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diff --git a/31730.txt b/31730.txt new file mode 100644 index 0000000..b8d64c6 --- /dev/null +++ b/31730.txt @@ -0,0 +1,1317 @@ +The Project Gutenberg EBook of Subspeciation in the Meadow Mouse, Microtus +montanus, in Wyoming and Colorado, by Sydney Anderson + +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: Subspeciation in the Meadow Mouse, Microtus montanus, in Wyoming and Colorado + +Author: Sydney Anderson + +Release Date: March 22, 2010 [EBook #31730] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK MEADOW MOUSE *** + + + + +Produced by Chris Curnow, Simon Gardner, Joseph Cooper and +the Online Distributed Proofreading Team at +http://www.pgdp.net + + + + + + + +UNIVERSITY OF KANSAS PUBLICATIONS + +MUSEUM OF NATURAL HISTORY + +Volume 7, No. 7, pp. 489-506, 2 figures in text + +July 23, 1954 + + + + + Subspeciation in the Meadow Mouse, + Microtus montanus, in Wyoming + and Colorado + + BY + + SYDNEY ANDERSON + + +UNIVERSITY OF KANSAS + +LAWRENCE + +1954 + + +UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY + +Editors: E. Raymond Hall, Chairman, A. Byron Leonard, +Robert W. Wilson + +Volume 7, No. 7, pp. 489-506, 2 figures in text + +Published July 23, 1954 + + +UNIVERSITY OF KANSAS + +Lawrence, Kansas + + +PRINTED BY + +FERD VOILAND, JR., STATE PRINTER + +TOPEKA, KANSAS + +1954 + +25-3560 + + + + +Subspeciation in the Meadow Mouse, Microtus montanus, in Wyoming and +Colorado + +BY + +SYDNEY ANDERSON + + +_Microtus montanus_ reaches the eastern limits of its geographic +distribution in Wyoming and Colorado. There the mountains, but in +general not the lowlands, are occupied by this species. A certain +minimum of moisture may be of direct importance to the mouse and +certainly is indirectly important, because certain hydrophytic or +mesophytic grasses used by the mouse for food, for protection from +enemies, and for shelter from the elements are dependent on the +moisture. Areas suitable for _Microtus montanus_ are separated by +deserts that are dominated by sagebrush and other xerophytic plants or +by forests or rocky exposures at higher altitudes. A relatively small +percentage, probably less than ten per cent, of the total area even in +the more favorable parts of the range of the species is suitable for +occupancy. In these mice, as in other microtines (Elton, 1942; Piper, +1909), there are seasonal, and irregularly multiannual fluctuations in +population density, which sometimes are extreme. Consequently the mice +at some times seem to be absent from suitable habitats, and at some +other times occur there in amazingly large numbers. + +Because the species is broken up into partly isolated, or at times +completely isolated, colonies or local populations it may be supposed +that various evolutionary forces such as selection and random genetic +drift operate to foster variation. The degree to which racial +distinction is attained may depend upon these forces and the time +available. In _Microtus montanus_ in the eastern Rocky Mountains the +degree of subspecific distinction is not great. + +The study here reported upon is based on 1,187 specimens of _Microtus +montanus_ from Wyoming, Colorado, Idaho and Montana, and on work in the +field. I spent approximately four months in the field in this area, in +the summers of 1950, 1951, and 1952. The specimens studied were arranged +according to localities and the larger series were compared +statistically. Each of two series, totaling 136 specimens, was studied +intensively to ascertain the kind and range of variation within single +populations. Twenty-seven measurements, various proportions based on +these measurements, and differences in color were analyzed. Fifteen +characters, judged to be most significant, were selected for use in +comparing all series. In addition, certain characters that can not be +expressed easily by measurements, such as inflation of the auditory +bullae and the curvature of the zygomatic arch, were observed. The +studies by A. B. Howell (1924) of variation in _Microtus montanus +yosemite_ Grinnell in California and those by O. B. Goin (1943) of +_Microtus pennsylvanicus pennsylvanicus_ (Ord) were useful. The external +measurements are from the collectors' field labels. The measurements of +the skull all were taken with dial calipers reading to a tenth of a +millimeter. The anteroposterior measurements of the skull all were taken +along the shortest line between the points specified below and are not +necessarily along a line parallel to the long axis of the skull. These +measurements were taken on the left side of the skull whenever possible. +Some of the skulls are damaged and therefore some measurements could not +be taken and are omitted in the computations. Measurements are in +millimeters. + +The results of these studies were submitted to the Department of Zoology +and the Graduate School of the University of Kansas in partial +fulfillment of the requirements for the degree of Master of Arts (1952) +and are available in manuscript form at the Museum of Natural History +and the library of the University of Kansas. + + +EXPLANATION OF MEASUREMENTS + + Caudal index.--the length of the tail expressed as a percentage of + the length of the head and body. The length of the head and body is + the collector's measurement of total length less the length of the + tail. + +CRANIAL MEASUREMENTS OF LENGTH. + + Condylobasilar length.--from the exoccipital condyle to the most + posterior point on the border of the alveolus of the upper incisor. + + Alveolobasilar length.--from the posterior border of the alveolus + of the third upper molar to the posterior border of the alveolus of + the incisor. + + Palatilar length.--from the anteriormost part of the posterior + border of the bony shelf of the palate to the posteriormost part of + the alveolus of the incisor. + + Alveolar length of upper molar tooth-row.--from the most posterior + point of the alveolus of the third upper molar to the most anterior + point of the alveolus of the first upper molar. + +MEASUREMENTS OF BREADTH. + + Zygomatic breadth.--greatest transverse width. + + Interorbital breadth.--the breadth of the interorbital + constriction. + + Lambdoidal breadth.--between the lateralmost points of the + lambdoidal crest. + + Prelambdoidal breadth.--between the medialmost margins of the + prominent fenestrae in the posterodorsal parts of the squamosal + bones. To these fenestrae Howell (1924:995) applied the adjective + "prelambdoidal," but other authors have used other names (see Hill, + 1935:127). + + Depth of braincase.--shortest distance from the ventral side of the + cranium at the suture between the basioccipital and basisphenoid + bones to the dorsal surface of the cranium (usually not + perpendicular to the long axis of the skull). + +The history of our knowledge of _Microtus montanus_ in this area begins +with the early work of the United States Bureau of Biological Survey +directed by C. H. Merriam (1891), and participated in by Vernon Bailey +(1900, 1917), Merritt Cary (1911, 1917), and others. The changes in +nomenclature which grew out of increased understanding of these mice +through additional collecting are expressed in the synonymies under the +accounts of subspecies. As a result of my studies two of the three +subspecific names previously proposed for mice from this area have been +retained although changes are proposed in the ranges assigned to the two +subspecies and two additional heretofore unrecognized subspecies are +named and described. Furthermore the additional specimens and my studies +of variation make modifications in the characterization of these +subspecies necessary. Not all of the samples here assigned to a single +subspecies are identical and I therefore list and discuss some of the +local variants. + + Numerous members of summer field parties from the Museum of Natural + History at the University of Kansas collected most of the specimens + studied and wrote field notes that have been helpful. I am grateful + to these persons and to Professor E. R. Hall and Dr. R. H. Baker + for their assistance and helpful suggestions. Specimens in the + following museums were made available by their respective curators: + Chicago Natural History Museum by Mr. Colin C. Sandborn, The Museum + of Zoology at the University of Michigan by Dr. E. T. Hooper, The + American Museum of Natural History by Mr. G. G. Goodwin, The United + States National Museum by Dr. David H. Johnson and the Biological + Surveys Collection by Miss Viola S. Schantz. A fellowship from the + National Science Foundation made possible the studies at the + museums other than at the University of Kansas. + + + +=Microtus montanus nanus= (Merriam) + + _Arvicola (Mynomes) nanus_ Merriam, N. Amer. Fauna, 5:62, July 30, + 1891. + + _Microtus montanus nanus_, Hall, Proc. Biol. Soc. Washington, + 51:131, August 23, 1938. + + _Microtus nanus_, Bailey, N. Amer. Fauna, 17:30, June 6, 1900 + (part). + + _Microtus montanus caryi_ Bailey, Proc. Biol. Soc. Washington, + 30:29, February 21, 1917. + + _Microtus nanus nanus_, Cary, N. Amer. Fauna, 42:43, October 3, + 1917 (part). + + _Type._--Adult male No. 23853/31253, U. S. National Museum, + Department of Agriculture collection, from Pahsimeroi Mountains, + Custer County, Idaho; obtained by C. Hart Merriam and Vernon + Bailey, September 16, 1890. + + _Range._--Idaho; southwestern Montana; most of the southwestern + half of Wyoming; southward to central Colorado. See figure 1. + + _Comparisons._--Comparisons with subspecies named as new in this + paper will be found in the accounts of those subspecies beyond. + From _Microtus montanus fusus_ Hall, the subspecies to the south, + _M. m. nanus_ from Idaho differs as follows: averages smaller; + slightly darker and less reddish and less yellowish in color; + slightly wider braincase (see measurement of prelambdoidal + breadth); larger bullae. + + _Measurements._--Average (= arithmetical mean) measurements of 34 + specimens, both male and female, from several localities in eastern + Idaho are: total length, 151; length of tail, 39; hind foot, 19.2; + condylobasilar length of the skull, 25.0; zygomatic breadth, 15.0; + alveolar length of upper molar tooth-row, 6.4; prelambdoidal + breadth, 8.9; and lambdoidal breadth, 11.7. + + Average and extreme measurements of six adult males from near + Pocatello, Bannock County, Idaho, and nine adult males from near + Afton, Lincoln County, Wyoming, are, respectively, as follows: + total length, 143(135-150), 163(143-179); length of tail, + 35.1(33-38), 42.8(36-49); caudal index, 32.0(28.0-33.1), + 35.7(30.6-41.9); hind foot, 18.9(18-20), 18.8(17-20); + condylobasilar length of skull, 24.4(24.0-26.0), 25.6(24.5-26.2); + alveolobasilar length, 14.1(13.7-14.5), 14.6(13.8-15.0); palatilar + length, 13.2(12.9-13.6), 13.8(13.2-14.5); alveolar length of upper + molar tooth-row, 6.3(6.1-6.5), 6.3(6.0-6.6); depth of braincase, + 7.7(7.5-7.9), 8.0(7.7-8.3); lambdoidal breadth, 11.4(11.0-11.7), + 12.0(11.3-12.7); prelambdoidal breadth, 9.1(8.6-9.4), 8.7(8.0-9.4); + zygomatic breadth, 14.3(13.8-14.7), 15.3(14.4-16.3); interorbital + breadth, 3.6(3.5-3.7), 3.5(3.3-3.7). The average length of the + nasal bones in the series from Pocatello is 7.1 mm. The averages, + which have not been included in Table 1, for three measurements of + the series from Carbon County, Wyoming, are as follows (Encampment, + males; Encampment, females; Savery, males; and Savery, females, + respectively): alveolobasilar length, 14.4, 14.3, 14.5, 14.3; + interorbital breadth, 3.5, 3.4, 3.5, 3.4; depth of braincase, 7.8, + 7.6, 7.9, 7.6. Additional measurements are included in Table 1 for + other series. + +_Discussion._--The name _Microtus montanus caryi_ Bailey is here placed +in synonymy under _M. m. nanus_ (Merriam). Vernon Bailey (1917) in his +description of _caryi_ made four assumptions that have been found to be +entirely or partly invalid. First, he assumed that this is an "extreme +variant which gradually changes in characters across Nevada and Utah, +and reaches its maximum variation in Wyoming." The differences pointed +out in subsequent descriptions of subspecies found in the above area do +not show a gradual change in any character, or in the number of +characters, nor is _caryi_ an extreme when compared with the other +subspecies. Second, _Microtus nanus_ was not, as Bailey assumed, a +different species than _Microtus montanus_. Third, he assumed that the +characteristics of adults of _nanus_ were adequately ascertainable from +the thirteen topotypes available to him. Subsequent sampling from Idaho +shows that the series of specimens available to Bailey was made up +mostly of young and subadult animals. Finally, _caryi_ does not occupy +as Bailey stated "the meadows along streams in the arid sagebrush +country of the Bear River, Green River, and Wind River valleys" +exclusively, or characteristically. When the localities from which the +species actually is known are plotted, it seems that the arid basin +serves as a barrier and that the species is more commonly and abundantly +found in montane meadows in the Transition and Canadian life-zones. + +Certain samples, here assigned to _M. m. nanus_, that vary from the +average of the subspecies deserve comment. For example, mice from the +area in Wyoming southwest of the Green River (in the Uinta Mountains) +have relatively smaller feet, but are larger in both total length and +size of skull. Specimens from near Afton, Lincoln County, Wyoming, are +relatively large in both total length and size of skull. This series and +specimens from Teton County, Wyoming, are intermediate between _nanus_ +from Idaho and the newly named subspecies from near Cody, Park County, +Wyoming, described below, in terms of both darkness and the amount of +reddish color. Mice from Laramie County are more richly reddish-brown. +The specimens from near Savery, in Carbon County, Wyoming, are darker. +The alveolobasilar length relative to the condylobasilar length is +smaller in the series from along Deer Creek, 16 mi. S, 11 mi. W Waltman, +Natrona County, Wyoming. The series from the southern tier of counties +in Wyoming and some of the specimens from Colorado have relatively wider +zygomatic arches. The specimens from southern Sweetwater County, +Wyoming, are relatively paler, have a relatively longer tail and longer +hindfeet, lesser condylobasilar length, and wider braincase. Most of +these variations are of questionable significance; they may be chance +variations owing to errors in sampling. + +Much of the south-central part of the state is relatively low and +relatively arid. This area includes the arid basin of the Green River +and its major tributaries and the arid Red Desert along the continental +divide in Sweetwater County. This area might have acted as a barrier to +the mice; gene flow might have been prevented between the populations of +the western part of the state and those farther east in the Medicine Bow +Mountains and Laramie Mountains. Nevertheless geographic variations of +subspecific worth have not taken place. The barrier has either not been +of as long duration, or has not been so complete and effective, as the +other barriers in the state, namely the Absaroka Range, the Big Horn +Basin, the Shoshone Basin, and the valley of the North Platte River. +These four barriers presumably have led to the differentiation of the +two subspecies that are newly named beyond. Each of the two areas which +is set apart by these barriers and in which one of the newly named +subspecies has evolved is small; therefore there is a lesser amount of +suitable habitat available for each of the newly named mice than there +is for _M. m. nanus_. It is conceivable, therefore, that in periods of +adverse conditions in each of the small areas the size of the effective +breeding population may have been so small that random genetic drift +could have operated effectively, or that selection was more critical +than in a larger, more stable population. It is difficult to test these +possibilities because the selective value of the taxonomic characters is +unknown. The observed pattern of variation and facts of distribution +are, however, not contradictory to the above possibilities. + + _Specimens examined._--Total, 993, distributed as follows: All + specimens unless otherwise indicated are in the University of + Kansas Museum of Natural History. Specimens in other museums are + labeled as follows: Chicago Natural History Museum (Chi); + University of Michigan, Museum of Zoology (Mich); American Museum + of Natural History (AMNH); United States National Museum (USNM); + Biological Surveys Collection (USBS). Localities that are not + represented in Fig. 1 because overlapping or crowding of the + symbols would result are Italicized. Localities are arranged from + north to south by states, within a state from northwest to + southeast by counties, and within a county from north to south. + + WYOMING: _Yellowstone Park_: Canyon Camp, 1 (USBS); Lower Geyser + Basin, 1 (USBS); Upper Yellowstone River, 2 (AMNH); _North end of + Lake_, _Yellowstone National Park_, 2 (AMNH). _Teton Co._: Pacific + Creek, 1 (USBS); _Big Game Ridge_, 3 (USBS 1, Mich 2); _Whetstone + Creek_, 7 (Mich); Moran and environs (6 localities within a 5 mile + radius), 28 (USBS 2, Mich 5); _S fork Buffalo River_, 7 (AMNH); 2 + mi. W pass, Black Rock Creek, 1 (USBS); _Jenny Lake_, 5 (Mich); Bar + BC Ranch, 2-1/2 mi. NE Moose, 6500 ft., 2; Teton Pass above Fish + Creek, 1 (USBS); Jackson and environs, 142 (Mich 141); _Sheep + Creek_, 2 (Mich). _Lincoln Co.: 13 mi. N, 2 mi. W Afton_, 2; _10 + mi. N, 2 mi. W Afton_, 4; _9-1/2 mi. N, 2 mi. W Afton_, 3; 9 mi. N, + 2 mi. W Afton, 9; _7 mi. N, 1 mi. W Afton_, 12; Afton, 1 (USBS); + Labarge Creek, 1 (USBS); Border, 6 (USBS); _Cokeville_, 2 (USBS); 6 + mi. N, 2 mi. E Sage, 1; Cumberland, 5 (USBS). _Sublette Co._: 34 + mi. N, 4 mi. W Pinedale, 1; _33 mi. N, 2 mi. W Pinedale_, 6; _32 + mi. N, 1 mi. W Pinedale_, 1; _31 mi. N Pinedale_, 4; Dell Creek, on + Ferris Ranch, 7 (Mich); Horse Creek, 7800 ft., Merna, 4 (USBS); Big + Piney, 1 (USBS). _Fremont Co._: 17-1/2 mi. W, 2-1/2 mi. N Lander, + 9500 ft., 3; _17 mi. W, 2 mi. N Lander, 9300 ft._, 4; Milford and + environs (5 localities within a 1 mile radius), 23 (USBS 4); 15-1/2 + mi. S, 7-1/2 mi. W Lander, 9200 ft., 1; South Pass City, 8000 ft, 8 + (USBS); _23-1/2 mi. S, 5 mi. W Lander, 8600 ft._, 7. _Natrona Co._: + Deer Creek, 16 mi. S, 11 mi. W Waltman, 6950 ft., 44; 6 mi. S, 2 + mi. W Casper, 5900 ft., 4; _6-4/5 mi. S, 2 mi. W Casper, 6100 ft._, + 1; _7 mi. S, 2 mi. W Casper, 6370 ft._, 3; _10 mi. S Casper, 7750 + ft._, 33; Sun, 2 (USBS); _5 mi. W Independence Rock, 6000 ft._, 4; + _5 mi. W, 1 mi. S Independence Rock_, 2. _Converse Co._: Beaver, 1 + (USBS). _Uinta Co.: 1-1/2 mi. W, 1/2 mi. S Cumberland_, 6; _16 mi. + S, 2 mi. W Kemmerer, 6700 ft._, 3; 10 mi. SW Granger, 3 (Mich); + Fort Bridger, 6650 ft., 25 (USNM 6); 9 mi. S Robertson, 8000 ft., + 9; _9-1/2 mi. S, 1/2 mi. W Robertson, 8600 ft._, 1; _10 mi. S, 1 + mi. W Robertson, 8700 ft._, 25; _14 mi. S, 2 mi. E Robertson, 9000 + ft._, 5; 4 mi. S Lonetree, 1 (USBS). _Sweetwater Co._: Farson, 3; + Bitter Creek, 3 (AMNH); Kinney Ranch, 21 mi. S Bitter Creek, 6800 + ft., 9 (USNM 1, AMNH 2); 32 mi. S, 22 mi. E Rock Springs, 7025 ft., + on Vermillion Creek, 15. _Carbon Co._: 18 mi. NNE Sinclair, 6500 + ft., 10; Bridgers Pass, 18 mi. SW Rawlins, 7500 ft., 7; Saratoga, 1 + (USBS); _6 mi. S, 13 mi. E Saratoga, 8500 ft._, 5; _6 mi. S, 14 mi. + E Saratoga, 8800 ft._, 1; Lake Marie, 10,440 ft., 2; _1 mi. S Lake + Marie_, 2; _1/2 mi. S, 2 mi. E Medicine Bow Peak, 10,800 ft._, 1; + Encampment (12 localities from 10 mi. N, 14 mi. E to 9 mi. N, 3 mi. + E Encampment and from 6500 to 8400 ft.), 63; 1/4 mi. N Riverside, + 7380 ft., 2; S base Bridger Peak, 8800 ft., Sierra Madre Mountains, + 1; _2 mi. S Bridger Peak, 9300 ft._, 2; Savery (10 localities from + 8 mi. N, 21 mi. E to 4 mi. N, 8 mi. E Savery and from 7300 to 8800 + ft.), 80. _Albany Co._: _30 mi. N, 10 mi. E Laramie, 6760 ft._, 6; + _29-3/4 mi. N, 9-1/2 mi. E Laramie, 6350 ft._, 1; 26 mi. N, 4-1/2 + mi. E Laramie, 6960 ft., 8; _26-3/4 mi. N, 6-1/2 mi. E Laramie, + 6700 ft._, 3; _3 mi. N, 13 mi. E Laramie, 7500 ft._, 1; _7 mi. N, 2 + mi. E Laramie_, 1 (Chi); 5 mi. N Laramie, 7400 ft., 15; _Laramie_, + 4 (AMNH); _1 mi. E Laramie, 7160 ft._, 4; 7-7/10 mi. SSW Laramie, + 7200 ft., 4; 6-1/2 mi. S, 8-3/4 mi. E Laramie, 8200 ft., 1; + _Headquarters Park, 10,200 ft., Medicine Bow Mountains_, 3 (USBS); + Centennial, 8120 ft., 1; _2-1/4 mi. ESE Brown's Peak, 10,300 ft._, + 3; _3 mi. ESE Brown's Peak, 10,000 ft._, 12; _2 mi. S Brown's Peak, + 10,600 ft._, 1; _Pole Mountain, 15 mi. SE Laramie_, 4 (USBS 3); _1 + mi. SSE Pole Mountain, 8350 ft._, 4; _2 mi. SW Pole Mountain, 8300 + ft._, 13; _3 mi. S Pole Mountain, 8100 ft._, 1; Sherman, 2 (AMNH). + _Laramie Co._: 5 mi. N, 1 mi. W Horse Creek P. O., 7200 ft., 1; + Meadow, 2 (USBS); 11 mi. N, 5-1/2 mi. E Cheyenne, 5450 ft., 7; _7 + mi. W Cheyenne, 6500 ft._, 10; Cheyenne, 3 (USNM). + + COLORADO: _Moffat Co._: Lay, 6160 ft., 1 (AMNH). _Routt Co._: + Wright's Ranch, Yampa, 7700 ft., 2; Gore Range, 8 mi. E Toponas, + 8000 ft., 2 (USBS). _Larimer Co._: _12-1/2 mi. W, 1-1/2 mi. S + Rustic_, 1; 11 mi. W, 1 mi. S Rustic, 1; Cache La Poudre River, 1 + (Chi); _Estes Park_, 3 (USBS 1, AMNH 2); 19-1/2 mi. W, 2-1/2 mi. S + Loveland, 7280 ft., 6; _16 mi. W Loveland, 6840 ft._, 1; 6 mi. W, + 1/2 mi. S Loveland, 5200 ft., 1. _Rio Blanco Co._: Meeker, 1 + (USBS); _9-1/2 mi. SW Pagoda Peak_, 7700 ft., 3; 5 mi. S Pagoda + Peak, 9100 ft., 2. _Eagle Co._: Eagle, 1 (USBS); Pando, 2 (USBS). + _Grand Co._: Mt. Whiteley, 2 (USBS); Arapahoe Pass, Rabbit Ear + Mountains, 2 (USBS); Coulter (near Granby), 5 (USBS); _Arrowhead_ + (near Dale), 1 (USBS). _Boulder Co._: 3/4 mi. N, 2 mi. W + Allenspark, 8400 ft., 4; _3 mi. S Ward_, 9000 ft., 3; Nederland, 16 + (Chi). _Clear Creek Co._: Mt. McLellan, 2 (USBS); Berthoud Pass, 4. + _Park Co._: Trout Creek Ranch, 2 mi. N Garo, 1 (USBS). + + Specimens examined of _M. m. nanus_ from eastern Idaho and Montana + are as follows: IDAHO: _Custer Co._: Challis, 7 (USBS); Mill Creek, + Challis Nat. Forest, 1 (USBS); Pahsimeroi Mts., 12 (USBS); Lost + River Mts., 1 (USBS). _Fremont Co._: N fork Snake River, 10 mi. SW + Island Park, 6200 ft., 2 (AMNH); Black Springs Creek, 4 mi. W + Ashton, 5200 ft., 1 (AMNH); 5 mi. W St. Anthony, 5000 ft., 1 + (AMNH). _Camas Co._: Camas Prairie, Corral, 5100 ft., 2 (USBS). + _Blaine Co._: Alturas Lake, 3 (USBS); _Sawtooth Lake_, 2 (USBS); + Craters of the Moon, Laidlow Park, 2 (Mich); Ticura, 10 mi. S + Picabo, 1 (USBS); 19 mi. NE Carey (Lava Lake), 8 (Mich). _Butte + Co._: _26 mi. SW Arco_, 12 (Mich). _Bingham Co._: Shelley, 6 + (USBS). _Bonneville Co._: 10 mi. SE Irwin, 4 (USBS). _Owyhee Co._: + Three Creeks, 3 (USBS). _Twin Falls Co._: Castleford Fenced Plot, + 11 mi. W, 9 mi. S Twin Falls, 1. _Minidoka Co._: _Heyburn_, 2 + (USBS). _Cassia Co._: 2 mi. S, 2 mi. W Burley, 5. _Bannock Co._: + Pocatello, 23 (USBS 4); Swan Lake, 1 (USBS). _Bear Lake Co._: + Montpelier Creek, 6700 ft., 3 (USBS). MONTANA: _Gallatin Co._: W. + Fork of W. Fork, Gallatin River, 1 (USBS). _Park Co._: Lamar River, + 7000 ft., 1 (USBS); Gardiner, 1 (USBS). _Sweet Grass Co._: 14 mi. S + Big Timber, 1 (USBS); _McLeod_, 1 (USBS); West Boulder Creek, 18 + mi. SE Livingston, 2 (USBS). + + +=Microtus montanus codiensis=, new subspecies + + _Type._--Female, adult, skin and skull; No. 27578, Museum of + Natural History, University of Kansas, from 3-1/5 mi. E and 3/5 mi. + S Cody, 5020 ft., Park Co., Wyoming; obtained on August 11, 1948, + by James W. Bee, original number 18-8-11-48. + + _Range._--In northwestern Wyoming eastward from the Absaroka and + Wind River ranges into the western part of the Big Horn Basin. + + _Diagnosis._--A relatively large _Microtus montanus_; tail actually + and relatively long; hind foot actually but not relatively large; + skull large; zygomatic expanse actually and relatively large; + alveolobasilar length relatively large; upper molar tooth-row + relatively long; color relatively light, not reddish. + +[Illustration: FIG. 1. Geographic range of _Microtus montanus_ in +Wyoming, Colorado, and adjacent areas. The solid circles represent +localities from which specimens have been examined; the hollow circles +represent type localities. The ranges of subspecies in Utah are after +Durrant, 1952. + +Guide to subspecies + +1. _M. m. nanus_ +2. _M. m. codiensis_ +3. _M. m. zygomaticus_ +4. _M. m. fusus_ +5. _M. m. micropus_ +6. _M. m. nexus_ +7. _M. m. amosus_ +8. _M. m. rivularis_ +] + + _Comparisons._--As compared with the specimens of _M. m. nanus_ + from Idaho, the size is larger (see diagnosis and measurements). + Certain proportions which differ from those of _nanus_ and which + are not in close agreement with the observed differences with age + in specimens of _nanus_ of a size comparable to _codiensis_ are + relatively large alveolobasilar length, relatively long alveolar + length of upper molar tooth-row, relatively wide-spreading + zygomatic arches, and relatively long tail. The color in + _codiensis_ is lighter than in _nanus_. As compared to the new + subspecies named below from the Big Horn Mountains to the east, + _codiensis_ is of similar size in head-body length, but has a + relatively as well as actually longer tail; the hind foot averages + longer; the upper molar tooth-row is relatively longer; the color + is slightly paler and less grizzled; the bullae are larger and less + flattened; the angle formed at the suture between the basioccipital + and basisphenoid bones is less acute; and the region of the suture + is less prominently elevated between the bullae when viewed from + the ventral aspect. The pterygoid plates mesial and posterodorsal + to the posterior end of the last upper molar are less fenestrated, + and the incisive foramina are less constricted posteriorly. + +[Illustration: FIG. 2. Map showing the major barriers to _Microtus +montanus_ in Wyoming and Colorado; the barriers are the low areas named +on the map (the name "Black Hills" is on the map for another reason; +these hills are not a barrier). The major mountainous areas higher than +approximately 8000 feet in elevation in Wyoming, Colorado and Utah are +stippled. These mountainous areas include the habitat that is most +suitable for the montane meadow mouse. The Black Hills are unoccupied by +this species but these hills seem to be ecologically suitable for the +species.] + + _Measurements._--The average and the extremes for some measurements + of 34 males and females, 27 from the type locality and 7 from other + localities in the range assigned to this subspecies, are as + follows: total length, 165 (146-186); length of tail, 44.2 (35-55); + hind foot, 19.6 (17-21); condylobasilar length of the skull, 25.5 + (24.0-27.5); zygomatic breadth, 15.6 (14.7-16.6); alveolar length + of upper molar tooth-row, 6.6 (6.2-7.0); prelambdoidal breadth, 8.8 + (8.1-9.5); lambdoidal breadth, 12.0 (11.2-12.8). As an indication + of variability and for comparison with other series the coefficient + of variability and two times the standard error of the mean for + each measurement in this series are included in Table 1. The + averages for some measurements of 27 topotypes are as follows: + total length, 162; length of tail, 45.5; hind foot, 19.9; + condylobasilar length, 25.6; palatilar length, 14.0; molar series, + 6.6; alveolobasilar length, 14.9; zygomatic breadth, 15.6; + interorbital breadth, 3.5; lambdoidal breadth, 12.1; prelambdoidal + breadth, 8.9; depth of braincase, 7.8. + +_Discussion._--Three species of _Microtus_ were collected by James W. +Bee at the type locality. _Microtus montanus codiensis_, _Microtus +longicaudus mordax_, and _Microtus pennsylvanicus modestus_ were taken +in the same runways in the same meadow, at the same time. _Microtus +ochrogaster haydeni_, although not taken at this locality, occurs in the +Big Horn Basin. These four species differ in their geographic ranges, +being largely allopatric, except _M. montanus_ and _M. longicaudus_ +which are sympatric. Although the different species have ecological +preferences and habits which differ, several species of _Microtus_ may +occur together in local areas such as the above. Certain of the +characteristics of _M. m. codiensis_ are intermediate between those of +the species _M. montanus_ on one hand and those of the other three +species on the other hand. Could interspecific hybridization between +"good species" of _Microtus_ take place in nature and possibly alter the +characteristics of a local population? + + _Specimens examined._--Total, 50, distributed as follows + (abbreviations for collections are given in the account of _M. m. + nanus_; localities that are not represented in Fig. 1 because + overlapping or crowding of the symbols would result are + Italicized): + + MONTANA: _Carbon Co._: Beartooth Mountains, 2 (USBS); _Beartooth + Lake_, 1 (USBS). + + WYOMING: _Park Co._: Black Mountain, head of Pat O'Hara Creek, 3 + (USBS); 13 mi. N, 1 mi. E Cody, 5200 ft., 1; SW slope Whirlwind + Peak, 9000 ft., 1; _5 mi. N Cody, 6300 ft._, 1 (USBS); 3-1/5 mi. E, + 3/5 mi. S Cody, 31; Ishawooa Creek, 6300 ft., 2 (USBS); _Valley_, 1 + (USBS); Needle Mountain, 10,500 ft., 4 (USBS). _Hot Springs Co._: 3 + mi. N, 10 mi. W Thermopolis, 4950 ft., 3. + + +=Microtus montanus zygomaticus=, new subspecies + + _Type._--Male, adult, skin and skull, No. 32761, Museum of Natural + History, University of Kansas, from Medicine Wheel Ranch, 9000 ft., + 28 mi. E Lovell, Big Horn County, Wyoming; obtained by R. Freiburg, + original number 105. + + _Range._--The Big Horn Mountains of north-central Wyoming. + + _Diagnosis._--A large _Microtus montanus_ with a relatively short + tail; short molar series; broad zygomatic arches well rounded in + lateral outline when viewed from above; small and flattened bullae; + raised basioccipito-basisphenoid suture. + + _Comparisons._--For comparison with _M. m. codiensis_ from the + west, on the other side of the Big Horn Basin, see the account of + that subspecies. In comparison with _nanus_ this subspecies is + slightly paler, in this respect showing more resemblance to + _codiensis_ although not so pale, and more grizzled or unevenly + colored. This difference in color between _zygomaticus_ and + _codiensis_ may not be of taxonomic significance. From both the + topotypes of _nanus_, and the series of it from Wyoming, + _zygomaticus_ differs on the average in having a relatively shorter + tail, a relatively shorter upper molar tooth-row, relatively more + rounded and relatively more wide-spread zygomatic arches, and + smaller more flattened bullae. + + _Measurements._--Average and extreme measurements of 24 adult males + and females from several localities here referred to _M. m. + zygomaticus_ are as follows: total length, 159(150-175); length of + tail, 37.6(31-46); hind foot, 18.6(17-20); condylobasilar length of + the skull, 25.3(24.2-26.7); zygomatic breadth, 15.3(14.1-16.7); + alveolar length of upper molar tooth-row, 6.2 (5.7-6.8); + prelambdoidal breadth, 8.7(8.3-9.4); lambdoidal breadth, + 11.9(11.0-12.5). Average and extreme measurements of a series of 12 + adult male topotypes are as follows: total length, 159(144-174); + length of tail, 36.4 (30-41); hind foot, 18.2(16-20); + condylobasilar length of skull, 25.8(24.7-26.7); alveolobasilar + length, 14.8(13.8-15.3); palatilar length, 13.8 (12.7-14.2); + alveolar length of upper molar tooth-row, 6.4(5.9-6.6); zygomatic + breadth, 15.9 (15.0-16.7); interorbital breadth, 3.6(3.4-3.7); + lambdoidal breadth, 12.1 (11.5-12.5); prelambdoidal breadth, + 8.6(8.3-8.9); depth of braincase, 8.0 (7.6-8.3). + +_Discussion._--This subspecies is separated from _M. m. codiensis_ to +the west by the Big Horn Basin. A series from along Buffalo Creek, 27 +mi. N, 1 mi. E Powder River, 6075 ft., in Natrona County, Wyoming, is +intermediate between the topotypes of _zygomaticus_ and _nanus_ in the +characters cited above as distinguishing the two, but shows greater +resemblance to _zygomaticus_ in the shape of the zygomatic arch, in +color which is paler than in topotypes of _zygomaticus_, and in the +short hind foot. On these and on geographic grounds this population is +referred to _zygomaticus_. Unfortunately we cannot be certain in many +cases that an intermediate condition in a certain character indicates a +genetically intermediate population and therefore true intergradation +between the two subspecies to which the population is geographically +intermediate. The topotypes of this subspecies are the most distinct of +all the series which I have studied from the eastern Rocky Mountains, in +terms of the degree of morphological departure from the norm for the +species. After _zygomaticus_ the following populations are arranged +according to their degree of deviation from this norm (_codiensis_ +deviates most): topotypes of _codiensis_, _fusus_ and a population from +southern Sweetwater County, Wyoming, and lastly the _nanus-caryi_ +complex. Within the latter group, as I have mentioned, there are a +number of local variants most of which do not differ significantly and +do not conform to any geographic pattern. + + _Specimens examined._--Total, 55, distributed as follows + (abbreviations for collections are given in the account of _M. m. + nanus_; localities that are not represented in Fig. 1 because + overlapping or crowding of the symbols would result are + Italicized): WYOMING: _Big Horn Co._: Medicine Wheel Ranch, 9000 + ft., 28 mi. E Lovell, 30; W slope, head of Trappers Creek, 9500 + ft., 2 (USBS). _Washakie Co._: 9 mi. E, 5 mi. N Tensleep, 7400 ft., + 1. _Johnson Co._: 7-1/2 mi. W, 1 mi. S Buffalo, 6500 ft., 3; Big + Horn Mountains, 3 (USBS). _Natrona Co._: Buffalo Creek, 27 mi. N, 1 + mi. E Powder River, 6075 ft., 16. + + +=Microtus montanus fusus= Hall + + _Microtus nanus_, Bailey, N. Amer. Fauna, 17:30, June 6, 1900 + (part); Cary, N. Amer. Fauna 33:123, August 17, 1911. + + _Microtus montanus fusus_ Hall, Proc. Biol. Soc. Washington, + 51:131-134, August 23, 1938; Warren, The Mammals of Colorado, Univ. + of Okla. Press, p. 229, 1942. + + _Type._--Male, adult, skin and skull; No. 61281, Museum of + Vertebrate Zoology; 2-1/2 miles east of summit of Cochetopa Pass, + Saguache County, Colorado; Sept. 21, 1933; collected by Annie M. + Alexander; original number 2568. Type not seen by me. + + _Range._--Southern Colorado and northern New Mexico. + + _Comparisons._--For comparison with _M. m. nanus_, the subspecies + to the northward, see the preceding account of that subspecies. For + comparison with _M. m. amosus_ the subspecies to the west see Hall + (1938) and Durrant (1952). I have not examined specimens of + _amosus_. + + _Measurements._--Average and extreme measurements for 17 adults + including both males and females from several localities in + southern Colorado are as follows: total length, 160 (136-179); + length of tail, 42 (35-55); hind foot, 19.2 (17-23); condylobasilar + length of the skull, 25.2 (24.0-26.0); zygomatic breadth, 15.0 + (14.1-15.5); alveolar length of upper molar tooth-row, 6.4 + (6.0-6.7); prelambdoidal breadth, 8.7 (8.3-9.2); lambdoidal + breadth, 11.7 (11.1-12.6). + + Average and extreme measurements of 4 adults (2 males and 2 + females) from the type locality and 11 adults (4 males and 7 + females) from other localities in southern Colorado are as follows: + total length, 162 (157-168), 157 (137-169); length of tail (means + only), 44.5, 40.5; hind foot, 18.8 (18-19), 18.6 (18-23); + condylobasilar length of skull, 24.5 (24.0-24.7), 25.2 (24.3-26.1); + alveolobasilar length, 14.2 (13.9-14.5), 14.6 (14.1-15.1); + palatilar length, 13.2 (13.0-13.4), 13.5 (13.1-14.2); alveolar + length of upper molar tooth-row, 6.3 (6.0-6.6), 6.4 (6.3-6.7); + zygomatic breadth, 15.0 (14.3-15.5), 14.9 (14.1-15.5); interorbital + breadth, 3.5 (3.3-3.6), 3.5 (3.3-3.7); lambdoidal breadth, 11.8 + (11.1-12.6), 11.7 (11.2-12.3); prelambdoidal breadth, 8.6 + (8.3-9.2), 8.8 (8.3-9.0); depth of braincase, 7.5 (7.2-7.8), 7.6 + (7.1-7.9). + +_Discussion._--There is no sharp boundary between _M. m. fusus_ of +southern Colorado and the subspecies to the north, _M. m. nanus_. +Although the line separating these two subspecies is drawn somewhat +arbitrarily, on the whole the samples from north of this line more +closely resemble _nanus_. All of the means for total length given above +are larger than the maximum given in Hall's description of _fusus_. The +caudal index (38 and 35% in two series) is slightly larger than that +cited by Hall (33.3%) and is not significantly different from that in +_nanus_ (35.2%). The color in both young and old mice is variable, but +in general is more yellowish, and less grayish, than in any other series +studied. + +There is a large area in western Colorado and eastern Utah, between the +known ranges of _M. m. fusus_ and _M. m. amosus_ from which there are no +specimens. Probably the species occurs only at certain places in this +arid region which seems to be a partial barrier to the species. + +Specimens of _M. montanus_ from northern New Mexico have been referred +previously to _M. m. arizonensis_. When he named _M. m. fusus_, Hall +mentioned its resemblance to _arizonensis_ in reddish coloration, but +pointed out that _fusus_ is less reddish. Of six specimens from Valle +Santa Rosa, Jemez Mountains (USBS), 8500 ft., Rio Arriba County, New +Mexico, three are immature, and the skulls of the remaining specimens +are damaged. In reddish color and relatively large size these few +specimens resemble _arizonensis_ more than _fusus_ although the locality +of occurrence is closer to the geographic range of the northern _fusus_ +than to that of _arizonensis_. The identification of these specimens as +_arizonensis_ is provisional; additional specimens are needed from the +area, 200 miles wide, which separates the ranges as now known of +_arizonensis_ in Arizona from the occurrence in New Mexico. There is a +single specimen from this area, the damaged skull of which prevents +conclusive identification. The specimen is either _M. montanus_ or _M. +mexicanus_, and is from Nutria, on the southern edge of the Zuni +Mountains (USBS). Detailed comparison of _fusus_ and _arizonensis_ is +not attempted here although it may be stated that in several characters +_fusus_ is intermediate between _arizonensis_ to the south and _nanus_ +to the north. + + _Specimens examined._--Total, 89, distributed as follows + (abbreviations for collections are given in the account of _M. m. + nanus_; localities that are not represented in Fig. 1 because + overlapping or crowding of the symbols would result are + Italicized): + + COLORADO: _Pitkin Co._: 5 mi. W Independence Pass, 11,000 ft., 1 + (Chi). _Lake Co._: _Independence Pass, 12,095 ft._, 2 (Chi). + _Gunnison Co._: _Gothic_, 2 (USBS); Decker's Ranch, Crested Butte, + 2 (AMNH); Almont, 3 (USBS). _Montrose Co._: Coventry, 5 (USBS 4, + AMNH 1). _Saguache Co._: Cochetopa Pass and environs, 44 (USBS + 22). _Hinsdale Co._: Ruby Lake, 1 (USBS). _Mineral Co._: 3 mi. E + Creede, 1; 23 mi. S, 11 mi. E Creede, 9300 ft., 7. _La Plata Co._: + Florida, 6800 ft., 1. _Conejos Co._: 1 mi. S, 19 mi. W Antonito, + 10,200 ft., 3; _4 mi. S, 23 mi. W Antonito_, 1; _5 mi. S, 24 mi. W + Antonito, 9600 ft._, 9. + + NEW MEXICO: _Rio Arriba Co._: 6 mi. W Hopewell, 9900 ft., 6 (USBS); + _Tusas River, 8700 ft._, 1 (USBS). + +TABLE 1. AVERAGE MEASUREMENTS, IN MILLIMETERS, OF ADULTS OF MICROTUS +MONTANUS. + +Key to column headings: + +A: No. of individuals averaged +B: Total length +C: Length of tail +D: Length of hind foot +E: Condylobasilar length +F: Alveolar length of upper molar tooth-row +G: Zygomatic breadth +H: Lambdoidal breadth +I: Prelambdoidal breadth + +========================================================================= + Locality | A | B | C | D | E | F | G | H | I +------------------+------+-----+-----+-----+-----+-----+-----+-----+----- + | _M. m. codiensis_, all + | +Average | 34 |165.3|44.2 |19.6 |25.47| 6.56|15.55|12.05|8.76 +2 x stand. error | | 3.56| 1.84| .395| .308| .067| .198| .144|.129 +Coeff. variab | | 6.0|11.6 | 5.6 | 3.5 | 3.0 | 3.65| 1.20|1.47 +------------------+------+-----+-----+-----+-----+-----+-----+-----+----- + | _M. m. nanus_, Eastern Idaho + | +Average | 21[1]|151.1|39.4 |19.2 |25.00| 6.44|14.99|11.74|8.94 +2 x stand. error | | 3.20| 2.89| .293| .286| 1.15| .295| .210|.182 +Coeff. variab. | | 6.1|21.1 | 4.38| 2.49| 3.99| 4.10| 3.79|4.31 +------------------+------+-----+-----+-----+-----+-----+-----+-----+----- + | _M. m. nanus_, Wyoming + | +Teton Co. | 35 |160.5|40.7 |18.6 |25.16| 6.51|15.17|11.86|8.77 +Fremont Co. | 26 |157.0|41.4 |19.6 |25.23| 6.25|15.05|11.88|8.91 +Lincoln Co. | 24 |159.9|41.8 |18.9 |25.08| 6.26|15.10|11.82|8.75 +Uinta Co. | 26 |162.4|41.3 |19.0 |25.33| 6.42|15.31|12.16|8.89 +Sweetwater Co. | 12 |159.8|43.7 |20.1 |24.98| 6.31|15.00|11.84|9.02 +Natrona Co. | 40 |159.6|41.0 |19.6 |25.04| 6.40|15.00|11.84|8.93 +Carbon Co. |108 |158.7|40.0 |19.1 |24.96| 6.27|15.05|11.83|8.72 + Encampment [M] | 27 |161 |41.7 |18.9 |25.1 | 6.16|15.2 |11.9 |8.7 + Encampment [F] | 11 |159 |41.1 |19.4 |24.9 | 6.18|14.9 |11.6 |8.6 + Savery [M] | 23 |159 |41.0 |19.2 |25.3 | 6.32|15.2 |12.2 |8.8 + Savery [F] | 25 |155 |37.1 |18.8 |24.7 | 6.33|14.8 |11.6 |8.6 +------------------+------+-----+-----+-----+-----+-----+-----+-----+----- + | _M. m. nanus_ + | +Northern Colo. | 8 |163.1|42.4 |19.6 |25.20| 6.44|14.86|11.70|8.56 +------------------+------+-----+-----+-----+-----+-----+-----+-----+----- + | _M. m. fusus_ + | +Southern Colo. | 17[2]|159.8|42.4 |19.2 |24.97| 6.43|14.98|11.73|8.69 +------------------+------+-----+-----+-----+-----+-----+-----+-----+----- + +[Footnote 1: For external parts, 34 individuals were used.] + +[Footnote 2: For external parts, 29 individuals were used.] + +Some measurements not given above are included in Table 1, together with +the number of specimens and the sex if restricted to one sex. So that +the variability can be evaluated more adequately, the coefficient of +variability and 2 times the standard error of the mean are included for +the measurements in two series. The series consist of all the adult +specimens (with a condylobasilar length of 24.0 mm. or more) of both +sexes from the areas specified. Various barriers are shown in Fig. 2 for +comparison with the distributions of the subspecies and the localities +of known occurrence shown in Fig. 1. _Microtus montanus_ has not been +taken in the Black Hills area of extreme northeastern Wyoming. Suitable +montane habitat is present and both _Microtus pennsylvanicus insperatus_ +and _Microtus longicaudus longicaudus_ occur there. The arid basin of +the Powder River presumably is a barrier that has prevented _M. +montanus_ from reaching this area. + + +REFERENCES CITED + +BAILEY, V. + + 1900. Revision of American voles of the genus _Microtus_. N. Amer. + Fauna, 17:1-88, June 6. + + 1917. A new subspecies of meadow mouse from Wyoming. Proc. Biol. + Soc. Washington, 30:29-30, February 21. + +CARY, M. + + 1911. A biological survey of Colorado. N. Amer. Fauna, 33:1-256, + August 17. + + 1917. Life zone investigations in Wyoming. N. Amer. Fauna, 42:1-95, + October 3. + +DAVIS, W. B. + + 1939. The Recent mammals of Idaho. 400 p., front., illus., maps, + diagrs., Caldwell, Id., The Caxton Printers Ltd., April 5. + +DURRANT, S. D. + + 1952. Mammals of Utah, taxonomy and distribution. Univ. Kans. + Publ., Mus. Nat. Hist., 6:1-549, 91 figs, in text, 30 tables, + August 10. + +ELTON, C. + + 1942. Voles, mice and lemmings; problems in population dynamics. + 496 p., illus. (maps), tables, Oxford, The Clarendon Press, London. + +GOIN, O. B. + + 1943. A study of individual variation in _Microtus pennsylvanicus + pennsylvanicus_. Jour. Mamm., 24:212-224, June 7. + +HALL, E. R. + + 1938. Notes on the meadow mice _Microtus montanus_ and _Microtus + nanus_ with descriptions of a new subspecies from Colorado. Proc. + Biol. Soc. Washington, 51:131-134, August 23. + +HILL, E. A. + + 1935. Cranial foramina in rodents. Jour. Mamm. 16(2):121-129. + +HOWELL, A. B. + + 1924. Individual and age variation in _Microtus montanus yosemite_. + Jour. Agr. Res., 28(10):977-1015, June 7. + +KELLOGG, R. + + 1922. A study of the California forms of the _Microtus montanus_ + group of meadow mice. Univ. California Publ. Zool., 21:245-274, + April 18. + +MERRIAM, C. H. + + 1891. Results of a biological reconnaissance of south-central + Idaho. N. Amer. Fauna, 5:1-113, July 30. + +PIPER, S. E. + + 1909. The Nevada mouse plague of 1907-8. U. S. Dept. Agr., Farmers' + Bul. 352, pp. 1-23, 9 figs. + +WARREN, E. R. + + 1942. The mammals of Colorado, their habits and distribution. + Second (revised) edition, Univ. Oklahoma Press, Norman, xviii-330 + p., front., 50 plates. + + +_Transmitted March 22, 1954._ + + + +[SQUARE] + +25-3560 + + + * * * * * + +Transcriber's Notes + +Italic typeface in the original is indicated by by _underscores_. + +Bold typeface in the original is indicated by =equals=. + +The symbols for [Male] and [Female] are indicated by [M] and [F]. + +One typographical error was corrected: "Castlford" was corrected to +"Castleford" in "Twin Falls Co.: Castleford Fenced Plot". + + + + + +End of the Project Gutenberg EBook of Subspeciation in the Meadow Mouse, +Microtus montanus, in Wyoming and Colorado, by Sydney Anderson + +*** END OF THIS PROJECT GUTENBERG EBOOK MEADOW MOUSE *** + +***** This file should be named 31730.txt or 31730.zip ***** +This and all associated files of various formats will be found in: + http://www.gutenberg.org/3/1/7/3/31730/ + +Produced by Chris Curnow, Simon Gardner, Joseph Cooper and +the Online Distributed Proofreading Team at +http://www.pgdp.net + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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