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diff --git a/34984-0.txt b/34984-0.txt new file mode 100644 index 0000000..1e0d302 --- /dev/null +++ b/34984-0.txt @@ -0,0 +1,9648 @@ +The Project Gutenberg EBook of A Guide for the Study of Animals, by +Worrallo Whitney and Frederic Lucas and Harold Shinn and Mabel Smallwood + +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: A Guide for the Study of Animals + +Author: Worrallo Whitney + Frederic Lucas + Harold Shinn + Mabel Smallwood + +Release Date: January 16, 2011 [EBook #34984] + +Language: English + +Character set encoding: UTF-8 + +*** START OF THIS PROJECT GUTENBERG EBOOK A GUIDE FOR THE STUDY OF ANIMALS *** + + + + +Produced by Larry B. Harrison and the Online Distributed +Proofreading Team at https://www.pgdp.net + + + + + +Transcriber's notes: Obvious typographical errors have been +corrected, but otherwise the author's spelling has been preserved. + + + + + A GUIDE FOR THE + STUDY OF ANIMALS + + + BY A COMMITTEE FROM THE + BIOLOGY ROUND TABLE OF THE CHICAGO + HIGH SCHOOLS + + + WORRALLO WHITNEY, Chairman + BOWEN HIGH SCHOOL + + FREDERIC C. LUCAS + ENGLEWOOD HIGH SCHOOL + + HAROLD B. SHINN + SCHURZ HIGH SCHOOL + + MABEL E. SMALLWOOD + LANE TECHNICAL HIGH SCHOOL + + + D. C. HEATH & CO., PUBLISHERS + BOSTON -- NEW YORK -- CHICAGO + + + + + Copyright, 1911, + By D. C. Heath & Co. + 1 E 3 + + + + +PREFACE + + +The following guide to the study of animals is intended for pupils in +secondary schools. It was prepared by the authors at the request of +the Biology Round Table, an association composed of the teachers of +Biology in the Chicago High Schools, to whom the authors wish to take +this opportunity of expressing their appreciation of the many helpful +suggestions and criticisms of the manuscript. + +The time has passed when a high school course in zoölogy consists +simply of a somewhat simplified edition of a similar course in +college. All teachers now recognize that the motivization of any +course should be its adaptability to the needs of the student, and +that zoölogy must be taught from the standpoint of the student rather +than that of the subject. In preparing this guide, the authors have +tried to keep these points in mind. + +The matter of presentation, the order of topics, and the choice of +material has been much discussed, but the trend of opinion has +finally set in toward an ecological rather than a type study of +animals; that there should be in the case of young students a brief +study of rather a large number of animals to bring out some general +biological law, rather than an exhaustive study of a very few types. +It is further recognized that the use of a reference library is +absolutely essential in connection with and to supplement the +laboratory work, as there are some topics beyond the ability of the +young student for original investigation as well as impossible in +the amount of time usually allotted to the subject in our crowded +curricula. Of great importance is the economic side of zoölogy, +especially its bearing upon the applied sciences of medicine, +sanitation, household science, and agriculture, and this phase has +received special attention in this guide. + +The desirability of field work has always been recognized, but the +special conditions under which schools must work are so variable as +to make any set directions for field work of little value, and so +they have in most cases been omitted in this work. Each teacher can +easily give such special direction for collecting material and study +in the field as the locality of the school and the time available for +it shall determine. + +Since zoölogy will probably be the pupil's first laboratory science, +the authors have preceded the more formal portion of the manual with +a series of short exercises on familiar and easily obtained animals +in order to introduce the pupil to the laboratory method and to +stimulate his interest, training him at the outset to be constantly +on the outlook for specimens and to show him how much may be learned +from common things right around him, if he will only use his eyes. We +have also begun the more formal portion of the guide with insects, +since in the fall they are easily collected and may be studied alive. +They illustrate, moreover, the principles of classification and +method of using keys and other means of finding out the names of +animals. This would seem to be pedagogically sound, for some recent +experiments with pupils show that the first question that comes into +a child's mind upon seeing a new or strange specimen is "What is it?" + +A larger portion of the guide is given to the chordates than is +usually the case. The authors also believe that this is correct and +in accord with the natural interest of the pupil. It will serve to +connect his zoölogy more closely with his daily experiences. + +There is material enough provided to allow the teacher a chance to +select that best adapted to his purposes or conditions as well as to +provide for those schools that give more than one year to zoölogy. + + + + +CONTENTS + + PAGE + + +CHAPTER I + + INTRODUCTORY STUDIES OF LIVING ANIMALS 1 + +Fly, 1; Maggot, 3; Cockroach, 4; Spider, 5; Cricket, 6; Grasshopper, +7; Butterfly or Moth, 9; Caterpillar, 10; Tussock Moth, 11; Beetle, +13; Damsel Fly Larva, 14; Plant Lice and Scale Bugs, 15; Water Bugs +and Beetles, 17; Getting Acquainted with the Library, 18. + + +CHAPTER II + + STUDIES OF INSECTS 20 + +Field Studies, 20; Grasshoppers or Locusts, 23; Comparative Study of +Orthoptera, 28; Key to Orthoptera, 29; Dragon Fly, 30; Honeybee, 31; +General Study of Insects, 33; Review of Insects, 35; Key to Principal +Orders, 36; Some Common Butterflies, 38; Summary of Insects, 37; +General Review and Library Exercise, 40. + + +CHAPTER III + + THE CONNECTION BETWEEN STRUCTURE AND FUNCTION 44 + +_Protozoa_: A Study of the Cell, 44; Comparative Study, 48; Review +and Library Exercise, 49; Sponges, 51; Review and Library Exercise, +53. _Cœlenterates_: Hydra, 54; Comparative Study, 58; Review and +Library Exercise, 59. _Worms_: Living Earthworm, 61; External +Morphology, 64; Internal Morphology, 64; Microscopic Anatomy, 66; +Summary, 68; Review and Library Exercise, 70; Connection between +Structure and Function, 72. + + +CHAPTER IV + + ADAPTATION TO SURROUNDINGS 73 + +_Crayfishes_: Living Crayfish, 73; Morphology, 75; Summary, 79; +Review and Library Exercise, 81. + + +CHAPTER V + + ADAPTATION FOR PROTECTION FROM ENEMIES 83 + +_Mollusca_: Clam, 83; Snail, 87; Squid, 89; Comparative Study, 91; +Review and Library Exercise, 92. Comparative Study of Exoskeletons, +93; Protective Coloration, 94; Animal Associations, 96; Protective +Habits and Powers, 98; Defensive Structures, 99; Thesis: "Adaptation +for Protection," 99. + + +CHAPTER VI + + VERTEBRATES 101 + +_Fishes_: Living Fish, 101; External Structure, 103; Mouth and Gills, +105; Alimentary Canal and Circulatory System, 107; Review and Library +Exercise, 110. Primitive Chordates, 112. _Amphibia_: Living Frog or +Toad, 114; Mouth, 116; Organs of Digestion, Absorption, and +Excretion, 117; Organs of Circulation and Respiration, 120; Nervous +System, 123; Endoskeleton, 125; Comparative Study, 129; General +Review and Library Exercise, 129. _Reptiles_: Living Snake, Lizard, +and Turtle, 130; Review and Library Exercise, 132. _Birds_: Living +Pigeon, 133; Plumage, 136; Birds and Migration, 139; Laboratory +Exercise, 139; Field Work, 141; Review and Library Exercise, 142; +Migration in General, 145. _Mammals_: Rodents: Domestic Rabbit, 146; +Wild Rabbit, 148; Guinea Pig or White Rat, 149; Squirrel, 150; +Library Exercise, 152. _Carnivora_: Laboratory Exercise, 153; Library +Exercise, 155. _Ungulates_: Laboratory Exercise, 157; Library +Exercise, 160. The Horse, 162. Homology of the Vertebrate Skeleton, +168. + + +CHAPTER VII + + ADAPTATIONS FOR THE PRESERVATION OF THE SPECIES 170 + +Methods of Reproduction: Simple or Asexual Method, 170; Complex or +Sexual Method, 171. Development: Structure of an Egg, 172; +Development of an Egg, 173; Metamorphosis of a Mosquito, 174; +Metamorphosis of a Butterfly, 176; Development of the Chick, 177. +Protection and Care of Young: Library Exercise, 179. Adaptation for +the Preservation of the Species: Review and Library Exercise, 180. + + +CHAPTER VIII + + POULTRY 182 + + * * * * * + + + GLOSSARY 189 + + + + +A GUIDE FOR THE STUDY OF ANIMALS + + + + +CHAPTER I + +INTRODUCTORY STUDIES OF LIVING ANIMALS + + +In the following brief exercises the primary purpose is to arouse an +active, attentive interest on the part of the pupil in various forms +of animal life which may be at hand, reminding him of what and how +various creatures eat, how they breathe, how they get ideas of the +world, how they get about, and perhaps how they succeed where others +fail. Of secondary importance is the introduction of laboratory +methods by easy stages. The pupil should feel that his natural +curiosity is only being directed to definite ends and that he is free +to investigate in his own way. + +The types here given are only a few of the many to be found in the +early fall, and these exercises in several cases may be used for +other forms than those definitely mentioned. There should be a great +deal of promiscuous collecting by the class, and in the mass of +material gathered the following types will probably be fairly +abundant. + + +THE LIVING FLY + + + _Materials._ + +Living flies in cages and individual specimens in small wide-mouth +vials with cotton stoppers for the admission of air. Sugar crystals +may be used for feeding. Simple lenses. + + + _Observations._ + +Notice the division of the body into three regions: head, thorax, and +abdomen. The six legs, the large wings, and the small feelers may be +easily found, as are the large eyes, the extensible mouth, and +beneath the larger wings the small undeveloped ones looking like tiny +knobs. + +1. State the general color of your specimen and give any special +markings on its body. + +2. Is the body smooth or has it a covering of any kind? Do you regard +the fly as a cleanly animal? Why? + +3. Under what conditions does the fly use its legs? its wings? What +enables it to walk upside down? What use can you assign to the small +wings? + +4. Judging by the relative size of the feelers and the eyes, do you +think the fly relies more upon its sight or its feeling? Since the +eyes can probably see you any place where you see them, determine +through how much of a circle the fly can see. + +5. How does the fly eat? Does it eat solid or liquid food? + +6. Where is the extensible mouth (_proboscis_) kept when not in use? +What is the fly doing when "washing its face"? + +7. From your own observation in the barn and the alley what do you +know about the fly's cleanliness in choosing its food? How would it +affect articles in the pantry? + +8. From the foregoing statements show how flies may be a serious +factor in dealing with disease. + +9. What means may be employed as protection against adult flies? +against their breeding places and "maggots"? + + + _Suggested drawing._ + +a. The entire fly, seen from above, × 4. + + +THE LIVING MAGGOT + + + _Materials._ + +Living specimens in pans or cotton-stoppered bottles, with some food +material and moist cloth or paper; lenses. + + + _Observations._ + +Notice the general worm-like form of the maggot, or grub, the plain +and uniform color, and the absence of all elaborate structures, as +wings and feelers. + +1. Since this creature is destined to become a flying or walking +insect, what organs will have to appear? Is there any indication of +these structures at present? + +2. Give the color of the specimen, and explain how the presence or +absence of strong light seems to have affected the color. Is this +effect usual in animals or plants that you know? + +3. Tell how the animal gets from place to place, describing any +special structures you find which aid in this work. + +4. How can you tell the head end? Tell how the amount of work that +the mouth and mouth parts do affects their size and indirectly that +of the region where they are. + +5. What senses and sense organs has the maggot? Test any of these +senses or organs gently, by any means at your disposal, or recall any +experience you have had along this line. Which senses or organs seem +to be best developed? + + 6. Explain briefly how the active or sluggish habits either + determine or are determined by the condition of the senses or + sense organs. + + 7. Since "Mother Nature" seems to want maggots to develop + rapidly, tell how she economizes in energy and material when + forming them. + + 8. Show how the development of maggots in refuse matter is + actually beneficial. + + 9. From the standpoint of flies and human welfare, show why + maggots should not be allowed to live,--stating how they may be + prevented. + + 10. Look up the story of the pupa of the house fly; the + development and work of the botfly; of the ox-warble; of the + tsetse fly. + + + _Suggested drawing._ + +a. The maggot or grub, side view, × 4. + + +THE LIVING COCKROACH + + + _Materials._ + +Individual specimens in cages, jars, or wide-mouth vials with cotton +stoppers to admit air. Several roaches in large cages with material +for food and concealment. + + + _Observations._ + +1. What is the general color and the average size of cockroaches? + +2. During what time of the day are roaches most active? Where do they +hide at other times? How do their shape and color aid concealment? +Note any odd or striking colors or marks which might make them +distinguishable to their mates. + +3. Is the roach a quick or a slow moving animal? How does it get +about,--by running, jumping, walking, crawling, swimming, or flying? +Turn your specimen on its back and see how it recovers its proper +position. Notice the relative size and development of the wings and +their use in flying. + +4. If uninjured, your specimen has six legs. Why don't they step on +each other? Notice the stiff hairs on the legs and the white pads +under the feet. How would these structures be useful to the animal? + +5. The large, black, shiny eyes are on the front and sides of the +head; the long "horns," or feelers, are attached just below the eyes. +Upon which sense, sight or feeling, do you think the roach depends +more? Explain your statement. + +6. Beside the mouth are a long and a short pair of "feelers"; perhaps +these are for tasting or smelling. What do roaches like to eat? Do +they choose their food? What damage do they do? + + 7. How can a house be rid of cockroaches? + + + _Suggested drawing._ + +a. A cockroach, seen from above. + + +THE LIVING SPIDER + + + _Materials._ + +Living spiders, preferably large ones, in cages; individual specimens +in battery jars or wide-mouth bottles. Cocoons. Simple lenses. + + + _Observations._ + +Each pupil may feel sure that if treated fairly any of the common +spiders may be handled without fear of bite or injury. + +1. Note that the spider's body is of two regions, the head-thorax and +the abdomen, and that it is supported by eight legs. To what part of +the body are the legs attached? + +2. Find the feelers; if they are club-shaped, your specimen is a +male. State their number and tell where they are attached. What is +the sex of your spider? + +3. Usually there are eight tiny near-sighted eyes on the front of the +head. State the color of the eyes and by a diagram indicate their +arrangement. + +4. With what kind of material is the body covered (use the lens)? + +5. What is the color of your specimen? What special markings has it? + + Find out the name of your kind of spider. + +6. Holding the spider aloft in your fingers, allow it to drop upon +the thread it will spin, and watch it climb and spin. Record the +number of the spinners, their situation, and how they act. Are the +threads sticky? If so, why doesn't the spider stick to its web? Is +the web used for a home or for a snare? + +7. Try to discover how the feet are enabled to cling to the thread. + +8. Examine a cocoon, noting its outer form and structure, and look +for an opening at the top. If you can open a cocoon carefully with +scissors, look for its two coats and inspect its contents. + +9. State three uses for the spider's silk. + + 10. What is the work of spiders amongst the animal population of + the earth, or of what use are they? + + 11. Out of doors find webs of various kinds: wheel web, tent web, + triangle web, etc. + + 12. How do the jumping spiders differ from others in their + spinning and feeding habits? + + 13. Look up what is meant by ballooning spiders. Find out when + ballooning occurs and what is accomplished by it. + + + _Suggested drawings._ + +a. The entire spider, seen from above. + +b. A cocoon. + + +THE LIVING CRICKET + + + _Materials._ + +Living crickets in cages, with materials for food and concealment, +and individual specimens in wide-mouth bottles or vials with cotton +stoppers. + + + _Observations._ + +1. What is the average size and the general color of crickets? + +2. Just what do they do when you try to catch them? What structures +enable them to do these things? + +3. Of the three pairs of legs, which extend sidewise for running or +grasping, and which backward for jumping or climbing? What structures +have the legs to enable them to do their work properly? + +4. Notice how well developed the cricket's wings are, and state how +much they are used or how they influence the habits of the animal. + +5. How many projecting spines are there on the hinder end of the +body? Are they ornamental or useful? how? The female crickets have a +special spear-shaped spine for depositing eggs. + +6. In a column make a list of the senses (sight, feeling, etc.), and +opposite each state what kind of an organ is used and where it is +located. The ears are oblong white spots on the second long piece of +the front legs. + +7. Find out whether the cricket chews solid food or sucks liquid +food, and whether it has biting jaws or protrusible lips. See whether +it will attack a toothpick or your finger, and if the crickets +have been confined long, whether there has been any attempt at +cannabalism. Is its natural food animal or vegetable matter? + + 8. How do crickets chirp? + + 9. What work do they do in nature? + + 10. How does a baby cricket develop? + + +THE LIVING GRASSHOPPER OR LOCUST + + + _Materials._ + +Individual specimens in wide-mouth bottles or jars, and other +specimens in cages, with turf or foliage for food and concealment. +Simple lenses. + + + _Observations._ + +Notice the form and size of your specimen, its color, the number of +its legs and of its feelers. Find the eyes; the two large eyes, a +tiny one between the two feelers, and near the inner edge of each +large eye, another tiny one. With a lens notice the markings on the +large eyes. Find the mouth, and note its lips and finger-like +feelers. Draw out an outer wing, and then carefully draw out the +delicate under wing, allowing them both to fold into place again. +Under the wings find the circular or crescent-shaped membranes, the +eardrums. Watch the grasshopper's body expand and contract in +breathing, and find the small breathing holes along each side the +body. Compare its rate of breathing with your own. + + + _Questions._ + +1. In what surroundings and how does the grasshopper's color protect +it? What color markings has it which might serve for other +grasshoppers to see as signals? Explain how this signaling is done. + +2. Explain how the legs are placed so as to act as springs in jumping +and alighting. + +3. What advantages in having the wings attached on the upper side and +the legs on the under side of the body? + +4. Explain how the small wings are protective, and how the large ones +are protected. + +5. Why is it better for the grasshopper to have its mouth on the +under side of its head instead of in front? + +6. The large eyes are supposed to be far-sighted, the small ones +near-sighted. State how the large eyes have the more advantageous +position, and around how much of a circle they can see. + +7. Describe how the grasshopper breathes. + + +THE LIVING BUTTERFLY OR MOTH + + + _Materials._ + +Individual specimens in large jars or cages, and other specimens in +cages with foliage; simple lenses and a needle or pin. + + + _Observations._ + +Butterflies may generally be distinguished from moths by their habit +of holding their wings together above them when at rest, by the +feelers which are knobbed at the end, and by the rather slender +abdomen. Moths generally either fold their wings or hold them +outstretched, their feelers are not knobbed, and their bodies are +rather bulky. + +Observe these points in your specimen and the colors of the upper and +under sides of the wings. Find the large eyes and examine them with a +lens. With the needle or pin carefully uncoil the sucking tube which +you may find under the head between two shields. Note the fuzziness +of the body and the "dust" which covers the wings. Examine some of +this dust under a lens. + + + _Questions._ + +1. Is your specimen a butterfly or a moth? Prove your statement. If +possible, give the name of your specimen. + +2. Write a description of your specimen--its size, general color, and +special color pattern. + +3. Describe the sucking tube, or "proboscis," and name some flowers +from which it might obtain nectar. Try to find out how the tube is +operated. + +4. Why is it that moths and butterflies never bite? Do they sting? +How do you think they protect themselves from enemies? + +5. State how the fuzz and dust on your specimen might influence a +bird's liking for it. + +6. Contrast the size and usefulness of the wings of the butterfly +with those of some other insect you know about; contrast their legs; +state how development of one set of structures may cause another set +to be simple or feeble. + +7. Most moths are active by night. What explanation can you give for +their large eyes and expanded feelers? Feelers of insects may be for +any or all of the following: touch, taste, smell, and hearing. + + + _Suggested drawings._ + +a. The butterfly or moth. + +b. An antenna (feeler). + + +THE LIVING CATERPILLAR + + + _Materials._ + +Living caterpillars in cages or covered jars for individual study, +and other specimens in cages with foliage for food or concealment. + + + _Observations._ + +The pupil should observe the general form and external construction +of the caterpillar, watching it feeding, in action, and at rest. + +Notice how the creature moves. Find its head, its segments (similar +divisions of the body), and its breathing holes along the sides of +the body. Try to find its eyes, any feelers, wings or paddles. Try to +loosen it from its support; find the tiny hooks on the feet for +clinging fast. + + + _Questions._ + +1. Give the general color of your specimen and explain how this color +may make it conspicuous or may aid its concealment. + +2. Describe the outer surface or covering of the caterpillar. What +structures, if any, are there, which might make the animal +distasteful or inedible? + +3. How many pairs of legs are there? How are they distributed along +the body? Counting the segments, state which ones bear no legs. + +4. To what extent do the legs act in locomotion? Are they mere organs +for attachment while the body swings forward and backward, or do the +legs do this, as in a horse? Make a complete statement. + +5. Notice the openings of the internal breathing tubes. How are they +protected against dust and other foreign matter? + +6. Does the caterpillar seem to be a warm-blooded animal? State how +the free access of air along the body would influence internal +temperature. + +7. What do you know about a caterpillar's appetite? How might +caterpillars be beneficial or harmful? What means has nature of +holding their numbers in check? + +8. Recalling that caterpillars finally "sleep" for several days or +weeks and awaken as winged creatures, how can you account for their +appetites? + + +THE TUSSOCK MOTH + + + _Materials._ + +Directions for the study of the caterpillar stage will be found in +the exercise "The Living Caterpillar," and directions for the study +of the adult male form will be found in the exercise "The Living +Butterfly or Moth." The female tussock moth is a wingless, +thick-bodied creature, gray in color, very downy, and about three +fourths of an inch long. The following directions apply more +particularly to the study of the cocoons and the general harmfulness +of the tussock moth. + +This exercise may be done best outside of the classroom, the pupil +answering the questions on scrap paper and rewriting these notes in +the laboratory. Living caterpillars, cocoons, some of them bearing +their frothy masses of wax and eggs, pupæ, and adult moths of both +sexes may be used in the laboratory. + + + _Observations and Questions._ + +1. On what kinds of trees are the cocoons and the caterpillars +generally found? What effect have the caterpillars on the trees, and +what may possibly be the final effect upon the trees of the locality +or the entire district? + +2. Upon what part of the tree are the cocoons made, and why? Where on +the bark are they, and why? + +3. Is the opening of the cocoon at the upper or the lower end? What +reason can you assign for this? + +4. Count the number of cocoons upon the entire tree or estimate it by +counting those upon a part of the tree. Now count the number of eggs +on a cocoon. Assuming that one half of the cocoons bear eggs, +calculate the number of caterpillars on a tree next year. + +5. How is the waxy covering of the eggs a particularly good +protection against winter weather? + +6. Investigate the interiors of several cocoons and state what you +find. + +7. On the pupa find the jointed and tapering hinder end, abdomen, and +at the head region and lying along the under side, the marks of the +legs and the feelers, and possibly the wings, all pressed close +against the body. Find also the breathing pores along the sides of +the abdomen. + +8. Unlikeness between male and female is called "sexual dimorphism." +Explain how the tussock moth shows this. For what work does each form +seem particularly adapted? + +9. What methods would you use that the tussock moth might be +destroyed or kept out of a community? + + The numerous small worm-like creatures often found are the + caterpillar stages of another insect, an ichneumon fly, which + laid its eggs under the skin of the tussock caterpillar. How has + their development affected that of the tussock moth? What great + result does nature accomplish by this arrangement? + + + _Suggested drawings._ + +a. A caterpillar, × 2. + +b. A cocoon with its egg mass. + +c. A pupa as seen from the under side. + +d. An adult moth, either male or female. + + +THE LIVING BEETLE + + + _Materials._ + +Living beetles in cages, together with portions of the plant upon +which they are found; or if water beetles are used, they should be +kept in aquaria. Individual specimens in battery jars or wide-mouth +bottles, and preserved beetles in pans or vials for reference. + + + _Observations._ + +1. Upon what plant or in what surroundings is your kind of beetle +generally found? If you can, give its common name. + +2. What is the length, breadth, and thickness of your beetle? Would +you describe it as a "small" insect or a "large" one? + +3. Of what general color is it? Describe any color markings you see. + +4. If any of the legs differ from the others or are of peculiar +shape or length, describe them and tell what you think they may be +fitted to do. + +5. As a rule, beetles have harder "shells" than other insects. Does +this shell completely inclose the body, or can you find any soft +parts exposed? How are the head, thorax, and abdomen joined so as to +carry out the apparent purpose of protection? What is the outline of +the body--a continuous line or one with many irregularities? + +6. If possible, try to lift up one side of the "shell" from the +hinder end of the body. You will discover that this portion of the +shell is a pair of hard sheath wings, and beneath them is another +pair. How are the under ones unlike the upper in size and texture? in +use? in arrangement when not in use? + +7. Does a beetle spend most of its life on the wing, like bees and +flies? How might the body covering and the structure of the outer +wings affect or determine the beetle's habits, even against its will? + +8. Are the feelers or are the eyes of your specimen more easily +distinguished? Upon which of the special senses does it seem to place +most dependence? + +9. Is your kind of beetle good for anything, either in nature or in +human affairs? Make a statement regarding what good or what harm it +may do. + + +THE DAMSEL FLY LARVA + + + _Materials._ + +Living larvæ of the damsel fly in shallow watch glasses of water for +individual use, and others in large pans or aquaria. Simple lenses or +dissecting microscopes. + + + _Observations._ + +1. What is the color and the shape of the larva? how long is it? +Notice in what surroundings in the water the larva lives, and answer +to yourself how its form and color would protect it in those +surroundings. + +2. Since the larva is an insect, though immature, its body is +composed of three regions: head, thorax, and abdomen. How do these +regions differ from each other? + +3. What structures has your specimen to enable it to move from place +to place? If fully developed wings are not present, what indication +is there of their being formed? + +4. What sense organs has the larva? Which ones seem to be the largest +and most useful? + +5. Although the aquatic larva is preparing for adult life in the air, +there should be some arrangement for securing air in the water. Where +do you find outgrowths of the skin which might increase the +air-absorbing surface? How many of these structures are there? Look +within them for the air tubes,--fine branching black lines. + +6. If possible, without injury to the specimen, examine the larva's +mouth. Try to discover how it is used and how it is protected when +not in use. + + + _Suggested drawings._ + +a. The entire larva, × 4. + +b. A gill, as seen through the microscope. + +c. The feeding apparatus, × 10. + + +PLANT LICE AND SCALE BUGS + + +Plant Lice (Aphids) + + + _Materials._ + +Plant lice on various kinds of plants, such as house plants, golden +glow, and other plants from the garden or field. Garden asters with +root lice (the asters should be transplanted into pots). + + + _Observations._ + +1. Describe the size, appearance, and colors of the plant lice in +your collection and their relation to the host plant. + +2. Are the lice active or sluggish? (Compare with a house fly, for +instance.) What proportion of them have wings? What is the usual +method of locomotion? + +3. Examining a single winged specimen, how many wings do you find? +How do they fold? What is the character of the wings? + +4. What is the food of the plant lice? How is the food obtained? +(With a hand lens identify the piercing organ.) On what parts of the +plants are they found? Does the plant show any indication of being +harmed by the lice? If so, how? + +5. Make a count of the plant lice upon a portion of a plant and +estimate the whole number upon a plant. Why are plant lice a very +serious pest? + +6. If any plant lice have ants associated with them, study the +behavior of the ants in this curious relationship. What advantages +result from this relationship of ant and aphis to either or both +insects? + + +Scale Bugs + + + _Materials._ + +Twigs of trees, leaves, fruit, ferns, etc., infested with these bugs. +If possible, have samples of San José scales, maple scales, and +oyster scales. + + + _Observations._ + +1. What is the general size and appearance of the various scale bugs +in your collection? How do they differ in form and size and color? + +2. Remove a scale and study it carefully with a lens. What is under +the scale? Of what is the scale composed? What do you discover about +these bugs to indicate that they are really insects? + +3. What can be said about the number of scale bugs? Why are they +difficult to exterminate? How can they be distributed from one place +to another, as from orchard to orchard, since only the males have +wings? + + + _Drawings suggested._ + +a. A single aphis as seen with hand lens. + +b. Various scale bugs as seen with a hand lens. + +c. Twigs showing the distribution and numbers of scale bugs. + + +WATER BUGS AND BEETLES + + +Water Bugs + + + _Materials._ + +Water bugs and beetles of several species in small aquaria covered +with a wire net. + + + _Observations._ + +1. With what legs does the bug swim? Describe their appearance and +tell how used and how fitted for this use. Which legs are not used in +swimming? + +2. Remove the bug from the water for a moment to test other methods +of locomotion, as jumping, crawling, flying. What do you discover? + +3. Watch the bug as it gets a fresh supply of air, and describe the +process. Where is the air stored for use when under water? Does the +bug sink or rise when it stops swimming? Why? + +4. Identify the bug's mouth parts. What is their appearance and +probable manner of use? How are the forelegs fitted for grasping +food? + +5. What is the shape of the body? What is the position of the wings? +Do the two cover (fore) wings meet in a straight line or do they +cross at their tips? Are they smooth throughout and sheath-like, or +are they thick at the base and thin at the tips? + + + _Summary._ + +Summarize your study of the bug by enumerating the various ways the +bug is adapted for life in the water. + + +Water Beetles + + +Use the same questions for the study of water beetles as for water +bugs. In addition answer the following:-- + +1. Identify the eyes of the whirligig beetle and note their peculiar +construction. How can you explain this peculiar form of the eyes on +the basis of use? Why are the antennæ of both water bugs and beetles +so small? + + + _Suggested drawings._ + +a. The dorsal view of both bug and beetle. + +b. Ventral view of the bug's head to show the beak and first pair of +legs. + + +GETTING ACQUAINTED WITH THE LIBRARY + + + _Directions._ + +The books in a zoölogical library may be roughly divided into three +groups:-- + + 1. Reference books. + a. Advanced textbooks. + b. Elementary textbooks. + c. Natural histories. + d. Books for classifying or naming animals. + 2. Descriptive books. + e. Life histories and habits of animals. + f. Adventures with animals--popular accounts of animals seen on + walks and travels. + 3. Economic zoölogy. + g. Books on harmful animals and methods of destroying them. + h. Books on useful nondomesticated animals and their products. + i. Books on domestic animals. + j. Books of a general nature not included in the above. + +Examine as many of the books in your library as you can and record +for each one in your notebook:-- + +1. Title of the book; author's name; publisher; date of publication. + +2. The kind of book as classified above. + +3. What it includes or what animals or topics are covered by the +book. + +4. Whether the style is popular or technical, _i.e._ whether it is +easy for you to read. + +5. The general character of its illustrations and whether they appear +to be especially helpful. + +6. Comments on the value or interest of the book as it appears to +you. + +7. Select a book which interests you, for future reading. + + + + +CHAPTER II + +STUDIES OF INSECTS + +_The effect of great numbers upon the structure and habits of +animals. The use of keys in finding the names of animals._ + + +1. FIELD STUDIES + + + _Materials._ + +1. _Boxes_ for carrying insects. 2. A _net_. This may be homemade, +using mosquito netting or fish net and a stout wire. If it is to be +used for a dragnet for water insects, the wire must be stout and the +netting strong. Make the net twice as long as wide. 3. A _cyanide +jar_ for killing insects. 4. A few _paper triangles_ for carrying +butterflies. 5. A _notebook_. + + _Note._--Your instructor will give directions for obtaining the + material called for in 3, 4, and 5. + + + _Directions._ + +Look carefully and quietly in the various situations noted below. Do +not be in a hurry. Weedy meadows or vacant lots and neglected +roadsides are good places for your first trips. Note concerning each +insect found: (a) its name or something by which to identify it, (b) +where you found it, (c) what it was doing, (d) its probable food. +Record these observations in your notebook. Make a special study of +such insects as your instructor may designate. + + +Where to look for Various Insects + + +_Grasshoppers, locusts, katydids._ Look along roadsides, waste +places, gardens, especially weedy ones, weedy lots, and grassy +meadows and pastures. + +_Crickets._ Under old boards, along the edges of board or stone +walks, along fences. + +_Beetles._ Same locations as for crickets, and also on flowering +plants, under loose bark of trees and stumps, in rotten logs, etc. +For _water beetles_ drag edges of ponds and streams. + +_Dragon flies._ Along water-courses, ponds, and swamps. Drag ponds +and ditches for larvæ. + +_Bees._ On flowering plants, especially on large patches of wild +asters, golden-rods, and thistles. + +_Wasps._ Sandy stretches,--especially along the water,--among +flowering plants, under the eaves and roofs of outbuildings. Nests +may be found in these latter places. + +_Butterflies and moths._ In fields where there are many flowering +plants; look carefully on the leaves of plants for caterpillars, and +for eggs. Also look very carefully on the under side of leaves, on +twigs, and on the bark of trees for chrysalids of butterflies and +cocoons of moths. + +_Bugs._ In same locations as for bees and grasshoppers and water +beetles. Also on fruit. + +_Aphids._ On the fresh growing tops of plants. + +_Tree hoppers._ On trees and shrubs. Hold your net on the under side +of branches and shake the branch vigorously. + +_Flies._ Around decaying substances, as garbage, fruit, etc.; on +flowering plants. + +_Ants._ Sandy waste places, decayed logs, along walks, often in +kitchens. + + _Note._--At night many kinds of insects fly around electric + lights or into open windows, attracted by the light and may + easily be collected. + + +Form for Field Trip Report + + +The notes taken on a field trip may be conveniently tabulated for +permanent record in the form indicated below:-- + + FIELD TRIP REPORT + + Date________ Time________ Locality________ Pupil's Name________ + ---------------------------------------------------------------- + Name of Insect | Where Found | What it was Doing | Probable Food + ---------------+-------------+-------------------+-------------- + | | | + | | | + +In case the name of the insect is not known to you, use a number and +some designation as to color or other mark by which it may be known +until you have leisure to look up its name by means of keys or books +on insects. + + +Special Field Studies + + +The questions below may be used for a more careful field study of any +insect. + +1. Just where was the insect found? + +2. Note carefully what the insects are doing before they are +disturbed by your presence. What did the insects do when you +disturbed them? If you think this related to securing safety, explain +what leads you to think so. + +3. What senses do you conclude are well developed? Reason for your +conclusion. + +4. Has the insect a home? If so, what is its character? + +5. What is the color? What is the relation between the color of the +insect and its surroundings? + +6. Is the insect solitary in its habits or associated with others of +the same species? If in association with others, note the numbers, +and what they are doing. + +7. What modes of locomotion do you observe in this insect? Which is +the most common? If it flies or jumps, note the distance. + +8. If you find the young, note whether they differ from the adult in +general appearance, and if so, in what ways they differ. Do they +differ in food? + +9. What other insects do you find in the same habitat? + + +2. A STUDY OF GRASSHOPPERS (LOCUSTS) + +_Insects adapted to Life in Grassy Meadows and Fields_ + + + _Materials._ + +Both living and dead specimens of grasshoppers. Various stages of +young grasshoppers either dead or living. Some mounted specimens with +wings spread. The wings of grasshoppers mounted in pairs between two +glass slides for use with microscope or hand lens. Mounted +preparations of mouth parts and tracheæ. + + + _Definitions._ + +_Orthoptera_, straight-winged insects, order to which belong +grasshoppers, locusts, katydids, crickets, cockroaches, etc. + +_Vivarium_, a cage in which living animals are kept. + +_Anterior_, toward the head of an animal. + +_Posterior_, opposite to anterior. + +_Dorsal_, the upper surface of an animal. + +_Ventral_, opposite to dorsal. + +_Regions_, principal divisions of the body of an animal. + +_Head_, _thorax_, and _abdomen_, the three distinct regions into +which the body of a grasshopper is divided. + +_Somite_, a ring-like division of the body of an animal. + +_Prothorax_, _mesothorax_, and _metathorax_, the three divisions or +somites into which the thorax of any insect is divided. A pair of +legs is borne on each division. + +_Exoskeleton_, an external skeleton. + +_Femur_, _tibia_, and _tarsus_, the three principal divisions of the +leg corresponding to thigh, shank, and foot. + +_Veins_, thread-like thickenings of the wings. + +_Ocelli_, the single or simple eyes of an insect, composed of a +single eye element. + +_Compound eyes_, made up of many eye elements. + +_Auditory sacs_, organs for hearing in many animals. + +_Antennæ_, the feelers borne on the head. + +_Labrum_, the upper lip. + +_Labium_, the lower lip, formed by the growing together of the second +maxillæ. + +_Mandibles_, primary jaws situated under the labrum. + +_Maxillæ_, secondary jaws just in front of the labium, each composed +of three parts, a palp, a spoon, and a tooth. + +_Palps_, the jointed finger-like structures used to handle food, one +pair on the labium and one pair on the maxillæ. + +_Spiracles_, openings into the trachea found along the sides of the +abdomen and thorax. + +_Tracheæ_, slender tubes used for breathing organs among insects. +They carry the air direct to the tissues in all parts of the body. + +_Ovipositors_, structures on the posterior end of the abdomen of a +female, used to deposit eggs. + +_Metamorphosis_, refers to the development of the young of animals +when striking changes in structure occur in the course of their +growth. Metamorphosis is called _complete_ when the young have no +resemblance to the adults, and _incomplete_ when there is a +resemblance to the adult. In complete metamorphosis the stages are +_larva_, _pupa_, and _adult_. In incomplete metamorphosis the stages +are _nymph_ and _adult_. + + + _Observations._ + +_The Body._ + +1. Show how the shape of the grasshopper's body is well adapted to +its needs. + +2. Which region of the body is the thickest? What seems to be the +reason for this? Which regions are capable of movement? + +_Locomotion._ + +3. What are the various kinds of locomotion a grasshopper can use? +Which are used in the vivarium and which when free in the laboratory? + +4. Which legs are used in jumping? How are these legs especially +adapted to this, in length, structure and direction? Could a +grasshopper jump if the third pair of legs were arranged like the +other two pairs? Why? + +5. How is the animal able to cling to grass stems and not slip down? +What is the direction of the body in relation to the stem or grass +blade? + +6. What is the position of the wings when at rest? when in use? How +do the hind wings fold? How are the principal veins of the wings +arranged to permit or facilitate this folding? + +7. Contrast the fore and hind wings with respect to thickness, size, +and use. + +8. To which somites of the thorax are the wings attached? Nearer +which surface, the dorsal or ventral? Why? + +_Sense Organs._ + +9. Discover all you can about the uses of the antennæ by carefully +observing grasshoppers at rest, feeding, jumping and crawling, +approaching an object or another grasshopper, etc. + +10. How many compound eyes has the grasshopper? How many simple eyes? +Where are they located? + + Examine a preparation of the compound eye with the low power or + as demonstrated with the stereopticon. What is the shape of an + eye element of the compound eye? About how many eye elements are + there in a compound eye? + +_Feeding._ + +11. Do grasshoppers eat and drink while in captivity? Put a fresh +bunch of grass which has been sprinkled with water in a vivarium with +grasshoppers that have had no food or drink for twenty-four hours and +watch results. + +12. What is the position of the grasshoppers in feeding? In what +direction do the jaws move in feeding? Compare this with the +direction of movement of your own jaws. What is the use of the palps? +What do you think is the use of the "molasses" or saliva that flows +from the mouth? + +_Respiration._ + +13. Describe the breathing movements of a grasshopper and explain the +relation of the movements to inhalation and exhalation of air. + +14. Find the exact location and number of spiracles on the abdomen. +There are two pairs of spiracles on the thorax. Find them. How do the +spiracles prevent the entrance of dust? + + Describe a trachea as seen in a mounted preparation with the aid + of a microscope or stereopticon. + +_Protection._ + +15. Explain how the colors of the grasshopper may be protective or +useful when at rest in its natural habitat and when in flight. + +16. Does the shell cover the entire body? What are the advantages of +such a covering? A shell is likely to hinder activity, sensitiveness, +and growth. How are such disadvantages overcome in this case? + +17. What senses are probably most relied upon to detect approaching +danger? Give evidence to support your answer. + +18. What is the position of the hind legs when at rest? What relation +has this to safety? + +_Reproduction and Development._ + +19. Describe the ovipositors and the probable method of their use. +Describe the egg packets of grasshoppers, if discovered. About how +many eggs in one? (They are sometimes seen against the glass sides of +the vivaria.) + +20. If you have young grasshoppers of various ages, arrange a set of +them in what seems to you to be the order of their development. How +do young grasshoppers differ from adults? What changes take place as +they develop? What kind of metamorphosis is this? + + +Summary of Important Points in the Study of the Grasshopper + + +1. How many and what distinct regions of the body are there? + +2. How many antennæ? Compare their length with that of the body. +What other sense organs did you discover? + +3. How many legs? For what specially adapted? How? + +4. How many wings? What is their resting position? How do the fore +wings differ from the hind wings? How do the hind wings fold? + +5. To what kind of feeding are they adapted, biting or sucking the +food? How many and what sets of mouth parts are there? + +6. How is air necessary for respiration obtained? + +7. In what various ways are grasshoppers fitted for life in meadows +and weed plots? + +8. How do they meet winter conditions? + +9. What kind of metamorphosis has the grasshopper? + + + _Drawings suggested._ + +a. Side view with the legs and wings removed. Label all parts shown +in this drawing. (See Definitions on pages 23 and 24 for names of +parts.) + +b. Face view of the head, showing the simple and compound eyes, the +antennæ, labrum, and palps. + +c. One of the third pair of legs. Label parts. + +d. A fore and a hind wing arranged in natural position. + +e. A young grasshopper. + + +3. COMPARATIVE STUDY OF ORTHOPTERA + + + _Materials._ + +Mounted specimens of various common species of orthoptera. + + + _Observations._ + +1. Where does the insect live? What is its color? + +2. What is the size and shape as compared with the grasshopper? + +3. What is the length of the antennæ as compared with the length of +the body? + +4. To what kind of locomotion are the legs adapted? How? Are the +forelegs specially adapted for grasping? + +5. What is the position of the wings when at rest? Are they large or +small as compared with the size of the body? + +6. Are the ovipositors long or short? (Compare with those of the +grasshopper.) + +7. Find the group to which the insect belongs and its name by the key +in the following section. + + +4. KEY TO SOME COMMON ORTHOPTERA + + +A. Groups + + + ============================================================================= + LEGS |ANTENNÆ| OTHER CHARACTERS | GROUPS + -----------------+-----------------------------------------+----------------- + Similar, fitted | Long | Body flattened, wings folded on | Cockroaches + for running | | dorsal surface of the abdomen | (_Blattidæ_) + -----------------+-------+---------------------------------+----------------- + First pair of | Rather| Prothorax long and slender, | Mantis + legs enlarged | long | wings folded on dorsal | (_Mantidæ_) + for grasping | | surface of abdomen | + -----------------+-------+---------------------------------+----------------- + Similar, fitted | | Body usually greatly elongated | Walking stick + for walking | Long | and stick-like, usually no | (_Phasmidæ_) + | | wings | + -----------------+-------+---------------------------------+----------------- + Hind legs fitted | | Body somewhat compressed, | Short-horned + for jumping | Short | wings folded on side of | grasshoppers + | | abdomen | (_Acrididæ_) + |-------+---------------------------------+----------------- + | | Body compressed, wings folded | Long-horned + | Long | on sides, tarsus four-jointed | grasshoppers + | | | (_Locustidæ_) + |-------+---------------------------------+----------------- + | | Body somewhat flattened, wings | Crickets + | Long | folded on the back, tarsus | (_Gryllidæ_) + | | three-jointed | + ============================================================================= + + +B. Species or Genera + + + ============================================================================ + CHARACTERS OF SPECIES | COMMON NAME | GROUPS + -------------------------------------+----------------------+--------------- + Large size, brown color | American cockroach | + Small size, pale brown | "Croton bug" | Cockroaches + Dark color, often wingless | Oriental cockroach | + -------------------------------------+----------------------+--------------- + Body long, anterior portion slender | Mantis or rear horse | Mantis + -------------------------------------+----------------------+--------------- + Long body, long legs, no wings | Walking stick | Walking sticks + -------------------------------------+----------------------+--------------- + Very large size, wings very small | Lubber grasshopper | + Small to medium size, legs marked | Red-legged | + with red | grasshopper | Short-horned + Large size, greenish brown color | Differential locust | grasshoppers + Medium to large size, sand color | Carolina locusts | + (gray) | | + -------------------------------------+----------------------+--------------- + Rather large, green, wings large | Angle-wing katydid | + and angled | | Long-horned + Small to rather large, usually green | Meadow grasshopper | grasshoppers + Wingless, brown color | Cricket grasshopper | + -------------------------------------+----------------------+--------------- + Usually rather large, black | Field cricket | Crickets + Wingless, front legs shovel-shaped | Mole cricket | + ============================================================================ + + +5. THE DRAGON FLY + +_An Insect adapted to Aerial Life_ + + + _Materials._ + +Mounted specimens of dragon flies, some moist preserved specimens, +living specimens if practicable, simple lenses. + + + _Observations._ + +1. Identify the three regions of the body and note the presence of a +distinct neck. What is the length of the insect? What is its general +form? If you have living specimens, discover what movements the head +and abdomen are capable of making. + +2. What is the position and general character of the wings? Explain +how these wings are made very efficient for flying. Why should they +not fold? + +3. For what do the legs seem best adapted? Why? + +4. Note the size of the eyes and of the antennæ? How do you account +for the great size of the eyes and the relatively small antennæ? + +5. What is the type of mouth parts, biting or sucking? If you have +living dragon flies, try feeding them flies or mosquitoes and note +how they are seized. + +6. The food of dragon flies is mosquitoes and flies caught while on +the wing. In what various ways is the dragon fly specialized for +getting food in this manner? + + + _Summary._ + +How is the dragon fly fitted for its aerial life with respect to its +body, means and method of locomotion, sense organs, kind of food and +manner of obtaining it? + + + _Suggested drawing._ + +a. Dorsal view, showing veining of one wing. + + +6. THE HONEYBEE + +_A Study of Adaptations for Community Life_ + + + _Materials._ + +Preserved specimens of workers in small vials and in watch glasses, +and some mounted specimens. A demonstration case showing the three +kinds of members of the community, stages in the development of the +workers and queens and the cells in which they are reared, specimens +of the comb. Small pieces of beeswax, a box of honey, and specimens +of comb free for examination. Mounted preparations of mouth parts and +stings. Simple lenses and compound microscopes. + + + _Observations._ + +_The Worker Bee._ + +1. Observe and describe the form, size, regions, and covering of the +bee. What are its colors? + +2. Observe and describe the texture, veining, relative size, and +position of the wings. Discover how the fore and hind wings are +hooked together. What advantage in having them hooked together? + +3. For what kind of locomotion are the legs best adapted? + +4. Find the pollen basket on the tarsus of a hind leg. How is it +fitted for carrying pollen? What are the wax shears? + + a. Examine and describe the structure at the posterior end of the + body used for stinging. (Use a mounted preparation for this with + low-power of microscope.) + + b. The mouth parts are fitted for both biting and sucking. Find + what makes this possible. (Use mounted preparation.) + +5. Describe the antennæ and the number, position, and shape of the +eyes. Are the eyes fitted for keen sight? Give reason for answer. + +6. The worker bee gathers honey and pollen and defends the entire +community from enemies. What various adaptations fit it for this +work? + +_The Community of Bees._ + +7. How do the workers, drones, and queen differ in general +appearance? + +8. Describe the appearance of the comb and the arrangement and shape +of the cells. Why this shape? How are the cells closed when full of +honey? + +9. How do the cells used for rearing worker bees differ from those +used for rearing queens? What is the appearance of the larvæ? Of the +pupa? + +10. Examine and test in various ways a small piece of beeswax. What +are the qualities possessed by this wax which make it suitable for +making comb and protecting the home from storms? + + +Supplementary Studies of Bees + + + _Materials._ + +For this study an observation hive of bees or opportunity to visit an +apiary will be helpful. If neither are practicable, then look up the +answers in books. There are government bulletins on bee-keeping and +much helpful information can be obtained from large dealers in bees +and bee supplies. + + + _Observations._ + +1. How do bees protect their hives from rain and storm and light? + +2. What are honey boxes? Where are they placed in the hive? Can the +honey be removed late in the fall? + +3. How is it safe to approach and handle bees in removing honey and +caring for them? + +4. What are their habits in entering and leaving the hive? What is +the appearance of a returning loaded worker bee? + +5. How do bees survive the winter? Why are the drones driven away or +killed? + +6. Watch bees gathering nectar and pollen from flowers and describe +the process. Try following a bee on its journeys. + +7. When the bees are in the hive, how may you know the queen and +drones from the workers? + +8. What is swarming? When does it take place? How is the swarm hived? + +9. What is the home of wild honeybees? How found? + + +Summary of the Study of Honeybees + + +How is the work of the community of bees divided among the bees? How +is each fitted for the work? What do you think of the success of this +kind of life? Give reasons for your answer. + + +7. GENERAL STUDY OF INSECTS[1] + + [1] This study is intended for an alternative study in case it is + not practicable to use the studies of living insects. With slight + adaptation it can be made useful for any insect, either preserved + or living. + + + _Materials._ + +Both living and preserved specimens of the insects studied should be +at hand, if practicable. There also should be specimens of the young. + + + _Observations._ + +_The Body._ + +1. What is the shape and size of the insect and the number of regions +in its body? Does the shape seem to be in any way adapted to the mode +of life of the insect? If so, how? + +_Locomotion._ + +2. What methods of locomotion has the insect? Which is the most used? + +3. What is the position of the wings when at rest? What is the +texture (_e.g._ thick, smooth, leathery, shell-like, membranous) of +the fore and hind wings? + +4. For what kind of locomotion are the legs fitted? How? + +_Sense Organs._ + +5. How many antennæ has the insect? What is their character as to +shape and length? How many simple and compound eyes? + +_Feeding._ + +6. What is the food of the insect? How are the mouth parts specially +adapted to obtaining this food? + + _Note._--The mouth parts of insects may be jaws for biting, or + may form a tube for sucking, or a beak for piercing and sucking. + +_Respiration._ + +7. Look for movements of the body indicating breathing, and describe +what you find. Discover the location of the spiracles. + +_Protection._ + +8. What are the enemies of this insect? (Among the most important +enemies of insects are birds, certain other insects, and various +small vertebrates such as frogs, snakes, lizards, turtles, etc.) How +does the insect protect itself from these enemies? + +9. Describe the shell with respect to thickness and flexibility. What +is the character of the surface as to roughness or smoothness or +covering of hairs or scales? + + _Reproduction and Development._ + + _Note._--It may be necessary to get answers to these questions + from books. + + 10. Where are the eggs deposited? What is the number of the eggs? + How soon do they hatch? + + 11. What is the food of the larva or nymph? Are the food habits + of the insects harmful to man? If so, how? + + 12. Describe the larva as to form, color, and appendages. Is it + capable of locomotion? + + 13. Is the metamorphosis complete or incomplete? If complete, + describe the pupa and tell where it may be found. + + + _Drawings._ + +There should be one drawing of the insect to show its general +characteristics; usually a dorsal view is best. For other drawings +ask your instructor. + + +8. A REVIEW OF INSECTS + + + _Directions._ + +The answers to questions in this study may be conveniently written in +the form of a table. Construct this table by placing the topics at +the left and the names of insects at the top. Allow ample space, +about one half inch for the horizontal spaces and one and one half +inches in width for the vertical columns. Use one or two insects from +each of the principal orders, letting the table extend across two +opposite pages. + + + _Topics._ + +1. What is the habitat? + +2. What regions has the body? + +3. How many antennæ? What is their form? + +4. What kinds of eyes has the insect? How many of each kind? + +5. How many legs? + +6. For what kind of locomotion are the legs adapted? Which legs are +thus used? + +7. How many wings? Membranous or thickened? + +8. What is the position of the wings when at rest? + +9. If the fore wings are thickened, what is their texture,--leathery, +smooth and sheath-like, partly membranous, covered with scales? + +10. What kind of mouth parts,--jaws for biting, a beak for piercing, +a tube for sucking, adapted for both sucking and biting? + +11. By what means is respiration accomplished? + + +Summary of Important Points from the Table + + +1. What characters are common to all the insects described in the +table? + +2. What are the various types of wings? Why do they vary? + +3. What are the various types of legs? How are they characterized? + +4. What are the various types of mouth parts? + +5. Show how the variations in insects are related to the habitat and +mode of life of the insect. + + +9. KEY TO THE PRINCIPAL ORDERS OF INSECTS + + + A^1 Insects with _no_ wings. (See list below.) + + A^2 Insects with wings B + + B^1 With _two_ pairs of wings. (See Note 1 below.) C + + B^2 With _one_ pair of wings Diptera + + C^1 Both pairs of wings _alike_ in structure, either + membranous or scaly D + + C^2 Fore and hind wings _unlike_ in texture, fore wings + fold over hind wings E + + D^1 Both pairs of wings _membranous_, not covered with + scales F + + D^2 Both pairs of wings covered with _scales_; mouth parts + tubular for sucking Lepidoptera + + E^1 Fore wings very _smooth_, sheath or shell-like, + meeting in a _straight line_ when folded; legs + adapted for walking, running, or swimming; mouth + parts for biting Coleoptera + + E^2 Wings not as in E^1 I + + F^1 Wings membranous, usually folded or partly folded; + _few nerves_ G + + F^2 Both pairs of membranous wings usually _outspread_, + _many nerves_; mouth parts for biting H + + G^1 Wings membranous, hooked together and partly folded, + or outspread, _few nerves_ in the wings; mouth parts + for _both biting and sucking_; regions of the body + usually very distinct Hymenoptera + + G^2 Wings membranous, usually folded, _few nerves_; + _mouth parts_, a _beak_ for sucking and piercing Hemiptera + + H^1 _Outspread membranous_ wings, nearly equal in size; + _antennæ very short_ and inconspicuous Odonata + + H^2 As in F^2, but _antennæ not short_; wings sometimes + folded Neuroptera + + H^3 Both pairs of wings membranous, folded above the back; + fore wings much larger than hind wings; ovipositors + long; mouth parts rudimentary Ephemerida + + I^1 Fore wings folded over hind wings, _crossing_ at their + tips, which are membranous, base of wings thickened, + mouth parts a beak for piercing Hemiptera + + I^2 _Fore wings leathery_, folding either at side of body + or on the back; mouth parts for biting, legs often + adapted for _jumping_ Orthoptera + + _Note 1._--When wings are folded, it will be helpful to remember + that thickened fore or cover wings always have membranous wings + folded beneath them. + + _Insects with no wings_ _Order_ + + a. Body long and slender, stick-like; legs for walking. + Walking stick Orthoptera + + b. Grasshopper-like. Cricket grasshopper Orthoptera + + c. Small size; regions very distinct; abdomen + spindle-shape. Ants Hymenoptera + + d. Small size; ant-like in appearance; pale white. White + ants Isoptera + + e. Flattened body, small size; no compound eyes. + Springtails and fish moths Thysanura + + +10. SUMMARY OF THE STUDIES OF INSECTS + + +The Effect of Great Numbers + + +1. Take some insect for illustration, as the house fly, mosquito, +tussock moth, or aphis, and show how insects increase in numbers with +great rapidity. + +2. What can be said about the number of species of insects? + +3. There is said to be great competition among insects. Why? For +what? + +4. How is the great increase of insects held in check by natural +means? + +5. What are the various habitats of insects? Give as many as you can +with examples of insects that use the habitat. + +6. Give examples to show how greatly the food of insects and the +method of obtaining it varies. + +7. Give some illustrations of the great muscular development of +insects. Why is this needed? + +8. In what various ways are insects protected against their enemies? +Give examples to illustrate your statement. + +9. Show how and why the great numbers of insects have affected the +structure and mode of life of the insects. + + +Classification + + +1. By means of illustrations from your studies of insects show how +classification is based upon likeness of structure. + +2. In the same manner show how differences in structure affect +classification. + +3. Show how variation in the wings and mouth parts is used to +separate insects into orders. + +4. What are the principles of classification? + + +11. REVIEW AND LIBRARY EXERCISE ON INSECTS + + +General Topics + + +1. General characteristics of insects. + +2. Principal orders of insects with characteristics and examples of +each order. + +3. Respiration and air sacs of insects. Use of air sacs in flight. + +4. The heart and blood of insects. How the function of the blood +differs from that of other animals, as man. + +5. Special senses of insects: their character, location, and +efficiency. + +6. Sound-making organs of insects. + +7. Power of communication among insects, as among ants, for example. + +8. Organs for depositing eggs, ovipositors. How they vary. + +9. Homes of insects. Evidences of architecture in some of the homes. + +10. How some plants make homes for insects. Galls and gall insects. + +11. In what various ways do insects survive the winter? Illustrate +with examples. + +12. Community life among insects. Types of communities. + +13. Pollination of flowers by insects. Why insects do this work and +how the flowers compel them to do it in the right manner. Value to +the plants. Types of insects useful for this purpose. + +14. Adaptations for protection against enemies. Classify these +adaptations and illustrate with examples. + +15. The principal insect pests of the orchard and their work. + +16. The principal insect pests of the garden and the work of each. + +17. The principal insect pests of shade trees and their +characteristics. + +18. The principal insect pests of the household and methods of +extermination. + +19. The work of birds in helping to keep the number of harmful +insects down. + +20. A spraying table showing what poisons are used, when and for what +plants and insects. + +21. The principal beneficial insects and the ways in which they are +beneficial. + + +Special Topics + + +Much of the information called for by the topics below may be +obtained from United States and state government bulletins. Most of +these may be obtained free from the Department of Agriculture and +from various state agricultural colleges, while others may be +obtained by purchase at a nominal price. + +_Orthoptera._ + +1. Locust migrations and their cause. + +2. The locust plagues of the "great plains." + +3. Crickets and their "songs." + +_Hemiptera._ + +4. The fight against the orange scale of California. + +5. History of the introduction and spread of the San José scale bug +and the efforts to find a natural enemy. How people fight the pest. + +6. Aphids. + +7. Relations of ants and aphids. + +8. Phylloxera and its work. + +9. The methods of fighting the chinch bug. + +10. Scale bugs. + +11. Cochineal bug and the lacs. + +_Coleoptera._ + +12. The carrion beetle and its peculiar habits. + +13. Fireflies. + +14. Egyptian scarabs. + +15. The curculio and methods of fighting it. + +16. The weevils and their work. + +17. History of the Colorado potato beetle. + +18. Lady-bird beetles, their habits and use in exterminating harmful +pests. + +_Diptera._ + +19. The investigations in Cuba of the cause of yellow +fever. + +20. The fight against yellow fever in New Orleans. + +21. Methods of preventing plagues of mosquitoes. + +22. How flies are carriers of disease. Methods of preventing plagues +of flies. + +23. The tsetse fly. + +24. Sleeping sickness. + +25. The house fly and typhoid. + +26. Parasitic larvæ of flies. + +_Lepidoptera._ + +27. The silkworm and the silk industry. + +28. Story of the gypsy moth. + +29. Life history of the clothes moth. + +30. Harmful butterflies. + +31. The tussock moth and its history. + +32. Blastophaga and fig culture. + +33. The codling moth and its work. + +34. Cutworms. + +35. The brown-tail moth. + +_Hymenoptera._ + +36. The honeybee and honey making. + +37. Gall and gall insects. + +38. The habits of the digger wasp. + +39. The homes of ants. Habits of ants. + +40. Slavery among ants. + +41. Agricultural ants. + +42. Homes of bees. + +43. Ichneumon flies and their beneficial habit. + +44. Evidences of intelligence among ants. + + +SOME COMMON BUTTERFLIES--A Reference Table and Key + + + =============================================================================== + GROUP + + |COMMON NAME |WING |BROODS |FOOD PLANTS OF |HAUNTS OF THE + | |EXPANSE | |CATERPILLAR |BUTTERFLY + | |IN INCHES| | | + |CHARACTERISTIC COLORS, MARKINGS, ETC. + + ------------------------------------------------------------------------------- + Milkweed Butterflies + + |Monarch | 4-4½ |May and Oct|Milkweed and dogbane|Open fields + | | | | | everywhere + |Brick-red color, veins black, borders of wings black + + ------------------------------------------------------------------------------- + Fritillaries or Silver Spots + + |Variegated | 1¾-2½ |August |Passion flower |Low fields + | fritillary | | | | + |Orange-brown color, checkered with black, no silver spots. A southern + | species + + |Regal fritillary | 3-4 |July,Aug |Violets, pansies |Low fields + |Upper side of wings reddish with wavy black lines, hind wing dark + + |Great spangled | 3-4 |July,Aug |Violets, pansies |Meadows + | fritillary | | | | + |Similar to _idalia_, but hind wings lighter. Silver spots on under + | surface of wings + + |Silver-bordered | 1½ |Jul,Aug,Sep|Violets, pansies |Meadows, + | fritillary | | | | hillsides + |Edge of wings tipped with silver, silver spots below + + |Meadow fritillary| 1¾ |Jul,Aug,Sep|Violets, pansies |Meadows + |No silver border, silver below + + ------------------------------------------------------------------------------- + Checker Spots + + |Baltimore | 1¼-2½ |June,July |Turtlehead and aster|Swamps + |Groundwork of black with many red and white spots. Conspicuous border of + | red spots + + |Harris checker | 1½ |June |Aster and daisy |Clover meadows + | spot | | | | + |Wings dark bordered, lighter band across middle of wings + + ------------------------------------------------------------------------------- + Crescent Spots + + |Silver crescent | 1¼-2 |July |Asters |Roadsides + |Groundwork of orange-red mottled with black, silver crescents on under + | margin of hind wings + + |Pearl crescent | 1¼-1⅝ |July,Sep |Asters, daisy |Roadsides + |Similar to silver crescent but colors are paler + + ------------------------------------------------------------------------------- + Angle wings + + |Comma | 2 |May,Jun,Aug|Elm, nettle, hop |Along woods and + | | | | | waste places + |Pale red, angled wings, under surface light gray marked with silver commas + + |Interrogation | 2½ |May,Jul,Aug|Elm, nettle, hop |Near trees + |Similar to comma, but marked with silver semi-colons + + ------------------------------------------------------------------------------- + Tortoise Shells + + |Compton's | 2¾ |Feb,Oct |Willow |Near water + | tortoise | | | | + |Looks much like the angle wings, but has no silver spots + + |Milberts's | 1¾ |May,June, |Nettle |Roadsides + | tortoise | | Aug,Sep | | + |Broad, reddish yellow band across both wings + + |Mourning cloak | 3 |Apr,Jul,Sep|Willow, poplar |Everywhere + |Black with yellow or cream-bordered wings + + ------------------------------------------------------------------------------- + The Beauties + + |Red admiral | 2 |May,Jul,Sep|Nettle, elm |Waste land + |Bright red band circling across both wings + + |Painted beauty | 2 |May,Jul,Sep|Everlasting, |Thistles + | | | | thistle, burdock | + |Mottled with pink, black and white, under surface mottled, two large spots + | on under surface of hind wing + + |Thistle butterfly| 2-2¼ |May,Jul,Sep|Thistles |Pastures + |Like the painted beauty, but has several small eye spots + + ------------------------------------------------------------------------------- + The White Admirals + + |Red-spotted | 3 |July |Wild cherry, apple, |Near trees + | purple | | | etc. | + |Purple and blue above, six red spots on under surface of wings + + |Banded purple | 2½ |July |Hawthorn |Open woods + |A broad white band across both wings + + |Viceroy | 2½ |June,Aug |Poplar, willow |Roadsides + |Imitates the monarch, but is smaller and has a black line across the hind + | wings + + ------------------------------------------------------------------------------- + The Satyrs + + |Grass nymph | 1¾ |July |Grass |Meadows + |Dull brown, twenty spots in two rows across the wings + + |Little wood satyr| 1¾ |July |Grass |Hillsides + |Dull brown, six spots + + |Wood nymph | 2 |July |Grass |Hillsides + |Dull brown, two eye spots on each fore wing in a larger yellow spot + + ------------------------------------------------------------------------------- + Hairstreaks + + |Hop hairstreak | 1⅛ |May,July |Hop |About shrubbery + |Dark color, hind wings have slender tail-like projection and black spots + | crowned with crimson + + ------------------------------------------------------------------------------- + The Coppers + + |American copper | 1 |May,Jun,Sep|Sorrel |Everywhere + |Orange-red fore wings spotted with black, hind wing with orange border + + ------------------------------------------------------------------------------- + The Blues + + |Common blue | 1 |May,July |Pea |Roadsides + |Male light violet, female lighter with reddish bordered wings + + |Tailed blue | 1 |May,Aug,Sep|Clover, etc. |Roadsides, + | | | | | fields + |Purplish violet color, has small tail-like projection on hind wings + + ------------------------------------------------------------------------------- + The Whites + + |Common white | 2 |May,Jul,Sep|Mustard family |Gardens + |White checkered with black on fore wings, female brownish + + |Cabbage butterfly| 2 |May,Jul,Sep|Cabbage, etc. |Gardens + |White, black tip on fore wing, one or two spots on hind wing + + ------------------------------------------------------------------------------- + The Sulphurs + + |Common sulphur | m. 1¾, |May,Jun,Sep|Clover |Meadows + | | f. 2¼ | | | + |Yellow, bordered with black + + |Cloudless sulphur| 2½ |July |Cassia and legumes |Fields + |Canary-yellow color + + ------------------------------------------------------------------------------- + The Swallowtails + + |Tiger swallowtail| 3-5 |June,Aug |Cherry, tulip tree |Open woods + |Yellow with black lines across wings + + |Black swallowtail| 3-4 |June,Aug |Parsley |Gardens, + | | | | | roadsides + |Black with two bands of yellow spots and one band of blue spots + + |Green-clouded | 3¾-4¾ |June,Sep |Spice bush, |Open woods + | swallowtail | | | sassafras | + |Black, one row yellow spots, hind wing clouded with green + + |Blue swallowtail | 3¾-4¼ |July,Sep |Dutchman's pipe vine|Near houses + |Black shaded with blue green, one row whitish spots + + =============================================================================== + + + + +CHAPTER III + +THE CONNECTION BETWEEN STRUCTURE AND FUNCTION + + +1. A STUDY OF THE CELL AND OF PROTOZOA + +_To show what Single Cells can Do_ + + + _Materials._ + +Some single cells of plant or animal tissue, stained to show +structure. Slides of a one-celled animal, stained. Living one-celled +animals. + + + _Definitions._ + +_Cell_, the smallest living unit. + +_Protoplasm_, the living material composing the cell. + +_Nucleus_, a dense bit of protoplasm, usually near the center of the +cell, often staining dark. + +_Cytoplasm_, the less dense protoplasm outside of the nucleus, +usually taking a lighter stain. + +_Nucleolus_, _paranucleus_ or _micronucleus_, a very small, dense, +dark-staining body, either within the nucleus (nucleolus) or near it +(paranucleus or micronucleus) + +_Cell wall_, the lifeless membrane surrounding many cells, secreted +by the protoplasm. + +_Food balls_, bits of food inside the cells of many one-celled +animals, usually showing through the walls. + +_Food vacuole_, a small drop of water containing digestive material +and a food ball. + +_Contracting_ or _pulsating vacuoles_, small, clear spots in the +cell, filled with water. In the living cell these disappear at +intervals and then appear again. + +_Oral groove_, a funnel-shaped groove in one side of some one-celled +animals, conducting food to the mouth. In paramecium it often shows +as an oblique line when the animal rolls. + +_Gullet_, the inner end of the oral groove. + +_Cilia_, numerous minute, vibrating, protoplasmic hairs on the +surface of many cells. + +_Respiration_, the passage of oxygen into the tissues of a living +organism and of carbon dioxide out of them. These gases can pass +through any thin, moist, organic membrane. When such a membrane +separates two fluids which differ in the amount of oxygen they +contain, oxygen passes to the fluid containing the smaller amount.[2] +The same is true of carbon dioxide. Respiration is believed to occur +in all living organisms. + + [2] This passage of fluids through membranes is known as _osmosis_. + +_Digestion_, the process of making food materials soluble, so that +they can pass through membranes and be used to build up protoplasm. A +few forms of cells are able to take in solid food and digest it in +their protoplasm, but most cells can admit only fluid food. + +_Fission_, a method of reproduction used in all cells, by which a +cell divides itself into two, usually through the center. In some +one-celled animals this may be preceded by _conjugation_, when two +animals unite temporarily and exchange nuclear substance; or in some +forms two cells may fuse and the resulting cell may divide. _Budding_ +is a form of fission in which a small projection is formed on the +parent cell and then cut off, making a new individual. + +_Protozoa_ (first animals), animals of one cell, existing alone or in +loose colonies. + + + _Observations._ + +1. Examine a single cell, stained to show structure. Identify +the nucleus, cytoplasm, and, if present, the nucleolus or the +micronucleus, and the cell wall. Draw to show the form of the cell +and the details of its structure. Label all details. + +2. Examine some stained paramecia. Select a typical one and identify +in it nucleus, micronucleus, cytoplasm, and cell wall or cell +membrane. You may also be able to see vacuoles, looking like holes in +the stained protoplasm. Give reasons for considering this animal to +be a single cell. Draw one, to show its cellular structure. Label all +details. + +3. Clean a slide and cover glass, place a drop of water containing +living paramecia on the slide, cover it, and examine. What structures +do you see which you saw in the stained paramecia? What structures do +not show? Identify any new structures you may observe. Identify also +the leading end and the side containing the oral groove. + +4. Describe the shape of the animal. + + What is the actual length of the animal? + +5. After watching the animal for some time, describe the path +followed by a given specimen as it crosses the field of the +microscope. What reason can you see, if any, why this paramecium is +moving? What external factors, if any, seem to determine the path it +follows? + +6. How rapidly do paramecia really move? What structures do they use +in locomotion? + + How do they manage to move in one direction, instead of + alternately backward and forward? How do they manage to move in a + straight line, though their bodies are not symmetrical? + +7. What is the food of the paramecia? How do they find it? Find a +specimen at rest and watch the oral groove. Suggest a method by which +food may be collected into it. If possible, note the process of +swallowing, and the resulting food ball. + + _Note._--If powdered carmine be placed in the water with some + paramecia, it can be seen in the food balls a half hour or so + later. + +8. Where are the food balls located? Watch them in an individual +until you notice their motion. Where are the larger food balls? the +smaller ones? Assuming them to have been of approximately equal sizes +when they were taken in, how can you account for differences now? + +9. Where are the contracting vacuoles? How many are there? How often +does one contract? + + What is their function? + +10. As you have been studying paramecia, to what external influences +(as contact, heat, light, etc.) have you seen them respond? How do +they show it when they do respond? Is such a response an advantage to +them or not? What would be the result if they were not able to detect +changes in their surroundings? + +11. Where does respiration occur in paramecia? Where do they obtain +their supply of oxygen? + +12. Among the paramecia you are studying you usually find at least +one in the process of fission. Watch it until the halves separate, if +you can. Compare the halves. Do they rank as parent and offspring? If +so, which is which? If not, which are they, parent or offspring? + +13. If you happen to find a pair conjugating, notice the process, as +far as you can, in the living animals. + + + _Suggested drawings._ + +a. A drawing to show all the details seen in the living paramecium. + +b. A diagram to show the path followed by a paramecium to get around +some obstacle. + +c. Drawings to show that paramecia are constant in shape and yet +flexible. + +d. A drawing to show at least one stage in fission. This may be from +a permanent preparation. + +e. A drawing to show paramecia conjugating. This also may be from a +permanent preparation. + +f. Instead of all these separate drawings they may be combined into +one. Represent the field of the microscope, and in it draw all +necessary figures, to show the facts called for in the first five +drawings and any other facts you have observed about living protozoa. +Make the whole drawing to scale. + + +Summary of Important Points in the Study of Paramecia + + +1. Look back over your study of paramecia and list the different +kinds of work you saw paramecia doing; also the kinds of work you +infer they can do. What organs have they to use? When there is no +organ to do a given thing, _e.g._ to digest food, how is the work +done? + +2. What conditions are favorable to paramecia? Why are they so +numerous under favorable conditions? + +3. What would you call a successful animal? Are paramecia successful? +Give reasons why they are or are not. + + +Comparative Study of Protozoa + + +To enlarge your idea of what a cell can do, spend as much more time +on the one-celled animals as your course will permit. Any stagnant +water may furnish several kinds. By means of reference books, +identify as many as you can. In each case notice:-- + +1. Its size, shape and general appearance, comparing and contrasting +it with paramecium. + +2. Its usual surroundings, _i.e._ the conditions it has to meet. + +3. The means it has of finding out facts about its surroundings. + +4. The means it has of adjusting itself to its surroundings. For +example, is it stationary? If so, what does it do when conditions +change? Is it locomotory? If so, how effective is its locomotion? + +5. What is its food? How does it find food? + +6. Can it do as many kinds of work as paramecium can? Can it do any +that paramecium cannot do? If so, what? + + +Review and Library Questions on Protozoa + + +1. What are the characteristics which distinguish protozoa from other +animals? + +2. What are the classes of protozoa? Characteristics of each class? + +3. What is digestion? Where does it take place in the protozoa? + +4. What results from the fact that the amœba has no cell wall? (Give +at least two points.) + +5. In what ways are paramecia more specialized than amœba are? How +does their greater specialization show in their work? + +6. What different methods of locomotion are shown among protozoa? By +what means is locomotion accomplished in each case? + +7. What is encysting? Name some protozoa which encyst. How long may +an encysted animal live? When do they encyst? Why? + +8. Give methods of reproduction among protozoa. Which method is +fitted for rapid multiplication, for withstanding drouth; for +renewing vitality? + +9. Many scientists speak of protozoa as immortal. What argument is +there to support such a statement? + +10. Why are no protozoa large animals? Give at least two reasons. + +11. Why are protozoa so numerous? Why more numerous in stagnant +water? + +12. Where are protozoa found? + +13. Why are protozoa so widely distributed? + +14. Write the probable history of a piece of chalk. + +15. What connection is there between protozoa and some polishing +powders? + +16. Where in the human body are malarial protozoa found? How are they +transferred from one human being to another? Why is there likely to +be more malaria in newly settled regions than in older ones? If you +were obliged to spend some time in a region where malaria existed, +what precautions would you take? + +17. Name other diseases caused by protozoa. How are they fought? + +18. What beneficial effect have some protozoa upon the water of +stagnant ponds and ditches? How may some forms injure water for +household purposes? + +19. Give at least three reasons for thinking that protozoa are the +most ancient animals. + +20. Why are protozoa of great importance to the world? + + +2. A STUDY OF SPONGES + +_To show how cells loosely associated may work together_. + + + _Materials._ + +The simplest of the many-celled animals are the sponges, which, with +one exception, are salt-water forms. That one, the spongilla, is not +easily found and is very difficult to maintain in the laboratory. For +these reasons the material for this study is very meager, except at +the seashore, and much of the work must be done from diagrams and +reference books. Small simple preserved sponges and complex toilet +sponge skeletons will also be used. + + + _Definitions._ + +_Body wall_, the outer wall in bodies of the many-celled animals. + +_Central cavity_, the cavity surrounded by the body wall in the +simpler many-celled animals, as in the sponges. + +_Canals_, channels through the body walls of sponges. + +_Inhalent pores_, the outer ends of the canals. + +_Ostia_, the inner ends of the canals. + +_Osculum_, the large opening of the central cavity, at the distal end +of the sponge. + +_Spicules_, tiny needles of mineral substance found in the walls of +many sponges. + +_Fibers_, flexible threads of horny material found in the walls of +many sponges. + +_Endoderm cells_, cells lining the canals. They have cilia or +flagella (projections larger than cilia). + +_Ectoderm cells_, cells covering the outside of sponges and some +other animals. In sponges it is believed that endoderm and ectoderm +cells are able to exchange positions and functions. + +_Mesoglea_, a jelly-like layer between the endoderm and ectoderm +layers. In the sponges this contains many wandering cells, probably +from the other layers. + +_Porifera_ (pore bearers), animals with many more or less independent +cells, supported by solid skeletal parts and penetrated by a system +of canals which open on the surface as pores. + + + _Directions._ + +Study a simple sponge to see the shape, size, and point of +attachment. Identify the osculum. In a diagram of a long section of a +simple sponge identify the central cavity, body walls, canals, +inhalent pores, ostia, and osculum. In a simple sponge cut like the +diagram identify the same structures. Do the same for the toilet +sponge. + +Study a diagram of a portion of the body wall, considerably enlarged. +Identify the endoderm and ectoderm cells, the spicules or fibers, +and, among the spicules or fibers, irregular amœboid cells, sometimes +called mesoderm cells. + +Examine a fragment or section of each kind of sponge under the +microscope. Notice the arrangement, shape, and length of the spicules +and of the fibers. + +Test both kinds of sponges by dropping a bit of each into weak acid, +and noting the results. Also burn a bit of each and notice the odor. + + + _Questions._ + +1. What is the shape of a simple sponge? What enables a mass of cells +to retain such a definite shape? + +2. What seems to be the composition of the skeletons? Why is one type +of skeleton rigid and the other elastic? + +3. Since sponges are attached for most of their lives to stationary +objects, suggest means for obtaining food and oxygen, and for getting +rid of waste matter. + +4. Although individual cells are sensitive, a sponge as a whole is +not. What connection has this fact with the fact that sponges are +stationary? + + 5. Compare simple and complex sponges. + + + _Suggested drawings._ + +a. A view of a simple sponge. Label everything shown. + +b. A diagram of a simple sponge split in halves. Show by arrows the +path followed by the water as it passes through the sponge. + +c. A few spicules. + +d. A few fibers. + + +Summary of Important Points in the Study of Sponges + + +1. What are two functions of the spicules or fibers? + +2. What are at least two of the functions of the endoderm cells? + +3. What can you suggest as functions for the ectoderm cells? + +4. In what cases do cells show "team work" in accomplishing an +object? + +5. What degree of specialization is indicated by the fact that the +cells may exchange positions and functions? + +6. What work can any single cell of a sponge do? Compare the work +done by such a cell with that done by a paramecium. + +7. What work can a whole sponge do? Compare that with the work done +by a paramecium. + + +Review and Library Exercise on Sponges + + +1. What are the distinguishing characteristics of Porifera? + +2. Sponges were once supposed to be plants. In what respect are they +plant-like? What made students finally class them as animals? + +3. How do sponges reproduce? How are they distributed to new +locations? + +4. Where, as to depth of water, do most sponges grow? Where, as to +oceans? Where, as to latitude? + +5. What are some of the difficulties which confront a stationary +animal? How are they overcome? + +6. To what class of sponges do the "toilet" sponges belong? Why? + +7. What conditions are necessary for toilet sponges to thrive? Where +are the best ones found? Where are they most numerous? How are they +collected? How are they prepared for market? + +8. What is man able to do toward raising good sponges for market? + +9. Using reference books and museum specimens, describe some +especially odd sponges. + + +3. A STUDY OF CŒLENTERATES + +_To show cells working together more definitely than in Sponges_ + + +A Study of Hydra + + + _Materials._ + +Living hydras in permanent aquaria, undisturbed. Living hydras in +small aquaria, _i.e._ tumblers, test tubes, watch glasses, etc., with +pieces of water weed and if possible some of the microscopic animals +found in water where hydras are abundant. If kept cool, hydras may +live several days in such aquaria. Permanent slides of hydras; +some whole, some in sections, and some showing the organs of +reproduction. + + + _Definitions._ + +_Proximal end_, the end by which an animal is attached to an object. + +_Distal end_, the end opposite the proximal end. + +_Tentacles_, slender projections around the distal end. + +_Mouth_, the opening through the distal end, into the central cavity. + +_Bud_, a small hydra or other cœlenterate growing out from the wall +of the parent. + +_Mesoglea_, a thin, gluey partition, without wandering cells, between +the ectoderm and the endoderm. + +_Nettle cells_, very small cells, chiefly in the tentacles, easily +identified in permanent preparations as clear cells with small hairs + +projecting from them. See text-books for details of their structure. + +_Spermary_, the region or organ where the sperm cells are formed. + +_Ovary_, the region or organ where the egg cells are formed. + +_Cœlenterates_ (hollow bowels), sac-shaped animals, the digestive +tract having only one opening; the body wall is of two layers. + + + _Directions._ + +Take a small aquarium to your table, set it down carefully and leave +it undisturbed. Identify a hydra and watch it for some time. + + + _Observations on the living animals._ + +1. Describe the size and shape of a hydra when expanded. Disturb it +slightly by shaking the aquarium a little, and describe its shape +when contracted. Notice also the flexibility of the body. What do you +infer concerning the hydra's possession of a skeleton? What advantage +can it be to have a body so flexible? + +2. How many tentacles has the hydra that you are studying? What does +the hydra do with these tentacles when it is expanded? What is the +probable object of such actions? + +3. How does a hydra respond to contact? What seems to be the object +of such a response? + +4. Notice the location of the hydras in the large, undisturbed +aquaria. Where are they placed as regards the light side of the +aquarium? Of what value is such a response to light in their case? + +5. How can a hydra locate the small animals which are its food? + + How can it capture them? + +6. What motions may a hydra perform, while remaining attached by its +base? What are the results of these movements? + +7. If you have happened to see a hydra move from one place to +another, describe the process. If not, give the facts which lead you +to believe that it is able to do so. Suggest all the methods you +think it may be able to use. What is your opinion of the hydra's +power of locomotion? Of what use is it in getting food; in escaping +enemies; in following the fluctuations of the water supply? If you +had to class the hydra as either one, would you call it a stationary +or a locomotory animal? + +8. Study budding hydras. Compare the bud with the parent hydra as to +size, form and number and size of tentacles. Notice whether the bud +moves independently or only with the parent. When does it separate +from the parent? + + 9. In hydras collected late in the fall you may see another + method of reproduction. If such material is at hand, notice small + swellings near the proximal end and others near the tentacles. + Eggs are produced in the lower one, the ovary, and sperm cells + in the upper one, the spermary. Refer to your text-book for + further details. + + + _Details of structure._ + +1. Using an entire mounted specimen and a section of hydra, identify +the body wall and the central cavity. What is the extent of the +central cavity? (Examine both the body and the tentacles.) Where does +it open to the outside? What do you think is its use? + +2. In the body wall, identify the endodermal and ectodermal layers of +cells, separated by the mesoglea, which is usually stained more +deeply. Study these cell layers carefully. What work ought each to +do? What can you discover in its structure which would fit each layer +to do its work? + +3. In the tentacles, identify the nettle cells. Where are they? How +are they arranged? About how many of them would be discharged if a +small animal were to bump into a tentacle? + + +Summary of Important Points in the Study of Hydra + + +1. Name the different kinds of cells in a hydra. Which kind differs +most from such a cell as the starfish egg? What work does this +specialized cell do? + +2. How much of a hydra's body may be set in action by touching a +tentacle? Contrast this with the sponge. What do you infer concerning +the nervous power of these two animals? + +3. Look back over your notes and list the different kinds of work a +hydra can do. + +4. Can it do any more kinds of work than a paramecium or a sponge +can? If so, give further details. + +5. Can it do any of its work in any better way? Would you expect it +to be able to? Why, or why not? + + + _Suggested drawings._ + +a. Hydra undisturbed, and hydra after being touched or shaken. + +b. A hydra in successive poses to show its flexibility. + +c. A hydra taking food. + +d. Hydras to show reproduction in one or both ways. + +e. A section of hydra, showing details. + + +Comparative Study of Cœlenterates + + + _Materials._ + +Various cœlenterates, such as hydroids, hydro-medusæ, jellyfishes, +sea anemones, corals, sea fans, etc. Since nearly all the +cœlenterates except hydras are marine forms, these will usually have +to be dead specimens, preserved in formalin or alcohol, or put up as +permanent preparations for the microscope. + + + _Definitions._ + +_Colony_, as used in this group, a number of individuals descended by +budding from an original one, and remaining connected. + +_Polyp_, an individual cœlenterate; one of the individuals in a +colony. + + + _Observations._ + +1. How large is an individual specimen in the form you are studying? +If the form is colonial, how large is the colony or portion of a +colony you are studying? Estimate the number of individuals in it. Is +the colony free-swimming or attached? If attached, to what is it +usually fastened? + +2. Compare the individual you are studying with a hydra, as to size +and shape of the body, the location of the mouth, and the size, +number, and arrangement of the tentacles. + +3. Is there a skeleton? If so, describe it. What appears to be its +use? In corals, notice the radiating partitions. + +4. Has the specimen any nettle cells? If so, where are they located? + +5. Are all the polyps of the colony alike? If not, how many kinds are +there? How do they differ? + + What is each kind best fitted to do? What is the probable result + of this differentiation? + +6. What kinds of reproduction, if any, does the specimen you are +studying show? + + Find out from books what other forms of reproduction are + sometimes used by this animal. + + + _Suggested drawings._ + +a. At least one drawing of each cœlenterate you study. + + +Summary of the Comparative Study of Cœlenterates + + +1. How may polyps in colonial forms differ from polyps which live +singly? + +2. What variations in methods of reproduction are shown in this +group? + +3. Which of the polyps you have studied shows the greatest +differentiation? In what ways? + +4. What characteristic do you find common to all the cœlenterates you +have studied? + + +Review and Library Exercise on Cœlenterates + + +1. What are the characteristics which distinguish cœlenterates? + +2. Give the classes of cœlenterates, with the characteristics and an +example of each. + +3. What enables a hydra to stick to a support by its foot? + +4. What are the processes in a hydra by which food is captured, +swallowed, and digested? + +5. What is the chief fact of interest about Hydra viridis? + +6. Why do hydras reproduce all summer by budding and in the late fall +by eggs? + +7. What change would have developed a hydra and its offspring into a +plant-like colony instead of into a group of individuals? + +8. Why are ctenophores more easily seen in the night than other +cœlenterates are? + +9. What relations may exist between hydroids and hydro-medusæ? + +10. What are the advantages of a sedentary life? Of a locomotory one? + +11. What is meant by the expression "alternation of generations"? +Which animals are likely to develop alternation of generations, +sedentary ones or locomotory ones? Why? + +12. Give at least two differences between hydro-medusæ and true +jellyfishes. + +13. In the association between a hydractinia colony and a hermit +crab, what advantages are derived by the hydractinia? by the crab? +Define symbiosis. Give another illustration of it. + +14. How are new coral colonies started? How are large colonies +formed? + +15. What are the conditions of life under which corals can grow +vigorously? + +16. Where are corals most abundant? + + _Note._--Show by coloring the regions on a blank map of the + world. + +17. How may corals form a reef? Why do they, as a rule, form a reef +instead of adding directly to the mainland? + +18. Give Darwin's theory regarding the way a coral atoll may have +been formed. + +19. Where are fossil corals found in abundance? What does their +presence prove? + +20. What is polymorphism? Give an illustration. What may be a +disadvantage of polymorphism? What may be an advantage? + +21. In what ways is this group of economic importance? + + +4. A STUDY OF WORMS + +_To show cells associated even more closely than in cœlenterates, +forming tissues and systems of organs._ + + +#A STUDY OF EARTHWORMS# + + +The Living Earthworm + + + _Materials._ + +Living earthworms, some of which are left undisturbed from day to +day, in damp earth with leaves of various plants scattered upon it. + + + _Definitions._ + +_Anterior end_, the head end, usually the leading end. + +_Posterior end_, the end opposite the anterior end. + +_Ventral surface_, the lower surface, usually the one which contains +the mouth. + +_Dorsal surface_, the one opposite the ventral surface. + +_Somites_, the rings or segments of which some animal bodies are +composed. + +_Bilateral symmetry_, the symmetry usually shown by animals which +have differentiated dorsal and ventral surfaces, and right and left +sides. Animals which do not have such differentiated surfaces are +usually _radially symmetrical_, but sometimes asymmetrical (without +symmetry). + +_Girdle_, the somewhat transparent band frequently found near the +anterior end of an earthworm. + +_Anal opening_, the posterior opening of the food canal. + +_Setæ_ (singular form, _seta_), small bristles or stiff hairs. In +the earthworm these are set in the body wall at definite intervals, +and aid in locomotion. + +_Cuticle_, in the earthworm a delicate, shining cover over the body. + +_Egg capsules_, small, light-colored, spindle-shaped sacks, about the +size and somewhat the shape of a grain of wheat, containing the eggs +or young of earthworms. + + + _Directions._ + +Take a living earthworm to your table and keep it damp by placing it +in a wet tray or upon moist paper. Identify the anterior and +posterior ends, the dorsal and ventral surfaces, and the right and +left sides. Identify also the somites and the girdle, the mouth with +its projecting lip, and the anal opening. + + + _Observations._ + +1. Watch a living worm for some time. Does it seem to have a definite +object in its moving? If so, what is it? Upon what sense or senses +does it seem to depend for guidance? Which end usually leads? Why? + +2. Over what sort of surface does it move most easily? Why? Watch it +closely for some time and discover how it is able to move from place +to place. (_Suggestion._ What is the function of the setæ in this +process? How can you explain the alternate contraction and expansion +of parts?) + +3. From time to time, for perhaps a week, examine the leaves which +were scattered where the worms could reach them. Have the worms moved +them about at all? If so, where are the leaves left? Have any been +eaten, in part or entirely? If so, is there any evidence of +selection, either as to the kind of leaf or the portion of leaf +eaten? If earthworms select food, what senses would be useful for the +purpose? Have you any evidence that earthworms possess such senses? + +4. Looking through the dorsal wall, notice the meandering red line, +seen more easily in some regions than in others. This is the dorsal +blood vessel. How long is it? Where is it wider? Where narrower? +Notice its pulsations. How many times per minute does it pulsate? In +which direction is the blood forced? Is there a corresponding ventral +blood vessel? Place a small worm between two pieces of glass, so that +you may see through it more easily, and identify the blood vessels +encircling the digestive canal, near the anterior end. These are the +so-called "hearts" of the earthworm. If possible, decide in which +direction the blood flows through them. + +5. The food canal, or alimentary canal, lies underneath the dorsal +blood vessel, and is usually easily seen, especially if it is full of +food. Notice it when the worm is fully stretched and again when it is +contracted. How long is the canal? Why does it wrinkle when the worm +contracts? Where does it open to the outside? Why does it need to? + +6. Where do you infer respiration must take place in this animal? Why +do you think so? What fits this surface for such a purpose? Why does +an earthworm seem so uncomfortable when it is too dry? + + 7. Where do earthworms live? What conditions are necessary in + their habitat? + + 8. When do earthworms usually leave their burrows? Why at that + particular time rather than at another? Why does "the early bird + catch the worm"? + + 9. What enemies do earthworms have? How are they protected + against these enemies? + + 10. If you have found egg capsules when collecting worms, + describe them. + + +External Morphology of Earthworms + + + _Materials._ + +Preserved earthworms, the larger the better. + + + _Observations._ + +1. In what respects are the dorsal and ventral surfaces alike? In +what respects different? Why? + +2. Why are the right and left sides alike? + +3. In what respects are the two ends alike? In what different? Why? + +4. How many somites are there from the anterior end to the girdle? +How many under the girdle? How many from the girdle to the posterior +end? + +5. Where are the setæ located in a somite? How are they distributed +over the body? + + + _Suggested drawings._ + +a. An earthworm, dorsal aspect. + +b. An earthworm, ventral aspect. + +c. An outline diagram of a cross section, to show the location of the +setæ, the blood vessels and the alimentary canal. + + +Internal Morphology or Anatomy + + + _Materials._ + +(1) Preserved earthworms, as large as you can obtain. (2) Cross +sections of earthworms. (3) Longitudinal sections of earthworms. + + + _Definitions._ + +_Body cavity_, the space between the body wall and the alimentary +canal. + +_Septa_ (singular, _septum_), the thin walls between somites, seen +when the worm is opened. + +_Pharynx_, the hard-walled, rather bulbous, anterior portion of the +alimentary canal. + +_Esophagus_, the portion of the alimentary canal extending back from +the pharynx with thinner walls and smaller diameter. + +_Crop_, the short, wide portion of the canal back of the esophagus. + +_Gizzard_, the hard-walled, short region, just back of the crop. + +_Stomach-intestine_, the portion of the canal reaching from the +gizzard to the anus. + +_Ventral nerve cord_, a light-colored thread lying against the inner +surface of the ventral body wall. + +_Nerve ganglia_ (singular, _ganglion_), slight swellings on the +ventral nerve cord. + +_Nerve ring_ or _collar_, a pair of nerves extending from the ventral +nerve cord around the pharynx to a pair of ganglia (often called the +"brain") in the dorsal region of the anterior end. + +_Kidney tubes_ or _nephridia_, the excretory organs of the earthworm, +occurring as slender, paired tubes in nearly every somite. + + + _Directions._ + +Select a large worm and cut carefully through the body wall along one +side, midway between the dorsal and ventral surfaces, from the +anterior end to the posterior. Lay the worm on any convenient fairly +soft surface (a piece of pine, cork, peat, paraffin), preferably +under water, and pin out the walls so that you can see into the +interior. + +Identify the structures defined above, as well as the dorsal and +ventral blood vessels and the "hearts." + +The nephridia are not easily distinguished, though they are very +numerous. They are long, slender, coiled tubes, two in each somite, +lying in the body cavity, one on each side of the alimentary canal. +If possible, identify them. + +Notice that most of the internal organs are free from the body wall, +lying free in the body cavity. + + + _Questions._ + +1. What is the extent of the body cavity, anteriorly and posteriorly? +What is its shape? + +2. What, in general, is the shape of the food canal? How many +external openings has it? + +3. Into what regions is the food canal differentiated? Suggest one +advantage of having these specialized regions. + +4. How is the alimentary canal of the worm kept away from the body +walls? Why have it thus supported? + +5. What is a septum? How many septa are there? What vessels and tubes +pass through a septum? + +6. Locate the nerve cord. How long is it? How frequently do the +ganglia occur on it? Which end of the living worm is the more +sensitive. Suggest the connection between this fact and the location +of ganglia. + + + _Suggested drawings._ + +a. Earthworm, showing structures mentioned in this study. + + +Details of Structure--Microscopic Anatomy + + + _Materials._ + +Sections of earthworms, preferably both cross sections and +dorso-ventral, longitudinal ones. + + + _Directions._ + +In a section under a simple lens, identify the dorsal and ventral +surfaces, the body wall, the body cavity, the alimentary canal, and, +if possible, the dorsal and ventral blood vessels and the ventral +nerve cord. + +Under a microscope identify the same structures. Notice that the body +wall consists of three layers of cells: an outer single layer, the +_epidermis_; a middle layer, the _circular muscles_; and an inner +one, the _longitudinal muscles_. + +The nephridia show as loosely scattered fragments in the body cavity, +at the right and left of the alimentary canal. + +If you happen to have a section which shows one or more setæ, +identify the muscles which operate it, and the group of glandular +cells at its inner end, which are known as _setigerous_ (from _seta_) +cells. + + + _Questions._ + +1. Describe the epidermal cells. What is their probable function? +Among them notice larger cells, clear and rounded. These are the +_mucous_ (slime) cells. + + What is the use of mucus to the worm? + +2. Describe the muscle cells. In which direction do the muscle fibers +extend? What is their function? Which layer of muscle cells is +thicker, the circular or the longitudinal? Why should it be? + +3. Notice the cells in the walls of the alimentary canal. What layers +do you find? How are they arranged? + +4. If the section you are studying is a cross section from the region +back of the gizzard, the alimentary canal will look horseshoe shaped, +indented from the dorsal surface. What is the effect of this +indentation upon the amount of surface in the alimentary canal? + +5. Study the cells of the nerve cord. How do they compare in size and +shape with the muscle cells? + + + _Suggested drawings._ + +a. A diagram of a cross section, showing the relation of the organs. + +b. A diagram of a longitudinal section, at least through the body wall, +to show the arrangement of muscle fibers. + +c. A drawing of a portion of the body wall, to show details. + + +Summary of Important Points in Study of the Earthworm + + +1. Compared with a hydra, how many cells has an earthworm? + +2. Compared with a hydra, how much are the cells of an earthworm +differentiated? + +3. How are these differentiated cells usually arranged with respect +to one another? What advantage is there in this arrangement? + +4. Recall the kinds of work done by paramecium, sponge, hydra, and +worm, and at the same time consider also the efficiency of each. Can +earthworms do any more kinds of work than any of the others? Can they +do any more work? Can they do any of it better? Give the probable +reasons for this? + + +Comparative Study of Worms + + + _Materials._ + +As many different kinds of worms as you can get, living or dead. + + + _Directions._ + +Identify your specimens. Then study as many as your time will allow, +using these general questions for each:-- + + + _Questions._ + +1. How large is the specimen and what is its shape? + +2. Can you distinguish a head or a head end? If so, by what +peculiarities? + +3. State whether the body is segmented or not, and, if it is, whether +the segments are alike in form and appearance, _i.e._ whether the +segments are uniform. + +4. State whether the animal is bilaterally symmetrical, radially +symmetrical, or without symmetry. + +5. Compare this worm with the earthworm as to sense organs. + +6. What organs for respiration has it? + +7. What special protective devices has it? + +8. If possible, find out and state where this worm lives. What can +you see in the structure of this worm which enables it to live where +it does? + + +Summary of the Comparative Study of Worms + + +1. Name the different worms you have studied. What characteristics +have they in common? + +2. What different methods of obtaining food do they show? + +3. What variations do they show in senses? in sense organs? + +4. Which one seems to you best adapted to its habitat? In what ways? + + + _Suggested drawings._ + +a. One drawing of each worm studied. + + +Review and Library Work on Worms + + +1. What are the distinguishing characteristics of worms? + +2. Give the classes of worms, and the authority for this +classification. + +3. What kind of soil do earthworms seem to prefer? Why should they? +How do they form their burrows? What are the castings around the +mouth of a burrow? How are they placed there? + +4. In what ways do earthworms benefit the soil? How great is their +effect estimated to be? + +5. Give a brief sketch of the life of Charles Darwin, noting +especially the work he did with earthworms. + + Why is Darwin's work on earthworms noteworthy: because it is such + a large proportion of the work he did, or because it is so much + of the work which has been done on earthworms? + +6. How are earthworms protected against the cold of our winters? What +limits the northern range of earthworms? + +7. Where are earthworms found geographically? Why are they so widely +distributed? By what means are they extended from one locality to +another? + +8. How do earthworms reproduce? What care do they take of their +young? + +9. What tissues or organs of earthworms correspond in function with +the ectoderm of hydra; with the endoderm? Why does an earthworm need +a system of blood circulation more than a hydra does? + +10. Contrast the number of openings in an earthworm's alimentary +canal with the number in a hydra's digestive cavity. Which plan seems +a better one? In what respects? + +11. Contrast a cross section of hydra with one of earthworm as to the +number of cavities. Which seems to you the better plan? Why? + +12. Why does a nereis need more respiratory surface than an earthworm +does? + +13. Comparing earthworm and nereis, in what respects is the earthworm +degenerate? How does it manage to succeed so well with such a +degenerate body? + +14. What is a parasite? How many hosts does a typical parasite +require for its development? Which host is known as the intermediate +one? + +15. Trace the history of a tapeworm from the egg to the adult. At +what stage are they most likely to be destroyed? What provision is +there for this? What advantages are there to the host in the fact +that a tapeworm's egg cannot develop in the original host? What +advantages to the parasite? + +16. What organs has a parasite lost, if it ever had them? How does it +succeed without them? What connection is there between parasitism and +degeneration? Can you decide which is cause and which is effect? If +so, which is? + +17. Why do worms so easily become parasitic? What advantages are +there in becoming a parasite? What disadvantages? + +18. What is radial symmetry? Name two animals which show it. What is +bilateral symmetry? Name two animals which show it. What is the +relation between locomotion and symmetry? + +19. What is meant in biology by the term "regeneration?" To what +extent have we this power? To what extent have hydra and earthworm? +What are the results of this power? + +20. Name various methods of locomotion among worms. Give examples. +Name a fixed or sedentary worm. + +21. What is the economic importance of worms? Consider here not only +earthworms and tapeworms, but also the stomach worms of sheep, liver +flukes, trichinæ, hookworms, vinegar eels, and as many others as you +have time and books to look up. + + +5. THE CONNECTION BETWEEN STRUCTURE AND FUNCTION + +_A Review of the Work done on the First Four Groups of Animals_ + + +Review all your studies on the protozoa, sponges, cœlenterates, and +worms. Write the results in the following summary:-- + +1. What work, _i.e._ labor, must an animal do to live? + +2. How many cells are necessary to do this work? + +3. When this work is divided among a number of cells, what is the +effect upon the quantity and quality of work accomplished? + +4. When this work is divided among a number of cells, how does the +structure of the cells show it? How does the arrangement of the cells +also show it? Give examples. + +5. The technical expression for this specialization of cells, giving +them different functions, is "division of labor." Formulate a clear +definition for this expression, giving an example to illustrate it. + +6. Is division of labor a good thing for an animal body, or is it +not? Give reasons for your opinion, with examples for illustration. + + + + +CHAPTER IV + +ADAPTATION TO SURROUNDINGS + + +#A STUDY OF CRUSTACEA# + +#To Show the General Adaptation of an Invertebrate to its +Surroundings# + + +1. A STUDY OF CRAYFISHES + + + _Materials._ + +Crayfishes, living and preserved. Some of the living crayfishes +should be established in conditions as natural as possible _i.e._ in +an inch or so of fresh water, with rocks, weeds, etc., and left +undisturbed. Small crayfishes are desirable to show locomotion in +water. + + +Living Crayfishes + + + _Directions and observations._ + +1. Observe living crayfishes in their usual habitat or in a large +aquarium, without disturbing them, and see where they stay when they +are free to choose. Notice their position. What senses are on guard? +What is the color of the head and claws? How may this color aid the +animal in getting food or in escaping enemies? Why is the color of +the posterior region less important than the color of the anterior? + +2. Offer them bits of meat. If one takes food, notice the appendages +it uses. How does it discover the food? With what appendages does it +grasp the food? How is the food conveyed to the mouth? With what +senses, if any, does the animal test the food as it eats it? + +3. If the crayfishes are in plenty of water and you startle them in +any way, some of them may swim. Watch for such an occurrence and +notice it carefully. How is swimming accomplished? Which end leads in +swimming? How far does the animal swim at a stroke? How long does it +continue to swim? Where does it go? Does it see where it is going? +For what purpose would this method of locomotion be useful? + +4. Place a living crayfish in a tray with water to cover it, and take +it to your table. Watch the crayfish as it walks about in the water, +then take it out and let it walk out of water. Compare the two +processes. What causes the differences? + +5. How many appendages are used in walking? What order, if any, is +there in moving the legs? Which method, walking or swimming, does it +use in going to some particular spot, _e.g._ in going to find food or +cover? Why? + +6. Gently turn the animal on its back and watch the movements of its +appendages as it rights itself. Which appendages does it use and how +does it use them? How can it manage to use so many appendages in +harmony, for one result? + +7. For what different purposes have you seen the crayfishes use their +large claws? For which does the claw seem best fitted? Can you think +of any change which would make it more efficient for its main +purpose? If so, describe the change and tell how it would work. + +8. Test the distribution of the sense of feeling. Is it anywhere +especially acute? If so, where? Why have two pairs of feelers? Where +is each pair carried when the animal is at rest; when it is in +motion? How much territory can the two pairs guard? + +9. Touch the eyes. Compare their sensitiveness with that of your own +eyes. What movements can the eyes perform? How are they protected? +What range of territory can they guard? + +10. What other senses, if any, do you think a crayfish has? Why do +you think so? + +11. Early in the spring crayfishes may be found carrying eggs or +young. If such a specimen is at hand, notice where and how the eggs +or young are attached. How many are there? How are they cared for? +Can the young crayfish let go? If removed, can they attach themselves +again? How much care does the mother give them when they are removed? + + +Morphology of a Crayfish + + + _Definitions._ + +_Cephalo-thorax_, the anterior half of the body, divided into the +head and the thorax. + +_Cervical groove_, the groove dividing the head from the thorax. + +_Abdomen_, the posterior half of the body, consisting of a number of +somites. + + _Note._--The central part of the tail fin is usually included as + a somite. + +_Carapace_, the continuous shell-like portion of the exoskeleton +covering the cephalo-thorax. + +_Rostrum_, the sharp projection of the carapace at the anterior end. + +_Gill chamber_, a pocket on each side of the thorax, covered by a +flap of the carapace. + +_Appendages_, paired structures attached to the body. They are named +as follows:-- + + _Eyestalks._ (These are not classed as appendages by all students.) + + _Antennules_, the small feelers. + + _Antennæ_, the large feelers. + + _Mandibles_, the jaws, one on each side of the mouth. + + _Maxillæ_, the two pairs of small mouth parts just back of the + mandibles. + + _Maxillipeds_, the three pairs of appendages between the maxillæ + and the large claws. + + _Chelipeds_, the large claws or pinchers. + + _Walking legs_, the four pairs of appendages back of the chelipeds. + + _Swimmerets_, the appendages on the abdomen. + +_Openings_, five on the ventral surface, as follows:-- + + The openings from the excretory organs, through small white cones + on the bases of the antennæ. + + The mouth, farther back, between the maxillipeds. + + The anal opening, in the last segment of the abdomen. + + The opening from the reproductive gland, toward the posterior + part of the thorax. + + + _Observations._ + +1. How large is your specimen? How does it compare in size with other +crayfishes in the laboratory? + +2. Describe the shape of the body, contrasting the anterior end with +the posterior, and the dorsal surface with the ventral. + +3. Study the amount of motion permitted in different parts of the +body. What prevents motion? What permits it? Where is the body most +flexible? Why? Where is it most rigid? Why? + +4. How much of the surface is covered with exoskeleton? What +arrangement is there to permit the animal to feel contact? + + How can the animal grow with such an exoskeleton? + +5. Place a dead crayfish in dilute acid for a few hours. What is the +result? What has the acid done? Explain the fact that crayfishes are +often found alive and well with a soft shell? + +6. Compare the cephalo-thorax with the abdomen as to size, shape, and +flexibility. + +7. How many somites are there in the abdomen? Which way does it bend? +Study the somite shells on every side and then state what there is in +their construction which determines the direction and amount of their +motion. How are the somite shells arranged to protect the body during +bending? How is the ventral surface of the abdomen protected? + +8. Where are the appendages attached? Study a walking leg and +describe its general construction, the number and kind of joints, the +direction of motion in each joint, and the range of motion for the +whole leg. Study an antenna in the same way. What methods are used in +the crayfish to secure a wide range of motion? To secure flexibility? + +9. Carefully split a crayfish into right and left halves. To do this, +first cut through the ventral exoskeleton from end to end with +scissors, then with a sharp knife or razor cut through to the dorsal +exoskeleton and cut that with the scissors. Study one half, to get a +better idea of the attachment of the appendages. These may then be +removed and placed in order on a piece of paper upon which a list of +the appendages has been written. + +10. How many pairs of appendages are there? How may they be grouped +according to location; how grouped according to function? How many +pairs are there in each group? + +11. What similarities of structure do you find in nearly all of the +appendages? Assuming a swimmeret of the third, fourth, or fifth +somite to be the least changed from the primitive type, what changes +were necessary to make the sixth swimmeret; the third maxilliped; the +walking legs; the antennæ; the antennules? + +12. Remove the part of the carapace which covers a gill chamber. What +are the boundaries of the chamber? Where does it open to the water? + +13. Describe the appearance and the texture of a gill. How are the +gills kept moist when the crayfish is in water; when it is on land? +Why should they be kept moist? + +14. Would you class the gills as external structures or as internal? +Why do you think so? To what are they attached? How are the gills +affected by the motion of the legs? + + 15. What work goes on in the gills? How is the supply of oxygen + renewed? In this connection, try a live crayfish, kept quiet in + water just about deep enough to cover it. Float bits of paper + near it or carefully place a drop of ink in the water near it. By + some such method currents of water may usually be shown, and + their direction determined. Consider also the habitual motions of + mouth parts and swimmerets, the bubbles sometimes seen when a + crayfish is dropped into water and the habit crayfishes have of + lying on one side, close to the surface of the water. + + +Summary of the Study of Crayfishes + + +To summarize your study, write a connected account of the relations +of crayfishes to their environments, under the following topics:-- + +1. What are the varying conditions in their surroundings which +crayfishes must meet? Which are most important? + +2. What conditions must be maintained in order that crayfishes may +succeed, _i.e._ may live and reproduce? + +3. How does a crayfish know what are the conditions around it? + +4. How is it fitted to meet these conditions? (Answer in the +following details):-- + +a. How wide a food range has it, _i.e._ how many kinds of food does +it eat? How does it find its food? How does it reach it? How does it +take its food? How does it make food small enough to be eaten? + +b. What are the organs for taking in oxygen? Where are they? How are +they attached? How is the supply of oxygen kept up? How are the +organs kept from drying, from clogging, and from mechanical injury? + +c. What ranges of temperature can crayfishes endure? What temperature +is best? How do they avoid fatal extremes? + +d. What are the enemies of crayfishes? What protection against these +have they? + +e. How often do crayfishes reproduce? About how many times during a +normal lifetime? About how many eggs are there and how many of them +hatch? What care is given to the eggs and to the young? About how +many of the young reach maturity? (_Suggestion._ Do the crayfishes of +a region vary noticeably in numbers from year to year?) + +5. What limits the range of crayfishes, north and south? What limits +it on land? What in water? + +6. When the crayfishes of a given locality are not well adapted to +it, what can they do? + + + _Suggested drawings._ + +a. The whole animal, dorsal surface, preferably without appendages. + +b. One of each pair of appendages, except where they duplicate. + +c. The tail-fin. Label the sixth swimmerets, the sixth and seventh +somites. + +d. The gill chamber, with gills in position. Show circulation of +water by arrows. + +e. A gill, to show construction. + + +2. COMPARATIVE STUDY OF CRUSTACEA + + + _Materials._ + +Get together all the different specimens of crustacea you can +collect, and identify the material. Then study each specimen as +follows:-- + + + _Questions._ + +1. Briefly describe the exoskeleton, if there is one. + +2. What region or regions are clearly segmented? + +3. How much of the body is covered by a carapace? + +4. Has it segmented appendages? Classify the appendages as to their +use. + +5. Are the cephalo-thorax and abdomen equally developed? If not, +which is more developed? + +6. How many antennæ has it? Are the eyes stalked, or are they +sessile? + +7. What organs of respiration has it? Where are they attached? + +8. How many thoracic appendages has it, if any? + +9. What methods of locomotion does it use? + + + _Summary._ + +1. Does this animal seem to be adapted to life on land or in water, +or both? Give your reasons for your opinion. + +2. What characteristics are common to all the crustacea you have +studied? + + +3. REVIEW AND LIBRARY WORK ON CRUSTACEA + + +1. What are arthropods? + +2. Give the classes of arthropods with an example of each. + +3. What are the distinguishing characteristics of the class +crustacea? + +4. In what respects are most of the appendages of the crayfish +homologous, _i.e._ alike in the plan of structure? Which do you +consider the simplest, and why do you? Which do you consider the most +specialized, and why? + +5. Which somite of the crayfish is without appendages? How many +somites are there in a crayfish's body, if each somite bears only one +pair of appendages, as many scientists believe? How many of these are +in the head; thorax; abdomen? + +6. Compare the nervous system of the crayfish with that of the +earthworm as regards efficiency. Upon what do you base your answer? + +7. Name two points in which earthworms and crayfishes are alike. Name +three in which they differ. + +8. How are crayfishes caught for market? Where do those sold in +Chicago usually come from? How are they shipped? + +9. Compare the young forms of a crayfish and a crab. + +10. Describe any five different crustacea. + +11. Describe the work done by the United States government and by the +state governments to protect and to perpetuate the lobster. Why is it +thought necessary to do this? + +12. Discuss the process and the advantages and disadvantages of +molting, as seen in the crustacea. + +13. Name two advantages in having such a shell as crustacea have. +Name two disadvantages. On the whole, is such a shell favorable to an +animal's chances of success or is it not? + +14. Give the curious myth about goose barnacles. + +15. What crustacea are parasitic? Give an account of one. + +16. Why are barnacles classed among crustacea? Where were they once +classed? Why may they be considered degenerate, even though not +parasitic? How do they manage to succeed? What is their economic +importance? How are their effects checked or prevented? + +17. Describe some of the odd means of self-protection shown among +crustacea. + +18. Describe a compound eye. Give two theories as to what can be seen +with a compound eye. Why do we not know, instead of theorizing? + +19. What is the economic value of the very small crustacea? + +20. Discuss the value to man of the various forms of crustacea. + + + + +CHAPTER V + +ADAPTATIONS FOR PROTECTION FROM ENEMIES + + +#A. THE EXOSKELETON# + + +1. THE CLAM--A TYPE OF MOLLUSCA + +_To Show the Effect of a Heavy Exoskeleton_ + + + _Materials._ + +Living clams in aquaria, with enough moist sand to cover the clams, +preserved clams, sets of matched clamshells, a few shells with the +hinge unbroken, evaporating dishes, hydrochloric acid. + + + _Definitions._ + +_Mollusca_, a branch of the animal kingdom including those animals +with soft, unsegmented bodies, inclosed in two folds of skin known as +the mantle. They are often called shellfish as most of the forms have +a shell. + +_Lamellibranchiata_ or _Pelecypoda_, names given to the class of +Mollusca to which the clam belongs. The former term refers to the +broad, flap-like gills and the latter to the hatchet-like foot. + +_Valve_, one of two parts of the clamshell. + +_Hinge ligament_, the elastic structure which fastens the valves +together at the dorsal margin. + +_Umbones_, a pair of elevations near the anterior end of the shell. + +_Lines of growth_, concentric lines around the umbones. + +_Siphons_, two openings at the posterior end of the clam, the upper +opening is the _excurrent_ opening and the lower the _incurrent_. In +the salt water clam the siphons form a long tube, usually called the +"neck." + +_Hinge teeth_, projections near the dorsal margin on the inner +surface of the shell. The anterior irregular structure is the +_cardinal_ and the more posterior blade-like structure is the +_lateral_ tooth. + +_Muscle scars_, scar-like markings on the inner surface of the shell +indicating the point where muscles were attached. The large scar just +in front of the cardinal tooth is the _anterior adductor muscle +scar_, and the one just back of the lateral tooth is the _posterior +adductor muscle scar_. + +_Pallial line_, a line connecting the two muscle scars. + +_Mantle_, folds of skin covering the body of the clam and lying close +to the inner surface of the valves. + +_Foot_, a hatchet-shaped structure extending from the ventral edge of +the body. + +_Gills_, broad flap-like structures for respiration, situated each +side of the body in the mantle cavity. They consist of a double fold +of membrane through which run many perforations lined with cilia. The +waving of these cilia cause the current of water needed for +respiration. + +_Palps_, small flap-like structures near the anterior end of the +clam. They surround the mouth. On their surface are cilia which cause +currents of water toward the mouth. + +_Adductor muscles_, large muscles extending from valve to valve. + + + _Observations._ + +Identify anterior and posterior ends, dorsal and ventral surfaces, +right and left sides. + +1. Why may a clam be called a bivalve? + +2. What is the position of the clam in the mud? What is the position +of the foot if the clam is undisturbed? Are the two valves tightly +closed or slightly open at this time? + +3. What changes take place in the shell as the clam grows? What +markings on the surface of the shell indicate this? + +4. Where is the clam sensitive to touch or tactile stimulus? Why has +the clam no eyes? Zoölogists have found a structure in clams which +they have supposed to be an ear. Where do you think the structure is +located? Why is the clam successful without eyes? (There are many +bivalves which have them.) + +5. Examine several clams until you find some with enlargements in the +gills. Break off a small part of an enlargement with your forceps and +examine under the compound microscope. Describe what you see. + +6. Drop some powdered chalk or carmine in the water just above the +siphon, watch the siphons for several minutes, and note what happens. +What do you conclude to be the use of the siphons? Recalling what +took place in sponges, what would you suggest as the probable cause +of these currents? What does the clam thus probably obtain? How do +the two siphons differ? Why? + +7. Place a clam in water sufficient to cover it and heat slowly to +about 40 degrees Centigrade, until the valves open slightly. Remove +and proceed as follows: Raise one valve, separate the mantle from it, +and then cut through the two large firm structures (adductor muscles) +found at each end. What does the valve do when the muscles are cut? +What is the cause of this? State your theory as to how a clam opens +and closes its shell. + +8. Note the texture of the mantle. How many lobes has it? What is +their extent? How are the lobes related to the valves? + +9. Remove or lift up one mantle lobe. Identify the soft body, the +foot, the gills, the palps, and the mouth. Which of these structures +are arranged in pairs? + +10. Determine the structure and composition of the shell as +follows:-- + +a. Break a thick clamshell and examine the broken edge. Identify the +inner or pearly layer and the outer or chalky layers. What gives +color to the shell in the living clam? + +b. Burn a small piece of shell in an evaporating dish over a bunsen +burner. What is the appearance of the shell after burning? What has +been burned, animal or mineral matter? What then is the residue? + +c. Place a small piece of shell in acid. What results? Is there a +large amount of residue? What constitutes the greater part of the +shell, animal or mineral matter? + +d. (Optional) Devise some method and determine the approximate per +cent of mineral and of animal matter in the clamshell. + + + _Summary._ + +1. Why did we study the clam? (See title of exercise.) + +2. How has the heavy shell of the clam affected:-- + +a. The character of the clam's body, + +b. the locomotion, + +c. the development of sense organs. + +3. What special problems has the clam as regards getting food and +oxygen? How are these problems solved? + +4. How does the clam protect the young clam during development? + + + _Suggested drawings._ + +a. Dorsal margin of the clam. + +b. Side view of the clam. + +c. The clam with one valve removed or lifted back. + +d. The clam with one valve and one mantle lobe removed. + +e. The edge of a broken shell. + +f. Diagram of cross sections. + + +2. THE SNAIL--A TYPE OF MOLLUSCA + +_To show Another Type of Exoskeleton_ + + + _Materials._ + +Specimens of pond snails, edible snails, and "slugs," and other land +snails, and a collection of shells of various types. + + + _Definitions._ + +_Gasteropoda_, the name of the class to which the snail belongs. + +_Spire_, the coiled portion of the snail shell. + +_Aperture_, the opening of the shell. + +_Lip_, the edge of the shell forming the margin of the aperture. + +_Whorl_, a single coil of the spire. + +_Suture_, the depression between the whorls. + +_Foot_, the flat disk-like structure on which a snail creeps. + +_Breathing pore_, an opening in the mantle used in respiration. + +_Lingual ribbon_, the rasp or file like tongue of the snail. + + + _Observations._ + +1. Why is a snail called a univalve? + +2. Identify the head and mouth of the snail. Watch the snail feeding +and examine the mouth of the snail with a lens. What do you notice? +If your aquarium in which the pond snail is living has a green +coating (algæ) on the side, describe its appearance after the snail +has been crawling up and down over it. Explain. + +3. How many tentacles has a pond snail? a land snail? Where are the +eyes located in each case? What movements of the tentacles do you +notice? What is their purpose? + +4. How does the rate of locomotion of the snail compare with that of +the clam? Find out if the snail can creep backwards or on the surface +of the water. Does there seem to be any tendency for the snail to go +up and down the sides of the aquaria vertically rather than to the +right or left? + +5. What does a snail do when disturbed? What is gained by this +action? + +6. Search for pond snail's eggs on the side of the aquaria. Lift up +the bits of cabbage on which the slugs are feeding and search for +eggs. Describe what you find in each case, noting the size, +appearance, and whether the eggs are laid singly or in masses. + +7. Find the breathing pore. Describe its position and appearance. + +8. Contrast the various types of shells, and note with care in what +respects they differ. Holding the shell with the aperture toward you +and the spire pointing up, determine whether each shell has +the aperture on the right (right-handed shell) or on the left +(left-handed shell). Is the right-handed or the left-handed shell +more common? + +9. (Optional) By means of some book in the laboratory, determine the +scientific name of each of the snails found in the various aquaria in +the laboratory. + + + _Suggested drawings._ + +a. Drawings to show the pond snail in various positions in the +aquarium. + +b. A drawing of the slug. + +c. At least three different types of snail shell. + + + _Summary._ + +1. In what respects does a snail show resemblance to a clam? + +2. What are the chief points of difference? + +3. What reasons can you suggest for the better development of the +sense organs? + +4. What advantage has a snail over a clam in the matter of getting +food? + +5. How does the shell of the snail compare with that of the clam as +an organ for protection? + + +3. THE SQUID--A TYPE OF MOLLUSCA + +_To show the Effect of a Much Reduced or Rudimentary Skeleton_ + + + _Materials._ + +Small squids, and a few large specimens for comparison and +dissection. + + + _Definitions._ + +_Cephalopoda_, the name of the class to which the squid belongs. + +_Caudal fin_, a horizontal structure at the posterior end of the +squid. + +_Chromatophores_, irregular cells in the mantle which give color to +the squid. + +_Exhalent siphon_, a funnel or tube opening on the ventral side just +below the base of the arms or tentacles. + +_Pen_, a remnant of an exoskeleton imbedded in the mantle along the +dorsal side. + +_Ink sac_, a sac containing a dark, sticky liquid which may be thrown +out through the funnel into the water. The opening is near the inner +opening of the funnel. + + + _Observations._ + +1. What is the shape of the squid? To what is this shape adapted? + +2. Identify the head and the well-developed eyes. + +3. How many arms or tentacles are there? How are they arranged with +reference to the mouth? What do you find on the distal ends of the +arms? How do the arms vary as to size? What does the position and +arrangement of the arms suggest as to their function? + +4. Identify the exhalent siphon. Where may water enter the mantle +cavity? Recalling the action of the siphons in the clam, suggest a +method by which a squid is propelled through the water. In what +direction must it swim? + +5. Split the mantle along the ventral surface and spread apart. +Identify the long plume-like gills, the ink sac, and the inner +opening of the exhalent siphon. How many gills do you find? + + + _Suggested drawings._ + +a. The squid side view. + +b. The squid from the ventral side with the mantle split open, arrows +to show direction of water. + + + _Summary._ + +1. In what ways does a squid show relationship to the clam and the +snail? + +2. What has a squid gained through the reduction of its exoskeleton? +What has it lost? What changes were necessary in its structure to +offset the loss of an exoskeleton? + + +4. A COMPARATIVE STUDY OF MOLLUSCA + + + _Materials._ + +Specimens of as many different kinds of mollusks as possible, charts, +books. + + + _Observations._ + +1. What is the symmetry?[3] + + [3] This and the following questions are to be answered for each + specimen. The answers may be tabulated if desired. + +2. Is the body segmented or unsegmented? + +3. Are lateral appendages present or wanting? + +4. Is an exoskeleton present or wanting? If present, is it univalve +or bivalve; if absent, what other means of protection has been +developed to take its place? + +5. Is the animal fixed, or is it free to move? If fixed, in what way? +If it moves, what is the method and organ of locomotion? + +6. What are the organs of respiration? What is their character? + +7. How is food obtained? + +8. What senses are probably present? What sense organs are present? + +9. What is the habitat? + +10. In what ways if any does the animal show degeneration? + + + _Summary._ + +1. What characters are common to all mollusks? + +2. What is the principal means of protection among mollusks? + +3. Name three causes of degeneration among mollusks. + + +5. MOLLUSCA: REVIEW AND LIBRARY EXERCISE + + + _Characteristics._ + +1. What are the general characteristics of mollusks? + +2. Name the principal classes and give the characteristics of each. + + + _Morphology._ + +3. What is peculiar about the structure of a clam's heart? What is +its position? Contrast with the heart of a crayfish. + +4. Make cross-sectional diagrams to show the arrangement of parts in +a clam: (a) in the region of the umbone; (b) in the region just +in front of the posterior muscle; (c) in the region of the anterior +muscle. + +5. Describe the various types of eyes found in mollusks, and their +location. + +6. Describe the tongue or lingual ribbon of the snail, and its use. + +7. What is the operculum of snails? its use? + + + _Physiology._ + +8. Describe the circulation of water through the siphons and mantle +cavity of a clam. How is it caused? What three uses has it? + +9. What are the principal facts about the development of fresh-water +clams? + +10. Describe the circulation of blood in a clam. + +11. What various methods of locomotion are found among mollusca? + + + _Economics._ + +Write a short account of the following:-- + +12. Oyster culture. + +13. Typhoid-fever and oysters. + +14. Clams, scallops, and other edible shellfish. + +15. Pearls and pearl fisheries. + +16. Fresh-water clams and the button industry. + +17. Sepia, Tyrian dye, etc. + +18. Harmful and useful mollusks. + +19. The work of U. S. Fish Commission in propagating clams. + + + _Natural history._ + +20. Give the class, habitat, and some important fact about each of +the following: Pectens; wing shells; Tridacna gigas; abalones; +limpets; oyster drill; periwinkle; mussel; cuttle fish; octopus; +nautilus; argonaut. + + +6. A COMPARATIVE STUDY OF EXOSKELETONS + + + _Materials._ + +Charts, specimens, etc. Since this is partly a review exercise, your +notes and drawings of invertebrates should be at hand. + + + _Definitions._ + +_Exoskeleton_, a protective covering developed on the outside of an +animal. + + + _Questions._ + +1. What are foraminifera; radiolaria? How do they differ from other +protozoans? Of what two substances are the shells of protozoans +composed? + +2. How are the spicules formed in a simple sponge? What are glass +sponges? Give reasons why the skeletons of sponges may or may not be +considered exoskeletons? + +3. What are stone corals? What is the relation of the coral polyp to +the skeleton? What is the appearance of the coral when expanded as +compared with its appearance when contracted? Of what substance is +the coral composed? + +4. Describe the exoskeleton of a starfish. Contrast the exoskeleton +of the sea urchin and the starfish. Why does a sea cucumber need no +well-developed exoskeleton? + +5. What structure in an earthworm may be considered an exoskeleton? +What other types of exoskeletons are found in segmented worms? + +6. Of what substance is the exoskeleton of arthropods composed? What +additional substance is found deposited in the shell in the case of +crustaceans? What advantage in the arthropod type of exoskeleton? + +7. Why are mollusks so commonly called "shellfish"? What advantage in +the mollusk type of skeleton? What disadvantages? + + + _Summary._ + +1. What type of exoskeleton is common among invertebrates? + +2. What are the general purposes of exoskeletons? + +3. What is the explanation of the various forms of exoskeletons +found? + +4. Of what substances are exoskeletons composed? + + +#B. PROTECTIVE COLORATION# + +#To show how Color may be Protective# + + + _Materials._ + +Specimens such as the Kny-Scheerer mimicry collections, diagrams, +etc. + + + _Definitions._ + +_General protective resemblance_, the general resemblance between the +color of an animal and its surroundings. + +_Variable protective resemblance_, the changing of the color of an +animal to correspond to the change in its background. + +_Special protective resemblance_, the resemblance of an animal to +some object found in its background in color and form. + +_Mimicry_, the resemblance of an unprotected animal to a +well-protected one. + +_Warning colors_, bright colors which protect animals by causing +other animals to avoid it. + + + _Questions._ + +1. Show how the transparent color of a paramecium, the green color of +a cabbage worm, or the green color of a certain species of hydra may +result in protecting an animal from its enemies. Mention as many +other examples as you can. + +2. What is gained by the ability of a squid to change its color? How +is this change brought about? + +3. Explain the protective coloration of the following: Dead-leaf +butterfly, walking stick, geometrid larva. Hunt up other examples. + +4. Explain the protective coloration in the following: Hover flies, +clear-winged moths, viceroy butterflies. + +5. Make a list of several invertebrates that are protected by their +bright color. Explain the reason for the bright color. + +6. How may the difference between the color of the upper and lower +surfaces of animals be explained on the basis of use to the animal? + +7. (Optional) Find out some other uses of color to an animal aside +from protection. + + + _Summary._ + +1. Name four uses of color. + +2. Name four ways an animal is protected by being like its +background. + +3. Name one way it is protected by being unlike its background. + +4. What disadvantages in this method of protection? + + +#C. ANIMAL ASSOCIATIONS# + +#To show Another Method of Protection from Enemies# + + + _Materials._ + +Specimens, charts, etc., illustrating animal associations. + + + _Definitions._ + +_Animal communities_, associations of many animals of the same +species in communities in which there is a greater or less division +of labor. + +_Gregarious_, associations where there is but little division of +labor. + +_Parasitism_, an association where one animal lives at the expense of +the other. The animal on which the parasite lives is called the host. +If there are two hosts during the life cycle of the parasite, the +second host is called an intermediate host. + +_Symbiosis_, an association where two animals live together in +mutually helpful relations. + +_Commensalism_, an association where two animals live together in +relations not mutually helpful but without injury to either. + + + _Observations and questions._ + + _Note._--To find answers to many of these questions it will be + necessary to refer to the reference books in the laboratory. + +1. Examine a specimen of Volvox. Why may this be considered a +colonial protozoan and not a many-celled animal? What is gained by +the colonial habit? + +2. Is the colonial habit common or rare in sponges and cœlenterates? +What is chiefly gained? + +3. Describe the community life in one of the insects in each of the +following groups:-- + +a. ant, honeybee, termite. + +b. bumblebee, paper wasp, hornet. + +c. mining bee. + +d. carpenter bee, mud wasp, digger wasp. + +4. Name the host or hosts in the following cases: trichina, liver +fluke, malarial parasite, tapeworm, hook worm. Give the life history +of one or more of the parasites just enumerated. What is the effect +of parasitism on the structure of the parasite? + +5. What is the relation between ants and plant lice? Show how this +relation is mutually helpful. Mention other cases of symbiosis that +you have come across. + +6. With what animal are barnacles often associated? What is the habit +of the pea or oyster crab? What are "guest bees"? What structure is +lacking that is found in other bees? What are often found in the +cavities of sponges? Why are these associations called commensalism +rather than symbiosis? + + + _Summary._ + +1. Into what groups can animal associations be divided based upon the +number of species concerned? + +2. From the standpoint of protection, is this a good or a bad method +of protection? + +3. What disadvantages can you see in this method of protection. + + +#D. PROTECTIVE HABITS AND POWERS# + + + _Materials._ + +Specimens, charts, and books, showing habits of invertebrates. + + + _Definitions._ + +_Regeneration_, the power to grow new parts of the body when parts +have been lost or injured. + +_Masking_, the covering of an animal by some object or organism so as +to hide its identity. + +_Nocturnal habits_, the habit of hiding in the daytime and coming out +at night to feed. + +_Terrifying attitudes_, the protective attitudes assumed at times by +animals in order to ward off attack. + + + _Observations and questions._ + +1. How are Sabella and Serpula protected? What advantages and +disadvantages in this habit? What changes in structure are associated +with this tube-dwelling habit? + +2. What two protective habits has the earthworm? Name some other +animals that have similar habits. + +3. Describe the protective habits of the caddis-fly larva; of the +leaf-roller moth. What benefit to the hermit crab is the colony of +hydractinia growing on the snail shell which it inhabits? Give other +similar cases. + +4. Name as many cases of regeneration as you can. + +5. What peculiar habits has a puss-moth larva? a dragon fly? Give +other examples. + + + _Summary._ + +1. Name the various protective habits. + +2. State any advantages or disadvantages you can with reference to +these protective habits. + + +#E. DEFENSIVE STRUCTURES# + +#Another Method of Protection from Enemies# + + + _Materials._ + +Specimens, charts, books, etc., to illustrate the various defensive +organs found among invertebrates. + + + _Observations and questions._ + +1. Describe the stinging hairs of the paramecium. + +2. Describe the action and structure of nettle cells. Where are they +located in the case of hydra; of jellyfish? + +3. What defensive organs are found among the arthropods? + +4. What are stinkbugs? What peculiar organs of defense have the +caterpillars of the swallowtail butterflies? + +5. Where is the sting of a hornet located? To what in a grasshopper +does it correspond? Why does a hornet or bee inflict so painful a +wound? + +6. What peculiar organ of defense has a squid? + +7. Find other examples of defensive structures. + + + _Summary._ + +1. What advantages have organs of defense as a method of protection? + +2. What disadvantages? + + +#F. THESIS# + +#To sum up the Important Points in the Study of Adaptations for +Protection# + + + _Directions._ + +Write a connected account of what you have found out about protection +of animals from their enemies, using the following outline:-- + +1. The struggle for existence-- + + a. its cause, + b. its threefold nature, + c. the various kinds of adaptations. + +2. The various methods of protection from enemies. + + a. The exoskeleton. + b. Protective coloration. + c. Animal associations. + d. Protective habits. + e. Defensive structures. + + + + +CHAPTER VI + +VERTEBRATES + + +#A. STUDIES OF FISHES# + + +THE LIVING FISH + +_Vertebrates adapted to Water Life_ + + + _Materials._ + +Living goldfishes or other fishes in small aquaria for individual +study and a few fishes in a large aquarium where they have +considerable freedom of motion. + + + _Definitions._ + +_Trunk_, the portion of the body between the head and the tail. + +_Compressed_, a term used to describe the shape of the body when it +is narrower from side to side than from dorsal to ventral surface. +When the opposite is true, the body is said to be _flattened_. + +_Median fins_, the unpaired fins situated on the median line, dorsal +and ventral, including the tail or _caudal_ fin, the _dorsal_ fin, +and the _anal_ fin. + +_Paired fins_, fins occurring in pairs of which the more anterior are +the _pectoral_ fins and the posterior are the _pelvic_ fins. + +_Fin rays_, the framework or skeleton of the fins over which membrane +is stretched to form the fins. Fin rays are of two kinds: those +composed of _bone_ and those composed of _cartilage_. + +_Lateral line_, a sense organ extending along each side of the fish +in a line indicated by tubes or perforations in the scales. + +_Gills_, respiratory organs adapted for taking oxygen from the water. + +_Operculum_, the flaps covering the gills on each side of the head. + +_Pigment_, a substance which gives color to an object. + + + _Observations._ + +_Locomotion._ + +1. Watch the fishes in the large aquarium and determine which fins +are most used and how they are used (a) in swimming forward, (b) in +swimming upward and downward, (c) in maintaining balance, (d) in +remaining at rest, and (e) in guiding the movements of the fish. + +2. What advantages are there to the fish (a) in the power to open +and close the dorsal and anal fins, (b) in having no neck, and +(c) in having a compressed form? + +3. Enumerate the various ways by which the body of the fish is +adapted to rapid movement through the water. + +_Feeding._ + +4. What is the food of the fishes you are studying? Feed them and +watch them eat. Why is the upper jaw often called a "lip"? What is +the shape and size of the mouth when opened in feeding? Does the fish +chew its food? Describe in detail the fishes' method of feeding. + +_Respiration._ + +5. Identify the opercula and the gill openings. Watch the movements +of the opercula and mouth, and determine what movements are concerned +in breathing and their order. Describe in detail the circulation of +water used in breathing and how it is caused. + +_Sense Organs._ + +6. Identify the eyes, nostrils, and lateral line. How many nostrils +are there and where located? What is the position and extent of the +lateral line? + +7. Describe the location of the eyes. What is the shape of the outer +surface of the eyes? Why this shape? Can the eyes be moved, _i.e._ +can they be rotated, rolled, or retracted? From what direction might +an enemy approach without being seen? How would such an enemy be +detected? + +_Protection._ + +8. With what protective structures is the body covered? Do they +hinder the movements of the fish? What are the advantages of the +scale covering of fishes over the shell covering of grasshoppers or +crayfishes? + +9. In what other ways are the fishes you are studying protected +against enemies? Since you cannot account for the red color of +goldfishes on the basis of use to the fish, then how do you account +for this bright color? + +_The Body._ + +10. What is the symmetry of the fish? Into what regions is the body +divided? + + + _Summary of the study of the living fish._ + +Enumerate in one column the different adaptations which fit the fish +for life in water and in a second column state the special purpose of +each adaption. + + +The External Structure of the Fish + + + _Materials._ + +Freshly killed or preserved fish in dishes or shallow pans with +enough water to prevent drying. Simple or compound microscopes, +forceps, and a bristle. + + + _Directions._ + +Examine the fins and identify the membrane and the supporting rods, +or _rays_, of bone or cartilage. Notice how the ends of the +cartilaginous rays keep the membrane from tearing. + +Investigate the scales as to their arrangement, number, and size. +Remove a small patch of scales along the lateral line to find how +they are attached, where the fish's color is situated, and how access +to the sensory organs of the line is permitted. Examine a scale under +the microscope. + +Observe the eyes and identify the parts similar to those of the human +eye: lid, lash, tear-duct, cornea, iris, and pupil. + +In front of and between the eyes, find the nostrils. By means of a +bristle determine whether these are connected and whether they do or +do not open into the mouth or the throat. + + + _Questions._ + +1. Make a list of the fins, classifying them according to their +structure. + +2. Bearing in mind the differences in structure and consequent +action,--what can you say regarding the adaptation of the several +fins for protection? for rigidity or flexibility in locomotion? + +3. State how much of the body is covered with scales, and where the +largest and the smallest ones are found. + +4. How are the scales arranged with reference to each other? What +benefit is derived from this in protection? in locomotion? If you +have noticed any mucus or slime upon the body, state its use. + +5. Do the scales or the skin bear the pigment? Give the color pattern +of the kind of fish used in class. How would this be useful to the +fish in its natural home? + +6. Describe the structure of a scale and state how it is attached to +the skin. In what way is the lateral-line scale specialized? + +7. State how, when the fish is swimming, the nostrils catch odors. By +means of a diagram, with arrows show the probable direction of the +water current through the nose. + +8. State which of the structures of your eye are present in the +fish's eye, and which are missing. Could a fish weep? wink? How would +a fish sleep? + +9. Inasmuch as light penetrates water but a little way, so that +objects can be distinguished only within about thirty feet, would the +fish be nearsighted or farsighted? + + + _Suggested drawings._ + +a. A side view of the entire fish, fully labeled. + +b. A bony rayed and a cartilaginous rayed fin. + +c. A scale, showing its minute structure. + +d. A dorsal or a lateral view of the head, showing the sense organs. + + +The Mouth and the Gills of the Fish + + + _Materials._ + +The same materials as those used in the preceding exercise may be +used here. + + + _Directions._ + +The mouth, its structure and its action, can be seen by pulling the +upper jaw upward and forward until the mouth and the gill chambers +open fully. Examine the structure and action of the jaws, the tongue, +the throat, and the teeth on each jaw and on the roof of the mouth. + +Investigate the breathing apparatus from the throat side and from the +exterior, noting the number, form, and structure of the gills, their +attachment and their protection. + +The mouth may be kept open by a short splinter or a ball of paper. + +The pupil should identify the following structures:-- + +1. _Gill_, an organ for breathing the air dissolved in water. + +2. _Gill arch_, an arch of bone or cartilage supporting the gills. + +3. _Gill filaments_, fringe-like structures attached to the gill +arches, forming the gills. + +4. _Gill raker_, lateral projections from the gill arches. + +5. _Gill-slits_, openings between the gill arches for the passage of +water. + +6. _Operculum_, the flap-like covering of the gills on each side of +the head. + + + _Questions._ + +1. Compared with the size of its body, how wide can the fish open its +mouth? What do you infer as to the size of its "bite"? + +2. Are the jaws rigidly affixed to the skull? Why should they be so +attached, or why not? + +3. Of how many pieces is the upper jaw composed? the under jaw? + +4. Where are the teeth? Judging from their form, size, and situation, +what do you think must be their use? + +5. Do you think the tongue is used to assist in mastication? in +tasting? in speech? in swallowing? + +6. How many gills are there, and where are they situated? How are +they attached? Which one is not free from the body throughout its +length? + +7. What probably causes the color of the gill filaments? What is +there in their number and texture which fits them for their +function? + +8. What is the direction of the water current through the gill +chamber? Of what use are the gill rakers? + +9. How are the gills protected? + + + _Summary._ + +Write a complete account of how the fish eats and how it breathes. + + + _Suggested drawings._ + +a. A front view of the fish's face, with the mouth fully open. + +b. A side view, as above. + +c. A ventral view of the head, with both gill-chambers wide open and +the gills separated from each other. Indicate currents by arrows. + +d. A single gill. + + +The Alimentary Canal and the Circulatory System of the Fish + + + _Materials._ + +Small fresh fish, shallow pans or dishes of water, forceps, and +scissors. + + + _Directions._ + +If the instructor has not opened the fish previously, this is to be +done by the student as follows: On the ventral side, insert the +scissors in the vent (in front of the anal fin) and cut straight +forward to a point between the opercula. Care must be exercised in +opening the chamber about the heart; this lies between the gill +chambers. + +The various organs, so far as possible, should be carefully drawn out +and separated, in order that their structure may be distinguished. + +The pupil should identify the following parts:-- + +1. _Body cavity_, the entire internal space, divided by a membrane, +_false diaphragm_, into a large _abdominal cavity_ and a small +chamber, _pericardial chamber_, between the gill chambers. + +2. _Liver_, a large red or pink mass lying at the front end of +the abdominal cavity, and divided into two unequal lobes. The +_gall-bladder_, thin-walled and green, may be seen between these +lobes. + +3. _Alimentary canal._ + + a. _Mouth._ + + b. _Esophagus_, in the fish a very short tube. + + c. _Stomach_, white and muscular, beginning with a very short + esophagus and ending as a blind sac. If it is much distended, + open it to see what the fish may have eaten. + + d. _Small intestine_, thin-walled, tubular, and somewhat coiled. + + e. _Large intestine_, a short, thin-walled expansion at the + posterior end of the small intestine; usually less than half an + inch long. + + f. _Cœca_, from two to several small pouches attached where the + small intestine leaves the stomach. + +4. _Spleen_, a reddish brown _globule_ between the folds of the +intestine. + +5. _Swim bladder_, an elongated chamber lying against the backbone, +partitioned off from the cavity below by a delicate membrane. + +6. _Peritoneum_, the delicate, silvery membrane which lines the +abdominal cavity and enfolds the viscera. Note its spots of pigment. + +7. _Pericardial chamber_, the chamber around the heart; see § 1 +above. + +8. _Heart._ As the fish is placed belly upward in the pan the +_ventricle_ faces you, pink, conical, and muscular. Posterior to it, +on the dorsal side, is the _auricle_, a membranous sac. + +9. _Ventral aorta_, arising on the anterior surface of the ventricle +as a white muscular "cord" (really a tube) which is enlarged close to +the heart into a bulb, the _arterial bulb_. You should follow up this +aorta until you see it divide right and left to send its branches +outward into the gills, the branches being called _gill arteries_. + + + _Questions._ + +1. The fish frequently swallows its food alive. Why should the +stomach be muscular? Why is it better that the intestine does not +leave the stomach at the end opposite the esophagus? + +2. Of what use can the cœca be? What structure of the human intestine +do you recall that is at all like them in form or use? + +3. How many times the length of the body is the length of the +alimentary canal? Does this indicate that the fish is compelled to +eat a great deal of poor food or that its food is highly nutritious, +so that little need be taken? + +4. Near which end of the fish's body is the heart? Is this the usual +or the unusual condition among animals you know about? What +advantages can you think of in this arrangement? + +5. What advantages are there in having the heart in a chamber +separated from the other vital organs? + +6. Of how many chambers does the heart consist? Why should at least +one of them be muscular? + +7. How many times does the blood pass through the heart in making a +complete circuit of the body? Would you call this a single or a +double circulation? + +8. Does the heart force the blood onward or does it draw blood into +itself, _i.e._ is the heart a force pump or is it a suction pump? + +9. How is circulation made complete? If the heart is a force pump, is +its power sufficient to drive blood through artery, capillary, vein, +and into auricle, if the capillaries can stand the pressure, or is +another action concerned? If it is a suction pump, why does the blood +leave the heart? + + + _Suggested drawings._ + +a. The body cavity, with viscera undisturbed. + +b. The alimentary canal extended. + +c. The anterior end of the fish with the sinus held open, to show the +general situation of the parts. + +d. The heart in its chamber, with the outgoing vessels as far as +dissected. Use arrows to show direction of circulation. + +e. A copy of some good diagram or chart which illustrates the heart +of the fish with the connecting veins and arteries. + + +Fishes: A General Review and Library Exercise + + +1. Food and the feeding habits of young and of adult fishes. + +2. The diet and habits of cod; lantern-fish; swordfish; ramora; +hagfish; angler; gar-pike; sturgeon; shark; sawfish; paddle-fish. + +3. The variations, real or apparent, in the breathing habits of the +porcupine-fish; the climbing-fish; the lung-fish. + +4. Peculiarities in swimming as seen in the flying-fish; the +flounder; the sea-horse. + +5. Intensity of sound under water, and the corresponding structure of +the fish's ear. + +6. Light and sight under water (as in 5). + +7. Protection of fishes: sting-ray; torpedo; coral-fish; sturgeon; +lava-fish; swordfish; sawfish; pipefish. + +8. The social instinct of fishes, and "schools." + +9. The breeding habits of salmon; eel; stickle-back; sturgeon; +whitefish; shark; sea-horse; sunfish. + +10. The fishing industries of the Great Lakes or of the cold oceans, +with a list of the fishes caught and their values. + +11. Fish nets and traps: seine; gill-net; pound-net; trawl, French or +English; fish-wheel; fish-weir; spear; dip-net; set-line; spoon; fly. + +12. The U.S. Bureau of Fisheries: its locations, its problems, and +its methods. + +13. The State Fish Commission, as above. + +14. Game and fish laws; their purpose and their enforcement. + +15. Game fish of the fresh waters; trout, bass, pickerel, and +muskellunge. + +16. Game fish of the ocean: tarpon, tuna, sea-bass, swordfish, and +bluefish. + +17. Fish as food. + +18. Fish diet and leprosy. + +19. Fish diet and parasitic worms. + +20. Fish nuisances: carp, catfish, and dogfish. + +21. Commercial products of fishes, their preparation and their uses: +caviar, shagreen, cod liver oil, isinglass, and glue. + +22. The geographic distribution of fishes, with means of dispersal +and restriction. + +23. The faunal regions of the lake (or ocean), with characteristic +forms. + +24. Fishes of ancient times; of the Devonian period. + +25. The story of the early life of Louis Agassiz; of D. S. Jordan; of +C. H. Eigenmann; of Bashford Dean. + +26. Goldfish: their origin; how to care for them. + +27. Fashions in fish tails, old and new. + +28. Development and variation in scales; fashions in scales. + +29. The common orders of fishes, with examples. + + +Primitive Chordates + + + _Materials._ + +An acorn-tongued worm, a lancelet, a lamprey, a shark, and a perch. +If individual specimens are not available, the pupil's text-book and +charts are to be used. + + + _Observations._ + +_Acorn-tongued worm_: Notice the very simple form and structure of +the symmetrical body, the "proboscis," the collar surrounding the +neck with its simple rod of cartilage, the marks of internal gills +and gill slits extending some distance along the body, and the +presence or absence of sense organs. The acorn-tongued worm +(_Balanoglossus_) lives in the sand of the seashore and in shallow +water in temperate and tropical regions. + +_Lancelet_: Observe the form of the body, of the fin, and of the +mouth; note the presence or absence of sense organs, and find out the +number of gills or gill slits. The lancelet (_Amphioxus_) is similar +in habit to the acorn-tongued worm. By day it lies buried with only +the mouth exposed, but at night it swims actively about. It is +somewhat more confined to the tropics. + +_Lamprey_: Observe here also the primitive or unspecialized form of +the body, of the fin, of the jawless mouth, the number of gill slits, +and the sense organs. + +_Shark_: Examine the body, noting its form and differentiation into +regions, its covering, its fins, mouth, gill slits, and sense organs. + +_Perch_: If you have not already studied the bony fish, the points +suggested for the shark will be sufficient for this exercise. + +In each case, find out the condition of the skeleton. + + + _Questions._ + +1. Which of these animals seem most simple in form, and which most +complex? Give a reason for your answer. + +2. Give the stages which show how the fold of skin develops into +separate fins. + +3. How does the number of gills and gill slits change in the series? +(Give definite numbers.) How may the reduction in the number of gills +be compensated for in the amount of surface exposed for the exchange +of gases in breathing? + +4. How is protection afforded the delicate structure of the gills in +the final form? + +5. Give the stages in the formation of a definite, symmetrical mouth +with jaws of equal size. + +6. The presence of sense organs may be taken to indicate that there +is an organ of control, or brain. How is the development of this +organ like or unlike that of the other structures in the series? + +7. For the developing brain and nervous system what protection and +support is afforded in each case? + +The foregoing questions may be answered in tabular form by arranging +the names of the animals in a line and the questions in a column. + + + _Suggested drawings._ + +a. Acorn-tongued worm, × 1. + +b. Lancelet, × 1. + +c. Lamprey, × ½. + +d. Shark: 1, head as far as the pectoral fins; 2, the tail. + +e. Perch, as directed for shark. + + +#B. STUDIES OF AMPHIBIA# + +#Progress from Water-living Animals to Land-living Animals# + + +The Living Frog or Toad + +_To show how an Animal may be adapted to both Land and Water Life_ + + + _Materials._ + +Living frogs in small cages or aquaria; living toads; some pungent +liquid, as ammonia. + + + _Observations._ + +_The Body._ + +1. Contrast the body of the frog with that of the fish as to regions, +shape, and compactness. How do you account for the differences? + +_Locomotion._ + +2. What kinds of locomotion can a frog use? Why is it difficult for a +frog to crawl or walk? How far can a frog jump? How are swimming and +jumping accomplished? What do you think is the use of the "hump" on +the back? + +3. Identify in the legs the thigh, shank, ankle, foot, toes, and web, +and in the arm, the upper arm, forearm, wrist, hand, and fingers. +State in detail the differences in structure and in position between +the fore and hind limbs. How do you account for these differences? + +_Feeding._ + +4. Induce a frog or toad to eat by dangling food, such as a piece of +raw meat or meal worms, small earthworms, etc., before it. How does +it seize the food? What will it eat? How is the mouth adapted to +this manner of feeding? + +_Respiration._ + +5. The frog has no diaphragm, and therefore no chest cavity; watch +very carefully the movements of the mouth, the nostrils, the throat, +and the sides of the body to determine how the problem of breathing +(how the air is gotten into and out of the lungs) without a diaphragm +is solved. Write a detailed account of the frog's method of breathing +which shall explain just how the air is forced into the lungs. + +6. What would be the effect of propping open the mouth of the frog? +Why? Does the frog breathe in the usual manner while under the water? +If not, how do you explain its ability to remain under water for a +long period of time? + +_Sense Organs._ + +7. Investigate the efficiency of the five special senses in the frog +by devising experiments to test each sense; as, for example, giving a +frog its liberty on the floor and trying to catch it again, to test +the sense of sight. Write an account of your experiments and their +results. Which of the senses is best developed? Give reasons for your +answer. + +8. Compare the eye of the frog with respect to its shape, movements, +parts, and protective structures with that of the fish. In what +respects are they similar? in what respects different? Why should +they differ? + +9. Where are the frogs' ears located? What do you think of the +efficiency of an eardrum situated on the surface of the body? Why? + +10. The frog has certain other responses. Try turning the jar or cage +containing a frog around to face the frog in another direction. What +happens? How do you explain this response on the basis of use? What +other responses have you noticed? + +_Protection._ + +11. Has the frog an exoskeleton? Describe the color scheme of the +frog and explain how it may be protective. Why are frogs brighter in +spring than in fall? + +12. Why do frogs usually live near water? Do they ever leave the +vicinity of streams? If so, when? + + + _Summary._ + +In what ways is the frog adapted to water life? In what ways to life +on land? In what respects do toads differ from frogs? + + +The Frog's Mouth + + + _Materials._ + +Preserved or freshly killed frogs in dishes or shallow pans of water; +forceps and a bristle. + + + _Observations._ + +Open the frog's mouth as widely as possible and, if necessary, +insert a splinter to hold the jaws apart. Identify the following +structures:-- + +_Tongue._ Draw it forward until the free end extends from the mouth +and is outspread; observe its form, extent, and attachment. + +_Teeth._ Find those on the jaws and on the roof of the mouth. + +_Nostrils._ Push the bristle inward through a nostril to determine +its direction and extent. + +_Vocal cords._ These form a hard white mass in the floor of the +mouth, well back behind the tongue. + +_Glottis_, the slit inclosed between the vocal cords, opening into +the trachea. + +_Esophagus_, the passage to the stomach, at the posterior end of the +mouth. + +_Eustachian tubes_, small passages outward to the ears at the +junction of the upper and lower jaws. + + + _Questions._ + +1. Describe the probable action of the frog's tongue in catching a +bug. + +2. What advantage can you ascribe to the peculiar mode of attachment +of the tongue? + +3. Of what use is the notch in the inner end of the tongue? (Note its +position when the tongue lies at rest in the mouth.) + +4. If the frog chewed its food, how would the existing structure of +the nostrils be very inconvenient? + +5. Recall either the frog's habit of feeding or the structure of the +nostrils. Do you think the nostrils are of much service in smelling? +State the reason for your answer. + +6. Of what use are the vocal cords and why are they so muscular? +Consider their use in sound making and also their condition during +swallowing. + +7. Of what use are the teeth? Recall the form and use of the fish's +teeth. + + + _Suggested drawings._ + +a. The mouth, wide open and with tongue extended. + +b. A diagram showing the path of air and of food through the frog's +mouth. + + +The Organs of Digestion, Absorption, and Excretion + + + _Materials._ + +Freshly killed or preserved frogs in dishes or shallow pans of water, +forceps, and, if the pupil is to do any dissecting, scissors. + + + _Directions and Observations._ + +The specimens may have been opened by the teacher, or may be +dissected by the pupil as follows:-- + +Placing the frog on its back, with forceps firmly grasp the skin of +the abdomen and the muscles beneath, just in front of the hind legs, +and with the scissors cut straight forward in the middle line until +the floor of the mouth is reached; this will separate the arms. Care +must be taken not to cut too deeply, but this may be avoided by +keeping the skin uplifted. Now cut sidewise in front of each hind leg +in order that the body wall may be laid aside. Under the arms the +heart will be seen; it will be studied as a part of the circulatory +system. + + * * * * * + +Identify the following organs:-- + +_Liver_, the large red or brown mass, consisting of several divisions +and lying close up under the arms. + +_Bile sac_, small, green, and between the liver lobes. + +_Alimentary canal._ + + 1. _Mouth._ + + 2. _Esophagus._ + + 3. _Stomach_, the elongated, light-colored, firm, and muscular + portion. + + 4. _Small intestine_, a slender, more or less closely coiled, + tubular portion. + + 5. _Large intestine_, a thin-walled enlargement at the posterior + end of the canal. + + 6. _Duodenum._ This is a muscular portion of the small intestine + immediately following the stomach, against which it is folded. + +_Pancreas_, a yellowish, pulpy mass lying in the fold between the +stomach and the duodenum. + +_Spleen_, a dark red globule, usually smaller than a pea, lying +nearly free among the folds of the small intestine. + +_Fat bodies_, yellow fringe-like structures, sometimes found near the +stomach. + +_Kidneys_, a pair of elongated dark red organs, behind the spleen and +against the back. Note their numerous blood vessels. Possibly the +_ureters_, or urinal ducts, can be discovered and traced to their +junction with the _bladder_, a clear membranous sac in the posterior +extremity of the body cavity. + +_Peritoneum_, a thin membrane lining the body cavity and attaching +the vital organs to the backbone. + + _Note._--Specimens secured in late fall, winter, or early spring + may contain, if female, a large number of dark-colored eggs; or + if male, two white testes, located near the kidneys and similar + to them in form, though smaller. + + + _Questions._ + +1. Name the parts of the frog's alimentary canal. + +2. Name the glands or organs which are accessory to the canal. + +3. How long is the esophagus? How does the presence or absence of a +neck affect the esophagus? + +4. How does the thickness of the stomach wall compare with that of +the intestine, and how do you account for the difference? + +5. Measure the length of the trunk of the frog's body and that of the +outstretched alimentary canal. How many times the length of the one +is that of the other? How does this ratio compare with that of an +herbivorous animal? (The sheep's food canal is about thirty-two times +the length of its body.) + +6. What is the color of the bile, as seen through the walls of the +bile sac? This color is characteristic of carnivorous animals; in +herbivorous forms it is yellow. Find its color in some omnivorous +form, as man. + +7. Name the organs concerned in excretion. + +8. What holds the internal organs in place, and from what are they +suspended? + +9. The spleen is called a "ductless gland." Give its function, and +explain why a duct is not necessary to it. + +10. Since the frog swallows its food alive and entire, what work must +the stomach do? What digestive organs would be absent from the mouth, +or else poorly developed? + +11. Since the frog is carnivorous, what digestive ferments are +probably present, and what ones absent from the alimentary canal? + +12. Fat bodies are largest in the fall, and are rarely found in the +spring. How can you account for this? + + 13. When through with the general study of the alimentary canal, + you may open the stomach by cutting it lengthwise. Describe the + character of the stomach lining as to folds and villi, stating + the advantage of each being present and the reason for the + direction of the folds. Tell how the food is propelled onward + through the alimentary canal. Give the scientific name for this + action. + + + _Suggested drawings._ + +a. The viscera (internal organs) undisturbed. + +b. The alimentary canal extended. + +c. The excretory system. + + +The Organs of Circulation and Respiration of the Frog + + + _Materials._ + +The materials used in this exercise are the same as those used in the +preceding exercise. + + + _Observations._ + +The pupil should identify the following structures:-- + +_Pericardium_, a membrane that surrounds the heart and, in the case +of the frog, separates the body cavity into two portions, the +_abdomen_ and the _pericardial_ chamber. + +_Heart_, lying between the shoulders and in front of the false +diaphragm. It is conical in form and composed of three chambers. + +_Ventricle_, the pink, conical, and muscular portion of the heart, +pointing backward and outward. + +_Auricles_, right and left. These are anterior and dorsal to the +ventricle, thin, membranous, and dark-colored. + +_Arterial trunk_, the single large blood vessel, usually empty of +blood, and white. Note its origin and trace it as far as possible, at +least until you see it divide to encircle the throat. + +_Sinus venosus_, a large membranous sac dorsal to the heart and +connected with the right auricle. + +_Lungs_, two small oblong, pink, spongy sacs, lying between and +behind the shoulders. + + The pupil may also identify the following structures if a + specimen is available which has the blood vessels injected. + + _Conus arteriosus_, or "arterial trunk," a large artery passing + obliquely forward from the ventricle, and dividing into three + branches on each side. + + _Carotid arteries_, the first branches of the conus, to the head + and neck. + + _Aortas_, the second branches of the conus, to the dorsal region. + + _Pulmocutaneous arteries_, the third branches of the conus, to + the lungs and skin. + + _Dorsal aorta_, the large artery along the back, formed by the + union of the two aortas. + + _Iliac_, or _femoral arteries_, the two posterior divisions of + the dorsal aorta, supplying the legs. + + _Posterior_ (ascending) _vena cava_, a large vein close to the + dorsal aorta, passing forward from the kidneys. + + _Hepatic veins_, large veins connecting the liver with the + posterior vena cava. + + _Anterior_ (descending) _venæ cavæ_, large veins formed by the + junction of the veins from the arm, neck, and head on the right + and left sides. + + _Subclavian veins_, from the arms. + + _Jugular veins_, from the neck. + + + _Questions._ + +1. Of how many chambers does the frog's heart consist? Name them, and +describe them as to size, color, and structure. + +2. Which chamber receives blood from the body, and which receives +blood from the lungs? + +3. Name the large arteries and give the regions which they supply. +Name the large veins and give the regions from which they come. + +4. Describe the lungs as to size, both when inflated and when +uninflated. Describe their color; entirety or subdivision; texture. + +5. In the inflated lung, notice the interior partitions or chambers, +which are called _vesicles_. How do they affect the amount of surface +exposed for gas exchange in breathing? + +6. Measuring the lung collapsed and again when inflated, calculate +its approximate volume in each case and state how much air it may +take in during an inspiration. + +7. Describe the diaphragm and state its probable use as a factor in +respiration or as a partition. + + + _Advanced questions._ + + 8. Apparently the pure and the impure blood must commingle upon + entering the single ventricle, but by a simple device this + scarcely occurs. How would such commingling affect the purity of + the blood as it reached the tissues, and hence affect waste + removal, oxidation, body temperature, activity, and intelligence? + + 9. What are the chambers of the fish's heart? of the mammalian + (human) heart? How may the heart of the frog be regarded as + intermediate between these others? How and where might the growth + of a partition within it bring about the higher structure? (This + actually occurs in certain reptiles.) + + 10. The lungs are said to be outgrowths of the alimentary canal. + Explain how their connection would tend to show this. + + + _Suggested drawings._ + +a. The heart and lungs in their normal position. + +b. The circulatory system, as seen in the injected specimen. + +c. A copy of the diagram or model of the circulatory system. + +d. A diagram of the respiratory tract from the nostrils to the lungs, +by arrows showing the course of the air. + + +The Nervous System of the Frog + + + _Materials._ + +Specimens which have the brain exposed and other specimens whose +viscera have been removed so that the spinal nerves can be seen; pans +or shallow dishes of water and forceps. + + + _Observations._ + +The nerve tissues are generally white in color unless they have been +specially treated and stained. The pupil should identify the +following structures:-- + +_A. Brain_, those enlargements of nerve tissue situated in the head +and composed of four principal parts, as follows:-- + +1. _Cerebral hemispheres_, a pair of elongated lobes, the anterior +enlargements. + +2. _Mid brain_, or _optic lobes_, a pair of large ovoid structures, +projecting diagonally forward and sidewise. + +3. _Cerebellum_, a slender, transverse ridge, close behind the +midbrain. + +4. _Medulla_, the anterior end of the spinal cord, widest in front +and containing a triangular depression. + + (Frequently a pair of smaller enlargements is to be seen in front + of the cerebral hemispheres; they are the _olfactory lobes_, and + from them nerves pass forward to the nasal chamber.) + +_B. Spinal cord_, extending along the spine, giving rise to nerves. + +_C. Spinal nerves_, ten pairs of nerves which are connected with the +cord through dorsal (sensory) and ventral (motor) roots, and which +penetrate the body and its appendages. The first enters the neck; the +second and third join and enter the arm; the fourth to sixth +penetrate the skin and muscles of the trunk; the seventh to ninth +join by a plexus to form the sciatic nerve which supplies the leg, +and the tenth enters the posterior portion of the body. + + + _Questions._ + +1. Which lobes of the brain are paired? Give at least two possible +causes or reasons for their double structure. + +2. The optic lobes are connected with the eyes. Compare their size +with that of the other parts. Of how much use do you think they are +to the frog? + +3. If folds or convolutions in the surface of the cerebrum indicate +intelligence, thoughtfulness, or mind, what do you infer as to the +frog's mental condition and power to think? + +4. Has the frog brain or "brains"? Explain. + +5. Name several things done by an animal's brain. + +6. Which of the spinal nerves are specially large? Why should they be +large? + +7. What advantages are there in the frog's having a dorsal nerve cord +instead of a ventral one, as the earthworm has? + + What would be the effect of cutting or breaking the dorsal root + of a spinal nerve? the ventral root? the entire spinal cord? How + do you explain the convulsions of the brainless (beheaded) + chicken or frog? + + 8. What kinds of impulses originate outside of the nerve center, + and what kinds in the center? + + 9. Sensations reach the cord and brain through the dorsal root of + the spinal nerve. What kinds of messages travel through the + ventral root, and in what direction do they go? + + + _Suggested drawings._ + +a. The brain. + +b. The spinal cord and its nerves. + +c. The nervous system. + +d. A diagram of the cord and its nerves, showing the kinds and the +directions of the nerve impulses. + + +The Endoskeleton of the Frog + + + _Materials._ + +Prepared frog skeletons mounted in glass-covered boxes or in other +cases suitable for individual study; other vertebrate skeletons for +reference. + + + _Observations._ + +The pupil should examine his specimen and identify the following +structures:-- + +_A. Skull:--_ + +1. _Cranium_, or brain case, the central and hinder portion. + +2. _Nasal bone_, a triangular bone lying in front of each large +opening, or _eye orbit_, and attached to the anterior end of the +cranium. + +3. _Premaxillaries_, a pair of small bones which form the tip of the +nose. + +4. _Maxillary_, a slender bone forming the side of the upper jaw. + +5. _Dentary_, the bone of the lower jaw, corresponding to the +maxillary. + +6. _Occipital foramen_, the posterior opening or entrance into the +cranium, normally covered dorsally by cartilage and most easily seen +in a separate skull. + +_B. Vertebral Column:--_ + +1. _Cervical vertebra_, the first vertebra, supporting the skull. + +2. _Dorso-lumbar vertebræ_, vertebræ with small lateral processes. + +3. _Sacrum_, the ninth vertebra, bearing extra long lateral processes +or "arms." + +4. _Urostyle_, the last vertebra, lying in the median line, a long, +slender, blade-like bone, really formed by the fusion of several +vertebræ. + +_C. Vertebra:--_ + +1. _Centrum_, the solid, nearly circular portion. + +2. _Lateral process_, one of the paired projections, extending +outward on either side. + +3. _Neural spine_, the single projection, extending toward the dorsal +side. + +4. _Neural arch_, formed largely by a connection between the lateral +process and the neural spine. The arch above and the centrum below +inclose the _neural canal_. + +_D. Pectoral, or Shoulder, Girdle:--_ + +1. _Sternum_, the "breastbone," extending along the median ventral +line. + +2. _Coracoid_, a heavy bone extending from the sternum sidewise to +support the arm. + +3. _Clavicle_, the "collar bone," a light bone in front of the +coracoid. + +4. _Scapula_, the "shoulder blade," a broad, thin bone which arches +around to the dorsal side. + +_E. Pelvic, or Hip, Girdle:--_ + +1. _Ilium_, a long, slender, curved bone, with its mate uniting to +form an inverted "wishbone"; it is joined to the sacrum. + +2. _Pelvis_, the region of the socket at the junction of the ilia. + +_F. Fore Leg, or Arm:--_ + +1. _Humerus_, the single bone of the upper arm. + +2. _Radius_, the bone of the lower arm on the thumb side; in the frog +united to the ulna. + +3. _Ulna_, the bone of the forearm opposite the radius. + +4. _Carpals_, small bones of the wrist. + +5. _Metacarpals_, a single series of long bones forming the palm of +the hand. + +6. _Phalanges_, the bones of the fingers and thumb (singular +phalanx). + +_G. Hind Leg:--_ + +1. _Femur_, the thigh bone, next to the body. + +2. _Tibia_, the larger bone of the lower leg on the inner side; in +the frog united to the fibula. + +3. _Fibula_, the smaller bone of the lower leg. + +4. _Tarsals_, the small bones of the instep. + +5. _Metatarsals_, the long bones of the instep. + +6. _Phalanges_, the bones of the toes. + + + _Questions._ + +1. Whereabouts in the frog has nature made an attempt to inclose +delicate or vital structures in bony cases? + +2. Examining the inside of the mouth, find the teeth. Judging from +their size and structure, of what use are these teeth? + +3. What advantages can you see in having the arms and legs attached +to girdles instead of having them fastened directly to the vertebral +column? How has their development affected the shape of the trunk, as +opposed to that of the fish? + +4. Make a comparison of the two girdles as to their attachment to the +spine and their consequent rigidity or freedom of movement. + +5. How many vertebræ are there in the spinal column? What advantage +can you see in having the column composed of many small vertebræ +instead of a few large ones? Enumerate those having a special form or +structure, and state the use of each. + +6. On the vertebræ notice any irregularities, prominences, or +roughenings. For what are such bones better adapted than smooth bones +would be? + +7. How is the frog's humping permitted? How are the urostyle and the +pelvis connected, if at all? Has this any effect on motion? (See +living frog.) + +8. In parallel columns, keeping corresponding parts in a line, +tabulate the bones of the fore and hind limbs. + +9. State how extra length has been attained in the hind leg, and give +the purpose or the result of this lengthening. + +10. In the forearm notice the fusing of the radius and ulna. How +would these parts act in rotating the hand, as compared with your +own, where they are free? Compare also the tibia and fibula. Where in +the frog's leg is turning made possible by the use of parallel bones? + +11. Compare the frog's hand and foot as to number of fingers and +toes; as to length and spread. Have any fingers or toes only two +phalanges? + +12. How would an inner skeleton affect the growth and the size of an +animal, as compared with an outer skeleton, like the clam's? + +13. How would the lack of an outer skeleton influence sensitiveness, +activity, and intelligence? + + + _Suggested drawings._ + +a. The skull and trunk, with appendages of one side. + +b. Each set of bones separately, as the skull, the column, etc. + + +Comparative Study of Amphibia + + + _Materials._ + +Various amphibia, either dead or alive, such as newts, mud puppies +(_necturus_), salamanders, and several species of frogs and toads, +especially tree toads. + + + _Observations._ + +Answer the following questions with respect to each animal:-- + +1. What regions of the body are present? What is the general shape +and size of the body? + +2. For what kind of locomotion are the limbs fitted? How? + +3. Have the hands and feet any special adaptations? If so, what are +they and for what purpose? + +4. With what organs does the animal breathe? If with gills, are they +external or internal? + +5. Judging from the specimen, what do you think is the habitat? Give +reason for your answer. + + +Summary from the Comparative Study of Amphibia + + +1. Which of the amphibia in this study are fish-like in character? +What are the fish-like characters? Do you think these fish-like +amphibia are of a lower or higher type than the others? Give reasons +for your answer. + +2. Show how the variation in (a) the form of the body, (b) color +patterns, and (c) the structure of the legs and arms of the amphibia +are related to habitat and mode of life. + + +Amphibia: A General Review and Library Exercise + + +1. The usefulness of the American toad. + +2. The breeding habits of the common frog; of the Surinam toad; of +the obstetrical toad; of the "smith." + +3. The development of the axolotl. + +4. The habits of the tree frogs and their variable coloration. + +5. The croaking of frogs and of toads. + +6. The flying frog of Ceylon. + +7. The distribution and habits of the hellbender; of the mud puppy; +of the Congo "snake." + +8. The general absence of the amphibia from arid regions. + +9. Frog farming for city markets. + +10. Protective devices of various amphibia. + +11. Toads and warts. + +12. The homing and water instincts of toads. + +13. Hibernation, seasonal or prolonged, of toads and frogs. + +14. The changes in the respiratory and circulatory system during +metamorphosis. + +15. Ontogeny and phylogeny, as illustrated by amphibia. + +16. The structural defects which would prevent an ambitious frog from +becoming a highly trained and skillful animal. + +17. The classification of amphibia, with examples. + +18. The kinds of frogs and toads found in the region where you live. + + +#C. STUDIES OF LIVING REPTILES# + +#Showing Diversity of Adaptation among closely related Animals# + + +The Snake + + +1. What is the shape? What regions are present? How do you +distinguish between the trunk and the tail? Has the tail any use? +What are the advantages of a body without limbs? + +2. Describe the snake's path in locomotion. How is locomotion +accomplished? Is the absence of limbs a hindrance to the animal in +its locomotory activity? + +3. Describe the appearance and movements of the tongue. Of what use +are these movements of the tongue? + +4. What evidence is there that the snake breathes with lungs? + +5. What sense organs do you find? Compare the ears and eyes with +those of the frog. What explains the peculiar staring appearance of +the eyes? + +6. What is the color scheme? Does it appear to be protective? If so, +how? + +7. Of what does the exoskeleton consist? How are the scales arranged? +What variations in the size of the scales do you find? What special +use have some of the scales? How fitted for this? How does a snake +moult? Appearance before and after moulting. + + +The Florida Lizard + + +1. Describe the body as to regions and shape. Is the tail of use? + +2. What are the lizard's locomotory abilities? How is it fitted for +living in trees? + +3. Feed the lizard flies or meal worms and describe its method of +capturing them. + +4. Compare the lizard's respiration and sense organs with those of +the snake and frog. + +5. What is the usual color of the lizard? What have you discovered +about its power to change colors? How may this be of use to it? + +6. Of what does the exoskeleton consist? Is the entire body covered? +How are the scales arranged? How does the lizard moult? + + +The Turtle + + +1. In what important ways does the body of the turtle differ from +those of the snake and lizard? + +2. What methods of locomotion has the turtle? For which method is it +best fitted? How? Why are its movements in water so much less clumsy +than on land? (Compare weight on land with weight in water.) Compare +the efficiency of the locomotion of a turtle with that of a lizard +and suggest a reason for the difference. + +3. What do turtles eat while in the laboratory? Since turtles have no +teeth, how can they bite off their food? + +4. What can you discover with respect to the respiration of the +turtle? Does it breathe when under water? + +5. What sense organs has a turtle? Which appears to be most highly +developed? How do you know? + +6. In what various ways is the turtle protected against enemies? (You +should state several.) Are you afraid of a turtle? If so, why? Why +does the turtle need more protection than the snake or lizard? + +7. Describe the color pattern of the turtle you are studying. Is this +arrangement of colors the same for others of the same species? + +8. Describe the arrangement of the epidermal plates of the turtle's +shell. Are the arrangement, number, and form of plates the same for +all turtles of this species? Compare with the plates of other +species. What variations do you find? + + +Reptiles: A General Review and Library Exercise + + +1. Characteristics of reptiles. + +2. Orders of reptiles. Characteristics and examples of each order. + +3. Poisonous snakes found in the United States. The poison fangs of a +rattlesnake. Habits of the rattlesnake. + +4. Cures for snake bites, fabled and real. + +5. Snake charming. + +6. Famous poisonous snakes and their habits. + +7. The characteristics and habits of alligators. + +8. The characteristics and habits of marine turtles. How they differ +from pond turtles. + +9. For what is each of the following noted? Where does it live? The +terrapins? the horned toad? the Gila monster? the chameleon? the +glass snake? + +10. Reptiles of former (geological) times compared with those of the +present. + +11. Care of eggs and young. Swallowing of young by snakes. + +12. Food of snakes. Defend the proposition that non-poisonous snakes +are beneficial and should not be killed wantonly. + +13. Investigate and write an account of the economic value of +reptiles. + + +#D. STUDIES OF BIRDS# + +#Vertebrates specialized for Flight# + + +The Living Pigeon + + + _Materials._ + +Living pigeons in cages, and, if practicable, other birds such as +chickens, canaries, and sparrows. + +_The Body._ + +1. What divisions of the body are present? Compare the relative size +of these divisions with that of other vertebrates studied. Can you +account for the great increase in bulk of the trunk over the other +divisions? How do you account for the longer neck? + +_Flight._ + +2. What is the shape of the body? How is the body made smooth? To +what is the shape and smoothness adapted? (Recall the appearance of a +plucked pigeon or chicken.) + +3. Observe the size of the wings by measuring their width and spread +(measured from tip to tip when outspread). Where on the body are they +attached? How is this point of attachment advantageous? What is the +shape of the upper surface of a wing when spread? of the lower +surface? How is this shape advantageous in flight? + +4. Where are the largest and strongest feathers? How are they +arranged with respect to each other: (a) to prevent air passing +through on the down stroke of the wing? (b) to permit folding? + +5. What is the shape and width of the tail when outspread? when +folded? In what way does the tail assist in flight? + +_Walking and Perching._ + +6. Identify the parts of the leg as in the frog. (See study of frog.) +With what exoskeletal structures is each part covered? How many toes +are there? Does the pigeon walk on its foot or on its toes? Where is +the ankle joint? + +7. The bird's legs are arranged to support the body. How is this +brought about? Compare with the lizard and frog in this respect. + +8. Explain how the legs are adapted (a) to preserve the balance of +the body, and (b) for perching. Are they well or poorly adapted for +locomotion? Explain. For what other purposes are the legs sometimes +used? + +_Feeding and Drinking._ + +9. What is the form and character of the jaws of the pigeon (called +the beak)? Offer food, and watch the pigeons eat. How does a pigeon +seize and swallow food? Does it chew the food? Locate the crop. If +the pigeon chewed its food, would it have a crop? Why? How does a +pigeon drink? How does the chicken drink? + +_Respiration._ + +10. What parts move in breathing? + +11. Compare roughly the body temperature (by touch) of man, the +pigeon, and the frog. Which has the highest temperature? which the +lowest? How can you account for the higher temperature of the bird? +(Which of the three must be able to endure long-sustained effort? +What is the effect on your own body of long-continued effort?) + +_Sense Organs._ + +12. Identify the eyes, ears, and nostrils, and describe their +location. What are the advantages in having the eardrum at the bottom +of a canal? Is there any disadvantage? What is the probable function +of the inner thin eyelid? How does it work? + +13. Investigate the power of response of the special senses. Which +seems to be the most alert? State the experiments which you used and +your reasons for your answers to this question. Which senses are most +serviceable in finding food? in protecting against enemies? + +_Protection._ + +14. In what different ways are feathers protective to the bird? Study +the arrangement of the feathers to find how protection is increased +in this way. How do the feathers and parts of feathers which lie next +the body differ from those which are on the outer surface? What parts +of the body are unprotected by feathers? How are these protected, if +at all? + +15. Note the flexibility of the neck. Through what part of the arc of +a circle can the pigeon turn its head? How is this especially +important to birds? + +16. What means of defense has the pigeon when attacked? + + + _Summary._ + +1. Make a list of the important adaptations of the pigeon, (a) to +flight, (b) to feeding, (c) to perching, and (d) to protection. + +2. Which is the most highly specialized, the fish, frog, snake, or +bird? Give reasons for your answers. + +3. In what various ways are feathers of use to the bird? + + + _Suggested drawings._ + +a. Side view of the head. + +b. A foot. + +c. A wing. + +d. Side view of the pigeon. + + +Supplementary Studies of the Pigeon + + +These topics and questions should be answered from experience with +pigeons and observations of their habits and behavior, and from books +to be obtained from the school and public libraries. + +1. The homing instinct of the common blue pigeon and of carrier +pigeons. + +2. Nesting habits, number of broods and number of young in each +brood, feeding the young. Why is this method of feeding the young +necessary? + +3. Varieties or breeds of pigeons. How the various varieties were +produced; how they are kept true; reversions of type. + +4. Darwin's experiments with the pigeons; object of the experiment. +Whitman's experiments. + + +The Exoskeleton of the Bird: Plumage + + + _Materials._ + +Living birds, as perhaps pigeons, or mounted or stuffed skins, +separate feathers, portions of feathers, microscopes. + + + _Observations._ + +The pupils should study the arrangement of the feathers and their +variations in form and size, and should identify the following +principal kinds:-- + +_Contour feathers_, those feathers, generally broad, which cover the +body, giving to it its outline and color. + +_Coverts_, those feathers which cover joints, such as the joints of +the wing and tail. + +_Primaries_ or _pinions_, the long stiff feathers of the outside of +the wing, used in sustaining the bird in flight. + +_Secondaries_, the shorter, more symmetrical feathers lying next and +over the primaries. + +_Down_, soft feathers found on young birds and next to the skin on +some adults. + +_Thread feathers_, best seen about the eyes, ears, and beak. + +_Quill_, the bare stiff portion, one end of which is inserted in the +skin. Examine its internal structure. + +_Vane_, the broad expanded portion, the part ordinarily seen on the +bird. + +_Shaft_, the mid-rib of the vane. + +_Barbs_, the delicate outgrowths of the shaft making up the vane. + +_Barbules_, the subdivisions of the barbs, some of which are provided +with hooklets. These may well be studied microscopically. + + + _Questions._ + +1. How is the plumage arranged to offer least resistance to the air +in flight? How does a bird sit when exposed to the wind? + +2. In a column write the names of the parts of a feather, and +opposite each part state its particular use. + +3. Of what use are the hooklets on the barbules? + +4. State and explain the peculiar position of the shaft of the +primary feather; of that of a contour feather. + + The plumage of many birds contains all stages of feather + specialization, from down to pinion. Find as many of them as you + can on your specimen. + +5. What reason can you assign for the fluffy base and the compact end +of the contour feather? + +6. How much of the feather of a full-grown bird seems to be supplied +with blood vessels? How does this bloodless or full-blooded condition +affect the weight of the feather; of the plumage; of the bird? + +7. How would the above condition affect the temperature of the blood +and of the body? Would it tend to cool the animal or to conserve its +heat? + +8. Show how the air lying motionless amongst the plumage may serve +the same purpose as that in the packing of a fireless cooker or a +"thermos bottle." + +9. How would the above condition affect the growth and repair of the +feather? What connection has it with moulting? + +10. What kind of feathers forms most birds' "baby clothes"? What kind +forms the adults' "underclothes"? + + + _Suggested drawings._ + +a. A typical feather. + +b. A feather of each kind. + +c. A bird with wings outspread, showing positions of feathers. + +d. The minute structure of a feather. + + +Birds and Migration + +_To illustrate Distribution_ + + +Work in the Laboratory + + + _Materials._ + +Bird skins or mounted birds, at least one representative of each +order and, better still, of each family of the birds which pass +through or remain in your neighborhood; specimens in a museum may +also be used. Some guide to the identification of birds, as Walter's +"Wild Birds in City Parks" or Reed's "Bird Guide." A good diagram of +a bird. + + + _Directions._ + +Your object here is to familiarize yourself with the appearance of +birds of different types, and with the terms used in describing them. +Study first a diagram of a bird and learn the terms and their +applications. + +An important item in the description of a bird is its length. This is +obtained by measuring from the tip of the beak, over the curve of the +head, to the end of the tail. This measures a curved line and gives a +greater length for a bird than the straight line you would naturally +estimate. Train your eye by watching house sparrows (so-called +English sparrows) and fixing their length as a unit. They are called +six inches long, and in the field other birds may be measured by +them. The robin is ten inches long, and may be used to measure the +larger birds. + +In describing the colors of birds, great discussions often arise +because pupils do not use terms correctly. Consult Chapman's "Birds +of Eastern North America" for a color key or chart, and train +yourself to observe colors carefully and name them correctly. You +will find more colors among birds than are given there, but the +chart will help you a great deal. + +Study in the laboratory as many birds as you can. Try to get one of +each order at least and, among the perching birds, one of each +family. The answers to the following questions should be recorded +upon the blank outlines of birds, or else in the form of a table. + + + _Questions._ + +1. How long is the bird? + +2. What is the general color of the upper surface; of the lower? + +3. What are the markings or peculiarities of the head, if there are +any? + +4. Note any peculiarities of the tail, as to shape, length, or color, +if there are any. + +5. If the wings are not like the back, note their color, and, if +there are wing bars, note their number and color. + +6. What are the markings on the breast, if there are any? + +7. Note any other markings, as rump spot, etc. + +8. What sort of beak has the bird? + +9. What sort of feet has it? + +10. Identify the bird, using any key or guide you have. Do not ask +any one to help you until you have exhausted your own resources. + + +Comparative Study of Birds + + +1. In what ways do the feet of birds vary? Give examples to +illustrate your answer. What are the principal results of these +variations? + +2. In what ways do the beaks of birds vary? Give examples of the +variations and of the special uses of the beaks. + +3. How do water birds differ from land birds; flesh-eating birds from +seed eaters; insect-eating birds from seed eaters; shore and swamp +birds from land birds? + + +Work in the Field + + + _Materials._ + +(1) Birds in the field, field or opera glasses, and bird guides. (2) +Some extra time, as field work is rather slow. (3) Considerable +energy, as birds rise early and may be up and away before the usual +hour for your appearance. + + + _Directions._ + +The object of this work is to become acquainted with the living bird, +to learn not only its name, but also some of its ways. You will need +to spend time to do this, and as a rule the more time you spend the +more you will see. Every time you go out after birds, _record at the +time_ every kind of bird you see, so that at the end of the season +you will know not only when each kind of bird came, but also how long +it staid. When you see a new bird, record immediately its colors, +markings, actions, notes, and anything else which may help you later +to identify it. Do not trust to memory nor to the inspiration of the +classroom. After weeks of observation, write the following summary. + + +Summary of the Results of Field Study of Birds + + +1. Over what length of time have your observations extended? Where +have you studied? What have you found to be the best conditions for +studying birds? How many birds have you identified? + +2. When in the year do birds migrate; when in the twenty-four hours? + +3. In spring migration which birds come first; which come last? What +reason is there for this order? + +4. What may retard migration? What may hasten it? + +5. What could prevent certain birds from ever coming here, or, if +they did come, from staying? + +6. Name some birds which stay here permanently; some which come only +for the winter; some which come for the summers; some which merely +pass through, going and coming. + +7. Can you see anything which may determine whether a bird will nest +here or farther north? If so, what is it? + +8. Why is the house sparrow so successful? + +9. Why are blue jays so nomadic in winter? + +10. What months do the herring gulls stay here? When do they leave? +Where do they go when they leave? What do they do while they are +gone? When do they return? What is their economic value? + +11. How many birds' nests have you seen this spring? To what kinds of +birds did they belong? If you have been able to study one in +particular, give its history as far as you know it. + +12. Tell what you have learned by your own observation this spring +concerning the kinds of food birds eat, and their methods of +obtaining food. + +13. What bird songs have you learned to know? When do these birds +sing most? Does a bird have more than one song? + +14. What birds have you seen near your home? What attached them to +the vicinity? How might you attract more birds? + + +Birds; Review and Library Exercise + + +1. What are the distinguishing characteristics of birds? + +2. Give the orders of birds, with the characteristics of each order +and an example of each. + +3. Define and give illustrations of the meaning of the expressions: +"land birds;" "water birds;" "shore birds;" "swamp birds;" +"scavengers;" "policemen of the air." + +4. Discuss the temperature of birds, the amount of energy they show, +and the oxygen they use. + +5. Beaks of birds. + +6. Feet of birds. + +7. The crop and gizzard. Why absent in many birds? + +8. What is there in a bird's construction which enables it to twist +its head so far around? What are the advantages in being able to do +so? + +9. Account for the oiliness of plumage of water birds; for the +complete feathering of legs and feet in some forms. + +10. Define moulting and discuss its advantages and disadvantages. + +11. Give reasons why you would not expect a bird to hibernate. + +12. Name two or more kinds of birds which show "recognition marks." +What sort of birds would you expect to find with such marks? Why? + +13. Is a bird's egg alive when it is laid? Why does it have so much +food stored in it? What direct interest have we in this fact? + +14. How are the eggs of various birds protected while they are +developing? + + _Note._--Do not be satisfied with only one way. A bird seldom is. + +15. Compare præcocial and altricial birds as to their stage of +development when hatched; the location and character of the nest; the +care given by the parents; the singing habit of the parents; the +success of the type. + +16. Name at least three insect-eating birds and tell how many insects +it is estimated each will destroy in a day. Effect in a garden? + +17. If you had an orchard to protect from insects would you spray it +with poison, or would you police it with birds? + + _Note._--Consider both sides. There is much to be said on each. + +If you decided that you needed more birds, how would you get them? + +18. Suppose you had a city lot in the suburbs, 50 feet wide by 200 +feet deep, with a house covering the first 50 feet. Make a plan of +the back yard to show what you could do to attract the birds to it in +the summer; in the winter. Remember that birds must have protection +against enemies as well as against changes in weather, etc. + +19. For what purposes are birds killed by man? Which of these do you +consider legitimate? Which birds may not legally be killed at any +time of the year in this state? Which may at certain seasons? Which +may at any time? When should an "open season" be permitted? How long +should it last? + +20. Give a short biography of Audubon. Describe the purpose of the +Audubon Society and some of the work accomplished by it. + +21. When were the house sparrows, or, as we call them, the English +sparrows, introduced into this country? Where? Why? Have they proved +a success from our standpoint? From their own? Why have they +increased so enormously? What part of the country is still free from +them? Why? Give the reasons for and the methods of fighting English +sparrows. + +22. The history of the passenger pigeon. + +23. What has the quail or bobwhite to do with our food supply? + +24. Poultry keeping. + +25. Name three bird magazines and give a characteristic of each one. + +26. Fossil birds and the light they shed on the probable ancestry of +birds. + + +Study of the Migration of Animals in General + + +The migration of birds is only one case of a phenomenon which is +comparatively common. From your text and reference books find other +examples of migration. What are the causes which make animals +migrate? What methods do various animals use? What are some results +of these migrations? Summarize your study in the following thesis:-- + + + _The distribution of animals._ + +1. The necessity for this distribution. + +2. Methods of distribution--voluntary--involuntary. + + _Note._--See in review the methods used to spread corals, + hydroids, and other sedentary forms, starfish, clams, etc., as + well as those used by the various vertebrates. + +3. Time when migration occurs. Consider here the young of most +animals, and the movements of many birds, as well as movements caused +by some accidental occurrence. + +4. Distance that animals move from the place of their birth. + +5. Factors which determine the routes of distribution. + +6. Factors which limit distribution. + + + _Migration maps._ + +1. A map to show the migration route of the birds of your region. + +2. A map to show the migration of the potato beetle (or English +sparrow or any other animal the extension of whose range has been +studied). + +3. A map of the world, showing the zonal areas. + +4. A map of North America, showing the distribution of the ungulates, +with the boundaries and barriers marked. + +5. A map of North America, showing the distribution of the +fur-bearing animals. + +6. A map of the world, showing the distribution of the human races. + + +#E. STUDIES OF MAMMALS# + +#To illustrate Man's Relation to Other Animals; the Connection +between Mode of Life and Structure# + + +The Rabbit + +_The effects of domestication upon an animal. A burrowing type of +rodent._ + + + _Materials._ + +Living rabbits--young rabbits are more desirable for laboratory +study. + + + _Observations._ + +_The Body._ + +1. What divisions of the body are there? Compare the length and use +of the neck with that of the pigeon. Describe the character and +length of the tail. What use has it, if any? + +_Locomotion._ + +2. What methods of locomotion has the rabbit? Which is most commonly +used? + +3. Study the limbs, and find the ankle and wrist. Does the rabbit +walk on its foot or its toes? Note the number and character of the +toes and fingers and their claws. What is the effect of the +nonretractile power of the claws upon the uses to which claws can be +put? + +4. What uses have the fore or the hind limbs other than locomotion? +Explain how the usual sitting or resting posture is advantageous for +quick locomotion. + +5. By means of printer's or writing ink smeared over the soles of the +feet, and a long piece of clean white paper get prints of a rabbit's +tracks as it hops over the paper. Explain how the peculiar formation +of the tracks occurs. + +_Feeding._ + +6. Offer a rabbit various kinds of food. How does it test the food +before eating? Does the rabbit ever use its forelimbs to assist in +feeding? If so, when and how? How is the food eaten? How are the +teeth fitted for the rabbit's method of feeding? Does your rabbit +drink? If so, how? + +_Respiration._ + +7. What movements of the body are concerned in breathing? + +8. Compare the frequency of the breathing movements with your own. +Can you distinguish the heart beats? If so, how and where? Count +them. + +_Sense Organs._ + +9. Note the position of the eyes, shape of their surface, shape and +size of the pupil. What external protecting structures are +present,--such as eyelids, eyelashes, eyebrows? Study the movements +of the eyelids. Is there a third eyelid as in the bird? Compare the +use of the neck in enlarging the range of vision with that of the +bird. Is the rabbit's range of vision greater or less than your own? + +10. What is the location of the nostrils? What advantages are gained +by the prolongation of the face forward? Note any peculiarity in the +form or movement of the nostrils. How do you explain these movements? +Are the nostrils more or less useful than those of other vertebrates +you have studied? How? + +11. Note the shape, size, and position of the external ears and +explain what relation, if any, these characters of the ears have to +hearing. Note the various movements of the ears and the reasons for +these movements. + +12. What special organs for touch has the rabbit? Under what +circumstances are these of use? What parts of the body are most +sensitive to touch? + +_Protection._ + +13. What home-making habits do you observe in the rabbit? What habits +relating to secrecy, comfort, and safety, do you observe? + +14. Study the fur and hair of the rabbit. How do you distinguish +between fur and hair? What variations do you find in the fur and +hair? What parts of the body are uncovered? Why? What are the various +functions of the fur and hair covering of rabbit? + +15. Have rabbits any means of defense or offense? Explain. + +_Social Habits._ + +16. Notice and describe anything in the behavior of the rabbits which +may be classed as social,--such as play, fondness for company, +display of affection, homing instincts, care of young, etc. + + +Supplementary Study of Wild Rabbits + + +If you cannot answer these questions from observations of wild +rabbits, the answers may be obtained by reading some good natural +history. Ernest Thompson Seton's story of a rabbit's life is good for +the purpose. + +1. What method of locomotion is more highly developed in wild rabbits +than in domestic rabbits? Why? + +2. When do wild rabbits do their feeding? Why? In what ways do they +sometimes do damage in feeding? + +3. What senses will probably be more alert than those of the domestic +rabbit? Why? + +4. Where do wild rabbits usually make their homes? Why? How do they +guard against being cornered in their homes? + +5. In what ways do they guard against surprise when feeding? What are +the principal enemies of rabbits? What devices do they employ to +escape enemies when pursued by them? What is thumping? When used? + +6. How many young rabbits are usually produced at one time? How many +litters in a season? How long does it take a young rabbit to mature? + +7. How are the young of rabbits guarded against danger from enemies +and weather? What are the various causes that tend to keep down the +numbers of rabbits? + +8. Give an account of the plagues of rabbits in Colorado and +Australia, including the reasons for the great increase in numbers +and the methods used to destroy the rabbits. + + +Summary of the Study of Rabbits + + +1. What has been the general effect of domestication upon rabbits? + +2. What are the most important characters and habits that fit the +wild rabbit for its life? + + +The Guinea Pig or White Rat + + + _Materials._ + +Living animals. + + + _Observations._ + +1. What regions of the body can you identify? What is the relative +length of the neck, ears, legs? What about the tail? + +2. Describe the color scheme of the animal. Is it protective or the +result of breeding? What is the character of the covering? + +3. Describe the method and rate of locomotion. Would this method of +locomotion enable the animal to escape from enemies (_e.g._ dogs)? + +4. What is the shape of the foot? What is the shape and length of the +claws? For what are they adapted? + +5. What sounds do the animals make? + +6. What is the appearance and shape of the eye? What is the color of +the eye? + +7. State the size and shape of the external ear. What movements are +characteristic? + +8. What motions of the nostrils do you see? + +9. Feed the animal various kinds of food. How does it eat? State any +facts you observed, to show that it has or has not a choice as to +food. + +10. Watch the animal for some time to determine its mental +characteristics. Is it alert? curious? timid? Does it show much +intelligence? affection? + + What is the relation between mental development and success in + the struggle for existence? + + + _Summary._ + +1. What are the general characteristics of the animal? + +2. To what kind of life is it adapted? + +3. What are some of the characteristics that make the animal a good +pet? + + +The Squirrel + + + _Materials._ + +Living specimens in cages, mounted specimens, pictures, charts, +lantern slides, etc. + + + _Directions._ + +Before taking up the study of the squirrel in the laboratory a trip +should be made to some park or wooded region and the habits of +squirrels noted. Take your camera and try to take some snapshots. +After the laboratory exercise visit some museum or zoölogical garden +and study the relatives of the squirrel. + + + _Observations based upon field work._ + +1. What different postures does the squirrel assume? + +2. What does it do when frightened? + +3. What use have the forelegs other than locomotion? + +4. How does a squirrel go up a tree? down? from branch to branch? +State all the forms of locomotion you have noticed. + +5. What is the appearance of the tail? What is the position of the +tail when the squirrel is sitting? running? on a branch? Describe any +motions of the tail you noticed. Is there anything expressed by these +motions or are they without meaning? + +6. Tempt the squirrel with some nuts. State the evidence that leads +you to think that the squirrel is alert, timid, curious. Do you +think the squirrel acts most from instinct or as the result of +intelligence? + +7. In what various ways does a squirrel attempt to escape notice? +What does it do when you chase it? + + + _Observations in the laboratory._ + +1. What divisions are there to the body? What is the length of the +neck? the length and appearance of the tail? + +2. What is the relative length of the legs as compared with the body? +How does the length of the front and hind legs compare? + +3. Does the animal walk on its toes or on the sole of its foot? How +many toes on each foot? What is the length of the claws? For what +could they be used? + +4. Offer the squirrel various kinds of food and see if it has a +choice. Describe its methods of eating. + +5. Note the position of the eyes, the shape of their surface, and the +shape and size of the pupil. How many eyelids do you notice? Why do +the squirrel's eyes appear so "bright"? Are eyebrows, eyelashes, or +tear glands present? + +6. Note the size, shape, and appearance of the squirrel's external +ears. + +7. What movements of the nostrils do you notice? For what does a +squirrel chiefly use his nostrils? What explanation can you suggest +for the nostrils, eyes, and ears having the same relative position in +all vertebrates? + +8. How does a squirrel protect itself? + + 9. Smear the feet of a squirrel with ink and allow it to run over + a roll of clean paper as in the case of the rabbit. How do its + tracks differ from those of the rabbit? + + + _Summary._ + +1. What are the general characteristics of the squirrel? + +2. To what kind of life is it adapted? + +3. What adaptations has the squirrel to protect it from its enemies? + +4. What characteristics make the squirrel a good pet? What objections +to it? + + +Library Exercise on Rodents + + +1. General characteristics and examples of rodents. The teeth of +rodents. + +2. Show how variation in habitat depends upon structure among rodents +by comparing, for example, squirrels, beavers, and woodchucks. + +3. Variations in the tails of rodents. What are the causes of this +variation? + +4. Pocket gophers and their economic relations. + +5. Species of mice. Their habits. + +6. The dancing mouse. + +7. Damage by mice. Plagues of field mice in Nevada. Method of +extermination. + +8. Habits and kinds of rats. + +9. Economic importance of rats. Methods of extermination. + +10. Rats and the bubonic plague. + +11. Squirrels, kinds and habits. + +12. The economic value of rabbits. + +13. The groundhog myth. Habits of woodchucks. + +14. The beaver--their habits and sagacity. Methods of trapping them. + +15. Prairie dogs--their habits and economic importance. How +exterminated? + +16. What are porcupines? + +17. Variation in the homes among rodents. Usual means of defense. + +18. Make a list of rodents in a column, and in another column +opposite each name write the various ways the animal is of economic +importance. Sum up with a statement showing the most important ways +rodents are of value to man and harmful to man. + +19. Defend the proposition that rodents are on the whole harmful +animals and should be exterminated. + +20. How some rodents contribute to the science of medicine, more +especially to bacteriology. + + +The Cat or Dog--Carnivora + + + _Materials._ + +Living specimens of cats or dogs. Pictures, books, lantern slides, +etc. Supplement the laboratory study with trips to museums and +zoölogical gardens to observe the relatives of the cat. + + + _Definitions._ + +_Carnivora._ An order of mammals, chiefly flesh-eating, with claws +and well-developed canine teeth. + +_Carnivorous_, flesh-eating. + +_Herbivorous_, plant-eating. + +_Omnivorous_, eating both plants and animal food. + +_Digitigrade_, walking on the toes. + +_Plantigrade_, walking on the soles of the feet. + +_Vibrissæ_, long hairs on the face--"whiskers." + + + _Observations._ + +1. Into what regions is the body divided? + +2. What is the shape of the head and the length of the neck? + +3. Are the legs relatively long or short? How do the front and hind +legs compare in length? How many toes on each foot? Is the cat +digitigrade or plantigrade? + +4. How many pads on the sole of the foot? What use can you suggest +for these structures? What is the size and shape of the claws? Are +they retractile or nonretractile? For what purposes may the claws be +used? + +5. Describe the tail as to length and appearance. Movements. + +6. What is the size and appearance of the external ears? What +movement do you notice? + +7. Are the eyes large or small? What eyelids can you find? What other +accessory structures? What is the shape and direction of the pupil? + +8. What other sensory structures do you find? What is their function? + +9. Watch the animal eat. Does it chew or "fletcherize" its food? +What teeth seem well developed? Is the movement of the jaws simply up +and down, or is there a lateral movement as well? + +10. Try to find out some of the mental characteristics of the animal, +_i.e._ is it sluggish or active? Is it alert? Does it show curiosity? +fear? What evidence of intelligence? + + + _Supplementary studies._ + +a. Smear the feet of a cat with ink and allow it to run on a sheet of +clean paper. Make a diagram to show tracks. Do the same in case of a +dog. How do these tracks differ? Why? + +b. What is the difference between a cat and a dog as to the manner of +eating a bone? + +c. As you see dogs and cats outside do you see any evidence in either +case of a tendency to gather in packs (gregariousness)? + +d. What different emotions are expressed by a dog's tail? a cat's +tail? + +e. What sounds do cats and dogs make? Significance? + +f. Contrast the sleeping habits of cats and dogs. + +g. How large is the litter in case of dogs and cats? Condition of +young at birth? How long before the eyes of the young are open? Care +of young. + + + _Summary._ + +To what kind of life does a cat or dog seem best adapted: (a) as to +food? (b) protection from enemies? + + +Carnivora; Review and Library Exercise + + + _Characteristics._ + +1. The general characters of carnivora. + +2. Five important families. The characteristics and examples of each +family. + + + _Morphology and physiology._ + +3. The dentition of the cat, the dog, and the bear. Variation in the +"chewing teeth." + +4. Three types of paired appendages among carnivora. Relation to +habitat. + +5. The difference in structure and use of the posterior legs of the +seal and walrus. + +6. The alimentary canal of a cat and rabbit compared. + +7. The tongue of cats and dogs contrasted as to structure and use. + + + _Economics._ + +8. The difference between hair and fur. + +9. The fur-bearing carnivora. Families, and habitat. + +10. Trapping. + +11. Game laws and game wardens. Hunters' licenses. + +12. Hunting big game. + +13. Carnivora harmful to man. + +14. Carnivora useful to man. + +15. Carnivora as pets. + +16. Chief types or breeds of domesticated dogs. Characteristics. +Special value of each. + +17. Chief types or breeds of domesticated cats. + +18. Dogs as burden bearers. + + + _Natural History._ + +19. Distribution and range of carnivora. Carnivora of the United +States. + +20. Winter habits among carnivora. + +21. Food of carnivora. Various methods of obtaining it. + +22. The hunting habits of the dog and cat family. + +23. The habits and distribution of the raccoons. + +24. The color schemes of the more important families of the +carnivora. + +25. Seasonal variation in color. + +26. Distribution and habits of the ferrets and weasels. + +27. How carnivora protect themselves from enemies. Which carnivora +have been most successful in resisting man's advance? + +28. Peculiar and interesting carnivora to be seen in museums and +zoölogical gardens. + +29. Origin of the domestic dog. + +30. Intelligence of dogs. + +31. Fox-hunting. + +32. Coyotes and their relation to stock raising, etc. + + +The Ungulates + + + _Materials._ + +Pictures, charts, lantern slides, and books showing cow, sheep, hog, +goat, horse, etc. Diagram of skeleton. + + + _Directions._ + +Since it is impossible to have living ungulates in the laboratory, +this study should be supplemented by trips to a museum and to a +zoölogical garden. Observe also such hoofed animals as may be common +in your neighborhood. Use your camera and make "snapshots," showing +characteristic attitudes of these animals. + + + _Definitions._ + +_Ungulates_, an order of mammals characterized by the possession of +hoofs. + +_Ruminant_, a division of ungulates, which "chew the cud." + +_Perissodactyl_, a division of ungulates with an odd number of toes. + +_Artiodactyl_, a division of ungulates with an even number of toes. + +_Carnivorous_, flesh-eating. + +_Herbivorous_, plant-eating. + +_Omnivorous_, eating both plant and animal food. + + + _Observations in the laboratory._ + + _Note._--Answer the following questions for one or more of the + following: The cow, sheep, goat, hog, and horse. If desired, the + questions may be answered in the form of a table. + +1. What is the relative length of the neck? What is its direction +with reference to the body? Of what importance is this length and +direction? + +2. What is the length and appearance of the tail? What is its use? + +3. What is the relative length of the legs? Locate the heel, knee, +and elbow. (Reference should be made to a diagram of a skeleton.) +When the leg is long, in which bone is this lengthening accomplished +(compared with human skeleton)? + +4. How many toes on each foot? Is the animal an artiodactyl or a +perissodactyl? Is it plantigrade or digitigrade? + +5. What is the relative size and position of the ears (external ear)? + +6. What is the relative size and position of the eyes? nostrils? + +7. Are horns of any kind present? If so, note the size, shape, and +direction. Are they present in both sexes? If not, in which one? If +in both, note any differences distinguishing the sexes. + + + _Suggested drawings._ + +a. Head, side view. + +b. Entire animal, side view. + + + _Observations in the field or at home._ + +1. Note how the animal uses its lips, tongue, and teeth in feeding. +Is it a ruminant? + +2. In what order does the animal use its feet? Look up the definition +of _walk_, _run_, _gallop_, _canter_, _trot_, _lope_, _single foot_, +_pace_. Which of these forms of locomotion are optional with the +animal? + +3. Describe the process when the animal lies down and gets up. + +4. Describe the covering of the animal, noting its length, fineness, +etc. What variations in different regions of the body? + +5. Is the animal alert or sluggish? Upon what senses does it most +depend? What mental characteristics are most marked, _e.g._ +curiosity, fear, suspicion. + +6. Note any movements of the ear. What is gained by these movements? + +7. What is the position of the eye? What is the shape and direction +of the pupil? Reason? + +8. What means has the animal for getting away from its enemies. + + + _Observations based upon museum trip or natural history._ + +1. Identify as many ungulates as you can; for example, buffalo, musk +ox, big-horn sheep, Rocky Mountain goat, chamois, antelope, giraffe, +red deer, elk, moose, reindeer, wild boar, peccary, rhinoceros, +zebra, hippopotamus. + +2. Answer the following questions about each:-- + +a. What is the family, scientific name? + +b. What is the size of the animal? the relative length of the hind +and fore legs? the relative length of the neck? + +c. What is the nature of the covering of the animal? + +d. Are any horns developed? If present, what is their size, shape, +direction, and appearance? + +e. What is the habitat of the animal? its distribution and social +life? + + + _Summary._ + +In a short thesis summarize the facts you have found out about +ungulates, using the following outline:-- + +1. Why called ungulates? Variation in number of toes. + +2. General fact about the food of ungulates. The two divisions. + +3. The general adaptations for protection. + +4. The social life of the ungulates. + +5. The native ungulates of the United States. + +6. Commercial uses and value. + + +Ungulates: Review and Library Exercise + + + _Characteristics._ + +1. Classification of ungulates based upon number of toes, kind of +horns, "chewing the cud," etc. Some of the more important families +with examples. + + + _Morphology and physiology._ + +2. The variation in the number and kinds of teeth. The dentition (or +dental formula) of horse and cow. + +3. The various types of horns. Shedding of horns and sexual +variation. + +4. The structure and function of the stomach of a ruminant. Meaning +of the cud-chewing habit. + +5. The structure of the stomach of a camel. + + + _Economics._ + +6. Ungulates which have been domesticated. + +7. Breeds of cattle--their distinguishing marks and valuable points. + +8. Breeds of horses--their distinguishing marks and valuable points. + +9. Breeds of sheep--their distinguishing marks and valuable points. + +10. Breeds of hogs--their distinguishing marks and valuable points. + +11. Angora goats. + +12. The making of butter and cheese. Kinds of cheese. Substitutes for +butter. + +13. The packing industry. Ungulates useful as food. + +14. The various methods of preserving meat. + +15. Cattle ranches and "round-ups." Free cattle in winter. + +16. Cattle raising in your state; in other countries. + +17. Transportation of cattle. Stock cars, care and feeding. + +18. Useful products derived from ungulates. + +19. Tanning. Varieties and use of leather. + +20. Diagrams showing chief cuts of meats. + +21. Sheep husbandry. Shearing. + +22. Ungulates as beasts of burden. Advantages and disadvantages. + +23. Government inspection--quarantine. + + + _Natural History._ + +24. Geographical distribution of ungulates. Habitat and range. + +25. Native ungulates of North America. + +26. How, when, and by whom cattle and horses were introduced into +America. + +27. The geological history of the horse. + +28. The story of the buffalo. + +29. Deer hunting. + +30. Methods of protection from enemies among ungulates. + +31. Breeding habits and care of young in case of ungulates. + +32. Intelligence in the case of horses. + +33. Strange and peculiar ungulates to be seen in museums and +zoölogical gardens. + + +The Horse + + +The pupil is expected to study carefully the account of Eohippus or +Hyracotherium in his text or any other available reference book, and +to supplement that work and this brief sketch with original +observations upon horses on the street, at a local store, or wherever +possible or convenient. + +From the early horses which migrated from North America there arose +in Asia and Africa the ass, famous in the history of early +civilization and still used in some localities as beasts of burden or +for the breeding of mules, which are the crosses between ass and +horse. There also arose the zebra and the most primitive of modern +horses, Przewalskii's horse, a wild pony of western China, about +forty inches high and almost identical with the drawings of the horse +made by early man, 30,000 years ago. Doubtless the modern ponies of +Ireland, Iceland, and Shetland are descendants of the original +Przewalskii type and not, as is often claimed, true horses stunted by +rigors of climate and scant fare. + +The horse is characterized largely by the presence of a lock of hair +between the ears, a full mane and tail, small ears, large hoofs, and +peculiar neigh. The ass has no forelock, a scanty mane and tail, long +ears, small hoofs, and a distinct bray. + +By means of various crusades and raids, the modern horse was +introduced into Europe from Asia, where it is clearly traced in +history to the reign of King Solomon. Here, in Europe, because of +local conditions and demands, it assumed differing type forms. The +roadster type is closest to the Arabian in character. The draft or +heavy type was bred in western Europe when heavy armor came into use +for rider and horse, and the coach or carriage type was developed +when armor was abandoned for gunpowder. Finally explorers and +colonists brought the horse back to America, its original home. + +The various types and varieties may be briefly described. + +_A._ The draft type has short legs, short neck, large round body, and +ranges in weight from 1400 pounds to 2000 pounds. + +_Varieties:--_ + +1. _Percheron_: generally about 1700 pounds in weight, 16 hands (64 +inches) high, gray or black, blocky body, steep rump, clean legs, and +quick action. + +2. _Shire_: generally about 1800 pounds in weight, 17 hands high, bay +or brown, white marked feet and face, hairy legs and feet, and slow +action. + +3. _Belgian_: generally about 1800 pounds in weight, 16 hands high, +chestnut or roan in color, compact body, short, steep rump, and small +feet. + +_B._ The coach or carriage type has legs and neck of medium length, a +body full-chested but not blocky, and a weight varying from 1150 +pounds to 1400 pounds. + +_Varieties:--_ + +1. _Hackney_: generally of full, broad, powerful body, short legs and +back, high action and high carriage of neck and head, bay or chestnut +in color, 15 hands high, and 1400 pounds in weight. + +2. _Coach_: generally lighter than the Hackney, with longer legs and +long stride; height, 16 hands; weight, 1300 pounds. + +3. _Cleveland bay_: averaging 16½ hands in height, 1350 pounds in +weight, high, broad hips, strong action, and bay color. + +_C._ The roadster type is long and lean of limb and body, and +averages about 1100 pounds in weight. + +_Varieties:--_ + +1. _Thoroughbred_: of small head, long neck, level back, of variable +color, 14½-16½ hands high, about 1000 pounds in weight. + +2. _American saddle_: an American production; not a distinct breed, +but a roadster of high quality. + +3. _American trotter_: a superior type of good speed. The off +forefoot and the nigh hind foot act together, the nigh fore and the +off hind feet together, giving a two-beat gait. + +4. _Pacer_: similar to the trotter, but using both off feet and both +nigh feet together, giving a swinging gait. + +The horse is very similar to man in its physical and mental +character, being subject to the same ailments and treatment and +having the same impulses of affection, hatred, fear, jealousy, +obedience, willfulness, memory, and perhaps reason. It is of all +animals most careful in its eating and drinking; because its stomach +is small, the food should not be bulky but concentrated, grain +forming a goodly portion of the ration. + +Perhaps the most important point in the structure of the horse is the +form of the leg and foot. The shoulder should slope slightly backward +and the pastern joint, immediately above the hoof, slightly backward. +The hips, or "quarters," should slope downward somewhat, and the +hock should be comparatively wide to afford ample leverage for the +pulling muscles. The legs should be straight as pillars when seen +from front or rear. The outer walls of the hoof support most of the +weight though the frog should normally touch the ground. In nature +the hoof wears away properly of itself, but the shod hoof needs +regular trimming attention, while the frog must not be trimmed, for +it is the soft growing part that nourishes the hoof. In this +treatment the foot is comparable with the human finger and finger +nail. + + + _Observations._ + +If access to a living animal is impossible or inconvenient, the pupil +may use reference book or pictures for most of these points. A +measuring tape or ruler should be at hand, and the assistance of an +experienced person is a valuable aid. If several horses are studied, +they should be distinguished by name or number. + +Record the color, condition, weight, and height of the horse at the +shoulder. (Height is given in "hands," a hand being the breadth of +the palm, or 4 inches.) Note the slope of the shoulder, of the back +and the hips, the general form of the head and neck, and the facial +expression. Find the chestnuts, warty growths on the inside of each +leg. Examine the foot, finding the V-shaped frog in the center, +surrounded by the horny hoof. + +Find the pulse by passing the fingers downward from the upper curve +of the neck, along the inside of the jaw; count the pulse. Notice the +position and motion of the ears with their lining of hair, and the +position of the eyes, the form of the pupil, and the probable range +of vision. Watch the horse use its lips, and examine the mouth and +teeth, finding the grinding teeth far back in the mouth, the incisors +in front, and the space where the canines are missing. + + The male may have canines in the upper jaw. + +On the surfaces of the incisors are the depressions, or "cups," by +means of which age is determined. + + At six years the cups leave the lower center teeth; at seven the + adjoining teeth; and at eight, the outer lower teeth. At nine + years they leave the upper center incisors; at ten, the adjoining + teeth; and at eleven, the outer teeth above. At the age of ten + years a spot appears in the outer upper incisors, at fifteen + years the groove has worn to the center of the tooth, and at + twenty-one years the groove is worn to the bottom of the tooth. + + + _Questions._ + +1. Describe the horse you studied as to its name or number, its +color, markings, weight, and size. Of what type and breed is it a +specimen? + +2. Upon how much of the foot does the horse walk? How does this +affect ease or speed of action? How does an athlete imitate this in +sprinting? + +3. How many toes has each foot? What advantage or disadvantage can +you see in this unusual structure? + +4. How is the hoof constructed to distribute the weight over a +surface broader than the leg? How general is this among terrestrial +animals? + +5. What is the difference in the position of the chestnuts of the +fore and hind legs? + +6. Where in the foreleg is a springiness permitted by curvature? +Where does the back leg accomplish the same thing? + +7. How do you account for the elongating of the face? + +8. Explain the uses of the lips, telling how they are fitted for +their work. + +9. Tell where the bit lies in the horse's mouth, and how the +structure permits this. + +10. Where are the ears situated? How does this peculiar position +affect the range of hearing and general alertness? Of how much +movement are they capable? Describe the lining of the ear, and state +its use. + +11. What is the rate of the pulse? + +12. Measure the height at shoulder and at croup, length of body from +withers to rump, of head, of neck; thickness of body from the +shoulder to the chest and of distance of chest from ground. Point out +any equalities or ratios you find. + + + _Topics for investigation._ + +1. The meaning of the terms _gee_, _haw_, _nigh_, _off_, _run_, +_gallop_, _trot_, _pace_, _single foot_, _rack_. + +2. The location, cause, and effect of these troubles: heaves, blind +staggers, knee sprung, shoe boil, quitter, ring bone, spavin, capped +hock, flat foot, hoof bound, glanders, mange, sweeny, hide bound, and +thrush. + +3. The record time for a trotted and a paced mile. + +4. The meaning of "one horse power." How much a horse can pull on +good roads. + +5. Record prices for valuable horses. + +6. Current prices for horses; for ponies; for mules. + +7. The origin and the use of the mule. + +8. Balanced rations. + +9. The number and care of the young, and their relative development +at birth. + +10. Other animals used as beasts of burden in peculiar conditions or +localities. + + +Homology of the Vertebrate Skeleton + + + _Materials._ + +Prepared skeletons of an amphibian, a reptile, a bird, another +mammal, and man. If any of these be lacking, lantern-slide +illustrations may be used in a partially darkened room. + + + _Observations._ + +Having studied the frog's skeleton in detail, the student can readily +compare each of these types with it. Compare in a very general way +the skulls, the girdles, and the limbs; their form and use. Note +variations in the form and number of the vertebræ and the number of +the ribs. + + + _Questions._ + +1. In which types of vertebrates are the joints between the skull +bones bound with cartilage? How does the joining change in later +types? + +2. What dissimilarities occur in the series as regards closure or +boxing in of the eye orbits, nostrils, and skull bones? How would +these changes in joining and closure affect strength, rigidity, and +protection? + +3. What evidence is there that such improvement has affected brain +capacity and intelligence? + +4. State how the attachment of the skull to the vertebral column +changes as the animal man assumes an erect position. + +5. Are the vertebræ of these types alike in structure? What is the +general form of an horizontally placed vertebra, as in the horse or a +reptile, and of a vertically placed one, as in man? If you see any +differences, account for them. + +6. Wherever possible, find the vertebræ of the neck (cervical), and +note the number of them in each case. + +7. How is flexibility of the column accomplished in certain types or +in certain places of one type? How is rigidity gained? State +instances in each answer. + +8. Examining the interior of the turtle's "shell," find out and +explain how the vertebræ have been modified to form the upper +"shell." How has the under portion (_plastron_) been formed? + +9. In round numbers, which skeleton has the greatest number of +vertebræ and which the least? + +10. Which skeleton has the greatest number of ribs, and which has the +least? + +11. In a summarizing statement explain any variations you find in the +pectoral and pelvic girdle for strength (rigidity); flexibility. This +answer may be written as a table, naming the bones, opposite each +stating its condition, and then what it affords or is adapted to. + +12. What is accomplished by having two bones in the shank of the leg? +In what types or forms is there but one, and which one is it? + +13. Can you assign any advantages in power, agility, length of leg, +or position of leg and foot accruing from a long ankle? (See horse, +frog, _et al._) + +14. Enumerate the types or forms, and opposite each state the number +of fingers and toes. + +15. Make a table, heading one column "Form or type"; another, +"Habitat"; and a third, "Habit." Judging from the structure which you +see or from your previous knowledge or experience, fill in the table, +stating whether the type is aquatic, terrestrial, or aërial; whether +it burrows, walks, runs, or climbs, etc. + +16. From your statements in 15, explain how the peculiar mode of life +affects the structure of these types. + + + + +CHAPTER VII + +ADAPTATIONS FOR THE PRESERVATION OF THE SPECIES + + +#A. METHODS OF REPRODUCTION# + + +1. The Simple or Asexual Method of Reproduction + + + _Materials._ + +Slides or diagrams, showing a dividing amœba, a dividing paramecium, +a dividing vorticella, reproduction in some form of sporozoa, budding +hydra, gemmules of spongilla, and some species of worm as Dero or +Nereis in the process of dividing. + + + _Definitions._ + +_Spore_, a cell capable of developing into a new organism. + +_Asexual reproduction_, reproduction by division of the cell or body. + +_Sexual reproduction_, reproduction by means of the conjugation of +two reproductive cells known as the egg and sperm cells. + +_Fertilization_, the fusion of the male or sperm cell with the egg or +female cell. + +_Ovary_, an organ producing eggs. + +_Spermary_, an organ producing sperm cells. + +_Cross fertilization_, fertilization in which the sperm and egg cells +are produced by different individuals. + +_Diœcious_, the different kinds of reproductive organs found in +different individuals. + +_Monœcious_, the different kinds of reproductive organs found in the +same individual. + + + _Directions._ + + _Note._--Refer to your notes, if the animals mentioned in these + exercises have been already studied. This exercise may be largely + review. + +Study the methods of reproduction in the specimens or diagrams before +you. Determine first, in what respects the methods of reproduction +are similar in all; second, in what respects there is a variation. + + + _Questions._ + +1. What has an amœba gained by dividing? What powers has each new +cell that the original amœba had lost? What would have been the fate +of the amœba if it had not divided into new cells? + +2. What various forms of cell division did you find? + +3. What is the simplest method of reproduction? + + +2. The Complex or Sexual Method of Reproduction + + + _Materials._ + +Slides or diagrams showing hydra and sponge reproducing sexually. +Conjugating paramecia, fertilized and unfertilized starfish eggs. + + + _Directions._ + +Identify the reproductive organs or gonads of the hydra. These are +slight swellings on the surface. The one nearer to the mouth end is +the spermary and that near the attached end is the ovary. + + + _Questions._ + +1. How is an egg cell produced in hydra? In general how do the +reproductive cells of sponges and hydra originate? + +2. What is gained by limiting the process of reproduction to special +cells? + +3. What is the difference between the appearance of the nucleus of +the fertilized and the unfertilized egg? + +4. What is the advantage of cross fertilization? How accomplished in +Hydra? What reason can you suggest for the spermary's position? + +5. Describe the conjugation of a paramecium. + +6. Describe the process of maturation and fertilization in a starfish +egg. + + + _Suggested drawings._ + +a. Diving Amœba or Paramecium. + +b. Budding Hydra. + +c. Hydra showing gonads. + +d. Starfish egg--fertilized and unfertilized. + + +_Summary_ of important points in the study of methods of +reproduction:-- + +1. What are the two principal methods of reproduction? How do they +differ? + +2. Why is reproduction necessary? + + +#B. DEVELOPMENT# + + +1. The Hen's Egg + + + _Materials._ + +Hen's eggs, hydrochloric acid. + + + _Definitions._ + +_Germ spot_, a white spot, imbedded in the "yolk." This is the point +at which development begins. + +_Yolk_, the yellow portion of a bird's egg. This is a food material, +rich in fat. + +_Albumen_, the white, viscous portion of a bird's egg. + +_Chalaza_, the spiral portion of albumen always seen in the bird's +egg. + + + _Directions._ + +Boil an egg at least ten minutes in water deep enough to cover it. +Note which side is uppermost and mark this part of the shell for +reference. Remove the egg and pick away the shell from about half the +egg, leaving the shell on that portion which was underneath when +placed in water. With a sharp knife remove this half of the egg. Note +the thickness of the shell. Test its composition (use hydrochloric +acid). Find the membrane lining the shell and note that at one end it +separates into two parts to inclose an air space. + +1. What is this for? How does it change after an egg has been +incubated for a week or more? + + Break an uncooked egg in a saucer. Note the germ spot. Note also + the difference in the consistency of the "white" (albumen) and + yellow portion ("yolk"). + +2. Why does the latter retain its shape? + +3. Why do the white and yolk not mix unless shaken or beaten +together? + +4. Look for the chalaza. + +5. What do you think is the use of this structure? + + Weigh a fresh egg, place it in a dry atmosphere for a week, and + weigh it again. Record result. Why may eggs be kept a long time + perfectly fresh if coated with paraffin or if put in "water + glass"? + + + _Suggested drawings._ + +a. The egg as it appears in the saucer. + +b. The egg after part of the shell has been removed. + + +2. Early Embryonic Development of an Egg + + + _Materials._ + +Slides or diagrams, showing various stages in the development of some +animal through the gastrula stage. + + + _Definitions._ + +_Cleavage stages_, two, four, eight, sixteen cells, etc., arising by +repeated division, starting with the egg. + +_Blastula_, a hollow sphere, the wall of which is composed of a +single layer of cells. + +_Gastrula_, a stage formed from the blastula by pushing in one side +of the latter, so as to form a more or less cup-shape structure. + + + _Observations._ + +1. Is there any considerable difference between the size of the egg +and the size of the blastula and gastrula? Has development taken +place by an increase of size or by an increase of complexity? + +2. Contrast the blastula and gastrula as to number of cavities, +number of cell layers, number of external openings. + +3. Suggest protozoans that resemble the egg and blastula +respectively. What invertebrates resemble the gastrula in body plan? + + + _Suggested drawings._ + +a. Some of the cleavage stages. + +b. A blastula. + +c. A gastrula. + + +3. Postembryonic Development or Metamorphosis of a Mosquito + + + _Materials._ + +Some specimens of the larvæ and pupæ of the mosquito, ordinarily +known as wrigglers. Either specimens or diagrams of egg packets +should also be provided. Mounted specimens of adult of both sexes. + + + _Definitions._ + +_Postembryonic development_, the changes taking place in the +development of an animal after birth or hatching. + +_Larva_, the active feeding stage. It is the first stage in +postembryonic development, and follows the gastrula stage. + +_Pupa_, usually a resting or quiescent stage. It is the stage +following the larva stage. + + + _Observations._ + +1. Describe the appearance of the egg packet both as seen with the +unaided eye and with a hand lens. Find the trapdoor. + +2. What is the difference between the appearance of the larva and the +pupa? How do their resting positions differ? + +3. What does the larva do when disturbed? Describe any characteristic +motions that you notice. + +4. Contrast the pupa with the larva under the same conditions and +note any differences. + +5. Where do you think the external openings of the respiratory organs +of the larva and those of the pupa are located? Give reasons for your +answer. + +6. Into what does the pupa change? Where must the pupa be at this +time? Is it easier for the pupa to stay at the surface or at the +bottom? + +7. Examine an adult mosquito. State the kind of mouth parts, the +number and appearance of the wings, the appearance of the antennæ. +How does the male and female differ in this respect? + + + _Suggested drawings._ + +a. A diagrammatic drawing representing the jar of water and showing +the various positions assumed by the wrigglers. + +b. Careful drawings of each stage. + + +4. Postembryonic Development or Metamorphosis of a Butterfly or Moth + + + _Materials._ + +The eggs, caterpillars, pupæ, cocoons, and adult of some moth or +similar stages of a butterfly. + + + _Definitions._ + +_Prolegs_, short, unsegmented appendages found in the larva. + +_Caterpillar_, the larva of a moth or butterfly. + +_Spiracles_, openings into the trachæ or breathing tubes. + +_Tubercles_, knob-like projections. + +_Chrysalis_, the pupa stage of a butterfly. + +_Cocoons_, the covering spun by the larva before changing to the +pupa. + + + _Observations._ + +1. State the color and appearance of the larva. If tubercles or +spines are present, state where. Where are the spiracles? How do you +distinguish the head, thorax, and abdomen in the case of the +caterpillar? + +2. What kind of mouth parts has the caterpillar? + +3. How many prolegs has the caterpillar? Of what use are they? + + How does the number of prolegs differ from that of the + caterpillar in the case of the grub? maggot? currant worm? + +4. What is the advantage of the cocoon? What is its color, +appearance, and material? Is it composed of a tough substance, or is +it easily torn? Where are cocoons found out of doors? Where would you +look for chrysalids? (Explain differences in locations.) + + Describe the cocoons of tussock moth, clothes moth, leaf roller. + +5. What is the difference between a Cecropia cocoon which contains a +living pupa and one that has been parasitized? What is the +appearance of a parasitized caterpillar? + +6. What rudimentary structures can you identify in the pupa? What +kind of mouth parts has this stage? + +7. Which of these stages is the active stage? Which stage is +quiescent? What is really going on in the quiescent stage? In which +stage does the insect grow? feed? If the insect were harmful, in +which stage would it do the damage? How? + +8. Describe what occurs when the pupa changes into the adult. What is +the appearance of the wings in the beginning? What changes take +place? + +9. What kind of mouth parts has the adult? Describe. + +10. Describe the antennæ. + + How do the antennæ of moths and butterflies vary? + +11. What is the size and appearance of the eggs? Are they laid singly +or in groups? + + + _Suggested drawings._ + +a. A caterpillar, side view. + +b. A pupa, ventral view. + +c. An adult, dorsal view. + +d. A few eggs. + + +5. Development of the Chick + + + _Materials._ + +An incubator, a brooder, a setting of eggs. + + + _Directions._ + +Read carefully the directions for setting up and regulating the +incubator. Remember that the temperature should average 103 degrees +and should not vary more than two or three degrees above or below +this. Candle the eggs from time to time and note difference in +appearance, as development proceeds, especially as to transparency +and size of the air space. An egg that is transparent after ten days +is probably infertile and should be removed. Eggs which are +developing properly will show from this time on a well developed air +space, and will be quite opaque. The veins often give a spider-web +appearance. + +Twice each day remove the tray of eggs and allow to cool slightly. +Once a day the eggs should be turned before the tray is returned to +the incubator. + + + _Questions._ + +1. Describe the appearance of the shell when the chick is about to +come out. In about how many days after you put the eggs in the +incubator did you first note this change? You should watch the +incubator carefully from the eighteenth day on. + +2. What proportion of the eggs hatched? What reasons can you suggest +for the failure of some to hatch? Did any which were pipped fail to +hatch? If so, break them open and see if you can discover the +trouble. + +3. How does the chick get out of the shell? How long does it take for +it to get out after the shell is chipped? How does a chick look as +soon as it has come out of the shell? + +4. With what is a chick covered when it is first hatched? How long +before feathers begin to develop? + +5. How long before a chick needs food? How does it recognize it? + + + _Summary._ + +1. What are the two kinds of development? + +2. What are the stages in embryonic development? + +3. What two general types of postembryonic development as determined +by the amount of the food supplied in the egg? + + +#C. PROTECTION AND CARE OF YOUNG# + + +Library Exercise + + + _Materials._ + +Books and diagrams showing as many methods for the care of young as +possible. + + + _Observations._ + +1. To what extent is care given to the eggs and young in the case of +fish? Is the number of eggs large or small? Contrast this condition +with that of the robin. What general conclusion is suggested? + +2. Describe the egg-laying habits of five or more of the following: +grasshopper, cecropia moth, tussock moth, leaf miner, case bearer, +leaf roller, sphinx moth, gall insects, ichneumon flies, spiders, +earthworm. How is the developing animal protected in each case? How +is food assured? + +3. Contrast the method of the honeybee and the solitary wasp as to +the method of caring for and feeding the young. + +4. Describe the nests of five or more of the following: spider, +honeybee, bumblebee, paper wasp, mud dauber, digger wasp. + +5. Describe the nests of the following: stickleback fish, sunfish. + +6. Describe the nests of ten birds common to your neighborhood. + +7. Describe the homes of the following: woodchuck, mole, squirrel, +rabbit, muskrat, prairie dog, beaver, bear. + +8. In case of birds which of the parent birds builds the nest and +cares for the little birds? + +9. How are the young cared for in the following cases: crayfish, +cyclops, pipefish, Surinam toad? + + + _Summary._ + +1. What general methods are there for protecting the young? + +2. What various devices for assuring plenty of food for the +developing animal? + +3. What is the relation between the care given the young and the +number of eggs produced? + + +#D. ADAPTATIONS FOR THE PRESERVATION OF THE SPECIES# + + +Review Questions and Library Exercise + + +1. Show how the sexual method of reproduction tends to produce +variations. + +2. What is meant by the term _heredity_? + +3. What are chromosomes? What do some zoölogists believe to be the +relation between these chromosomes and heredity? + +4. What are dominant and recessive characters? What is meant by +"Mendel law of heredity"? + +5. What is meant by the term _parthenogenesis_? What are some of its +advantages and under what conditions does it take place? Name some +animal in which parthenogenesis commonly takes place. + +6. What is sex dimorphism? Give some examples. + +7. What were the experiments of Professor Loeb and others in +connection with artificially fertilized eggs? + +8. How do eggs vary as to the kind of shell, amount of food, size, +etc.? What is the effect of the amount of food upon the rate of +development? On the stage of development at which the egg is +hatched? + +9. Contrast præcocial and altricial birds. + +10. What is the effect of ground nesting and tree nesting upon the +number of eggs and the care of the young? + +11. Describe the metamorphosis of grasshopper, June beetle, honeybee, +dragon-fly, cicada, may-fly, ant-lion, caddis fly. + +12. Compare the development of the crayfish, crab, and lobster. What +names are given to the larvæ? What is the significance in the fact +that the lobster hatches in the "mysis stage"? + +13. What are some of the peculiar names given to the larvæ in the +case of echinoderms, worms, and mollusks? Why should these have +received special names? + +14. Name the three primitive germ layers. State the principal organs +derived from each in the higher animals. + +15. What is ontogeny? phylogeny? What is the meaning of the law "The +ontogeny is an epitome of the phylogeny"? + +16. Who was Weissman? What important contribution did he make to +zoölogy? + +17. With what phase of zoölogy is the name of T. H. Morgan +associated? + + + + +CHAPTER VIII + +POULTRY + + + _Materials._ + +Either pictures or specimens of the different breeds of fowl. + + + _General Information._ + +Under the term poultry are included chickens as well as turkeys, +pigeons, ducks, geese, etc. Chickens are most generally raised, since +they do not require such special conditions as the others. In this +exercise only this form of poultry is considered. + +The hen has been domesticated from prehistoric times, being probably +derived from the so-called jungle fowl of India (_Gallus bankiva_), +which is still to be found in its native habitat. Through constant +attempts to improve the domestic fowl along the lines of greater +egg-production, size, etc., there have been developed a great many +different breeds of fowl. These may be divided into seven groups, as +follows: + + 1. The American Class. + 2. The Asiatic Class. + 3. The Mediterranean Class. + 4. The English Class. + 5. The Dutch Class. + 6. The French Class. + 7. The Ornamental and Exhibition Classes. + +The American Class includes fowls raised both for egg-production and +for eating. It includes the following well-known breeds: the Plymouth +Rocks, the Wyandottes, the Rhode Island Reds, and the less-known +breeds of Javas, Dominiques, and Jersey Blues. These all lay +good-sized brown eggs, are good winter layers, and stand confinement +well. The standard weight varies from six and one half pounds to +seven and one half pounds for the hen, and from eight and one half +pounds to nine and one half pounds for the cock, the Plymouth Rocks +being the heaviest of the breeds. + +There are three principal varieties of Plymouth Rocks--the Barred +Rocks, with grayish-white plumage regularly crossed with bars of +blue-black, the White Rocks, and the Buff Rocks. All have single +upright combs, which, with the wattles and the ear lobes, are bright +red, a large bright eye, and yellow legs. + +There are also three principal varieties of Wyandottes. The +Silver-laced Wyandotte has a silvery-white plumage, with black +markings in various parts of the body. The Golden Wyandotte is +similar in its markings, but has yellow where the Silver-laced has +white. The White Wyandotte is pure white. All have rose combs, red +ear lobes, and yellow legs. They are on the average about a pound +lighter than the Plymouth Rocks. + +The Rhode Island Reds are a much more recent breed that has of late +become very popular. They are of a reddish-brown color, about the +weight of the Wyandotte, with yellow legs. There are both single +combed and rose combed varieties. + +The Asiatic Class includes those breeds raised chiefly for the table. +The Brahmas, Cochins, and Langshans are the chief breeds. They +are considerably heavier than other breeds, and are specially +characterized by the feathers on the legs and feet. They all lay +brown eggs, and are in many cases good layers. + +The Brahmas include two principal varieties, the light and the dark. +The general color is black and white, and they have yellow legs, red +wattles, ear lobes, and comb, the latter being of the kind called a +pea-comb, which is of small size in the cock. + +There are four varieties of Cochins, the Buff being much more raised +than the Partridge, the White, or the Black. The Partridge somewhat +resembles a dark Brahma, but has red and brown plumage. Cochins have +single combs, yellow legs, and a general fluffy character to +the plumage, that of saddle and hackle meeting, thus giving a +characteristic appearance to these fowls. The eggs are not quite so +large as the other two breeds of this class. + +The Langshans are smaller and more active than the two breeds just +described. They have black legs, the feet are not so heavily +feathered, and in general these fowls are much less awkward in +appearance. There are two varieties, the White and the Black. + +The Mediterranean Class includes those breeds raised chiefly because +of their great egg-production. They are active birds, often +troublesome because of their ability to fly over high enclosures, so +that when kept in the city it is usually necessary to clip one wing. +They are not so good winter layers as a rule, but are non-setters. +They all lay white eggs. The chief breeds included are the Leghorns, +the Minorcas, and the Black Spanish. + +The Leghorns--the most popular of these breeds--include two chief +varieties, the Brown and the White. The comb is most commonly single, +falling to one side in the hen, the wattles long and pendulous, the +ear lobes white, and the legs yellow. + +The Minorcas are glossy black in color, with a large drooping comb in +the hen, and long, thin, pendulous wattle. They lay a very large egg. + +The Black Spanish resemble the Minorcas, but are distinguished by the +white face and cheeks and the white on the inner edge of the wattles. + +The English Class includes the Orpingtons and the Dorkings. The +Dorkings are one of the oldest breeds of fowl, and sufficiently +identified by the presence of a fifth toe. There are three +varieties--the White, the Silver-gray, and the Colored. The White +Dorking has a rose comb; the Silver-gray has a single comb and +silvery-gray plumage with black markings, the hen having a +salmon-colored breast; the Colored Dorkings have sometimes single and +sometimes rose combs, the plumage of the cock being black and +straw-colored and that of the hen being black and gray with the +breast salmon marked with black. + +The Orpingtons are short legged, with close plumage. They are of +large size, the hens being from seven to eight pounds and the cocks +from nine to ten pounds. There are three varieties--the black, the +buff, and the white. The black, except for shape, might be mistaken +for a Minorca, but has red ear lobes and black shanks. The Orpingtons +have the reputation of maturing early, some strains being known to +lay when four months old. + +The Dutch Class includes the Red-caps, the Campines, and the various +varieties of the Hamburgs--of which there are six: the Golden +Spangled, the Silver Spangled, the Golden Penciled, the Silver +Penciled, the Black and the White. They are all good layers and +non-setters, "but lay a small egg, white in color. They are readily +recognized by their peculiar rose comb with its long, spikelike +projection in the back, their red face, white ear lobes, and bluish +legs. The prevailing color of the golden varieties is a reddish bay +marked with black and of the silver varieties white marked with +black. The cock usually has more dark markings than the hen. + +The Red-caps are large fowl with a red and black plumage. The comb is +similar to the Hamburg's but larger, and the ear lobes are red. + +The Campines resemble the Hamburgs, but have a single comb. + +The French Class includes the Houdans, the Crevecœurs, and the La +Fleche. The Houdans are mottled black and white with pinkish white +legs, with a fifth toe like the Dorkings, and are easily recognized +by their peculiar crest. + +The other breeds of fowl, like the crested Polish, Bantams, and game +fowl, have less interest for the poultry raiser, though often seen in +exhibitions and poultry shows. + +To sum up, we may group all these breeds according to their value +into (1) the egg breeds, including the Leghorn, Minorca, Spanish, and +Red-cap; (2) the meat breeds, including the Brahmas, Cochins, and +Langshans; (3) the general purpose breeds, including the Plymouth +Rocks, Wyandottes, Rhode Island Reds, Dorkings, and Orpingtons; and +(4) the fancy breeds, including the Polish, Bantams, Games, etc. + + + _Definitions._ + +American Standard of Perfection, an illustrated volume published by +the American Poultry Association, indicating the desirable points of +each recognized breed of fowl. + +_Comb_, the fleshy outgrowth on the head. + +_Single comb_, a thin, upright comb. + +_Rose comb_, a flat comb with a rough or corrugated surface. + +_Pea comb_, resembling three single combs, united at the back. + +_Wattles_, the fleshy outgrowths from the underside of the throat. + +_Ear lobes_, the fleshy structure in the region of the ear. + +_Under-color_, the color noted when the coverts are raised. + +_Hackle_, the feathers on the neck. + +_Cape_, the feathers back of the hackle. + +_Saddle_, the feathers in the posterior region of the back. + +_Sickle_, the curved feathers of the tail in the cock. + +_Penciling_, small stripes or color markings on the feather. + +_Spangling_, large spots or splotches of color on the feather. + +_Shanks_, the exposed scaly portions of the legs, usually spoken of +as the "legs." + + + _Questions and observations._ + +1. Make a diagrammatic sketch of a fowl and locate the principal +regions used in the description of the various breeds. + +2. Observing the specimens or the pictures of the fowls at hand, note +the size and kind of comb, the appearance of the wattles, the color +of the eyes and ear lobes, the color in the various regions of the +body, the color and any peculiarity of the legs and feet. If you +wish, you may record your answers in tabular form. + + + _Topics for investigation._ + +1. Look up and report upon the average number of eggs laid annually, +and the number of eggs to the pound, in the case of the Plymouth +Rock, Wyandotte, Rhode Island Red, Dorking, Brahma, Leghorn, and +Minorca. + +2. Explain the terms "non-setter" and "winter layer." + +3. When do hens moult? How does this affect the laying? What schemes +have poultry men to bring this moulting at the most favorable season? + +4. What is a "balanced ration" as applied to fowls? What are some +methods of feeding which tend to secure greater egg-production? + +5. Explain some of the special features of such methods of housing +and keeping chickens as the Philo System, Corning System, etc. + +6. What precautions must be taken in raising chickens so as to +prevent disease and attacks of enemies? + +7. What does it cost per year to keep a dozen hens? How many can a +person keep profitably on a city lot, if he is not to make a special +business of chicken raising? + +8. How do chickens solve the problem of the garbage can? + +9. What are some of the objections made to keeping chickens in the +city? Are these objections well founded, and if so how may they be +met? + +10. Find out what breeds of chickens are kept in your neighborhood, +and note some of the reasons that are given for keeping these +particular breeds. + + + + +GLOSSARY + + +#Ab do' men#, (1) the hinder portion of the body of an invertebrate; +(2) of higher animals, the region or cavity containing the stomach, +intestine, etc. + +#Al bu' men#, (1) a proteid substance; (2) "white of egg." + +#A' nal#, pertaining to the anus, or hinder opening of the intestine. + +#Anal fin#, a ventral median fin of fishes, just back of the anus. + +#Animal Communities#, associations of many animals of the same +species. + +#An ten' na#, a segmented sensory appendage on the head of an +arthropod. + +#An ten' nule#, a small antenna. + +#An te' ri or#, farther forward, in front of; at the head or forward +end. + +#A or' ta#, a large artery arising at the heart and forming the trunk +of the arterial system. + +#Ap' er ture#, an opening. + +#Ap pend' age#, a projection from the body, usually one of a pair. + +#Ar throp' o da#, a group of animals with a segmented trunk and +paired, segmented appendages. + +#Ar ti o dac' tyl#, an ungulate with an even number of toes. + +#A sex' u al#, without sex. + +#Au' di to ry#, pertaining to hearing. + + +#Barb#, one of the lateral outgrowths of the shaft of a feather, +forming the vane. + +#Barb ule#, a small outgrowth of the barb of a feather. + +#Bi lat' er al sym' me try#, having the right and left sides mirror +images one of the other. + +#Body cavity#, the space between the body wall and the alimentary +canal. + +#Body-wall#, the outer wall in bodies of the many-celled animals. + +#Budding#, a form of fission in which a cell or portion of the body +forms a small protuberance or bud, which is then cut off from the +parent and forms a new individual. + + +#Canals#, channels through the body-walls of sponges. + +#Car' a pace#, the shell which covers a portion or all of the +cephalo-thorax in crustaceans. + +#Car' di nal#, pertaining to a cardo or hinge. + +#Car niv' or ous#, flesh-eating. + +#Car ot' id#, a large artery which supplies the brain and head with +blood. + +#Car' pal#, a bone of the wrist. + +#Cat' er pil lar#, the larva of a butterfly or moth. + +#Caud al#, pertaining to the tail. + +#Cell#, the smallest living unit. + +#Cell-wall#, the lifeless membrane surrounding many cells, secreted +by the protoplasm. + +#Central cavity#, the cavity surrounded by the body-wall in the +simpler many-celled animals, as in the sponges. + +#Ceph a lop' o da#, the class to which the squid, octopus, nautilus, +etc., belong. + +#Ceph' al o-tho' rax#, the division of the body formed by the fused +head and thorax in many arthropoda. + +#Cer' vi cal groove#, the groove marking the place of union when head +and thorax are merged into a cephalo-thorax. + +#Cha la' za#, one of the spiral masses of albumen found at the two +ends of a bird's egg. + +#Che' li peds#, the large claws in many crustaceans. + +#Chor-date#, animals with a notochord, present throughout life or +disappearing. + +#Chro mat' o phore#, color body. + +#Chrys' a lis#, the pupa stage of a butterfly. + +#Cil' i um# (pl. #cilia#), a minute vibrating hair on the surface of +many cells. + +#Co coon' #, the envelope spun by certain larval insects in which +they are inclosed during the pupa stage. A similar structure, as the +egg-case of spiders, earthworms, etc. + +#Cœ' cum# (se' kum), a blind pouch or bag; a sac open at one end. + +#Cœ len te ra' ta#, rather simple, sac-like animals with nettle cells +in the body walls. + +#Co le op' te ra#, beetles. + +#Col' o ny#, a group of animals of the same kind found in one +locality, usually related to each other and often actually connected. + +#Com men' sal ism#, an association of two animals, not mutually +helpful, but without injury to either. + +#Com pound eye#, an eye made up of many simple eyes or eye elements. + +#Com pressed' #, narrower from side to side than from dorsal to +ventral surface. + +#Con ju ga' tion#, a process occurring in some one-celled animals, +preceding reproduction. In this process two animals unite temporarily +and exchange nuclear substance, or in some forms the two cells fuse +into one. After this exchange or fusion fission occurs, usually more +rapidly than before. + +#Contracting# or #pulsating vacuoles#, small, clear spots in a cell, +filled with a watery fluid. In the living animal these alternately +disappear and then reappear. + +#Co' nus ar te ri o' sus#, a cone-shaped artery connected with the +ventricle of the heart. + +#Cov' ert#, a feather overlying the base of the large feathers of the +wing or tail. + +#Cra' ni um#, the skull, particularly that part of it inclosing the +brain. + +#Crop#, an enlarged portion of the esophagus. + +#Cross fertilization#, a form of fertilization in which the male and +female elements are produced by different individuals. + +#Crus ta' ce a#, aquatic, gill-bearing arthropods, with two pairs of +antennæ. + +#Cu' ti cle#, the thin outer skin. + +#Cy' to plasm#, the portion of the protoplasm of a cell which is +outside of the nucleus, less dense than the nucleus and usually +taking a lighter stain. + + +#Den' ta ry#, the terminal portion or bone of the lower jaw of +vertebrates lower than mammals, containing all or most of the teeth. + +#Di a phragm#, a muscular partition separating the abdomen and +thorax, in mammals. + +#Dig' i ti grade#, walking on the toes. + +#Di œ' cious#, reproductive organs in different individuals. + +#Dip' te ra#, insects with two wings, including flies, mosquitoes, +etc. + +#Dis' tal end#, the free end of any object which is attached by one +end. + +#Dor' sal surface#, the upper surface; the back. + +#Du' o de' num#, the first portion of the small intestine. + + +#Ec' to derm cells#, cells covering the outside of sponges and some +other simple animals. + +#Egg cell#, the large, non-motile reproductive cell, with which a +sperm cell fuses. + +#Em bry on' ic#, development within the egg or in the body of the +mother. + +#En' do derm cells#, cells lining inner cavities in the many-celled +animals. As a rule they have cilia or flagella. + +#E soph' a gus#, the portion of the alimentary canal connecting the +mouth (or the pharynx) with the stomach. + +#Eu sta' chi an# (eu sta' kian) #tube#, a passage between the pharynx +and the middle ear. + +#Ex ha' lent#, flowing or moving away from the body. + +#Ex' o skel' e ton#, an external skeleton. + +#Eye stalk#, an appendage which bears an eye on its free end. + + +#Fe' mur#, (1) the thigh bone; (2) the third joint of an insect's +leg. + +#Fer ti li za' tion#, the fusion of male and female elements in +reproduction. + +#Fi' bers#, flexible threads; fibers of a horny material are found in +the walls of many of the sponges. + +#Fib' u la#, the outer of the two long bones of the lower leg. + +#Fin#, a paddle-like structure for swimming. + +#Fin-rays#, the framework of the fins of fishes. + +#Fis' sion#, a method of reproduction used in all cells, by which a +cell divides itself into two, usually through the center. _See also_ +Conjugation and Budding. + +#Fla gel' lum# (pl. #flagella#), vibrating hairs larger than cilia +and less numerous. + +#Food-balls#, bits of food inside the cells of many one-celled +animals, usually showing through the walls. + +#Food-vacuole#, a small drop of water containing digestive material +and a food-ball. + +#Fo ra' men#, an opening or short passage. + + +#Gall-bladder#, a membranous sac for the storage of gall, or bile, at +the lower edge of the liver (syn. "bile sac"). + +#Gas ter op' o da#, the class to which the snail belongs. + +#Ge' nus# (pl. #genera#), a group of closely related species. + +#Germ-spot#, the region in the bird's egg in which development first +takes place. + +#Gill#, an apparatus for breathing the air dissolved in water. + +#Gill-cham' ber#, a pocket or cavity covered by a flap, in which the +gills lie. + +#Gir' dle#, the name applied to the smooth band often occurring near +the anterior end of an earthworm. + +#Giz' zard#, a portion of the alimentary canal with especially +thickened muscular walls. + +#Glot' tis#, the opening between the vocal cords, or the mouth of the +windpipe. + +#Gre ga' ri ous#, associations of animals with little division of +labor; gathering in flocks, herds, etc. + +#Gullet#, the inner end of the oral groove. + + +#He mip' te ra#, insects with a piercing organ for sucking their +food, Bugs. + +#He pat' ic#, pertaining to the liver. + +#Her biv' o rous#, plant-eating. + +#Hock#, the joint of the hind leg situated between the tibia and +tarsus, corresponding to the ankle in man. + +#Hu' me rus#, the long bone of the upper part of the arm or fore +limb. + +#Hy men op' te ra#, order of insects to which belong bees, ants, and +wasps. + + +#Ich neu' mon# (ic nu' mon), an insect that deposits its eggs upon or +in other insects, upon which its larvæ will feed. + +#In ha' lent#, flowing or moving toward the body. + +#In ha' lent pores#, the outer ends of the canals in the body-walls +of sponges. + +#Ink-sac#, a defensive structure found in the squid. + + +#Ju' gu lar#, pertaining to the throat. + + +#La' bi um#, lower lip. + +#La' brum#, upper lip. + +#La mell' i branch i a' ta#, the class to which the clam, oyster, +etc., belong; bivalves, sometimes called pelecypoda. + +#Lar' va#, (1) the early form of an animal when it is unlike the +parent, or undergoes a metamorphosis; (2) the first stage of +postembryonic development. + +#Lat' er al#, (1) situated to one side of the median plane; (2) +situated in the region of the hinge in a bivalve shell. + +#Lep i dop' te ra#, butterflies and moths. + +#Lig' a ment#, a strong band or cord binding two structures together. + +#Lin' gual#, pertaining to the tongue. + +#Lip#, any structure that bounds an orifice. + + +#Mam' mal#, vertebrates with a covering of hair or fur. + +#Man' di ble#, a jaw or a jaw-like mouth-part. + +#Man' tle#, folds of skin covering the body of a bivalve. + +#Masking#, the covering of an animal by some object so as to hide its +identity. + +#Max il' læ#, the appendages just back of the mandibles in +arthropods. + +#Max' il la ry#, pertaining to or situated near the jaw. + +#Max il' li peds#, the appendages back of the maxillæ in +crustaceans. + +#Me' di an#, pertaining to the middle. + +#Mes o gle' a#, a non-cellular layer between ectoderm and endoderm +cells. + +#Mes o tho' rax#, the middle division of the thorax. + +#Met a car' pal#, one of the bones between the wrist (carpus) and the +fingers (phalanges). + +#Met a mor' pho sis#, the series of changes which take place in the +development of some animals after they are hatched. + +#Met a tar' sal#, one of the bones of the metatarsus, between the +ankle and the toes. + +#Met a tho' rax#, the most posterior region of the thorax. + +#Mi cro nu' cle us#, _see_ Nucleolus. + +#Mimicry#, a method of protection due to the resemblance of an +unprotected to a well-protected animal. + +#Mol lus' ca#, the branch of animals to which clams, snails, etc., +belong. + +#Mo nœ' cious#, reproductive organs in different regions of the same +individual. + +#Mouth#, the anterior opening into the digestive cavity. + + +#Neph rid' i um# (pl. #neph rid' i a#), a tubule functioning as a +kidney in some of the worms. + +#Net' tle cells#, the stinging cells found in the cœlenterates. + +#Noc tur' nal#, pertaining to night. + +#Nu cle' o lus# (pl. #nucleoli#), a very small, dense, dark-staining +body, either within the nucleus or near it. In the latter case it is +often called the _paranucleus_ or _micronucleus_. + +#Nu' cle us# (pl. #nuclei#), a dense bit of protoplasm usually near +the center of a cell, often staining dark. + + +#O cel' lus#, a simple eye. + +#Om niv' o rous#, eating or living upon food of all kinds. + +#O per' cu lum#, a lid or cover. + +#O' ral#, pertaining to the mouth. + +#Oral groove#, a funnel-shaped groove in one side of some one-celled +animals conducting food to the mouth. + +#Or' der#, a term in classification used to designate a group of +genera. + +#Or thop' ter a#, the order to which locusts, grasshoppers, etc., +belong. + +#Os' cu lum# (pl. #oscula#), the large opening from the central +cavity in sponges. + +#Os mo' sis#, the process by which fluids of different densities +become equally diffused when separated by an organic membrane or by a +porous structure. + +#Os' ti a# (sing. #ostium#), the inner ends of the canals in the +body-walls of sponges. + +#O' va ry#, the organ in which the egg cells are developed. + +#O vi pos' i tors#, organs used to deposit eggs. + + +#Pal' li al#, a line connecting the two muscle scars in a bivalve +shell. + +#Palp#, (1) a jointed finger-like structure on the oral appendages of +arthropods; (2) oral appendages found in mollusca. + +#Pan' cre as#, one of the glands of the digestive system. + +#Par a nu' cle us#, _see_ Nucleolus. + +#Par' a si tism#, an association of two animals, one living at the +expense of the other. + +#Pec' to ral#, (1) pertaining to the thorax or breast; (2) the +anterior of the paired fins of fishes. + +#Pelvic#, (1) pertaining to the pelvis; (2) the posterior paired fins +of fishes. + +#Pen#, a remnant of exoskeleton found in the squid. + +#Per i car' di um#, a membranous bag surrounding the heart. + +#Per is so dac' tyl#, ungulates with an odd number of toes. + +#Per' i to ne' um#, a membrane that lines the body cavity. + +#Pha' lanx# (pl. #phalanges#), one of the bones of the fingers or +toes. + +#Phar' ynx#, the region of the alimentary canal just back of the +mouth cavity. + +#Pigment#, a substance which gives color to an object. + +#Plan' ti grade#, walking on the soles of the feet; flat-footed. + +#Pol' len bas ket#, the flattened hairy tibia of the hind legs of +honey bees, used for carrying pollen. + +#Pol' lin na tion#, the transfer of pollen from the anther of a +flower to the stigma. + +#Polyp#, any radially symmetrical animal, but usually an individual +in a connected colony. + +#Po rif' e ra#, the sponges, distinguished by the canals which +perforate the body wall. + +#Post em bry on' ic#, development after birth or hatching. + +#Pos te' ri or#, situated behind or toward the hinder part. + +#Pro bos' cis#, a prolonged, flexible snout or a tubular structure, +protruding from the head. + +#Pro' leg#, an unsegmented appendage found in the larvæ of some +insects. + +#Protective resemblance#, a method of protection due to the +resemblance of an animal to its background. + +#Pro tho' rax#, the most anterior division of the thorax. + +#Pro' to plasm#, the living material composing the cell; the physical +basis of life. + +#Pro to zo' a# (sing. #protozoön#), animals of one cell, existing +alone or in loose colonies. + +#Prox' i mal end#, the attached end of anything which has also a free +end. + +#Pulsating vacuoles#, _see_ Contracting vacuoles. + +#Pu' pa#, the stage in the development of an insect immediately +preceding the adult. + + +#Quill#, one of the large, stiff, strong flight feathers or tail +feathers of a bird; the hollow, basal part of a feather; a large, +hollow, sharp spine. + + +#Ra' di al sym' me try#, having the organs or parts arranged +symmetrically around a center. + +#Re gen er a' tion#, the power to grow new parts or organs. + +#Re' gions#, the principal divisions of the body, head, thorax, and +abdomen. + +#Res pi ra' tion#, the passage of oxygen into the tissues of a living +organism and of carbon dioxide out of them. These gases can pass +through any thin, moist, organic membrane. When such a membrane +separates two fluids which differ in the amount of oxygen they +contain, oxygen passes to the fluid containing the smaller amount. +The same is true of carbon dioxide. Respiration is believed to occur +in all living organisms. + +#Ro' dent#, mammals with curved self-sharpening incisor teeth, order +including mice, rats, squirrels, rabbits, etc. + +#Ros' trum#, a beak-like projection or snout. + +#Ru' mi nant#, chewing the cud. + + +#Sac#, a cavity or pouch. + +#Sa' crum#, a composite bone formed by the union of vertebræ in the +region of hips. + +#Scap' u la#, the shoulder-blade. + +#Sep' tum# (pl. #sep' ta#), a wall or partition between two cavities. + +#Se' ta# (pl. #se' tae#), small bristles or stiff hairs. + +#Sex' u al#, pertaining to sex. + +#Si' nus ve no' sus#, an enlargement of the termination of the large +veins. + +#Si' phon#, a tube-like organ. + +#So' mites#, the serial segments or rings composing the bodies of +many animals. + +#Spe' ci es#, a word used in classification to designate a group of +animals differing only in minor details. + +#Sper' ma ry#, the organ in which sperm cells are developed. + +#Sperm cells#, the small, often motile, reproductive cell, which +fuses with the egg cell. + +#Spic' ules#, tiny needles of mineral substance found in the walls of +many animals, notably sponges. + +#Spi' ra cle#, an opening into the tracheal breathing organs of +insects. + +#Spire#, the coiled portion of a gasteropod shell. + +#Spore#, a cell capable of developing into a new organism. + +#Sternum#, a bone extending along the lower middle line of the chest +region. + +#Stom' ach#, the region of the alimentary canal especially adapted to +digest food. + +#Stom' ach-in tes' tine#, a region of the alimentary canal adapted to +both digest and absorb food. + +#Sub cla' vi an#, situated beneath the clavicle. + +#Su' ture#, the junction of two contiguous structures. + +#Swim' mer ets#, the abdominal appendages in crustaceans. + +#Sym bi o' sis#, an association of two animals which is mutually +helpful. + + +#Tar' sal#, one of the bones of the tarsus or ankle. + +#Tar' sus#, (1) the ankle; (2) the fifth or terminal joint in an +insect's leg. + +#Ten' ta cles#, special organs for touch; also used sometimes for +other purposes. + +#Terrifying attitudes#, protective attitudes assumed by some animals. + +#Tho' rax#, the region of the body between the head and abdomen. + +#Tib' i a#, (1) the shin-bone; (2) the fourth joint of an insect's +leg. + +#Tooth#, (1) an organ used in mastication; (2) a tooth-like +projection. + +#Tra' che a#, a tube which carries air either to the respiratory +organ or to the tissues. + +#Trunk#, the portion of the body between head and tail. + +#Tu' ber cle#, a knob-like projection. + + +#Ul' na#, that bone of the forearm which is on the same side as the +little finger. + +#Um' bo# (pl. #umbones#), an elevation near the anterior end of a +bivalve shell. + +#Un' gu lates#, hoofed mammals. + +#U re' ter#, a duct connecting the kidney with the urinary bladder. + +#U' ro style#, a long bone forming the hinder extremity of the +vertebral column of tailless amphibia. + + +#Vac' u oles#, small, clear spots in cells, filled with a watery +fluid. _See_ Food-vacuoles _and_ Contracting vacuoles. + +#Valve#, (1) a membranous fold which allows the blood, or other +fluids, to flow in only one direction; (2) one of the two parts of +the shell of a bivalve. + +#Vein#, (1) a blood-vessel carrying blood toward the heart; (2) one +of the tubular thickenings of an insect's wing. + +#Ve' na ca' va#, a large vein emptying into the right auricle of the +heart. + +#Ven' tral#, situated on the under surface. + +#Ven' tri cle#, any cavity of a hollow organ, as of the brain or +heart. + +#Ver' mes#, the worms, a poorly defined group of animals, showing +bilateral symmetry but without segmented appendages. + +#Ver' te bra#, one of the bones of the spinal column. + +#Ver' te brates#, animals having a backbone. + +#Vi bris' sæ#, long hairs on the face. + +#Vis' ce ra# (pl. of #viscus#), the organs of one of the great +cavities of the body (the abdomen, the thorax, or the cranium), +usually meaning those of the abdomen. + +#Vi va' ri um#, a cage in which living animals are kept. + + +#Warning colors#, bright colors which render an animal free from +attack. + +#Whorl#, a single coil in the spire of a gasteropod shell. + + +#Yolk#, food material of an egg. + + + + + +End of the Project Gutenberg EBook of A Guide for the Study of Animals, by +Worrallo Whitney and Frederic Lucas and Harold Shinn and Mabel Smallwood + +*** END OF THIS PROJECT GUTENBERG EBOOK A GUIDE FOR THE STUDY OF ANIMALS *** + +***** This file should be named 34984-0.txt or 34984-0.zip ***** +This and all associated files of various formats will be found in: + https://www.gutenberg.org/3/4/9/8/34984/ + +Produced by Larry B. 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