _id._, _ibid._ v, p. 51 (1910).
+
+_Zoarium._ The whole colony is recumbent but branches freely and at
+short intervals in a horizontal plane, so that the zooecia become
+crowded together and the branches sometimes overlap one another. The
+zoarium often covers a considerable area, but growth seems to be mainly
+in two directions. When growing on the stems of water-plants the
+branches are often parallel and closely pressed together but remain
+recumbent in this position. A stout membrane sometimes extends between
+branches and individual zooecia.
+
+_Zooecia._ The walls of the zooecia are thick, stiff, and more or less
+darkly but not opaquely pigmented; the external surface, although not
+very smooth, is always clean. The two most noteworthy characters of the
+zooecia are (i) their truncated appearance when the polypide is
+retracted, and (ii) the conspicuous, although often irregular external
+annulation of their walls. The tip of each zooecium, owing to the fact
+that the invaginated part of the ectocyst is soft and sharply separated
+from the stiffened wall of the tube, terminates abruptly and is not
+rounded off gradually as is the case in most species of the genus;
+sometimes it expands into a trumpet-like mouth. The annulation of the
+external surface is due to numerous thickened areas of the ectocyst
+which take the form of slender rings surrounding the zooecium; they are
+most conspicuous on its distal half. On the dorsal surface of the base
+of each zooecium there is a conspicuous furrowed keel, which, however,
+does not usually extend to the distal end; the latter is oval in
+cross-section. The zooecia are short and broad; their base is always
+recumbent, and, when the zoarium is attached to a stone or shell, often
+seems to be actually embedded in the support; the distal part turns
+upwards and is free, so that the aperture is terminal; the zooecia of
+the older parts of the zoarium exhibit the specific characters much more
+clearly than those at the growing points.
+
+_Polypide._ The lophophore bears 20 to 30 tentacles, which are long and
+slender; the velum at their base extends up each tentacle in the form of
+a sharply pointed projection, but these projections do not extend for
+more than one-fifth of the length of the tentacles. Both the velum and
+the tentacular sheath bear numerous minute tubercles on the external
+surface. The base of the stomach is rounded, and the whole of the
+alimentary canal has a stout appearance.
+
+[Illustration: Fig. 44.--_Plumatella tanganyikae_ from Igatpuri Lake.
+
+A=outline of part of zoarium from a stone, x 16; B=outline of the tip of
+a single zooecium, x 70; C=free statoblast, x 70.]
+
+_Statoblasts._ Both fixed and free statoblasts are produced, but not in
+very large numbers. The latter are broadly oval and are surrounded by a
+stout chitinous ring, which often possesses irregular membranous
+projections; the surface is smooth. The free statoblasts are small and
+moderately elongate, the maximum breadth as a rule measuring about 2/3
+of the length; the capsule is relatively large and the ring of air-cells
+is not very much broader at the ends than at the sides; the dorsal
+surface of the central capsule is profusely tuberculate. The outline of
+the whole structure is often somewhat irregular.
+
+In deference to Mr. Rousselet's opinion expressed in a letter I have
+hitherto regarded the Bombay form of this species as distinct from the
+African one, and there certainly is a great difference in the appearance
+of specimens taken on the lower surface of stones in Igatpuri Lake and
+of the types of _P. tanganyikae_, one of which is now in the collection
+of the Indian Museum. The dark colour of the former, however, and their
+vigorous growth appear to be directly due to environment, for these
+characters disappear to a large extent in specimens growing on the stems
+of water-plants in the same lake. Indeed, such specimens are exactly
+intermediate between the form "_bombayensis_" and the typical form of
+the species. _P. tanganyikae_ is closely allied to _P. philippinensis_,
+Kraepelin, from the island of Luzon, but the latter has a smooth and
+polished ectocyst devoid of annulations, and zooecia of a more elongate
+and regular form.
+
+TYPES of the species in the British and Indian Museums, those of _P.
+bombayensis_ in the latter collection.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. tanganyikae_ is only known as yet from L.
+Tanganyika in Central Africa and from Igatpuri in the Bombay Presidency.
+
+BIOLOGY.--In both localities the zoaria were found in shallow water. In
+L. Tanganyika they were encrusting stones and shells, while at Igatpuri
+they were fixed for the most part to the lower surface of stones but
+were also found on the stems of water-plants. My specimens from the
+Bombay Presidency were taken, on two separate occasions, at the end of
+November. At that date the zoaria were already decaying and large
+blanks, marked out by fixed statoblasts, were often observed on the
+stones. Probably, therefore, the species flourishes during the "rains."
+
+
+35. Plumatella punctata, _Hancock_. (Plate IV, fig. 5.)
+
+    _Plumatella punctata_, Hancock, Ann. Nat. Hist. (2) v, p. 200, pl. iii,
+    fig. 1, and pl. v, figs. 6, 7 (1850).
+
+    _Plumatella vesicularis_, Leidy, P. Ac. Philad. vii, p. 192 (1854).
+
+    _Plumatella vitrea_, Hyatt, Comm. Essex Inst. iv, pl. ix, figs. 1, 2
+    (1866).
+
+    _Plumatella punctata_, Allman, Mon. Fresh-Water Polyzoa, p. 100,
+    fig. 15 (1857).
+
+    _Plumatella vesicularis_, _id._, _ibid._ p. 101.
+
+     _Plumatella vitrea_, Hyatt, Proc. Essex Inst. v, p. 225,
+     figs. 18, 19 (1868).
+
+     _Plumatella vesicularis_, _id._, _ibid._ p. 225.
+
+     _Hyalinella vesicularis_, Jullien, Bull. Soc. zool. France,
+     x, p. 133, figs. 165-172 (1885).
+
+     _Hyalinella vitrea_, _id._, _ibid._ p. 134, figs. 173-179.
+
+     _Plumatella punctata_, Kraepelin, Deutsch.
+     Suesswasserbryozoen, i, p. 126, pl. iv, figs. 115, 116; pl.
+     v, figs. 124, 125; pl. vii, figs. 153, 154 (1887).
+
+     _Plumatella vesicularis_, Braem, Unters. ue. Bryozoen suessen
+     Wassers, p. 8, pl. i, fig. 8 (Bibl. Zool. ii) (1890).
+
+     _Hyalinella punctata_, Loppens, Ann. Biol. lacustre, iii, p.
+     163 (1908).
+
+     _Plumatella punctata_, Annandale, Rec. Ind. Mus. v, p. 52
+     (1910).
+
+_Zoarium._ The zoarium is entirely recumbent and often appears to form
+an almost uniform flat layer instead of a dendritic body. Sometimes,
+however, it is distinctly linear, with lateral branches produced
+irregularly at considerable distances apart.
+
+_Zooecia._ The zooecia differ from those of all other species in having
+a greatly swollen, soft ectocyst which can be transversely wrinkled all
+over the zooecium by the action of the muscles of the polypide and is
+distinctly contractile. It is mainly owing to the swollen and almost
+gelatinous nature of the ectocyst that the dendritic character of the
+zoarium is frequently concealed, for the method of branching is
+essentially the same as that of _P. diffusa_, although the zooecia are
+not so distinctly elbowed. The ectocyst is colourless or faintly tinted
+with brown; as a rule it is not quite hyaline and the external surface
+is minutely roughened or tuberculate. The zooecia are not emarginate or
+furrowed.
+
+_Statoblasts._ Stationary statoblasts are not found.  The free
+statoblasts are variable and often asymmetrical in outline, but the free
+portion of the swim-ring is always of nearly equal diameter all round
+the periphery and the capsule relatively large. Some of the statoblasts
+are always broad in comparison with their length.
+
+_Polypide._ The polypide is comparatively short and stout. European
+specimens are said to have from 30 to 40 tentacles, but Indian specimens
+have only from 20 to 30.
+
+Shrunken specimens of the less congested forms of this species closely
+resemble specimens of _P. repens_, but the statoblasts are more variable
+in shape and the ectocyst, even in such specimens, is thicker. Living or
+well-preserved specimens cannot be mistaken for those of any other
+species. Jullien regarded _P. punctata_ as the type of a distinct genus
+(_Hyalinella_) but included in _Plumatella_ at least one form (P.
+"_arethusa_") which probably belongs to this species. Kraepelin
+distinguishes as "varieties" two phases, a summer phase ("var.
+_prostrata_") and an autumn phase ("var. _densa_"). The former often
+forms linear series of considerable length with only an occasional
+side-branch, while in the autumn phase branching is so profuse and the
+branches are so closely pressed together that the zoarium comes to
+resemble a uniform gelatinous patch rather than a dendritic growth. A
+phase resembling the European autumn form is the commonest in Calcutta
+and I have also found one intermediate between this and Kraepelin's
+"var. _prostrata_," neither having any seasonal significance in India.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. punctata_ is widely distributed in
+Europe and N. America, but in the Oriental Region it has only been found
+in Calcutta and the neighbourhood.
+
+BIOLOGY.--In this part of India _P. punctata_ flourishes both during the
+"rains" and in winter. I have found specimens in June and July and also
+in December and January. The majority of them were attached to bricks,
+but some were on the roots of duckweed, the stems of water-plants, and
+the tips of creepers falling into water. The species is often found
+together with _Stolella indica_ and also with other species of its own
+genus. It is most common, in the neighbourhood of Calcutta, in that part
+of the town which is near the Salt Lakes, and occurs in ponds the water
+of which is slightly brackish.
+
+
+Genus 2. STOLELLA, _Annandale_.
+
+    _Stolella_, Annandale, Rec. Ind. Mus. iii, p. 279 (1909).
+
+    _Stolella_, _id._, _ibid._ v, p. 53 (1910).
+
+TYPE, _Stolella indica_, Annandale.
+
+_Zoarium_. The zoarium consists of groups of zooecia (or occasionally of
+single zooecia) joined together by an adherent rhizome. There is no
+gelatinous investment.
+
+_Zooecia._ The adult zooecia resemble those of _Plumatella_ except in
+being sometimes more or less upright.
+
+_Polypide_ and _Statoblasts._ The polypide and statoblasts resemble
+those of _Plumatella_. Fixed as well as free statoblasts occur.
+
+This genus is closely allied to _Plumatella_, from which it is probably
+derived. The root-like tube from which the zooecia arise is formed by
+the great elongation of the basal part of a zooecium, and the zoaria
+closely resemble those of _P. punctata_, for it is not until several
+zooecia have been produced that the characteristic mode of growth
+becomes apparent.
+
+_Stolella_ has only been found in India and is monotypic[BJ].
+
+     [Footnote BJ: But see p. 246 (addenda).]
+
+
+36. Stolella indica, _Annandale_. (Plate V, figs. 3, 4.)
+
+    _Stolella indica_, Annandale, Rec. Ind. Mus. iii, p. 279, fig. (1909).
+
+    _Stolella indica_, _id._, _ibid._ v, p. 53 (1910).
+
+_Zoarium._ The zoarium is adherent and linear, having neither lateral
+nor vertical branches.
+
+_Zooecia._ The zooecia are short and slender, erect or nearly so,
+distinctly emarginate and furrowed. Their ectocyst is soft, colourless
+and transparent but minutely roughened on the surface.
+
+_Polypide._ The tentacles number from 30 to 35 and are rather short and
+stout, sometimes being slightly expanded at the tips. The stomach is
+comparatively short and abruptly truncated posteriorly.
+
+_Statoblasts._ Both free and fixed statoblasts are found, and both are
+variable in form, the latter varying in outline from the circular to the
+broadly oval. The free statoblasts resemble those of _Plumatella
+punctata_, but are sometimes rather more elongate.
+
+TYPE in the Indian Museum.
+
+[Illustration: Fig. 45.--Zoarium of _Stolella indica_ on stem of
+water-plant (from Calcutta), x 6.]
+
+GEOGRAPHICAL DISTRIBUTION.--So far as we know, this species is confined
+to the Indo-Gangetic Plain. Major Walton found it at Bulandshahr in the
+United Provinces, and it is not uncommon in the neighbourhood of
+Calcutta.
+
+BIOLOGY.--The zoaria of _S. indica_ are usually fixed to the roots of
+duckweed or to the stems of other plants. They are often found together
+with those of _P. punctata_. A slight infusion of brackish water into
+the ponds in which it lives does not seem to be inimical to this
+species, but I have found it in ponds in which nothing of the kind was
+possible. It flourishes during the "rains" and, to judge from specimens
+kept in an aquarium, is very short-lived. Major Walton found it growing
+over a zoarium of _Hislopia lacustris_.
+
+
+Subfamily B. LOPHOPINAE.
+
+The zoaria of this subfamily are never dendritic but form gelatinous
+masses which, except in _Australella_, are cushion-shaped or sack-like.
+With the possible exception of _Australella_, they possess to a limited
+extent the power of moving along vertical or horizontal surfaces, but it
+is by no means clear how they do so (see p. 172). The statoblasts are
+remarkable for their large size, and it is noteworthy that
+_Australella_, which is intermediate in structure between the
+Plumatellinae and the Lophopinae, possesses statoblasts of intermediate
+size. The swim-ring is always well developed, and fixed statoblasts are
+unknown.
+
+Only two genera (_Lophopodella_ and _Pectinatella_) have been definitely
+proved to occur in India, but a third (_Lophopus_[BK]) is stated to have
+been found in Madras. Should it be met with it will easily be recognized
+by the upright position of its polypides when their tentacles are
+expanded and by the fact that the statoblasts never bear marginal
+processes.
+
+     [Footnote BK: Only two species are known, _L. crystallinus_
+     (Pallas) from Europe and N. America, with oval statoblasts
+     that are produced and pointed at the two ends, and _L.
+     jheringi_, Meissner from Brazil, with irregularly polygonal
+     or nearly circular statoblasts.]
+
+
+Genus 3. LOPHOPODELLA, _Rousselet_.
+
+     _Lophopodella_, Rousselet, Journ. Quek. Micr. Club (2) ix,
+     p. 45 (1904).
+
+     _Lophopodella_, Annandale, Rec. Ind. Mus. v, p. 54 (1910).
+
+TYPE, _Pectinatella carteri_, Hyatt.
+
+_Zoarium._ The zoarium consists of a circular or oval mass of no great
+size. Polyparia do not form compound colonies.
+
+_Polypides._ The polypides lie semi-recumbent in the mass and never
+stand upright in a vertical position.
+
+_Statoblasts._ The statoblasts are of considerable size and normally
+bear at both ends a series of chitinous processes armed with double rows
+of small curved spinules.
+
+As a rule the genus is easily recognized by means of the statoblasts,
+but sometimes the processes at the ends of these structures are absent
+or abortive and it is then difficult to distinguish them from those of
+_Lophopus_. There is, however, no species of that genus known that has
+statoblasts shaped like those of the Indian species of _Lophopodella_.
+
+Three species of _Lophopodella_, all of which occur in Africa, have been
+described; _L. capensis_ from S. Africa, which has the ends of the
+statoblast greatly produced, _L. thomasi_ from Rhodesia, in which they
+are distinctly concave, and _L. carteri_ from E. Africa, India and
+Japan, in which they are convex or truncate.
+
+The germination of the gemmule and the early stages in the development
+of the polyparium of _L. capensis_ have been described by Miss Sollas
+(Ann. Nat. Hist. (8) ii, p. 264, 1908).
+
+
+37. Lophopodella carteri (_Hyatt_). (Plate III, figs. 4, 4_a_.)
+
+     _Lophopus_ sp., Carter, Ann. Nat. Hist. (3) iii, p. 335, pl.
+     viii, figs. 8-15 (1859).
+
+     ? _Lophopus_ sp., Mitchell, Q. J. Micr. Sci. London (3) ii,
+     p. 61 (1862).
+
+     _Pectinatella carteri_, Hyatt, Comm. Essex Inst. iv, p. 203
+     (footnote) (1866).
+
+     _Pectinatella carteri_, Meissner, Die Moosthiere
+     Ost-Afrikas, p. 4 (in Mobius's Deutsch-Ost-Afrika, iv,
+     1898).
+
+     _Lophopodella carteri_, Rousselet, Journ. Quek. Micr. Club,
+     (2) ix, p. 47, pl. iii, figs. 6, 7 (1904).
+
+     _Lophopus carteri_, Annandale, Rec. Ind. Mus. ii, p. 171,
+     fig. 3 (1908).
+
+     _Lophopodella carteri_, _id._, _ibid._ v, p. 55 (1910).
+
+_Zoarium._ The zoarium as a rule has one horizontal axis longer than the
+other so that it assumes an oval form when the polypides are expanded;
+when they are retracted its outline is distinctly lobular. Viewed from
+the side it is mound-shaped. The polypides radiate, as a rule in several
+circles, from a common centre. The ectocyst is much swollen, hyaline and
+colourless.
+
+_Polypide._ The polypide has normally about 60 tentacles, the velum at
+the base of which is narrow and by no means strongly festooned. The
+stomach is yellow or greenish in colour. The extended part of the
+polypide measures when fully expanded rather less than 3 mm., and each
+limb of the lophophore about the same.
+
+_Statoblast._ The statoblast is variable in shape and size but measures
+on an average about 0.85 x 0.56 mm. The ends are truncate or
+subtruncate; the capsule is small as compared with the swim-ring and as
+a rule circular or nearly so. The processes at the two ends are variable
+in number; so also are their spinules, which are arranged in two
+parallel rows, one row on each side of the process, and are neither very
+numerous nor set close together; as a rule they curve round through the
+greater part of a circle and are absent from the basal part of the
+process.
+
+[Illustration: Fig. 46.--Lophopodella carteri (from Igatpuri Lake).
+
+A=outline of a zoarium with the polypides expanded, as seen from below
+through glass to which it was attached, x 4; B=outline of a zoarium with
+the polypides highly contracted, as seen from above, x 4; C=statoblast,
+x 75.]
+
+
+37 _a._ Var. himalayana.
+
+     _Lophopus lendenfeldi_, Annandale (_nec_ Ridley), J. As.
+     Soc. Bengal, (n. s.) iii, 1907, p. 92, pl. ii, figs. 1-4
+     (1907).
+
+     _Lophopus lendenfeldi_ var. _himalayanus_, _id._, Rec. Ind.
+     Mus. i, p. 147, figs. 1, 2 (1907).
+
+     _Lophopus himalayanus_, _id._, _ibid._ ii, p. 172, fig. 4
+     (1908).
+
+This variety differs from the typical form in having fewer tentacles and
+in the fact that the marginal processes of the statoblast are abortive
+or absent.
+
+_Pectinatella davenporti_, Oka[BL] from Japan is evidently a local race
+of _L. carteri_, from the typical form of which it differs in having the
+marginal processes of the statoblast more numerous and better developed.
+The abortive structure of these processes in var. _himalayana_ points to
+an arrest of development, for they are the last part of the statoblast
+to be formed.
+
+     [Footnote BL: Zool. Anz. xxxi, p. 716 (1907), and Annot.
+     Zool. Japon. vi, p. 117 (1907).]
+
+TYPES. The statoblasts mounted in Canada balsam by Carter and now in the
+British Museum must be regarded as the types of the species named but
+not seen by Hyatt. The types of the var. _himalayana_ are in the Indian
+Museum and those of the subspecies _davenporti_ presumably in the
+possession of Dr. Oka in Tokyo.
+
+GEOGRAPHICAL DISTRIBUTION.--The typical form occurs in Bombay, the W.
+Himalayas and possibly Madras, and its statoblasts have been found in E.
+Africa; the var. _himalayana_ has only been taken in the W. Himalayas
+and the subspecies _davenporti_ in Japan. Indian localities are:--BOMBAY
+PRESIDENCY, Igatpuri Lake, W. Ghats (alt. _ca._ 2,000 feet); the Island
+of Bombay (_Carter_): W. HIMALAYAS, Bhim Tal, Kumaon (alt. 4,500 feet).
+
+BIOLOGY.--_L. carteri_ is found on the lower surface of stones and on
+the stems and leaves of water-plants, usually in lakes or large ponds.
+Although the zoaria do not form compound colonies by secreting a common
+membrane or investment, they are markedly gregarious. The most closely
+congregated and the largest zoaria I have seen were assembled amongst a
+gelatinous green alga of the genus _Tolypothrix_[BM] (Myxophyceae) that
+grows on the vertical stems of a plant at the edge of Igatpuri Lake; it
+is noteworthy that in this case the alga seemed to take the place of the
+common investment of _Pectinatella burmanica_, in which green cells are
+present in large numbers (p. 237). The zoaria of _L. carteri_ are able
+to change their position, and I found that if a number of them were
+placed in a bottle of water they slowly came together at one spot, thus
+apparently forming temporary compound colonies. Before a movement of the
+whole zoarium commences its base becomes detached from its support at
+the anterior end (fig. 32, p. 172), but the whole action is extremely
+slow and I have not been able to discover any facts that cast light on
+its exact method of production. At Igatpuri statoblasts are being
+produced in considerable numbers at the end of November, but many young
+zoaria can be found in which none have as yet been formed.
+
+     [Footnote BM: Prof. W. West will shortly describe this alga,
+     which represents a new species, in the Journ. Asiat. Soc.
+     Bengal, under the name _Tolypothrix
+     lophopodellophila_.--_April 1911_.]
+
+The larva of a fly of the genus _Chironomus_ is often found inhabiting a
+tube below zoaria of _L. carteri_. It is thus protected from its enemies
+but can protrude its head from beneath the zoarium and seize the small
+animals on which it preys.
+
+
+Genus 4. PECTINATELLA, _Leidy_.
+
+     _Cristatella_, Leidy, P. Ac. Philad. v, p. 265 (1852).
+
+     _Pectinatella_, _id._, _ibid._, p. 320.
+
+     _Pectinatella_, Allman, Mon. Fresh-Water Polyzoa, p. 81
+     (1857).
+
+     _Pectinatella_, Hyatt, Proc. Essex Inst. v, p. 227, fig. 20
+     (1867).
+
+     _Pectinatella_, Kraepelin, Deutsch. Suesswasserbryozoen, i,
+     p. 133 (1887).
+
+     _Pectinatella_, Oka, Journ. Coll. Sci. Tokyo, iv, p. 89
+     (1891).
+
+TYPE, _Pectinatella magnifica_, Leidy.
+
+This genus is closely allied to _Lophopodella_, from which it is often
+difficult to distinguish young specimens. Adult zoaria are, however,
+always embedded together in groups in a gelatinous investment which they
+are thought to secrete in common[BN], and the statoblasts are entirely
+surrounded by processes that bear curved spinules at their tips only.
+The polypides have the same semi-recumbent position as those of
+_Lophopodella_ but are larger than those of any species of
+_Lophopodella_ or _Lophopus_ yet known. The statoblasts are larger than
+those of any other Plumatellidae.
+
+     [Footnote BN: It is now perhaps open to doubt whether the
+     investment is actually secreted by the polyzoon, for Prof.
+     W. West has discovered in it the cells of an alga belonging
+     to a genus which habitually secretes a gelatinous investment
+     of its own (see p. 238, _post._).--_April 1911._]
+
+The type-species was originally found in N. America but has since been
+taken in several localities in continental Europe. Except this and the
+Indian form only one species is known, namely _P. gelatinosa_ from
+Japan. _P. magnifica_ has circular statoblasts with long marginal
+processes, while in _P. gelatinosa_ the statoblasts are subquadrate and
+in _P. burmanica_ almost circular, both Asiatic forms having very short
+marginal processes.
+
+The compound colonies formed by _Pectinatella_ are often of great size.
+Those of _P. gelatinosa_ are sometimes over 2 metres in length, while
+those of _P. burmanica_ in the Sur Lake appeared to be only limited as
+regards their growth by the shallowness of the water in which the reeds
+to which they were attached were growing. Some were observed that were
+over 2 feet long.
+
+
+38. Pectinatella burmanica, _Annandale_. (Plate III, fig. 5.)
+
+     _Pectinatella burmanica_, Annandale, Rec. Ind. Mus. ii,
+     p. 174, fig. 5 (1908).
+
+     _Pectinatella burmanica_, _id._, _ibid._ v, p. 56 (1910).
+
+     _Pectinatella burmanica_, _id._, Spol. Zeyl. vii, p. 63,
+     pl. i, fig. 3 (1910).
+
+_Zoarium._ The zoaria are circular or nearly so except when about to
+undergo division, in which case they are constricted in the middle. As a
+rule they measure nearly an inch (2 cm.) in diameter. The polypides have
+a definite arrangement in each zoarium, being divided into four groups,
+each of which has a fan-like form. In the first place they are separated
+into two main divisions in a line running through the centre of the
+zoarium, and secondly each main division is separated into two
+subordinate ones in a line running across the other at right angles. The
+number of zoaria joined together in a single compound colony is very
+variable; sometimes there are only about half a dozen and sometimes
+several hundreds. The common investment in living colonies is often as
+much as two inches thick and has a translucent dark greenish colour due
+to the presence in it of green cells.
+
+[Illustration: Fig. 47.--_Pectinatella burmanica._
+
+A=polypide with the lophophore expanded, x 15; _a_=oesophagus;
+_b_=cardiac limb of stomach; _c_=stomach; _d_=rectum; _e_=anus;
+_f_=funiculus. [The muscles are omitted and the external tubercles are
+only shown on part of the polypide. The specimen is from the Sur Lake,
+Orissa.] B=statoblast from Ceylon, x 35.]
+
+_Polypide._ The polypide can be extruded for a distance of at least 5
+mm. Its whole external surface is covered with minute tubercles. There
+are about 90 tentacles, which are long and slender, the velum at their
+base being narrow and almost straight. The stomach is of considerable
+stoutness.
+
+_Statoblast._ The statoblasts are of large size, measuring from 1 to
+1.75 mm. in diameter. In form they are almost circular, but one side is
+always slightly flattened. The marginal processes are very short and
+bear a single pair of hooks at the tip. The capsule is circular and
+small as compared with the free part of the swim-ring.
+
+TYPE in the Indian Museum.
+
+_P. burmanica_ is evidently a near relation of _P. gelatinosa_, Oka,
+from Japan, differing from that species in the shape of the statoblasts
+and in having much longer tentacles. The arrangement of the polypides in
+the zoarium and the general structure of the statoblasts are very
+similar in the two species.
+
+GEOGRAPHICAL DISTRIBUTION.--_P. burmanica_ was originally described from
+a swamp at Kawkareik in the Amherst district of Tenasserim but has also
+been found in the Sur Lake near Puri in Orissa. Dr. A. Willey obtained
+specimens from a pool by the roadside between Maradankadewela and
+Galapitagala, at the foot of Ritigala, N. Central Province, Ceylon.
+
+BIOLOGY.--The first specimen obtained was a statoblast fixed to a tube
+of the oligochaete worm _Aulophorus tonkinensis_ taken at Kawkareik in
+March. At the same time young zoaria, which did not yet possess a common
+investment, were found on a leaf growing on a twig which drooped into
+the water. Large compound colonies were taken in Orissa in October. They
+completely encased the stems of reeds, thus forming hollow cylinders,
+but slipped from their supports when the reeds were pulled out of the
+water. In life they resembled gelatinous algae rather than animals and
+exhibited a striking similarity to masses of zoaria of _Lophopodella
+carteri_ surrounded by such algae. Some of the colonies were evidently
+dying and contained few polypides in a living condition, but many
+statoblasts; others were in a flourishing condition and were producing
+larvae and statoblasts simultaneously.
+
+A piece of a colony full of larvae was placed before midday in an
+aquarium, which was kept in a shady verandah. Large numbers of larvae
+were set free almost immediately. They measured about 2 mm. in length
+and were distinctly pear-shaped; each contained a pair of polypides,
+which occupied a comparatively small part of the interior, the whole of
+the broader half being hollow. The larvae swam slowly, broad-end-first,
+by means of the cilia with which their surface was covered, occasionally
+gyrating on their long axis and always adopting an erratic course.
+Towards evening they showed signs of settling down, frequently touching
+the glass of the aquarium with their broad ends and sometimes remaining
+still in this position for some minutes. Many attempts were, however,
+made before fixation was completed, and this did not occur until after
+nightfall. By next morning every larva was fixed to the glass and had
+everted its two polypides. Unfortunately I was not able to trace the
+development further, but young compound colonies were found in which the
+secretion of the common investment had just commenced. The zoaria in
+these colonies measured about 1 cm. in diameter and already contained
+many polypides each.
+
+Oka has described the development from the statoblast of the allied
+Japanese species. He found that each statoblast produced in the first
+instance a single polypide, and that the statoblasts, which were
+produced in autumn, lay dormant through the winter and germinated in
+spring. As the Sur Lake begins to undergo desiccation as soon as the
+"rains" cease, the statoblasts in it probably do not germinate until the
+break of the next "rains" about the middle of June. I have had dried
+statoblasts in my possession for over two years. Their cellular contents
+appear to be in good condition, although the cells show no signs of
+development; but they have not germinated in my aquarium, in which some
+of them have now been kept for more than six months.
+
+The green cells of the common investment are peculiar bodies that
+deserve further study than it has yet been possible to devote to them.
+Each cell is of ovoid form, varying somewhat in size but as a rule
+measuring about 0.03 x 0.008 mm. There can be no doubt that these bodies
+represent a stage in the life-history of an alga[BO]. Diatoms, bacilli
+and other minute plants are often present in the membrane as well as the
+characteristic green cells, but do not form a constant feature of it.
+
+     [Footnote BO: Professor W. West identifies this algae as
+     _Dactylococcopsis pectinatellophila_, new species. It will
+     be described, before the publication of this book, in the
+     Journ. As. Soc. Bengal (1911). Prof. West has found,
+     associated more or less fortuitously with _P. burmanica_,
+     another alga, namely _Microcystis orissica_, also a new
+     species.--_April 1911._]
+
+
+
+
+APPENDIX TO THE VOLUME.
+
+
+HINTS ON THE PREPARATION OF SPECIMENS.
+
+_To preserve Spongillidae._--Spongillidae must be preserved dry or in very
+strong alcohol. Formalin should not be used.
+
+_To clean siliceous sponge spicules._--Place small fragments of the
+dried sponge (if alcohol is present, the reaction is apt to be violent)
+in a test tube, cover them with strong nitric acid and boil over the
+flame of a Bunsen burner or small spirit lamp until the solid particles
+disappear. Add a large quantity of water to the acid and filter through
+pure cellulose filter-paper, agitating the liquid repeatedly. Pass clean
+water in considerable quantities through the filter-paper and dry the
+latter carefully; place it in a spirally coiled wire and ignite with a
+match, holding the wire in such a way that the spicules released by the
+burning of the paper fall into a suitable receptacle. They may then be
+picked up with a camel's-hair brush and mounted in Canada balsam.
+
+_To examine the skeleton of a Spongillid._--Cut thin hand-sections with
+a sharp scalpel, dehydrate if necessary, and mount in Canada balsam.
+
+_To prepare gemmules for examination._--Place the gemmules dry in a
+watch-glass with a few drops of strong nitric acid. When gas is given
+off freely add water in considerable quantities. Remove the gemmules
+with a camel's-hair brush to clean water, then to 50%, 70%, 90% and
+absolute alcohol in succession, leaving them for an hour in each
+strength of spirit. Clear with oil of cloves and mount in Canada balsam.
+
+_To ascertain the presence of bubble-cells in the parenchyma of a
+Spongillid._--Tease up a small piece of the sponge with a pair of
+needles, mount under a thin cover-slip in strong spirit, and examine
+under a high power of the microscope.
+
+_To preserve Hydra in an expanded condition._--Place the polyp in a
+watch-glass of clean water and wait until its tentacles are expanded.
+Heat a few drops of commercial formaldehyde and squirt the liquid while
+still hot at the _Hydra_, which will be killed instantaneously. Remove
+it to a solution of formaldehyde and spirit of the following formula:--
+
+     Commercial formaldehyde      1 part.
+     Absolute alcohol             3 parts.
+     Distilled water              7 parts.
+
+Then pass the _Hydra_ through 50% and 70% alcohol and keep in 90%.
+
+_To examine the capsules of the nettle-cells._--Place a living _Hydra_
+in a small drop of water on a slide and press a thin cover-slip down
+upon it.
+
+_To preserve freshwater polyzoa in an expanded condition._--Place the
+polyzoa in a glass tube full of clean water and allow them to expand
+their tentacles. Drop on them gradually when they are fully expanded a
+2% aqueous solution of cocaine, two or three drops at a time, until
+movement ceases in the tentacles. Then pour commercial formaldehyde into
+the tube in considerable quantities. Allow the whole to stand for half
+an hour. If it is proposed to stain the specimens for anatomical
+investigation, they should then be removed through 50% and 70% to 90%
+alcohol. If, on the other hand, it is desired to keep them in a
+life-like condition they may be kept permanently in a solution of one
+part of commercial formaldehyde in four parts of water. Care must be
+taken that the process of paralyzing the polypides is not unduly
+prolonged, and it is always as well to preserve duplicate specimens in
+spirit or formalin with the lophophore retracted.
+
+_To prepare statoblasts for examination._--Place the statoblasts for a
+few minutes in strong nitric acid. Then remove the acid with water, pass
+through alcohol, clear with oil of cloves, and mount in a small quantity
+of Canada balsam under a cover-slip, taking care that the statoblasts
+lie parallel to the latter.
+
+
+
+
+ADDENDA.
+
+
+The following addenda are due mainly to an expedition to the lakes of
+Kumaon in the W. Himalayas undertaken by Mr. S. W. Kemp in May, 1911.
+
+
+PART I.
+
+
+Genus SPONGILLA.
+
+
+Subgenus EUSPONGILLA (p. 69).
+
+1 a. Spongilla lacustris, subsp. reticulata (p. 71).
+
+Specimens were taken in the lake Malwa Tal (alt. 3600 feet) in Kumaon,
+while others have recently been obtained from the Kalichedu
+irrigation-tank in the Pagnor _talug_ of the Nellore district, Madras
+(_G. H. Tipper_).
+
+4. Spongilla cinerea (p. 79).
+
+Specimens were taken in Naukuchia Tal (alt. 4200 feet) in Kumaon. They
+have a pale yellow colour when dry. This sponge has not hitherto been
+found outside the Bombay Presidency.
+
+
+Subgenus EUNAPIUS (p. 86).
+
+8. Spongilla carteri (p. 87).
+
+Specimens were taken in Bhim Tal (alt. 4450 feet) and Sat Tal (alt. 4500
+feet). Some of them approach the variety _cava_ in structure.
+
+
+Subgenus STRATOSPONGILLA (p. 100).
+
+12. Spongilla bombayensis (p. 102).
+
+Add a new variety:--
+
+13 a. Var. pneumatica, nov.
+
+  (i.)   The sponge forms a flat layer of a pale brownish colour
+         as a rule with short and very delicate vertical branches.
+         In one specimen it takes the form of an elegant cup
+         attached, only at the base, to a slender twig.
+
+  (ii.)  The gemmules are covered, outside the spicules, by a
+         thick pneumatic coat of irregular formation and with
+         comparatively large air-spaces.
+
+  (iii.) The gemmule-spicules are regularly sausage-shaped.
+
+TYPES in the Indian Museum.
+
+HABITAT. Naukuchia Tal (alt. 4200 feet), Kumaon, W. Himalayas (_S. W.
+Kemp_).
+
+
+Genus EPHYDATIA (p. 108).
+
+After _Ephydatia meyeni_, p. 108, add:--
+
+
+Ephydatia fluviatilis, _auct._
+
+     ? _Ephydatia fluviatilis_, Lamouroux, Encyclop. Method. ii,
+     p. 327 (1824).
+
+     _Spongilla fluviatilis_, Bowerbank (_partim_), Proc. Zool.
+     Soc. London, 1863, p. 445, pl. xxxviii, fig. 1.
+
+     _Ephydatia fluviatilis_, J. E. Gray (_partim_), Proc. Zool.
+     Soc. London, 1867, p. 550.
+
+     _Meyenia fluviatilis_, Carter (_partim_), Ann. Nat. Hist.
+     (5) vii, p. 92, pl. vi, fig. 11 _a_, _b_ (1881).
+
+     _Ephydatia fluviatilis_, Vejdovsky, Abh. k. Boehm.
+     Gesellschaft Wiss. xii, p. 24, pl. i, figs. 1, 2, 7, 10, 14,
+     19 (1883).
+
+     _Ephydatia fluviatilis_, _id._, P. Ac. Philad. 1887, p. 178.
+
+     _Meyenia fluviatilis_ var. _gracilis_, Potts, _ibid._, p.
+     224.
+
+     _Meyenia robusta_, _id._, _ibid._, p. 225, pl. ix, fig. 5.
+
+     _Ephydatia fluviatilis_, Weltner, Arch. Naturg. Berlin, 1895
+     (i) p. 122.
+
+     _Ephydatia robusta_, Annandale, Journ. As. Soc. Bengal,
+     1907, p. 24, fig. 7.
+
+     _Ephydatia fluviatilis_, Weltner, in Brauer's
+     Suesswasserfauna Deutschlands xix, Suesswasserschwaemme, p.
+     185, figs. 316, 317 (1909).
+
+     _Ephydatia fluviatilis_, Annandale, P. U. S. Mus. xxxviii,
+     p. 649 (1910).
+
+[Many more references to this common species might be cited, but those
+given above will be sufficient.]
+
+This species only differs from _E. meyeni_ in the following
+characters:--
+
+  (i.)   there are no bubble-cells in the parenchyma;
+
+  (ii.)  there is less spongin in the skeleton, which is less compact;
+
+  (iii.) the gemmule-spicules are longer, the shafts being as a rule
+         longer than the diameter of the rotulae;
+
+  (iv.)  the gemmules are armed with a single row of regularly
+         arranged spicules embedded in pneumatic tissue with
+         minute air-spaces.
+
+The sponge is a variable one and several "varieties" have been described
+from different parts of the world. My Indian specimens come nearest to
+the form described by Potts as _Meyenia robusta_, but have rather more
+slender skeleton-spicules and more elongate gemmule-spicules. The latter
+also appear to be less frequently "monstrous."
+
+TYPE ?
+
+GEOGRAPHICAL DISTRIBUTION.--_E. fluviatilis_ is widely distributed in
+Europe and occurs in N. America,[BP] S. Africa (var. _capensis_,
+Kirkpatrick), Australia, and Japan. Specimens were obtained by Mr. Kemp
+from several lakes in Kumaon, namely Naukuchia Tal (alt. 4200 feet),
+Bhim Tal (4450 feet), Sat Tal (4500 feet), and Naini Tal (6300 feet).
+The gemmules from Bhim Tal referred by me to _E. robusta_ (Potts) also
+belong to this species.
+
+     [Footnote BP: Most of the forms assigned by Potts to this
+     species belong to the closely allied _E. muelleri_
+     (Lieberkuehn).]
+
+_Biology._ The external form of the sponge is due in great part to its
+environment. Specimens on small stones from the bottom of the Kumaon
+Lakes consist of thin disk-like films, often not more than a few
+centimetres in diameter and a few millimetres thick: others, growing on
+thin twigs, are elevated and compressed, resembling a cockscomb in
+appearance, while others again form nodules and masses of irregular form
+among the branches of delicate water-weeds. Some of these last are
+penetrated by zoaria of _Fredericella indica_.
+
+Weltner has published some very interesting observations on the seasonal
+variation of minute structure in European representatives of the species
+(Arch. Naturg. Berlin, lxxiii (i), p. 273 1907) and has discussed the
+formation of the abnormal spicules that sometimes occur (_ibid._ lxvii
+(Special Number), p. 191, pls. vi, vii, figs. 27-59, 1901).
+
+
+Genus CORVOSPONGILLA (p. 122).
+
+After _Corvospongilla burmanica_, p. 123, add a new species:--
+
+
+Corvospongilla caunteri, nov.
+
+_Sponge_ forming thin films of considerable area not more than 3 or 4
+mm. thick, of a bright green colour, moderately hard but friable. The
+surface smooth; oscula inconspicuous, surrounded by shallow and
+ill-defined radiating furrows; a very stout basal membrane present.
+
+[Illustration: Fig. 48.--_Corvospongilla caunteri_ (type, from Lucknow).
+
+A=Gemmule; B=gemmule-spicules; C=flesh-spicules; D=Skeleton-spicules.]
+
+_Skeleton_ reticulate but almost devoid of spongin, the reticulations
+close but formed mainly by single spicules; skeleton-fibres barely
+distinguishable. A close layer of spicules lying parallel to the basal
+membrane.
+
+_Spicules._ Skeleton-spicules variable in size and shape, almost
+straight, as a rule smooth, moderately stout, blunt or abruptly pointed;
+sometimes roughened or spiny at the tips, often sharply pointed.
+Flesh-spicules minute, few in number, with smooth, slender shafts which
+are variable in length, never very strongly curved; the terminal spines
+relatively short, not strongly recurved. Gemmule-spicules
+amphistrongylous or amphioxous, irregularly spiny, slender, of variable
+length.
+
+_Gemmules_ free in the substance of the sponge, spherical or somewhat
+depressed, very variable in size but never large, having a thick
+external pneumatic coat in which the air-spaces are extremely small and,
+inside this coat, a single rather sparse layer of spicules lying
+parallel to the gemmule. A single depressed aperture present.
+
+TYPE in the Indian Museum.
+
+HABITAT. Hazratganj, Lucknow; on piers of bridge in running water (_J.
+Caunter_, 29-30. iv. 11).
+
+The structure of the gemmules of this species differs considerably from
+that in any other known species of the genus, in which these structures
+are usually adherent and devoid of a true pneumatic coat. In some of the
+gemmules before me this coat measures in thickness about 1/9 of the
+total diameter of the gemmule. _C. caunteri_ is the first species of
+_Corvospongilla_ to be found in the Indo-Gangetic plain.
+
+
+PART II.
+
+
+Genus HYDRA (p. 147).
+
+
+25. Hydra oligactis (p. 158).
+
+Mr. Kemp found this species common in Bhim Tal in May. His specimens,
+which were of a reddish-brown colour in life, appear to have been of
+more vigorous constitution than those taken by Major Stephenson in
+Lahore. Some of them had four buds but none were sexually mature.
+
+
+PART III.
+
+
+Genus FREDERICELLA (p. 208).
+
+
+28. Fredericella indica (p. 210).
+
+This species is common in some of the Kumaon lakes, in which it grows,
+at any rate at the beginning of summer, much more luxuriantly than it
+does in the lakes of the Malabar Zone in autumn, forming dense bushy
+masses on the under surface of stones, on sticks, &c. The vertical
+branches often consist of many zooecia. Mr. Kemp took specimens in Malwa
+Tal, Sath Tal, and Naini Tal (alt. 3600-6300 feet).
+
+
+Genus PLUMATELLA (p. 212).
+
+
+30. Plumatella emarginata (p. 220).
+
+Mr. Kemp took bushy masses of this species in Malwa Tal and Bhim Tal.
+
+
+32. Plumatella diffusa (p. 223).
+
+This species is common in Malwa Tal and Bhim Tal in May.
+
+
+33. Plumatella allmani (p. 224).
+
+Mr. Kemp only found this species in Malwa Tal, in which (at any rate in
+May) it appears to be less abundant than it is in Bhim Tal in autumn.
+Mr. Kemp's specimens belong to the form called _P. elegans_ by Allman.
+
+
+34. Plumatella tanganyikae (p. 225).
+
+Specimens taken by Mr. Kemp, somewhat sparingly, in Bhim Tal and Sath
+Tal in May exhibit a somewhat greater tendency towards uprightness of
+the zooecia than those I found in autumn in Igatpuri lake. The ectocyst
+is, in the former specimens, of a deep but bright reddish-brown. The
+zoaria are attached to twigs and small stones.
+
+
+Genus STOLELLA (p. 229).
+
+After Stolella indica, p. 229, add a new species:--
+
+
+Stolella himalayana, nov.
+
+This species may be distinguished from _S. indica_ by (i) its entirely
+recumbent zooecia, and (ii) the lateral branches of its zoarium.
+
+[Illustration: Fig. 49.--_Stolella himalayana_ (types, from the Kumaon
+lakes).
+
+A. The greater part of a young zoarium. B. Part of a much older
+zoarium.]
+
+_Zoarium_ entirely recumbent, consisting of zooecia joined together,
+often in groups of three, by slender, transparent, tubular processes.
+These processes are often of great relative length; they are formed by a
+modification of the posterior or proximal part of the zooecia, from
+which they are not separated by a partition, and they increase in length
+up to a certain point more rapidly than the zooecia proper. A zooecium
+often gives rise first to an anterior daughter-zooecium, the proximal
+part of which becomes elongate and attenuated in due course, and then to
+a pair of lateral daughter-zooecia situated one on either side. As a
+result of this method of budding a zoarium with a close superficial
+resemblance to that of _Paludicella_ is at first produced, but as the
+colony increases in age and complexity this resemblance largely
+disappears, for the zooecia and their basal tubules grow over one
+another and often become strangely contorted (fig. 49).
+
+_Zooecia_ elongate and slender, flattened on the ventral, strongly
+convex on the dorsal surface; rather deep in proportion to their
+breadth; the ectocyst colourless, not very transparent except on the
+stolon-like tubular part; dorsal keel and furrow as a rule absent;
+orifice unusually inconspicuous, situated on a tubercle on the dorsal
+surface.
+
+_Polypide_ stout and short; the tip of the fundus of the stomach capable
+of very complete constriction; the retractor muscles unusually short and
+stout.
+
+_Statoblasts._ Only free statoblasts have been observed. They resemble
+those of _S. indica_, but are perhaps a little longer and more elongate.
+
+TYPES in the Indian Museum.
+
+The discovery of this species makes it necessary to modify the diagnosis
+of the genus, the essential character of which, as distinguishing it
+from _Plumatella_, is the differentiation of the proximal part of some
+or all of the zooecia to form stolon-like tubules. From _Stephanella_,
+Oka, it is distinguished by the absence of a gelatinous covering, and by
+the fact that all the zooecia are attached, at least at the base, to
+some extraneous object.
+
+HABITAT. Malwa Tal, Kumaon (alt. 3600 feet), W. Himalayas (_Kemp_, May
+1911).
+
+BIOLOGY. Mr. Kemp took three specimens, all attached to the lower
+surface of stones. They contained few statoblasts and were evidently in
+a condition of vigorous growth. Between the lateral branches new
+polyparia were developing in several instances from free statoblasts,
+each of which appeared to contain two polypides.
+
+
+
+
+ALPHABETICAL INDEX.
+
+
+All names printed in italics are synonyms.
+
+When more than one reference is given, the page on which the description
+occurs is indicated by thickened numerals.
+
+  alba (Euspongilla) (Spongilla), 8, 9.
+  alba (Spongilla), 4, 22, 63, ~76~.
+  alba _var._ bengalensis (Spongilla), 4, 22, 63, ~77~.
+  alba _var_. cerebellata (Spongilla), 22, 63, ~76~.
+  _alba_ var. _marina_ (_Spongilla_), ~77~.
+  _Alcyonella_, 212.
+  Alcyonellea, 185.
+  allmani (Plumatella), 7, 8, 9, 23, 188, ~224~, 246.
+  _allmani_ var. _diffusa_ (_Plumatella_), 223.
+  _allmani_ var. _dumortieri_ (_Plumatella_), 222.
+  _attenuata_ (_Hydra_), 148, 158.
+  _aurantiaca_ (_Hydra_), 148.
+  aurea (Pectispongilla), 9, 22, 63, ~106~.
+  aurea _var._ subspinosa (Pectispongilla), 63, ~107~.
+
+  _benedeni_ (_Alcyonella_), 220.
+  bengalensis (Bowerbankia), 189.
+  bengalensis (Membranipora), 23.
+  bengalensis (Spongilla), 77.
+  bengalensis (Victorella), 4, 8, 9, 23, 187, ~195~.
+  blembingia (Ephydatia), 54.
+  bogorensis (Ephydatia), 54.
+  _bombayensis_ (_Plumatella_), 225.
+  bombayensis (Spongilla), 22, 63, 100, ~102~, 241.
+  bombayensis (Stratospongilla) (Spongilla), 8, 9.
+  Bowerbankia, 187, ~189~.
+  _brunnea_ (_Hydra_), 148.
+  burmanica (Corvospongilla), 8, 22, 64, ~122~.
+  burmanica (Pectinatella), 8, 10, 23, 188, ~235~.
+
+  calcuttana (Spongilla), 96.
+  _cambodgiensis_ (_Norodonia_), 202.
+  _Carterella_, 108.
+  carteri (Eunapius) (Spongilla), 7, 8, 9, 10.
+  _carteri_ (_Eunapius_), 87.
+  carteri (Lophopodella), 7, 8, 23, 188, ~232~, 233.
+  _carteri_ (_Lophopus_), 232.
+  _carteri_ (_Pectinatella_), 231,
+  carteri (Spongilla), 4, 22, 63, 86, ~87~, 241.
+  carteri _var._ cava (Spongilla), 22, 63.
+  carteri _var._ himalayana (Lophopodella), 23, 188.
+  carteri _var._ lobosa (Spongilla), 22, 63.
+  carteri _var._ mollis (Spongilla), 22, 63.
+  caudata (Bowerbankia), 189.
+  caudata _subsp._ bengalensis (Bowerbankia), 23, 189.
+  caunteri (Corvospongilla), 243.
+  cava (Spongilla), 88.
+  cerebellata (Spongilla), 76.
+  ceylonensis (Irene), 22, 140.
+  Cheilostomata, 184.
+  Chlorella, 50.
+  cinerea (Euspongilla) (Spongilla), 9.
+  cinerea (Spongilla), 22, 63, 72, 79, 241.
+  clementis (Stratospongilla) (Spongilla), 53.
+  coggini (Stratospongilla) (Spongilla), 53.
+  colonialis (Loxosomatoides), 23.
+  _contecta_ (_Spongilla_), 95.
+  _coralloides_ (_Plumatella_), 217.
+  Corvospongilla, 64, ~122~, 243.
+  crassior (Spongilla), 98.
+  crassissima (Eunapius) (Spongilla), 9.
+  crassissima (Spongilla), 4, 22, 63, ~98~.
+  crassissima _var._ crassior (Spongilla), 23, 63.
+  _crateriformis_ (_Meyenia_), 83.
+  _crateriformis_ (_Ephydatia_), 83, 84.
+  crateriformis (Euspongilla) (Spongilla), 8, 9.
+  _crateriformis_ (_Meyenia_), 83.
+  crateriformis (Spongilla), 22, 63, ~83~.
+  _Cristatella_, 235.
+  Cristatellina, 206.
+  Ctenostomata, 184, 185, 187, ~189~.
+  Cyclostomata, 184.
+
+  decipiens (Spongilla), 54, 96, ~97~.
+  diffusa (Plumatella), 7, 8, 9, 23, 188, ~223~, 245.
+  _di[oe]cia_ (_Hydra_), 158.
+  Dosilia, 64, ~110~.
+
+  _Echinella_, 199.
+  _elegans_ (_Plumatella_), 224.
+  Eleutheroblastea, 146, 147.
+  emarginata (Plumatella), 4, 8, 9, 10, 23, 188, 218, ~220~, 245.
+  _emarginata_ var. _javanica_ (_Plumatella_), 221.
+  Entoprocta, 183.
+  Ephydatia, 64, ~108~, 242.
+  _erinaceus_ (_Spongilla_), 114.
+  Eunapius, 63, ~86~, 241.
+  Euspongilla, 63, 67, ~69~, 241.
+
+  filamentata (Syncoryne), 22, 140.
+  fluviatilis (Ephydatia), 109, ~242~.
+  _fluviatilis_ (_Meyenia_), 242.
+  fluviatilis (Spongilla), 108, 242.
+  _fluviatilis_ var. _gracilis_ (_Meyenia_), 242.
+  fortis (Ephydatia), 52, 53.
+  fragilis (Spongilla), ~95~, 96.
+  fragilis _subsp._ calcuttana (Eunapius) (Spongilla), 9.
+  fragilis _subsp._ calcuttana (Spongilla), 22, 63.
+  fragilis _subsp._ decipiens (Spongilla), 22, 63.
+  Fredericella, 188, ~208~, 245.
+  FREDERICELLIDAE, 188, ~208~.
+  _friabilis_ (_Spongilla_), 87.
+  fruticosa (Plumatella), 4, 7, 8, 9, 23, 188, ~217~, 218.
+  _fusca_ (_Hydra_), 158, 159.
+
+  Gecarcinucus, 10.
+  gemina (Eunapius) (Spongilla), ~8~.
+  gemina (Spongilla), 22, 63, ~97~.
+  _glomerata_ (_Spongilla_), 95.
+  _grisea_ (_Hydra_), 148, 149.
+  Gymnolaemata, 184, 187.
+
+  Halichondrina, 65.
+  hemephydatia (Euspongilla) (Spongilla), 8.
+  hemephydatia (Spongilla), 22, 63, ~82~.
+  _hexactinella_ (_Hydra_), 148.
+  himalayana (Lophopodella), 233.
+  himalayana (Stolella), 246.
+  _himalayanus_ (_Lophopus_), 233.
+  Hislopia, 187, ~199~.
+  Hislopidees, 199.
+  HISLOPIIDAE, 187, ~199~.
+  Homodiaetidae, 191.
+  _Hyalinella_, 212.
+  Hydra, 146, ~147~, 245.
+  Hydraidae, 147.
+  HYDRIDAE, 146, 147.
+  hydriforme (Polypodium), 142.
+  Hydrozoa, 146.
+
+  _indica_ (_Ephydatia_), 83.
+  indica (Fredericella), 9, 23, 188, ~209~, 245.
+  indica (Spongilla), 22, 63, ~100~.
+  indica (Stolella), 4, 9, 23, 188, ~229~.
+  indica (Stratospongilla), (Spongilla), 9.
+
+  javanica (Plumatella), 4, 8, 9, 23, 188, ~221~, 222.
+
+  kawaii (Limnocodium), 141.
+
+  lacroixii (Membranipora), 23.
+  lacustris (Cordylophora), 141.
+  _lacustris_ (_Euspongilla_), 69.
+  lacustris (Hislopia), 4, 8, 9, 23, 187, 199, ~202~, 204.
+  lacustris (Spongilla), 63, 67, ~69~.
+  lacustris _subsp._ moniliformis (Hislopia), 9, 23, 187.
+  lacustris _subsp._ reticulata (Spongilla), 4, 8, 9, 22, 63, ~71~, 241.
+  _lacustris_ var. _bengalensis_ (_Spongilla_), 77.
+  lapidosa (Corvospongilla), 9, 22, 64, ~124~.
+  _lapidosa_ (_Spongilla_), 124.
+  latouchiana (Trochospongilla), 4, 8, 9, 22, 64, ~115~.
+  _leidyi_ (_Trochospongilla_), 115.
+  _lendenfeldi_ (_Lophopus_), 233.
+  _lendenfeldi_ var. _himalayanus_ (_Lophopus_), 233.
+  lobosa (Spongilla), 89.
+  LOPHOPINAE, 188, 211, ~231~.
+  Lophopodella, 8, 188, ~231~.
+  _Lophopus_, 8, 232.
+  _lordii_ (_Spongilla_), 95.
+  loricata (Spongilla), ~122~.
+  _loricata_ var. _burmanica_, (_Spongilla_), 122.
+  _lucifuga_ (_Plumatella_), 217, 220, 224.
+
+  magnifica (Pectinatella), 235.
+  meyeni (Ephydatia), 7, 9, 17, 22, 64, ~108~.
+  _meyeni_ (_Spongilla_), 108.
+  _Meyenia_, 108, 113.
+  microsclerifera (Euspongilla) (Spongilla), 53.
+  mollis (Spongilla), 88.
+  moniliformis (Hislopia), 204.
+  _mon[oe]cia_ (_Hydra_), 158.
+  _morgiana_ (_Spongilla_), 95.
+  _muelleri_ (_Ephydatia_), 109, 243.
+  _muelleri_ subsp. _meyeni_ (_Ephydatia_), 109.
+
+  _Norodonia_, 199.
+
+  oligactis (Hydra), 7, 22, 146, ~158~, 159, 245.
+  _orientalis_ (_Hydra_), 148, 149.
+  _ottavaensis_ (_Spongilla_), 95.
+
+  _pallens_ (_Hydra_), 148.
+  Paludicella, 187, ~192~.
+  PALUDICELLIDAE, 187, ~191~.
+  Paludicellidees, 191.
+  Paludicellides, 191.
+  Paludicellina, 186, 187, ~190~.
+  paulula (Spongilla), 120.
+  _pavida_ (_Victorella_), 194, 195.
+  Pectinatella, 188, ~235~.
+  pectinatellophila (Dactyloccopsis), 238.
+  Pectispongilla, 63, ~106~.
+  pennsylvanica (Trochospongilla), 9, 22, 64, ~118~.
+  _pennsylvanica_ (_Tubella_), 118.
+  _pentactinella_ (_Hydra_), 149.
+  philippinensis (Euspongilla) (Spongilla), 53.
+  phillottiana (Trochospongilla), 4, 8, 9, 22, 64, ~117~.
+  Phylactolaemata, 185, 188, ~206~.
+  Plumatella, 188, 208, ~212~, 245.
+  PLUMATELLIDAE, 188, ~211~.
+  Plumatellina, 188, ~206~.
+  PLUMATELLINAE, 188, 211, ~212~.
+  plumosa (Dosilia), 8, 9, 22, 64, ~111~.
+  _plumosa_ (_Ephydatia_), 111.
+  _plumosa_ (_Meyenia_), 111.
+  _plumosa_ (_Spongilla_), 111.
+  pneumatica (Stratospongilla) (Spongilla), 241.
+  _polypus_ (_Hydra_), 148, 159.
+  Polyzoa, 183.
+  _princeps_ (_Plumatella_), 220.
+  _princeps_ var. _emarginata_ (_Plumatella_), 220.
+  _princeps_ var. _fruticosa_ (_Plumatella_), 217.
+  proliferens (Euspongilla) (Spongilla), 8, 9, 10.
+  proliferens (Spongilla), 4, 8, 22, 63, ~72~.
+  Proterospongia, 27.
+  _punctata_ (_Hyalinella_), 228.
+  punctata (Plumatella), 9, 188, ~227~.
+
+  _repens_ (_Plumatella_), 217, 223.
+  reticulata (Spongilla), 71.
+  _rhaetica_ (_Hydra_), 158.
+  _robusta_ (_Ephydatia_), 109, 242.
+  _robusta_ (_Meyenia_), 242.
+  _roeselii_ (_Hydra_), 158.
+  ryderi (Microhydra), 141.
+
+  schilleriana (Sagartia), 2, 22, 140.
+  schilleriana _subsp_. exul (Sagartia), 22.
+  _sibirica_ (_Spongilla_), 95.
+  _sinensis_ (_Norodonia_), 202.
+  sinensis (Stratospongilla) (Spongilla), 53.
+  _socialis_ (_Hydra_), 158.
+  sowerbii (Limnocodium), 141.
+  Spongilla, 63, ~67~, 86, 241.
+  Spongilladae, 65.
+  SPONGILLIDAE, 65.
+  Stolella, 188, ~229~, 246.
+  Stolonifera, 185.
+  Stratospongilla, 63, ~100~, 241.
+  _stricta_ (_Plumatella_), 217.
+  subspinosa (Pectispongilla), 107.
+  sumatrana (Stratospongilla) (Spongilla), 53.
+
+  tanganyikae (Limnocnida), 142.
+  tanganyikae (Plumatella), 9, 23, 188, ~225~, 246.
+  Trachospongilla, 64, ~113~.
+  _Trachyspongilla_, 108.
+  travancorica (Euspongilla) (Spongilla), 9.
+  travancorica (Spongilla), 22, 63, ~81~.
+  _trembleyi_ (_Hydra_), 148.
+  Tubella, 64, 113, ~120~.
+
+  ultima (Spongilla), 22, 63, ~105~.
+  ultima (Stratospongilla) (Spongilla), 9.
+
+  VESICULARIDAE, 189.
+  Vesicularina, 186, 187, ~189~.
+  _vesicularis_ (_Hyalinella_), 228.
+  _vesicularis_ (_Plumatella_), 227, 228.
+  vesparioides (Tubella), 8, 22, 64, ~120~.
+  vesparium (Tubella), 54.
+  vestita (Bimeria), 22, 139.
+  Victorella, 189, ~194~.
+  Victorellidae, 191.
+  Victorellides, 191.
+  viridis (Hydra), 147.
+  _vitrea_ (_Hyalinella_), 228.
+  _vitrea_ (_Plumatella_), 227, 228.
+  vulgaris (Hydra), 4, 8, 9, 10, 22, 130, 146, ~148~, 149, 158.
+
+  whiteleggei (Cordylophora), 141.
+
+  yunnanensis (Euspongilla) (Spongilla), 53.
+
+
+
+
+  PLATE I.
+
+  SPECIMENS OF _Spongilla_ PRESERVED IN SPIRIT.
+
+
+  Figs. 1-3. _S. (Euspongilla) alba_ var. _bengalensis_ (nat.
+     size) from ponds of brackish water at Port Canning in the
+     delta of the Ganges. Fig. 1 represents the type-specimen of
+     the variety, and was taken in the winter of 1905-6. Figs. 2
+     and 3 represent specimens taken in the same ponds in the
+     winters of 1907 and 1908 respectively.
+
+  Fig. 4. _Spongilla_ sp. (? abnormal form of _S. (Eunapius
+     carteri_)) from an aquarium in Calcutta (x 10).
+
+  [Illustration: Freshwater Sponges.                     Plate I.
+  A. C. Chowdhary, del.                               SPONGILLA.]
+
+
+
+
+  PLATE II.
+
+  PHOTOGRAPHS OF DRIED SPECIMENS OF _Spongilla_, _Tubella_, AND
+  _Corvospongilla_.
+
+
+  Fig. 1. Part of a large specimen of _S. (Eunapius) carteri_
+     from Calcutta, to show the conspicuous rounded oscula
+     (reduced).
+
+  Fig. 2. Gemmules of _S. (Stratospongilla) bombayensis_ on a
+     stone from the edge of Igatpuri Lake, Bombay Presidency
+     (nat. size).
+
+  Fig. 3. Part of one of the type-specimens of _S.
+     (Stratospongilla) ultima_ from Cape Comorin, Travancore, to
+     show the star-shaped oscula (slightly enlarged).
+
+  Fig. 4. Part of the type specimen of _T. vesparioides_
+     (external membrane destroyed), to show the reticulate
+     skeleton and the numerous gemmules (nat. size).
+
+  Fig. 5. Part of a schizotype of _C. burmanica_ to show the
+     elevated oscula (nat. size).
+
+  [Illustration: Freshwater Sponges.                    Plate II.
+  Photo by A. Chowdhary.     Spongilla, Tubella, Corvospongilla.]
+
+
+
+
+  PLATE III.
+
+  PHOTOGRAPHS OF SPECIMENS OF _Plumatella_, _Lophopodella_, AND
+  _Pectinatella_.
+
+  Fig. 1. Specimen in spirit of _P. fruticosa_ (typical
+     form) on the leaf of a bulrush from a pond in the Calcutta
+     Zoological Gardens (nat. size).
+
+  Fig. 2. A small zoarium of the _benedeni_ phase of _P.
+     emarginata_ from Rangoon (nat. size). Part of the mass has
+     been removed at one end to show the structure. The specimen
+     was preserved in spirit.
+
+  Fig. 3. Part of a large zoarium of _P. diffusa_ on a log
+     of wood from Gangtok, Sikhim (nat. size). An enlarged figure
+     of another part of the same specimen is given in fig. 2, Pl.
+     IV. The specimen was preserved in spirit.
+
+  Figs. 4, 4 _a_. Specimens of _L. carteri_ from Igatpuri
+     Lake, Bombay, preserved in formalin. Fig. 4 represents a
+     mass of polyparia surrounded by a green gelatinous alga on
+     the stem of a water-plant; fig. 4_a_ an isolated polyparium
+     with the polypides fully expanded from the under surface of
+     a stone in the same lake. Both figures are of natural size.
+
+  Fig. 5. Part of a compound colony of _P. burmanica_ on
+     the stem of a reed from the Sur Lake, Orissa (nat. size,
+     preserved in formalin).
+
+  [Illustration: Phylactolaematous Polyzoa.            Plate III.
+  Photo by A. Chowdhary. Plumatella, Lophopodella, Pectinatella.]
+
+
+
+
+  PLATE IV.
+
+  SPECIMENS OF _Plumatella_.
+
+  Fig. 1. Vertical branch of a polyparium of _P. emarginata_
+     from Calcutta, to show method of branching (x 8). The
+     specimen was preserved in formalin, stained with haemalum,
+     and after dehydration and clearing, mounted in canada
+     balsam.
+
+  Fig. 1 _a._ Part of a young, horizontal zoarium of _P.
+     emarginata_ from Rangoon (x 4, preserved in spirit).
+
+  Fig. 2. Part of a zoarium of _P. diffusa_ from Gangtok,
+     Sikhim (x 4). See Pl. III, fig. 3.
+
+  Figs. 3, 3 _a._ Specimens in spirit of _P. allmani_ from
+     Bhim Tal (lake), W. Himalayas. Fig. 3 represents a mature
+     polyparium; fig. 3 _a_ a young polyparium to which the
+     valves of the statoblast (x) whence it had arisen are still
+     attached.
+
+  Fig. 4. Part of a zoarium of the _coralloides_ phase of _P.
+     fruticosa_ (from Calcutta) preserved in spirit, as seen on
+     the surface of the sponge in which it is embedded (x 3).
+
+  Fig. 5. Part of the margin of a living polyparium of _P.
+     punctata_ from Calcutta (x 8) with the polypides fully
+     expanded.
+
+  [Illustration: Phylactolaematous Polyzoa.             Plate IV.
+  A. C. Chowdhary, del.                              PLUMATELLA.]
+
+
+
+
+  PLATE V.
+
+  SPECIMENS OF _Plumatella_, _Stolella_, AND _Pectinatella_.
+
+  Fig. 1. Part of a zoarium of the _coralloides_ phase of _P.
+     fruticosa_ (x 10) from Calcutta. The specimen, which was
+     preserved in spirit, had been removed from a sponge of
+     _Spongilla carteri_.
+
+  Fig. 2. Terminal branch of a polyparium of _P. punctata_
+     from Calcutta (x 30). The specimen was preserved in
+     formalin, stained with haematoxylin, and finally mounted in
+     canada balsam.
+
+  Fig. 3. Part of an adult polyparium of _S. indica_ from
+     the United Provinces (x 30). The specimen was preserved in
+     formalin, stained with haemalum, and finally mounted in
+     canada balsam. The lower zooecium contains a mature free
+     statoblast, the upper one a fixed one.
+
+  Fig. 4. The growing point of a young polyparium of the
+     same species from Calcutta (x 30), to show the method of
+     formation of the stolon that connects the different groups
+     of zooecia. The specimen had been treated in the same way as
+     that represented in fig. 3.
+
+  Figs. 5, 5 _a_. Zoaria from a compound colony of _P.
+     burmanica_ from the Sur Lake, Orissa (x 2). The specimens,
+     which were preserved in formalin, are represented as seen
+     from the adherent surface of the colony.
+
+  [Illustration: Phylactolaematous Polyzoa.              Plate V.
+  A. C. Chowdhary, del.      Plumatella, Stolella, Pectinatella.]
+
+
+
+
+       *     *     *     *     *
+
+
+
+
+Transcriber's note:
+
+  In the Systematic Index, sub-family items were renumbered from 15.
+    through 38., to correspond to the numbers used in the text of the
+    book.
+  Greek letters used as symbols are spelled out, e.g. alpha, beta, etc.
+  Letters missing or mis-typeset were inserted, e.g. 'practica ly' to
+    'practically'
+  Footnotes were moved after the paragraph to which they pertain.
+  Raised dots were replaced with decimal points in numeric notations.
+  Bold page numbers in the index are surrounded by tildes, e.g. ~76~.
+  Punctuation was standardized.
+  Added a description of a sketch contained within one line of text.
+
+  Other changes:
+    'recognzied' to 'recognized' ... be recognized....
+    'benegalensis' to 'bengalensis' ... lacustris var. bengalensis,...
+    'pecular' to 'peculiar' ... the peculiar amphipod ...
+    'milar' to 'similar' ... similar in the two ...
+    'large' to 'larger' ... a little larger than the upper ...
+    'pennsylvania' to 'pennsylvanica' ...Tubella pennsylvanica...
+    'variely' to 'variety' ... specimens of the variety ...
+    'measurments' to 'measurements' ... the average measurements ...
+    'It' to 'Its' ... Its buds, however, possessed ...
+    'dispsition' to 'disposition' ... 'Y-shaped disposition of ...
+    'Wood's Holl' to 'Wood's Hole' ... Biol. Bull. Wood's Hole,...
+    '1852' to '1851' at the end of the citation of Leidy's paper, to
+       match date at the beginning of the citation paragraph.
+    'syoecium' to 'synoecium' ...in a gelatinous synoecium...
+    'Lacustre' to lower case ...Ann. Biol. lacustre,...
+    'Dactyloccopsis' to 'Dactylococcopsis' ... Dactylococcopsis
+       pectinatellophila ...
+    'amphioxus' to 'amphioxous' ... amphistrongylous or amphioxous ...
+    'Trida' and 'Trida' to 'Trida' for consistency ... Praze, Trida ...
+
+
+
+***END OF THE PROJECT GUTENBERG EBOOK FRESHWATER SPONGES, HYDROIDS &
+POLYZOA***
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author	Roger Frank <rfrank@pglaf.org>	2025-10-14 20:05:57 -0700
committer	Roger Frank <rfrank@pglaf.org>	2025-10-14 20:05:57 -0700
commit	3e6eae8e0027c4d703fb89aa87952ec628a0e159 (patch)
tree	76083f2747f9b0f8fdc2afbf57e8b9a311018b88