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UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATURAL HISTORY

VOLUME 1
1946-1950

EDITORS

E. RAYMOND HALL
DONALD S. FARNER
DONALD F. HOFFMEISTER
H. H. LANE
A. BYRON LEONARD
EDWARD H. TAYLOR
ROBERT W. WILSON

MUSEUM OF NATURAL HISTORY
UNIVERSITY OF KANSAS
LAWRENCE, KANSAS
1950




MUSEUM OF NATURAL HISTORY
UNIVERSITY OF KANSAS
LAWRENCE, KANSAS

PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1950

23-2413




CONTENTS


     1. The pocket gophers (genus Thomomys) of Utah. By Stephen
     D. Durrant. Pp. 1-82, 1 figure in text. August 15, 1946.

     2. The systematic status of Eumeces pluvialis Cope, and
     noteworthy records of other amphibians and reptiles from
     Kansas and Oklahoma. By Hobart M. Smith. Pp. 85-89. August
     15, 1946.

     3. The tadpoles of Bufo cognatus Say. By Hobart M. Smith.
     Pp. 93-96, 1 figure in text. August 15, 1946.

     4. Hybridization between two species of garter snakes. By
     Hobart M. Smith. Pp. 97-100. August 15, 1946.

     5. Selected records of reptiles and amphibians from Kansas.
     By John Breukelman and Hobart M. Smith. Pp. 101-112. August
     15, 1946.

     6. Kyphosis and other variations in soft-shelled turtles. By
     Hobart M. Smith. Pp. 117-124, 3 figures. July 7, 1947.

     7. Natural history of the prairie vole (Mammalian genus
     Microtus). By E. W. Jameson, Jr. Pp. 125-151, 4 figures in
     text. October 6, 1947.

     8. The postnatal development of two broods of great horned
     owls (Bubo virginianus). By Donald F. Hoffmeister and Henry
     W. Setzer. Pp. 157-173, 5 figures in text. October 6, 1947.

     9. Additions to the list of the birds of Louisiana. By
     George H. Lowery, Jr. Pp. 177-192. November 7, 1947.

     10. A check-list of the birds of Idaho. By M. Dale Arvey.
     Pp. 193-216. November 29, 1947.

     11. Subspeciation in pocket gophers of Kansas. By Bernardo
     Villa R. and E. Raymond Hall. Pp. 217-236, 2 figures in
     text. November 29, 1947.

     12. A new bat (Genus Myotis) from Mexico. By Walter W.
     Dalquest and E. Raymond Hall. Pp. 237-244, 6 figures in
     text. December 10, 1947.

     13. Tadarida femorosacca (Merriam) in Tamaulipas, Mexico. By
     Walter W. Dalquest and E. Raymond Hall. Pp. 245-248, 1
     figure in text. December 10, 1947.

     14. A new pocket gopher (Thomomys) and a new spiny pocket
     mouse (Liomys) from Michoacán, México. By E. Raymond Hall
     and Bernardo Villa-R. Pp. 249-256, 6 figures in text. July
     26, 1948.

     15. A new hylid frog from eastern Mexico. By Edward H.
     Taylor. Pp. 257-264, 1 figure in text. August 16, 1948.

     16. A new extinct emydid turtle from the Lower Pliocene of
     Oklahoma. By Edwin C. Galbreath. Pp. 265-280, 1 plate.
     August 16, 1948.

     17. Pliocene and Pleistocene records of fossil turtles from
     western Kansas and Oklahoma. By Edwin C. Galbreath. Pp.
     281-284, 1 figure in text. August 16, 1948.

     18. A new species of heteromyid rodent from the Middle
     Oligocene of northeast Colorado with remarks on the skull.
     By Edwin C. Galbreath. Pp. 285-300, 2 plates. August 16,
     1948.

     19. Speciation in the Brazilian spiny rats (Genus
     Proechimys, Family Echimyidae). By João Moojen. Pp. 301-406,
     140 figures in text. December 10, 1948.

     20. Three new beavers from Utah. By Stephen D. Durrant and
     Harold S. Crane. Pp. 407-417, 7 figures in text. December
     24, 1948.

     21. Two new meadow mice from Michoacán, México. By E.
     Raymond Hall. Pp. 423-427, 6 figures in text. December 24,
     1948.

     22. An annotated check list of the mammals of Michoacán,
     México. By E. Raymond Hall and Bernardo Villa-R. Pp.
     431-472, 2 plates, 1 figure in text. December 27, 1949.

     23. Subspeciation in the kangaroo rat, Dipodomys ordii. By
     Henry W. Setzer. Pp. 423-573, 27 figures in text, 7 tables.
     December 27, 1949.

     24. Geographic range of hooded skunk, Mephitis macroura,
     with description of a new subspecies from Mexico. By E.
     Raymond Hall and Walter W. Dalquest. Pp. 575-580, 1 figure
     in text. January 20, 1950.

     25. Pipistrellus cinnamomeus Miller 1902 referred to the
     genus Myotis. By E. Raymond Hall and Walter W. Dalquest. Pp.
     581-590, 5 figures in text. January 20, 1950.

     26. A synopsis of the American bats of the genus
     Pipistrellus. By E. Raymond Hall and Walter W. Dalquest. Pp.
     591-602, 1 figure in text. January 20, 1950.

     Index pp. 605-638.




The Pocket Gophers (Genus Thomomys)
of Utah

BY

STEPHEN D. DURRANT


University of Kansas Publications
Museum of Natural History

Volume 1, No. 1, pp. 1-82, 1 figure in text
August 15, 1946


UNIVERSITY OF KANSAS
LAWRENCE
1946




The Pocket Gophers (Genus Thomomys)
of Utah

BY

STEPHEN D. DURRANT


University of Kansas Publications
Museum of Natural History

Volume 1, No. 1, pp. 1-82, 1 figure in text
August 15, 1946


UNIVERSITY OF KANSAS
LAWRENCE
1946




UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY

Editors: E. Raymond Hall, Chairman, Donald S. Farner,
Donald F. Hoffmeister

Volume 1, No. 1, pp. 1-82, 1 figure in text.

Published AUGUST 15, 1946

UNIVERSITY OF KANSAS
Lawrence, Kansas

PRINTED BY
FERD VOILAND, JR., STATE PRINTER
TOPEKA, KANSAS
1946

21-2786




The Pocket Gophers (Genus Thomomys) of Utah

By

STEPHEN D. DURRANT

Contribution from the Department of Biology, University of Utah,
and the Museum of Natural History, University of Kansas.




INTRODUCTION


The history of pocket gophers of Utah begins with J. A. Allen's mention
in 1874 of mounds of these animals. For them he employed the name
"_Thomomys rufescens?_" (1874:65). Actual specimens were reported upon
a year later by Elliot Coues (1875:251, 256), who used the name
_Thomomys talpoides_ for specimens from "Utah" but later in the same
paper listed specimens from Provo as _Thomomys talpoides bulbivorus_.
Even as the great variation in Utah pocket gophers has been perplexing
to modern workers, so it was also to Coues seventy years ago who left
the problem with the statement that animals from Provo "exhibit among
themselves such variations that their labelling becomes a matter of
indifference"! In the same year in another report, Coues and Yarrow
(1875:112) used the name _Thomomys talpoides umbrinus_ for animals from
Provo. In 1877, Coues again referred these same animals to _Thomomys
talpoides bulbivorus_, using the name _umbrinus_ for the animals of
only southern Utah (Coues, 1877:627, 628). The two names _Thomomys
bottae_ and _Thomomys talpoides_, now applicable to gophers in Utah,
were synonomized under the name _Thomomys talpoides bulbivorus_ by
Coues (1875:256; 1877:627). After this beginning only three other
papers, all by J. A. Allen, appeared in the next twenty years. They
were reports on collections of mammals made by Walter W. Granger and
Charles P. Rowley. One of these contained the description of _Thomomys
aureus_. Likewise, in the ensuing twenty years there were only three
papers, one in 1901 by C. Hart Merriam in which he described _Thomomys
uinta_, one by Allen (1905:119), and Vernon Bailey's (1915) "Revision
of the pocket gophers of the genus _Thomomys_" in which he summarized
the information then available on these animals within the state.
Barnes (1922 and 1927) reprinted the information summarized by Bailey.
Since 1927 approximately twenty-five papers, mostly taxonomic, have
been published in which reference is made to Utah gophers, and
especially since 1930 much information has been accumulated about the
distribution and speciation of this genus within the state.

Specimens to the number of 1,045 have been available for this study.
Whereas Bailey (_loc. cit._) listed only four kinds belonging to four
different species, thirty-five kinds are now known from Utah. Seven of
these are herein described as new. The thirty-five kinds are found to
belong to only two instead of four full species.

Inasmuch as the literature is scattered and since names have been
applied in different ways at different times, I have attempted to give
a synonomy as complete as possible for each form found within the
state.

The bibliographies of Hayward (1936 and 1941) and Miller's (1924) "List
of North American mammals" have been of great use.

Capitalized color terms in the accounts are after Ridgway, Color
Standards and Color Nomenclature, Washington, D. C., 1912.

In the lists of specimens examined, the localities are listed by
counties from west to east, beginning at the northwestern corner of the
state, and within each county from north to south. When two localities
are on the same latitude, the westernmost is listed first.

     I am deeply indebted to Professor R. V. Chamberlin, of the
     University of Utah, for encouragement and support in my
     investigation. I also acknowledge critical assistance in the
     preparation of this paper from Professor E. Raymond Hall of
     the University of Kansas. For the loan of specimens I am
     grateful to the following: Clinton G. Abbott and Lawrence M.
     Huey, Natural History Museum of San Diego, San Diego,
     California; Harold E. Anthony and J. Eric Hill, American
     Museum of Natural History, New York City, New York; Seth B.
     Benson, Museum of Vertebrate Zoölogy, University of
     California, Berkeley, California; William H. Burt, Museum of
     Zoölogy, University of Michigan, Ann Arbor, Michigan; J.
     Kenneth Doutt, Carnegie Museum, Pittsburgh, Pennsylvania;
     Ross Hardy, Dixie Junior College, St. George, Utah; C. Lynn
     Hayward and Vasco M. Tanner, Brigham Young University,
     Provo, Utah; H. H. T. Jackson and Viola S. Schantz, United
     States Fish and Wildlife Service, U. S. National Museum,
     Washington, D. C.; Remington Kellogg and Alexander Wetmore,
     U. S. National Museum, Washington, D. C.; J. S. Stanford,
     Utah State Agricultural College, Logan, Utah.

     Unless otherwise indicated, specimens are in the Museum of
     Zoölogy, University of Utah, Salt Lake City, Utah. In lists
     of specimens examined, abbreviations are employed as
     follows:

(A. M. N. H.)      American Museum of Natural History.
(N. H. M. S. D.)   Natural History Museum of San Diego.
(M. V. Z.)         Museum of Vertebrate Zoölogy, University of California.
(U. M.)            Museum of Zoölogy, University of Michigan.
(C. M.)            Carnegie Museum.
(R. H.)            Collection of Ross Hardy.
(B. Y. U.)         Brigham Young University.
(U. S. N. M.)      United States National Museum.
(U. S. A. C.)      Utah State Agricultural College.
(K. U.)            Museum of Natural History, University of Kansas.

[Illustration: FIG. 1. Map showing the distribution of species and
subspecies of pocket gophers in Utah.]

Guide to subspecies:

     1. _T. t. gracilis_
     2. _T. t. wasatchensis_
     3. _T. t. oquirrhensis_
     4. _T. t. uinta_
     5. _T. t. pygmaeus_
     6. _T. t. ravus_
     7. _T. t. ocius_
     8. _T. t. moorei_
     9. _T. t. fossor_
     10. _T. t. parowanensis_
     11. _T. t. levis_
     12. _T. b. aureiventris_
     13. _T. b. robustus_
     14. _T. b. minimus_
     15. _T. b. nesophilus_
     16. _T. b. stansburyi_
     17. _T. b. albicaudatus_
     18. _T. b. bonnevillei_
     19. _T. b. centralis_
     20. _T. b. sevieri_
     21. _T. b. convexus_
     22. _T. b. tivius_
     23. _T. b. contractus_
     24. _T. b. lenis_
     25. _T. b. levidensis_
     26. _T. b. osgoodi_
     27. _T. b. howelli_
     28. _T. b. wahwahensis_
     29. _T. b. dissimilis_
     30. _T. b. aureus_
     31. _T. b. birdseyei_
     32. _T. b. virgineus_
     33. _T. b. planirostris_
     34. _T. b. absonus_
     35. _T. b. alexandrae_




GENUS =Thomomys= Wied


All pocket gophers of Utah belong to the genus _Thomomys_. There are
only two species within the state, _Thomomys bottae_ with twenty-four
subspecies and _Thomomys talpoides_ with eleven subspecies.

Due to marked mutational capacities and ready response to environmental
pressures and sedentary habits, pocket gophers differentiate readily
into numerous subspecies. It is well known that Utah by its highly
varied topography and climate possesses widely different types of
habitats. The aforementioned plasticity of these animals and possibly
the fact that both species are at the extreme limits of their ranges in
Utah account for the numerous forms found within the state.

The genus may be characterized as follows: Highly specialized fossorial
rodents, with heavy, thick bodies; all four legs of approximately equal
length, but front legs more muscular for digging, and feet provided
with long claws; external fur-lined cheek pouches; small eyes, short
ears and tail; upper incisors long and projecting external to lips.
Skull: Stout and flattened; zygomatic arches well developed and usually
widely spreading; all teeth with permanent pulp cavities; incisors
superficially smooth, but fine median groove present on anterior face
of each upper incisor; dental formula, i. 1/1, c. 0/0, p. 1/1, m. 3/3;
external auditory canal long; stapedial artery small and enclosed
within an osseous canal.


=Thomomys talpoides= (Richardson)

_Thomomys talpoides_ is a northern species that in Utah approaches the
southern limits of its range. The animals of this species inhabit the
mountains and high valleys. In the southward extension of their range,
as in Utah, they are found at higher elevations which zonally represent
lower elevations at more northern latitudes. The specific characters
are: Sphenorbital fissure absent; incisive foramina anterior to
infraorbital canal; anterior prism of P4 triangular; interparietal
relatively large; lambdoidal suture concave posteriorly in region of
interparietal, in Utah specimens.


=Thomomys talpoides gracilis= Durrant

     _Thomomys quadratus gracilis_ Durrant, Bull. Univ. Utah, 39
     (No. 6):3, February 28, 1939.

     _Thomomys talpoides gracilis_ Durrant, Bull. Univ. Utah, 30
     (No. 5):6, August 24, 1939; Goldman, Journ. Mamm., 25:414,
     December 12, 1944.

     _Thomomys quadratus fisheri_ Hall, Univ. California Publ.
     Zoöl., 37:4, April 10, 1931.

     _Thomomys uinta_ Bailey, N. Amer. Fauna, 39:114, November
     15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):83, April,
     1922; Bull. Univ. Utah, 17 (No. 12):104, June, 1927.

_Type._--Male adult, skin and skull; No. 44866, Museum of Vertebrate
Zoölogy, University of California; Pine Canyon, 6,600 ft., 17 mi. NW
Kelton, Box Elder County, Utah; July 12, 1930; collected by Annie M.
Alexander; original number 676.

_Range._--Mountainous regions of extreme northwestern Utah.

_Diagnosis._--Size medium (see measurements). Color: Upper parts
Buckthorn Brown grading over the sides and flanks to Light Buff on the
underparts; chin white; nose and postauricular patches grayish black.
Claws on front feet long and slender. Skull: Long and slender; rostrum
long and narrow; zygomatic and mastoidal breadths slight; palatal pits
deep; upper incisors narrow; basioccipital wide.

_Comparisons._--Compared with topotypes of _Thomomys talpoides
fisheri_, _gracilis_ is of approximately the same size. Upper parts
darker and underparts lighter; postauricular patches larger and darker;
claws on front feet longer and slenderer. Skull: Generally longer and
narrower; nasals and rostrum longer; basioccipital wider.

As compared with _T. t. uinta_, _gracilis_ is of approximately the same
size but differs as follows: Color: Lighter throughout; postauricular
patches markedly smaller and lighter; inguinal and pectoral regions
much lighter. One characteristic difference is in the ear. In _uinta_
the external opening of the ear is much larger; the pinna of the ear is
larger, more rounded at the tip, and lacks most of the pigmentation on
the inner margin. Skull: Generally narrower and longer; nasals longer;
zygomatic arches weaker and less angular; upper incisors narrower.

This form is easily distinguished from _bridgeri_ by smaller size, and
by the skull being longer, narrower and less angular.

From _Thomomys talpoides oquirrhensis_ to the southeast, _T. t.
gracilis_ can be distinguished by: Total length and ear shorter. Color:
Generally lighter, except the underparts which are about the same;
postauricular patches larger and more deeply pigmented. Skull:
Braincase less inflated; nasals truncated posteriorly as opposed to
rounded; zygomatic and mastoidal breadths less; rostrum shorter but
narrower; upper incisors narrower and shorter.

For comparisons with _wasatchensis_ see comparisons under that form.

In general, this mountain form can be distinguished from all other
_talpoides_ in Utah by lighter color, narrow, slender, "graceful" skull
whence the name _gracilis_ is derived.

_Remarks._--In Utah, _gracilis_ is limited to the extreme northwestern
corner of the state. This part of the state is in the Snake River
drainage. The main part of the range of this race lies in south-central
and southwestern Idaho and northeastern Nevada. The center of its range
might be considered to be in the Jarbidge Mountains area of Nevada. The
south slopes of these mountains are in the Humboldt River drainage,
while the north slopes are in the Snake River drainage, and this
subspecies occurs as far north as the Snake River and south and west
almost to central Nevada. No specimens are available from the area in
Utah between the Raft River Mountains inhabited by _gracilis_ and the
Wasatch Mountains in central Utah inhabited by _wasatchensis_. Judging
from the nature of the terrain, the range of _gracilis_ does not extend
eastward much beyond the Raft River Mountains. The type locality for a
gopher of a different species, _Thomomys bottae aureiventris_, is in
the first valley east of these mountains. Furthermore, all valleys to
the east and south, as far as known, are inhabited by gophers of the
_bottae_ group. Also, all mountain ranges in this area, as far east as
the Wasatch Mountains are inhabited by members of the _bottae_ group.

No specimens from Utah indicate intergradation between _gracilis_ and
_wasatchensis_, the form to the east, but specimens from farther north
at Albion, Cassia County, Idaho, do show intergradation. Bailey
(1915:116), Hall (1931:4), and Durrant (1939:6) have reported on these
specimens which at the present time seem best referred to _T. t.
gracilis_.

     _Specimens examined._--Total, 24, distributed as follows:
     _Box Elder County_: Yost, 4 (U. S. A. C.); Pine Canyon,
     6,600 ft., 17 mi. NW Kelton, 7 (M. V. Z.): Lynn Canyon, Raft
     River, 4; Park Valley, 3 (U. S. A. C.); Etna, 4 (U. S. A.
     C.); Raft River Mountains, Clear Creek Camp of Minnedoka
     National Forest, 1 (R. H.); Raft River Mountains, 1,500 feet
     above Clear Creek Camp of Minnedoka National Forest, 1 (R. H.).


=Thomomys talpoides wasatchensis= new subspecies

     _Thomomys quadratus uinta_ Hall, Univ. California Publ.
     Zoöl., 37:4, April 10, 1931.

     _Thomomys talpoides uinta_ Goldman, Journ. Mamm., 20:234.
     May 14, 1939.

     _Thomomys uinta_ Bailey, N. Amer. Fauna, 39:114, November
     15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):83, April,
     1922; Bull. Univ. Utah, 17 (No. 12):104, June, 1927;
     Stanford, Journ. Mamm., 12:360, November 11, 1931.

_Type._--Male, adult, skin and skull, No. 1604, Museum of Zoölogy,
University of Utah; Midway, 5,500 ft., Wasatch County, Utah; September
1, 1936; collected by S. D. Durrant; original number 1049.

_Range._--Wasatch Mountains and neighboring high valleys as far south
as Spanish Fork Canyon, Utah County.

_Diagnosis._--Size medium (see measurements). Color: Upper parts Snuff
Brown, finely mixed with black; sides and flanks Sayal Brown;
underparts overlaid with Cinnamon Buff, with suffusion of black on
underfur; postauricular patches black, extending around ear; ears
pointed and covered with black hairs; nose, cheeks, chin and top of
head dusky; front feet, hind feet and distal part of tail white; tail
covered proximally with light brown hairs. Skull: Moderately heavy and
ridged; nasals long, wide posteriorly and not markedly dilated
distally; posterior ends of nasals emarginate; zygomatic arches fairly
widely spreading and angular, being nearly straight in adults, but
tending to bow out slightly at posterior ends in young; zygomatic
processes of maxillae heavy; interparietal small and variously shaped,
but always wider than long; interorbital region fairly wide; well
marked dorsal depression in frontals posterior to ends of nasals;
interpterygoid space narrowly V-shaped; tympanic bullae large;
occipital condyles large and widely separated; foramen magnum large and
higher than wide; basioccipital wide; dentition light.

_Comparisons._--From topotypes of _Thomomys talpoides moorei_,
_wasatchensis_ differs as follows: Size slightly larger; ears longer
and more pointed. Color: Generally darker throughout; postauricular
patches smaller. Skull: Zygomatic arches not as widely spreading;
zygomatic processes of squamosals dip farther ventrally; premaxillae
less extended posterior to nasals; nasals wider posteriorly and less
dilated distally; median dorsal depression of frontals present;
tympanic bullae generally larger, but less inflated ventrally; foramen
magnum larger especially in dorsoventral dimension; occipital condyles
farther apart; basioccipital wider; alveolar length of upper molar
series less; molariform teeth smaller; upper incisors wider and
shorter.

Topotypes of _wasatchensis_ differ from topotypes and near topotypes of
_Thomomys talpoides uinta_ as follows: Size larger in every measurement
taken. Color: Darker throughout; ears longer and more pigmented;
opening of external ear smaller; postauricular patches larger. Skull:
In females larger throughout, more massive and angular; nasals longer,
wider and not so dilated distally; rostrum longer but wider; zygomatic
arches wider, more angular and less widely spreading posteriorly;
extension of premaxillae posterior to nasals less; tympanic bullae
larger, but less inflated ventrally; foramen magnum larger and more
ovoid; width across occipital condyles greater; basioccipital wider;
molariform teeth smaller; upper incisors shorter and wider.

Topotypes of _wasatchensis_ can be distinguished from those of
_Thomomys talpoides oquirrhensis_ as follows: Size larger; tail longer;
ears longer. Color: Slightly darker on sides and underparts. Skull:
Heavier, more ridged and angular; nasals more dilated distally;
posterior ends of nasals more deeply emarginate; zygomatic arches
heavier and more widely spreading, but more nearly parallel and less
divergent posteriorly; zygomatic processes of maxillae much heavier;
braincase and tympanic bullae larger; pterygoid hamulae shorter;
interpterygoid space more narrowly V-shaped; wider across occipital
condyles; foramen magnum larger and more ovoid.

From topotypes of _Thomomys talpoides gracilis_, _wasatchensis_ differs
as follows: Size larger; hind foot longer; ears longer and more
pointed. Color: Darker throughout; postauricular patches relatively
smaller. Skull: Larger, heavier and more angular; nasals emarginate
posteriorly as opposed to truncate; rostrum heavier; zygomatic arches
heavier and more widely spreading; zygomatic processes of maxillae much
heavier and more angular; mastoid breadth greater; interparietal
relatively smaller; extension of premaxillae posterior to nasals
actually as well as relatively less; palatal pits deeper; tympanic
bullae larger; interpterygoid space more narrowly V-shaped; foramen
magnum more ovoid; upper incisors wider.

Topotypes of _wasatchensis_ can be readily distinguished from those of
_Thomomys talpoides levis_ and _parowanensis_ by larger size; more
massive, ridged, angular skulls; larger tympanic bullae; large, ovoid
foramen magnum; and relatively smaller interparietal.

_Remarks._--Specimens from Mount Timpanogos and environs are
intergrades between _moorei_ and _wasatchensis_. They resemble _moorei_
in the shape and size of the tympanic bullae, and are intermediate in
the size and shape of the foramen magnum. In the majority of characters
they resemble _wasatchensis_ to which they are here referred. The
animals from east of Salt Lake City in Salt Lake County are intergrades
between _oquirrhensis_ and _wasatchensis_ and show some characters of
_uinta_, but are referable to _wasatchensis_. Animals from Morgan
County and western Summit County are intergrades between _wasatchensis_
and _uinta_. They resemble _uinta_ in size, shape of nasals and size of
tympanic bullae. The remainder of the cranial details place them with
_wasatchensis_. Morphologically the animals from Wellsville, Cache
County, were the closest to the topotypes of any obtained and are
nearly indistinguishable from them. Like the topotypes of
_wasatchensis_ this population inhabits a high valley. The remaining
specimens from Cache County resemble those from Morgan and Summit
counties.

     _Specimens examined._--Total, 119, distributed as follows:
     _Cache County_: Logan Canyon, Beaver Basin, Utah-Idaho Line,
     2 (U. S. A. C); Logan Canyon, Tony Grove Camp, 6 (U. S. A.
     C); Logan Canyon, Green Camp, 3 (U. S. A. C); Logan Canyon,
     3 (U. S. A. C); Logan Mountains, 20 mi. E Logan, 3 (U. S. A.
     C); Logan Peak area, 13 (U. S. A. C); near Providence Peak,
     Logan Mountains, 1 (U. S. A. C.); Wellsville, 10 (U. S. A.
     C); Hardware Ranch, Blacksmith Fork, 1 (U. S. A. C); Avon, 1
     (U. S. A. C); 1 mi. E Avon, 1 (U. S. A. C); 7-8 mi. E Avon,
     1 (U. S. A. C). _Weber County_: South Fork, Ogden River, 18
     mi. E Ogden, 4 (M. V. Z.). _Morgan County_: East Canyon, 18
     mi. NW Park City, 6,000 ft., 1. _Davis County_: 8 mi. NE
     Salt Lake City, 1. _Salt Lake County_: Mouth of Dry Canyon,
     1 mi. NE Salt Lake City, 1; 4 mi. above mouth City Creek
     Canyon, 5,000 ft., 1; mouth of Emigration Canyon, 1; mouth
     of Millcreek Canyon, 1; Lambs Canyon, 13 mi. SE Salt Lake
     City, 2 (C. M.); mouth of Big Cottonwood Canyon, 1. _Summit
     County_: Park City, 1 (U. S. N. M.). _Wasatch County_:
     Midway, 5,500 ft., 29. _Utah County_: Mt. Timpanogos, 1 mi.
     N Aspen Grove, 7,500 ft., 20; Aspen Grove, Mt. Timpanogos, 5
     (1, U. S. A. C.; 4, B. Y. U.); Head of Grove Creek, Mt.
     Timpanogos, 4 (B. Y. U.).

     _Additional Records_: _Weber County_: Ogden, 6. _Salt Lake
     County_: Parleys Canyon, 1 (Bailey, 1915:114).


=Thomomys talpoides oquirrhensis= Durrant

     _Thomomys talpoides oquirrhensis_ Durrant, Bull. Univ. Utah,
     30 (No. 5):3, October 24, 1939.

_Type._--Male, adult, skin and skull; No. 2605, Museum of Zoölogy,
University of Utah; Settlement Creek, Oquirrh Mountains, 6,500 ft.,
Tooele County, Utah; June 11, 1938; collected by S. D. Durrant;
original number 1461.

_Range._--Known only from the Oquirrh Mountains, which are in Salt
Lake, Tooele and Utah counties, Utah.

_Diagnosis._--Size medium (see measurements); ear long; tail short,
claws of front feet long and slender. Color: Upper parts Buckthorn
Brown, mixed with black, grading over the sides and flanks to Pinkish
Buff on the ventral surface; feet white; nose grayish black;
postauricular patches medium in size and black; chin and throat with
varying amounts of white; proximal two-thirds of tail dark brown,
distal third white. Skull: Long and slender, but relatively wide across
mastoidal region; nasals long and rounded posteriorly; rostrum long and
narrow; zygomatic arches weak and not widely spreading, tending to be
slightly bowed out posteriorly, but in the main roughly parallel to the
sides of the skull; outer margin of zygomatic arch slightly concave,
and zygomatic arch dips deeply ventrad; dorsal surface of skull smooth,
with weakly defined parietal crests; parietal crest nearly parallel,
but bowed medially, in parietal region, and flaring widely posteriorly
to pass lateral to interparietal; tympanic bullae large, truncate
anteriorly and markedly inflated ventrally; upper incisors short and
fairly robust.

_Comparisons._--From _Thomomys talpoides uinta_, _oquirrhensis_ may be
differentiated as follows: Color: Darker throughout; postauricular
patches larger and darker; ears longer and more pointed; inner margin
of pinna heavily pigmented; external opening of ear smaller. Skull:
Nasals rounded posteriorly rather than deeply emarginate, and less
flaring distally; zygomatic arches weaker and markedly less widely
spreading; pterygoid hamulae weaker; basisphenoid narrower; upper
incisors shorter and wider.

For comparisons between _oquirrhensis_ and _Thomomys talpoides
gracilis_, and _oquirrhensis_ and _wasatchensis_, see comparisons under
those forms.

Topotypical specimens of _oquirrhensis_ can be distinguished from those
of _Thomomys talpoides moorei_ as follows: Color generally darker, due
to greater admixture of black; terminal bands of hair actually lighter;
postauricular patches larger and darker; ears longer, more pointed and
with more heavily pigmented pinnae; tail shorter. Skull: About the same
size; smoother; zygomatic arches weaker and less widely spreading;
nasals rounded posteriorly as opposed to emarginate; mastoid breadth
less; pterygoid hamulae weaker; upper incisors wider.

_Remarks._--This race is limited to the Oquirrh Mountains, a high
mountain range that lies parallel to, and just west of the Wasatch
Mountains, in Utah, Salt Lake and Tooele counties. These mountains were
connected in past times to the Wasatch Mountains by the Transverse
Range, and by a sand and gravel bar deposited by Pleistocene Lake
Bonneville. The Jordan River in its course from Utah Lake to the Great
Salt Lake has cut a channel through the aforementioned bar. This
channel has been cut to the level of the surrounding valleys as is
indicated by the meandering nature of the stream through this part of
its course. As a result the Oquirrh Mountains are relatively isolated.
Although separated from the Wasatch Mountains by the Jordan River
Valley only a few miles wide, the pocket gophers are distinct on each
mountain. A population of _T. bottae_ is interposed between the two
mountain ranges as is indicated by specimens from Riverton, six miles
north of the Transverse Range. The populations of _bottae_ are
subspecifically the same on the two sides of the Jordan River.

On the east side of the Oquirrh Mountains, pocket gophers collected
from the Jordan Valley up Rose Canyon to about 5,000 feet elevation
were all of the species _T. bottae_. Between 5,000 and 6,000 feet there
is an area in which the ranges of _bottae_ and _talpoides_ overlap.
When trapping, it is possible to predict what species will be taken by
the types of burrows and soil. Gophers of the _bottae_ group have their
burrows in the areas of the deepest soil and heaviest vegetation,
whereas the areas of shallow, rocky soil covered with sparse vegetation
are the habitat of _talpoides_. Above 6,000 feet the only gopher
encountered is _talpoides_. Along Settlement Creek on the west side of
the Oquirrh Mountains, which is the type locality of _oquirrhensis_,
_bottae_ and _talpoides_ have essentially the same vertical
distribution as in Rose Canyon. On this mountain the two species appear
to be in competition.

The available information, based on collections, indicates that the
Oquirrh Mountains are the only mountains west of the Wasatch Range upon
which _talpoides_ occurs. In Utah, all other mountains to the west, as
far as known, are inhabited by subspecies of of _Thomomys bottae_.

     _Specimens examined._--Total, 41, as follows: _Tooele
     County_: Settlement Creek, Oquirrh Mountains, 6,500 ft., 14.
     _Salt Lake County_: Rose Canyon, Oquirrh Mountains, 5,650
     ft., 27.


=Thomomys talpoides uinta= Merriam

     _Thomomys uinta_ Merriam, Proc. Biol. Soc. Washington,
     14:112, July 19, 1901; Bailey, N. Amer. Fauna, 39:113,
     November 15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):83,
     April, 1922; Bull. Univ. Utah, 17 (No. 12):104, June, 1927;
     Stanford, Journ. Mamm., 12:360; November 11, 1931; Goldman,
     Journ. Washington Acad. Sci., 28:333, July 15, 1938; Davis,
     The Recent mammals of Idaho, pp. 239, 259, The Caxton
     Printers, Ltd., Caldwell, Idaho, April 5, 1939.

     _Thomomys talpoides uinta_ Goldman, Journ. Mamm., 20:234,
     May 14, 1939.

     _Thomomys quadratus uinta Hall_, Univ. California Publ.
     Zoöl., 37:4, April 10, 1931.

_Type._--Male, adult, skin and skull, No. 22501/30051, U. S. National
Museum (Biological Surveys Collection); north base Gilbert Peak, Uinta
Mountains, 10,000 ft., Summit County, Utah; June 6, 1890; collected by
Vernon Bailey; original number 1262 (after Merriam, type not seen).

_Range._--Uinta Mountains in Duchesne County, eastern Wasatch and
Summit counties, and western Uintah County south to the Roan, Brown and
Book cliffs in Carbon County.

_Diagnosis._--Size medium (see measurements). Color: Upper parts Snuff
Brown finely mixed with black, paling over sides and flanks to near
Pinkish Buff on underparts; postauricular patches relatively small and
dusky; external opening of ear large; pinnae usually lightly pigmented;
hind feet white; front feet usually white only at base of toes; distal
third to half of tail white; tail usually light below, with proximal
dorsal half covered with darker hairs; nose, chin, cheeks and top of
head dusky; usually considerable white on throat. Skull: Small,
slender, and not heavily ridged; nasals short and dilated distally;
posterior margins of nasals emarginate; zygomatic arches moderately
widely spreading, widest posteriorly; interparietal pentagonal or
subquadrangular; interpterygoid space V-shaped; tympanic bullae well
inflated ventrally; upper incisors long and narrow.

_Comparisons._--For comparisons with other subspecies of _Thomomys
talpoides_, see accounts of those forms.

_Remarks._--The range formerly ascribed to _uinta_ (Bailey, 1915:114;
Barnes, 1922:83, 1927:104) is now known to be inhabited by animals
belonging to three distinct subspecies. The range of _uinta_ as now
understood is restricted to the southern and western parts of the
Uinta Mountains and their environs. Three specimens from the Book
Cliffs, Sunnyside, Carbon County, are not typical, but in a majority of
their characters agree with _uinta_ to which they are here referred.

I have seen only one specimen from the type locality. It is one of the
series on which Merriam (1901:112) based his original description. In
addition, I have studied several large series of near topotypes. From
the material at hand, and from Merriam's description (_loc. cit._), I
regard the animals on which the name _uinta_ was based as intergrades
between _Thomomys talpoides ravus_, the race to the northeast, on the
one hand and the animals of the western and southern parts of the Uinta
Mountains on the other hand. The affinities of the type series are with
the animals from the latter area which are here all referred to
_uinta_.

     _Specimens examined._--Total, 41, distributed as follows:
     _Summit County_: 2 mi. S junction Bear River and Haydens
     Fork, 2 (C. M.); N base, Gilbert Peak, 10,000 ft., 1 (U. S.
     N. M.); Smith and Moorehouse Creek, 2; Bald Peak, 25 mi. NE
     Kamas, 15 (8, M. V. Z.; 6, C. M.). _Duchesne County_: Petty
     Mountain, 15 mi. N Mountain Home, 9,500 ft., 6 (C. M.).
     _Wasatch County_: Wolf Creek Pass, 18 mi. NW Hanna, 1 (U. S.
     A. C.); Lost Lake, Uinta Mountains, 10 (B. Y. U.); Current
     Creek, Uinta Mountains, 1 (U. S. N. M.). _Carbon County_:
     Forks, Sunnyside, 9,000 ft., 3.

     _Additional records._--_Summit County_: Uinta Mountains, 6
     (see Bailey, 1915:114).


=Thomomys talpoides pygmaeus= Merriam

     _Thomomys pygmaeus_ Merriam, Proc. Biol. Soc. Washington,
     14:115. July 19, 1901.

     _Thomomys talpoides pygmaeus_ Davis, The Recent mammals of
     Idaho, p. 252, The Caxton Printers, Ltd., Caldwell, Idaho,
     April 5, 1939.

_Type._--Male, adult, skin and skull, No. 55251, U. S. National Museum
(Biological Surveys Collection); 10 mi. NE Montpelier, in open
sagebrush of Transition Zone, 6,600 ft., Bear County, Idaho; July 29,
1893; collected by Vernon Bailey: original number 4150 (after Merriam,
type not seen: see, also, Bailey, 1915:109).

_Range._--Limited to Daggett County.

_Diagnosis._--Size: Small (see measurements). Color: Upper parts near
Bister slightly mixed with black, grading over sides and flanks to
Ochraceous Buff on underparts; postauricular patches small and dusky;
hind feet white; front feet dusky, being white only at base of claws;
chin and nose dusky; tail brown, lighter below and tipped with white.
Skull: Very small, slender and smooth; nasals short and slender;
zygomatic arches weak and not widely spreading; rostrum narrow;
extension of premaxillae posterior to nasals short; parietal ridges
hardly noticeable; interparietal large; extension of supraoccipital
posterior to lambdoidal suture long; tympanic bullae actually small,
but relatively large; basioccipital narrow; interpterygoid space narrow
and acutely angled; upper incisors markedly recurved; molariform teeth
relatively large.

_Comparisons._--This small pocket gopher can be distinguished from all
other members of _Thomomys talpoides_ occurring in Utah by remarkably
small size, and slender, weak, small skull with strongly recurved upper
incisors.

_Remarks._--The specimens used in this study were those recorded by
Svihla (1931:261). She reports that they were obtained in the
flood-plain banks of the streamsides, and preferred the pine belt. This
shows probably an extension of range with reference to life zones, as
heretofore the main reported localities of capture have been in
sagebrush in the Transition Life-zone.

Insofar as I am aware, Mrs. Svihla's specimens are the only ones of
this subspecies ever obtained in Utah. Additional work is necessary in
southwestern Wyoming to outline accurately the geographic distribution
of this subspecies. In comparison with topotypes, the specimens from
Utah are lighter in color and some specimens have slightly larger
skulls, suggesting slight intergradation with _Thomomys talpoides
uinta_.

     _Specimens examined._--Total, 18 (all in Museum of Zoölogy,
     University of Michigan), distributed as follows: _Daggett
     County_: Sheep Creek, 4; 1 mi. W Summit Springs, 4; Beaver
     Creek, 22 mi. S Manila, 9; Granite Park, 24 mi. S Manila, 1.


=Thomomys talpoides ravus= new subspecies

_Type._--Male, adult, skin and skull, No. 13690, Carnegie Museum;
Vernal-Manila Highway, 19 mi. N Vernal, 8,000 ft., Uintah County, Utah;
August 22, 1937; collected by J. K. and M. T. Doutt; original number
4718.

_Range._--Uinta Mountains in Daggett, northern Uintah and northern
Summit counties.

_Diagnosis._--Size large (see measurements); ears relatively narrow;
hind foot relatively small. Color: Upper parts between Drab and Light
Drab, darkest along middorsal line due to mixture of hairs tipped with
light brown; sides and flanks Light Drab; entire underparts creamy
white; front and hind feet, ventral surface of tail and end of tail
white; proximal two-thirds of tail covered dorsally with light brown
hairs; nose and cheeks dusky; postauricular patches black. Skull:
Large, heavy and ridged; rostrum long and narrow; nasals long,
moderately dilated distally and with a distal hump; posterior ends of
nasals emarginate; parietal and lambdoidal crests well developed;
zygomatic arches moderately heavy and widely spreading, widest
posteriorly; zygomatic processes of maxillae moderately heavy and
flaring abruptly from base of rostrum; marked middorsal depression in
frontals present; interparietal pentagonal; extension of premaxillae
posterior to nasals long; posterior tongues of premaxillae long,
slender and rounded proximally; braincase high, vaulted and relatively
narrow; tympanic bullae well inflated ventrally, and ridged in old
animals; pterygoid hamulae long; interpterygoid space narrowly
V-shaped; upper incisors long and narrow; molariform teeth medium.

_Comparisons._--Compared with topotypes of _Thomomys talpoides
bridgeri_, _ravus_ differs as follows: Size larger; hind foot smaller;
ears narrower. Color: Lighter throughout, grayish as opposed to brown.
Skull: Smaller, narrower, less angular and less massive; nasals,
rostrum, zygomatic processes of maxillae, ascending branches of
premaxillae and posterior tongues of premaxillae all narrower;
extension of premaxillae posterior to nasals longer; interparietal
wider; braincase higher and narrower; tympanic bullae approximately the
same size, but more inflated ventrally; interpterygoid space more
narrowly V-shaped; upper incisors narrower; molariform teeth weaker.

Compared with topotypes and near topotypes of _Thomomys talpoides
uinta_, _ravus_ differs as follows: Size larger in every measurement
taken. Color: Lighter throughout, being grayish as opposed to brown.
Skull: Larger in every measurement taken; rostrum and nasals actually
as well as relatively longer; extension of premaxillae posterior to
nasals longer; upper incisors longer and wider; molariform teeth
larger.

There is only one other gray subspecies of _Thomomys talpoides_ in
Utah, _Thomomys talpoides ocius_. Topotypes of _ravus_ differ from it
as follows: Size markedly larger in every measurement taken. Color:
Darker, more brown hairs. Skull: Larger in every measurement taken;
premaxillae extended farther posteriorly to nasals; extension of
supraoccipital posterior to lambdoidal suture markedly less; tympanic
bullae actually as well as relatively smaller; upper incisors longer
and more procumbent.

This new subspecies can be readily distinguished from all other
subspecies of _Thomomys talpoides_ occurring in Utah by markedly
greater size and paler, more grayish color.

_Remarks._--The range of this form appears to be limited to the north
slopes of the Uinta Mountains, except in Daggett County where it occurs
also on the south slopes. Intergradation in color and in cranial
details with _bridgeri_ is shown by animals from the East Fork of
Blacks Fork, thirty-one miles SSW Fort Bridger, and by those from
Henrys Fork, 8,300 ft., both in Summit County. Due to the grayish color
and the narrower, weaker skull they are referred to _ravus_.
Intergradation with _uinta_ is shown by specimens from the type
locality of the latter race. The type series of _uinta_ consists of
intergrades between _ravus_ and the animals to the west and south (see
remarks under _uinta_).

It is doubtful whether _bridgeri_ occurs in Utah. Material from Rich
County and extreme northern Cache County would settle the question.
Perhaps _bridgeri_ is restricted to the lower valleys in southwestern
Wyoming. Two specimens from northern Cache County, from Logan Canyon,
Beaver Basin, Utah-Idaho Line appear to be intergrades between
_bridgeri_ and _wasatchensis_, but are referable to the latter race.

     _Specimens examined._--Total, 38, distributed as follows:
     _Summit County_: Henrys Fork, 8,300 ft., 8; E Fork, Blacks
     Fork, 31 mi. SSW Fort Bridger, 4 (C. M.). _Daggett County_:
     Vernal-Manila Road, 4 mi. W Green's Lake, 7,500 ft., 6 (C.
     M.); Elk Park, Uinta Mountains, 5 (B. Y. U.). _Uintah
     County_: Trout Creek, SE Trout Peak, 22 mi. NW Vernal, 9,300
     ft., 5 (C. M.); Vernal-Manila Highway, 19 mi. N Vernal,
     8,000 ft., 6 (C. M.); Taylor Peak, 17 mi. N Vernal, 4 (C.
     M.).


=Thomomys talpoides ocius= Merriam

     _Thomomys clusius ocius_ Merriam, Proc. Biol. Soc.
     Washington, 14:114, July 19, 1901.

     _Thomomys clusius_ Allen, Bull. Amer. Mus. Nat. Hist.,
     13:246, November 25, 1896.

     _Thomomys ocius_ Bailey, N. Amer. Fauna, 39:107, November
     15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):83, April,
     1922; Bull. Univ. Utah, 17 (No. 12):102, June, 1927.

_Type._--Male, adult, skin and skull, No. 18852/25586, U. S. National
Museum (Biological Surveys Collection); dry sagebrush mesas at Harveys
Ranch, Smiths Fork, 6 mi. SW Fort Bridger, 6,657 ft., Uinta County,
Wyoming; May 24, 1890; collected by Vernon Bailey; original number 1194
(after Bailey, type not seen).

_Diagnosis._--Size small (see measurements). Color: Upper parts Tilleul
Buff overlaid with Avellaneous, grading over sides and flanks to nearly
white on underparts; underparts with faint wash of creamy white;
postauricular patches small and dusky and completely circling the ear;
nose and cheeks dusky; front feet, hind feet, throat, ventral surface
of tail and distal half of tail white. Skull: Small, slender but
compact; nasals rounded posteriorly; extension of premaxillae posterior
to nasals very short; zygomatic arches robust, but not widely
spreading, widest posteriorly; interparietal large and pentagonal in
shape; extension of supraoccipital posterior to lambdoidal suture long;
tympanic bullae actually as well as relatively large; basioccipital
narrow; pterygoid hamulae long and ridged; upper incisors short and
strongly recurved.

_Comparisons._--Compared with one topotype and seven near topotypes of
_Thomomys talpoides pygmaeus_, _ocius_ differs as follows: Size larger
in every measurement taken. Color: Lighter throughout, grayish as
opposed to brown; distal half of tail white as opposed to only a few
white hairs at tip of tail. Skull: Larger in every measurement taken;
skull more compact; zygomatic arches heavier and more widely spreading
posteriorly; tympanic bullae larger; upper incisors larger, but equally
strongly recurved; molariform teeth larger.

Topotypes of ocius can be distinguished from those of _Thomomys
talpoides uinta_ as follows: Color: Lighter throughout, grayish as
opposed to brown. Skull: Nasals rounded posteriorly as opposed to
emarginate; zygomatic arches more robust; interparietal pentagonal as
opposed to subquadrangular; extension of supraoccipital posterior to
lambdoidal suture markedly greater; tympanic bullae actually as well as
relatively much larger; upper incisors short and strongly recurved as
opposed to long and procumbent.

Specimens of this subspecies can be distinguished from all other
members of the species _Thomomys talpoides_ occurring in Utah by their
grayish color, and by small, compact skulls with very large tympanic
bullae and short strongly recurved upper incisors.

_Remarks._--Two specimens from Vernal, Uintah County, are intergrades
between _ocius_ and _uinta_. They resemble _uinta_ in size and dorsal
color, but are slightly lighter tending toward the color of _ocius_.
Ventrally they are intermediate in color but more like _ocius_. The
skulls are more like those of _ocius_ in general appearance, extension
of supraoccipital posterior to the lambdoidal suture, shape and
thickness of the zygomatic arches, posterior tongues of premaxillae,
size of tympanic bullae and recurved upper incisors. They more closely
resemble _uinta_ in shape of posterior ends of nasals, basioccipital
and shape of the zygomatic processes of the squamosals. In all of the
above mentioned characters, they are intermediate between the two named
forms, but tend towards one or the other as listed. The majority of
characters are more as in _ocius_ to which they are here referred.

When Goldman (1939:233, 234) listed the named subspecies of _Thomomys
talpoides_, he hesitated to include _ocius_ and merely mentioned that
_ocius_, _pygmaeus_ and _idahoensis_ might also belong to _talpoides_.
Davis (1939:240, 241) found intergradation between _idahoensis_ and
_fuscus_ and also between _idahoensis_ and _pygmaeus_, and, therefore,
arranged the last two mentioned forms as subspecies of _talpoides_.
This present study reveals intergradation between _ocius_ and _uinta_,
and also between _ocius_ and _fossor_ (see account of _fossor_).
Therefore, _ocius_ is properly to be treated as a subspecies of the
series of intergrading forms of which _talpoides_ is the earliest
named.

All specimens of _ocius_ known from Utah are from the extreme eastern
part of the northeastern corner of the state. The type locality of
_ocius_ is near Fort Bridger, Wyoming, which is north of Utah. I have
seen one specimen from 12 miles west of Linwood, Daggett County, Utah,
on Henrys Fork in Wyoming. Additional collecting in northern Utah
probably will reveal _ocius_ to inhabit also parts of northern Utah.

     _Specimens examined._--Total, 4, distributed as follows:
     _Uintah County_: Vernal, 2 (C. M.); Uncompahgre Indian
     Reservation, 2 (A. M. N. H.).


=Thomomys talpoides moorei= Goldman

     _Thomomys fossor moorei_ Goldman, Journ. Washington Acad.
     Sci., 28:335, July 15, 1938.

     _Thomomys talpoides moorei_ Goldman, Journ. Mamm., 20:234,
     May 14, 1939.

_Type._--Male, adult, skin and skull, No. 248222, U. S. National Museum
(Biological Surveys Collection); 1 mi. S Fairview, 6,000 ft., Sanpete
County, Utah; February 19, 1928; collected by A. W. Moore; X-catalogue
number 24799 (after Goldman, type not seen).

_Range._--Wasatch Plateau in Sanpete, Utah, Carbon and Emery counties,
and in Wasatch Mountains south of Spanish Fork Canyon.

_Diagnosis._--Size medium (see measurements). Color: Upper parts
between Cinnamon and Sayal Brown, with mixture of black hairs, grading
through Cinnamon on sides and flanks to Pale Pinkish Buff on
underparts, clearest on inguinal and pectoral regions; nose and cheeks
dusky; postauricular patches medium in size and black; ears black; chin
buffy white; front and hind feet white; tail mostly white with brownish
hairs on dorsal surface. Skull: Large, robust; nasals long and deeply
emarginate on posterior ends, and dilated distally; zygomatic arches
robust and widely spreading; zygomatic processes of maxillae heavy;
interparietal comparatively small, but always wider than long;
extension of premaxillae posterior to nasals short; tympanic bullae
moderate in size, but markedly inflated ventrally; pterygoid hamulae
long; interpterygoid space narrowly V-shaped; upper incisors long and
moderately recurved; molariform teeth light.

_Comparisons._--Topotypes of _moorei_ differ from topotypes and near
topotypes of _Thomomys talpoides uinta_ as follows: Size slightly
larger. Color: Upper parts and sides lighter; tail lighter;
postauricular patches larger and darker; ears more pointed, smaller and
darker. Skull: Larger, heavier and more massive; nasals longer, but
deeply emarginate posteriorly as in _uinta_; rostrum wider and longer;
zygomatic arches heavier and more angular; zygomatic processes of
maxillae heavier; interparietal generally smaller and shorter;
braincase wider; tympanic bullae more inflated ventrally;
interpterygoid space more narrowly V-shaped; upper incisors longer, but
not as procumbent; molariform teeth smaller.

Topotypes of _moorei_ can be distinguished from those of _Thomomys
talpoides oquirrhensis_ as follows: Size slightly larger; tail longer;
ears larger, less pointed. Color: Lighter throughout; postauricular
patches larger. Skull: More ridged and angular; nasals narrower
posteriorly, but more dilated distally; posterior ends of nasals more
deeply emarginate (while shallowly emarginate in _oquirrhensis_, they
tend to be somewhat rounded); rostrum narrower; extension of
premaxillae posterior to nasals greater; least interorbital breadth
less; zygomatic arches more angular and widely spreading; zygomatic
processes of maxillae heavier; interparietal smaller; tympanic bullae
larger and more inflated ventrally; upper incisors generally longer.

The characters that distinguish _moorei_ from _Thomomys talpoides
parowanensis_ are: Color: Lighter throughout. Skull: Broader, more
angular and more nearly flat; zygomatic arches more widely spreading;
zygomatic processes of maxillae heavier; posterior ends of nasals
emarginate rather than rounded; upper incisors longer.

For comparisons of _moorei_ with _Thomomys talpoides levis_ and
_wasatchensis_ see accounts of these forms.

_Remarks._--Specimens from Colton, show intergradation between
_moorei_, _uinta_ and _wasatchensis_, but are referable to _moorei_ in
the majority of characters. Specimens from Mount Nebo, and the mouth of
Reddicks Canyon, in the Wasatch and San Pitch mountains, respectively,
are intergrades between _moorei_ and _wasatchensis_, but are referable
to _moorei_.

That part of the Wasatch Mountains south of Spanish Fork Canyon is
inhabited by pocket gophers that are intergrades between _moorei_ and
_wasatchensis_, but the cranial details show them to be referable to
_moorei_. The range here ascribed to _moorei_ consists of the Wasatch
Plateau to the east of Sanpete Valley, the San Pitch Mountains and the
southern part of the Wasatch Mountains. The type locality of _moorei_
is situated in the southern end of a high valley that separates the
Wasatch Plateau from the San Pitch and Wasatch mountains. Topotypical
animals are larger and have more ridged, angular skulls than those from
the mountains.

     _Specimens examined._--Total, 48, distributed as follows:
     _Utah County_: Near Payson Lake, 1 (R. H.); Mt. Nebo, 25 mi.
     SE Payson, 10,000 ft., 20; Colton, 8 (B. Y. U.). _Sanpete
     County_: 1 mi. S Fairview, 6,000 ft., 12 (U. S. N. M.).
     _Juab County_: Mouth of Reddicks Canyon, Wales Mountain (=
     San Pitch Mountains), 7,500 ft., 5. _Emery County_: Lake
     Creek, 11 mi. E Mt. Pleasant, 2 (C. M.).

     _Additional records._--_Sanpete County_: Ephraim, 5 (see
     Goldman, 1938:336).


=Thomomys talpoides fossor= Allen

     _Thomomys fossor_ Allen, Bull. Amer. Mus. Nat. Hist., 5:51,
     April 28, 1893; Bailey, N. Amer. Fauna, 39:111, November 15,
     1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85, April, 1922;
     Bull. Univ. Utah, 17 (No. 12):102, June, 1927; Hall, Univ.
     California Publ. Zoöl., 37:4, April 10, 1931.

     _Thomomys talpoides fossor_ Goldman, Journ. Mamm., 20:234,
     May 14, 1939.

_Type._--Male, adult, skin and skull, No. 5240/4120, American Museum of
Natural History; Florida, 7,200 ft., La Plata County, Colorado; June
25, 1892; collected by Charles P. Rowley (after Allen, type not seen).

_Range._--In the mountains of San Juan and Grand counties, east of the
Colorado and Green rivers.

_Diagnosis._--Size medium (see measurements). Color: Upper parts
Dresden Brown, grading over sides to Pale Buff on underparts; chin
white; ears small, pointed, with deeply pigmented pinnae; postauricular
patches grayish black; nose dusky. Skull: Long and narrow; nasals long,
rounded proximally and usually simple distally; rostrum long;
interparietal triangular; tympanic bullae large, and well inflated
ventrally; basioccipital narrow; palate narrow; palatal pits shallow;
dentition light.

_Comparisons._--Near topotypes of _fossor_ can be distinguished from
topotypes of _Thomomys talpoides ocius_ as follows: Size larger
throughout. Color: Darker throughout, being dark brown as opposed to
grayish. Skull: Longer and narrower; nasals and rostrum longer;
extension of supraoccipital posterior to lambdoidal suture markedly
less; tympanic bullae markedly smaller; upper incisors longer and not
as strongly recurved.

Among the races of _Thomomys talpoides_ occurring in Utah, _fossor_
most closely resembles _Thomomys talpoides uinta_ in color and size,
but differs from it as follows: Ears smaller, more pointed and with
more darkly pigmented pinnae. Skull: Longer, narrower and weaker;
rostrum longer; nasals longer, and rounded proximally as opposed to
markedly emarginate; interparietal triangular instead of roughly
pentagonal; tympanic bullae larger and more inflated ventrally;
basioccipital narrower; palate narrower, palatal pits shallower;
dentition lighter.

_Remarks._--Bailey (1915:111) remarked that _fossor_ was one form that
held its distinctive characters over a wide range. At that time, its
range was understood to include practically all of the mountainous
parts of Colorado, Utah as far west as the central part of the state,
and parts of New Mexico, Arizona and Wyoming. Subsequently three new
forms have been named from central Utah, (Goldman 1938:334-337) thereby
showing variation to be much more prevalent than formerly supposed.
The range of _fossor_ in Utah, as now understood, is limited to the
mountainous parts of the state south and east of the Colorado and Green
rivers in Grand and San Juan counties.

The Utah specimens are not typical. At first glance some differences
are noted in the premaxillae and nasals. Four specimens in the
collections of the Museum of Natural History, University of Kansas,
three from 3 miles east of Creede, Mineral County, and one from 10
miles east of Lake City, Hinsdale County, Colorado, both of which lie
north and east of the type locality of _fossor_ show the same
characters as the Utah specimens.

Eight specimens from Oak Spring are intergrades between _fossor_ and
_ocius_. In size and color they are like _fossor_, but the skulls are
intermediate. Because the animals are more like _fossor_ in the
majority of characters, they are here referred to that race.

As a result of these studies and due to the paucity of specimens from
Utah, it is advisable, for the present, to refer all these Utah animals
to _fossor_. Additional specimens may reveal characters that will merit
the separation of the Utah animals from typical _fossor_; a desertlike
area unfavorable to _Thomomys_ exists between the type locality and
eastern Utah.

     _Specimens examined._--Total, 21, distributed as follows:
     _Grand County_: Oak Spring, Middle Fork Willow Creek, 15 mi.
     N Thompson, 8 (C. M.); La Sal Mountains, 1 (U. S. N. M.);
     Warner Ranger Station, La Sal Mountains, 3 (B. Y. U.). _San
     Juan County_: Geyser Pass, 18 mi. SE Moab, La Sal Mountains,
     3 (1, B. Y. U.; 2, C. M.); 5 mi. W Monticello, 1 (C. M.);
     Cooley Pass, 8 mi. W Monticello, 2 (C. M.); Joshua Flat, Elk
     Ridge, 8,300 ft., 3 (M. V. Z.).


=Thomomys talpoides parowanensis= Goldman

     _Thomomys fossor parowanensis_ Goldman, Journ. Washington
     Acad. Sci., 28:334, July 15, 1938.

     _Thomomys talpoides parowanensis_ Goldman, Journ. Mamm.,
     20:234, May 14, 1939; Long, Journ. Mamm., 21:176, May 14,
     1940.

     _Thomomys fossor_ Bailey, N. Amer. Fauna, 39:112, November
     15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85, April,
     1922; Bull. Univ. Utah, 17 (No. 12):102, June, 1927; Hall,
     Univ. California Publ. Zoöl., 37:4, April 10, 1931;
     Presnall, Zion-Bryce Mus. Bull., 2:14, January, 1938;
     Tanner, Great Basin Nat., 1:111, 1940.

_Type._--Male, adult, skin and skull, No. 158072, U. S. National Museum
(Biological Surveys Collection); Brian Head, Parowan Mountains, 11,000
ft., Iron County, Utah; September 8, 1908; collected by W. H. Osgood;
original number 3483 (after Goldman, type not seen).

_Range._--High mountains of eastern Iron and Beaver counties, and
western Kane and Garfield counties.

_Diagnosis._--Size medium (see measurements). Color: Upper parts Sayal
Brown moderately mixed with black, lightest on head; sides lightly
washed with Buff; underparts Pinkish Buff, clearest on inguinal and
pectoral regions; nose and cheeks dusky; postauricular patches large
and black; front feet, hind feet and distal half of tail white. Skull:
Long and fairly slender; zygomatic arches not widely spreading; nasals
long; rostrum long and slender; posterior ends of nasals truncate or
moderately emarginate; extension of premaxillae posterior to nasals
usually short; tympanic bullae relatively small; upper incisors long
and narrow; molariform teeth large.

_Comparisons._--Compared with _Thomomys talpoides kaibabensis_,
_parowanensis_ differs as follows: Size smaller. Skull: Shorter; nasals
shorter; zygomatic breadth less; nasals truncate or shallowly
emarginate posteriorly as opposed to rounded; upper incisors narrower.

Topotypes of _parowanensis_ differ from topotypes and near topotypes of
_Thomomys talpoides uinta_ as follows: Size larger. Color: Usually
lighter; postauricular patches larger and darker; ears small with
pinnae deeply pigmented as opposed to large and lightly pigmented.
Skull: Larger; zygomatic arches more widely spreading; nasals longer;
rostrum longer; posterior ends of nasals truncate or shallowly
emarginate as opposed to deeply emarginate; sides of zygomatic arches
nearly parallel and not so divergent posteriorly; interparietal larger
and less quadrangular; extension of premaxillae posterior to nasals
less; upper incisors less procumbent; molariform teeth larger.

Among named races of _Thomomys talpoides_, _parowanensis_ most closely
resembles _levis_, the race nearest geographically to the east, but
differs from _levis_ as follows: Size larger. Skull: Longer and wider;
rostrum and nasals longer; interparietal quadrangular as opposed to
roughly elliptical; upper incisors longer.

For comparisons with _Thomomys talpoides moorei_ and _wasatchensis_ see
accounts of those forms.

_Remarks._--The mountains of south central Utah are inhabited by pocket
gophers that have been designated as _Thomomys talpoides parowanensis_
and _T. t. levis_ by Goldman (1938:334, 336). They are nearly
indistinguishable in color and each is variable in cranial details. The
diagnostic characters of each form occasionally appear, in varying
degrees, throughout the range of the other. The Sevier River Valley
separates the ranges ascribed to these two forms. This valley is
inhabited by pocket gophers that belong to a different species,
_Thomomys bottae_. The ranges of these two races of _talpoides_
converge southward at the headwaters of the Sevier River. Specimens of
_parowanensis_ from the northern limits of its range from the Beaver
Mountains in eastern Beaver County and those of _levis_ from the
northern limits of its range in the Fish Lake Mountains are readily
distinguishable from each other. As the ranges converge to the
southward, there is progressively more intergradation. The type
locality of _parowanensis_ is located in the southern part of its
range, while that of _levis_ is in the extreme northern part of its
range. Therefore, due to the convergence of the two ranges at the
south, the specimens from localities near the type locality of
_parowanensis_ show the greatest amount of intergradation, if we regard
specimens of _parowanensis_ from the type locality as typical of the
race. Four specimens from Webster Flat, sixteen miles east of Cedar
City, Iron County, and three from Duck Creek, Cedar Mountains, Kane
County could equally well be assigned to either _levis_ or
_parowanensis_.

     _Specimens examined._--Total, 24, distributed as follows:
     _Beaver County_: Britts Meadows, Beaver Mountains, 8,500
     ft., 7 (3, M. V. Z.; 2, U. S. N. M.; 2, C. M.); Puffer Lake,
     Beaver Mountains, 1 (U. S. N. M.); Kents Lake, Beaver
     Mountains, 1 (R. H.). _Iron County_: Lava Beds, 3-1/2 mi. SW
     Panquitch Lake, 1 (C. M.); Brian Head, Parowan Mountains, 2
     (1, U. S. N. M.; 1, C. M.); Webster Flat, 16 mi. E Cedar
     City, 4; Bear Valley, 2 mi. E B. V. Ranger Station, 1 (R.
     H.). _Garfield County_: 1/4 mi. W Sunset Point, Bryce
     National Park, 8,000 ft., 1 (M. V. Z.). _Kane County_:
     Navajo Lake, 3 (R. H.); Duck Creek, Cedar Mountains, 9,000
     ft., 3 (1, R. H.).

     _Additional records._--_Garfield County_: Panquitch Lake, 1
     (see Goldman 1938:335). _Iron County_: Beaver Mountains, 9
     (see Bailey, 1915:112); Buckskin Valley, 1 (see Goldman,
     1938:335).


=Thomomys talpoides levis= Goldman

     _Thomomys fossor levis_ Goldman, Journ. Washington Acad.
     Sci., 28:336, July 15, 1938.

     _Thomomys talpoides levis_ Goldman, Journ. Mamm., 20:234,
     May 14, 1939.

     _Thomomys fossor_ Bailey, N. Amer. Fauna, 39:112, November
     15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85, April,
     1922; Bull. Univ. Utah, 17 (No. 12):102, June, 1927.

_Type._--Female, adult, skin and skull, No. 158079, U. S. National
Museum (Biological Surveys Collection); Seven Mile Flat, 5 mi. N Fish
Lake, Fish Lake Plateau, 10,000 ft., Sevier County, Utah; October 1,
1908; collected by W. H. Osgood; original number 3616 (after Goldman,
type not seen).

_Range._--Fish Lake Mountains in Sevier County south into Garfield
County, Utah.

_Diagnosis._--Size medium (see measurements). Color: Upper parts near
Sayal Brown, moderately mixed with black, darkest on head and middorsal
region, grading to Cinnamon Buff on sides and flanks; underparts
Pinkish Buff, clearest on inguinal and pectoral regions; chin, cheeks
and nose dusky; postauricular patches large and black; front feet, hind
feet and distal half of tail white; ears small and deeply pigmented.
Skull: Slender and weak; zygomatic arches not widely spreading;
posterior ends of nasals rounded; nasals moderately long and narrow;
rostrum long and narrow; extension of premaxillae posterior to nasals
short; interparietal usually much wider than long; pterygoid hamulae
ridged; interpterygoid space usually narrowly V-shaped; upper incisors
short.

_Comparisons._--Compared with topotypes of _Thomomys talpoides moorei_,
_levis_ differs as follows: Size smaller; tail shorter. Color: Darker
throughout, especially on dorsal surface due to more black of the
underfur; underparts deeper buff. Skull: Narrower, less massive;
zygomatic processes of maxillae weaker and not as widely spreading;
interparietal generally wider; extension of premaxillae posterior to
nasals less; posterior ends of nasals rounded rather than emarginate;
upper incisors shorter, less procumbent.

Topotypes of _levis_ differ from near topotypes of _Thomomys talpoides
uinta_ as follows: Size larger. Color: Upper parts slightly darker;
postauricular patches much darker and larger; ears small and deeply
pigmented as opposed to large and lightly pigmented; tail darker all
around at base, with white part more extensive and with fewer
buff-colored hairs. Skull: More convex dorsally; zygomatic arches more
widely spreading and angular; nasals longer; rostrum longer;
interparietal wider and more elliptical; posterior ends of nasals
rounded as opposed to emarginate; extension of premaxillae posterior to
nasals less; pterygoid hamulae more ridged; interpterygoid space more
narrowly V-shaped; upper incisors shorter and less procumbent.

Topotypes of _levis_ can be distinguished from those of _Thomomys
talpoides kaibabensis_ by markedly smaller measurements.

For comparisons with _Thomomys talpoides parowanensis_ and
_wasatchensis_ see accounts of those forms.

_Remarks._--Specimens from the Escalante Mountains and the Aquarius
Plateau are not typical. They are of approximately the same color as
_levis_, but are larger than _levis_ and have cranial details that
indicate intergradation with _kaibabensis_ to the south. They resemble
_kaibabensis_ in large size, long nasals and widely spreading zygomatic
arches, but are like _levis_ in shape of the interparietal, extension
of premaxillae posterior to the nasals, rounded posterior ends of
nasals, ridged pterygoid hamulae and relatively short upper incisors.
Additional material from these regions may prove these animals to merit
separation and naming.

     _Specimens examined._--Total, 15, distributed as follows:
     _Sevier County_: Seven Mile Flat, 5 mi. N Fish Lake, Fish
     Lake Plateau, 10,000 ft., 2 (U. S. N. M.); Fish Lake
     Experiment Station, 2 (U. S. A. C). _Garfield County_: Posy
     Lake, Aquarius Plateau, 2 (B. Y. U.); 18 mi. N Escalante,
     9,500 ft., 3; Steep Creek, Boulder-Teasdale Road, Boulder
     Mountain, 4 (B. Y. U.); Summit Birch Creek, Escalante
     Mountains, 2 (B. Y. U.).


MEASUREMENTS OF ADULT MALES OF THOMOMYS

(In millimeters)

======================================================================
       Total length
       |    Length of tail
       |    |   Length of hind foot
       |    |   |   Basilar length
       |    |   |   |     Length of nasals
       |    |   |   |     |    Zygomatic breadth
       |    |   |   |     |    |      Mastoid breadth
       |    |   |   |     |    |      |     Interorbital breadth
       |    |   |   |     |    |      |     |    Alveolar length of
       |    |   |   |     |    |      |     |    upper molar series
       |    |   |   |     |    |      |     |    |    Extension of premax
       |    |   |   |     |    |      |     |    |    post. to nasals
       |    |   |   |     |    |      |     |    |    |    Length of
       |    |   |   |     |    |      |     |    |    |    rostrum
       |    |   |   |     |    |      |     |    |    |    |     Breadth
       |    |   |   |     |    |      |     |    |    |    |     of rostrum
----------------------------------------------------------------------

_T. t. gracilis_, 4; topotypes
Av.    204  53  28  31.5  13.4  21.7  18.3  6.4  7.6  1.3  15.4  7.2
Min.   194  47  27  30.3  12.9  21.1  17.8  6.3  7.3  1.0  14.7  6.7
Max.   210  63  28  33.5  14.2  22.0  19.0  6.5  7.9  1.7  16.4  7.5

_T. t. oquirrhensis_, 4; topotypes
Av.    209  58  28  32.2  13.9  21.9  19.0  6.9  7.6  0.9  15.8  7.7
Min.   197  55  28  31.9  13.7  21.4  18.5  6.7  7.2  0.6  15.5  7.5
Max.   216  60  29  32.8  14.3  22.8  19.5  7.1  7.9  1.0  16.2  7.9

_T. t. wasatchensis_, 10; topotypes
Av.    221  67  28  31.3  13.4  21.5  18.9  6.5  7.4  1.1  15.1  7.4
Min.   204  60  26  27.4  11.6  19.1  17.2  6.0  6.6  0.9  14.0  6.7
Max.   237  75  31  34.5  15.2  23.7  20.4  7.3  8.0  2.0  16.5  8.2

_T. t. uinta_, 5; SW slope Bald Peak, Uinta Mts.
Av.    199  51  27  31.5  13.1  21.7  19.4  6.3  7.6  1.1  15.2  7.4
Min.   185  47  26  29.6  12.1  20.3  19.0  5.7  7.3  0.7  13.5  7.2
Max.   208  54  28  32.8  13.8  22.2  20.0  6.5  7.8  1.4  15.6  7.6

_T. t. moorei_, 7; topotypes
Av.    216  65  29  32.4  13.9  22.9  19.2  6.5  7.7  1.5  15.9  7.3
Min.   203  52  27  31.3  13.0  21.5  18.4  6.0  7.3  0.9  14.8  6.7
Max.   236  72  31  34.7  14.5  23.7  20.0  7.0  8.2  2.0  16.3  7.7

_T. t. fossor_, 8; Cascade Creek, La Plata Co., Colo.
Av.    215  61  29  31.7  13.2  21.2  18.7  5.9  7.5  0.6  15.5  7.1
Min.   202  54  27  30.5  12.0  20.5  18.2  5.5  7.0  0.0  14.5  6.9
Max.   228  70  30  33.0  14.4  23.5  19.9  6.3  7.9  1.1  16.9  7.4

_T. t. ravus_, 3; topotypes
Av.    248  73  30  35.2  14.6  24.8  21.4  6.3  8.3  2.4  17.1  8.2
Min.   244  70  29  34.5  14.3  23.6  20.5  6.0  8.2  2.2  16.7  8.1
Max.   253  74  30  35.9  15.1  25.7  22.5  6.7  8.4  2.7  17.5  8.5

No. 55270 (U. S. N. M.) _T. t. pygmaeus_, 1; topotype
       165  40  20  24.6  10.2  16.3  15.1  5.4  5.9  0.7  12.0  5.7

No. 177506 (U. S. N. M.) _T. t. ocius_, 1; 12 mi. W Linwood,
  Henrys Fork, Wyo.
       200  62  26  27.5  11.5  19.9  17.8  6.2  6.8  1.0  13.5  7.0

_T. t. parowanensis_, 2; Britts Meadow, Beaver Mountains
Av.    215  59  28  34.3  14.5  22.4  18.6  6.0  8.1  1.4  17.3  7.9
Min.   202  48  27  34.1  14.1  22.0  18.4  5.8  8.0  1.0  17.2  7.6
Max.   228  69  29  34.6  14.8  22.7  18.9  6.2  8.2  1.7  17.3  8.2
----------------------------------------------------------------------


MEASUREMENTS OF ADULT FEMALES OF THOMOMYS

(In millimeters)

======================================================================
       Total length
       |    Length of tail
       |    |   Length of hind foot
       |    |   |   Basilar length
       |    |   |   |     Length of nasals
       |    |   |   |     |     Zygomatic breadth
       |    |   |   |     |     |     Mastoid breadth
       |    |   |   |     |     |     |     Interorbital breadth
       |    |   |   |     |     |     |     |    Alveolar length of
       |    |   |   |     |     |     |     |    upper molar series
       |    |   |   |     |     |     |     |    |    Extension of premax
       |    |   |   |     |     |     |     |    |    post. to nasals
       |    |   |   |     |     |     |     |    |    |    Length of
       |    |   |   |     |     |     |     |    |    |    rostrum
       |    |   |   |     |     |     |     |    |    |    |     Breadth
       |    |   |   |     |     |     |     |    |    |    |     of rostrum
----------------------------------------------------------------------

_T. t. gracilis_, 2; topotypes
Av.    190  58  27  29.7  12.0  19.7  17.3  6.4  7.3  1.2  14.0  6.5
Min.   185  54  27  29.5  11.9  19.7  16.9  6.3  7.2  1.1  14.0  6.4
Max.   194  61  27  29.9  12.0  19.7  17.6  6.5  7.4  1.4  14.0  6.6

_T. t. oquirrhensis_, 7; topotypes
Av.    203  56  27  30.2  12.9  20.4  18.2  6.8  7.5  0.8  14.8  7.2
Min.   193  52  25  28.5  12.2  19.5  17.5  6.6  6.7  0.5  14.2  6.9
Max.   215  59  28  31.5  13.3  21.0  19.1  7.2  8.0  1.0  15.5  7.5

_T. t. wasatchensis_, 19; topotypes
Av.    205  62  27  31.5  12.7  20.5  18.0  6.5  7.4  0.9  14.6  7.2
Min.   180  52  23  28.1  11.2  19.3  17.2  6.2  6.0  0.6  13.0  6.8
Max.   222  70  30  32.5  14.5  22.0  19.9  6.7  8.1  1.2  16.2  7.5

_T. t. uinta_, 2; SW slope Bald Peak, Uinta Mts.
Av.    181  49  25  28.4  11.6  19.8  17.3  6.6  7.2  1.3  13.5  6.8
Min.   177  47  25  28.3  11.6  19.8  17.2  6.4  7.0  1.1  13.3  6.8
Max.   185  50  25  28.4  11.6  19.8  17.4  6.7  7.3  1.5  13.6  6.8

_T. t. moorei_, 5; topotypes
Av.    206  62  26  29.9  12.8  21.5  18.4  6.6  7.3  1.3  14.6  6.8
Min.   198  55  24  29.0  12.3  21.0  18.0  6.4  7.0  1.0  14.0  6.4
Max.   213  69  28  31.2  14.1  22.5  19.1  6.8  7.5  1.6  15.6  7.0

_T. t. fossor_, 4; Cascade Creek, La Plata Co., Colo.
Av.    215  57  29  32.6  14.2  22.0  19.0  6.0  7.5  0.7  16.2  7.3
Min.   204  51  28  31.3  13.6  21.5  18.0  5.7  7.1  0.5  15.9  7.0
Max.   223  63  30  34.0  14.8  22.9  19.6  6.3  7.8  1.0  16.3  7.5

No. 13684 (C. M.) _T. t. ravus_, 1; topotype
       241  71  28  35.7  14.5  24.4  21.5  6.2  7.8  2.7  17.1  8.1

No. 178868 (U. S. N. M.) _T. t. pygmaeus_, 1; Fossil, Wyo.
       167  52  20  24.0  10.2  16.5  14.8  5.2  5.6  0.7  11.1  5.8

_T. t. ocius_, 3; topotypes
Av.    201  60  25  30.0  13.5  20.5  17.9  6.2  7.2  0.8  15.0  7.4
Min    196  57  25  29.9  13.0  19.9  17.5  6.1  7.1  0.5  14.7  7.3
Max.   205  64  25  30.1  14.0  21.5  18.6  6.3  7.3  1.0  15.3  7.5

_T. t. parowanensis_, 4; Britts Meadow, Beaver Mountains
Av.    221  58  29  33.2  14.5  22.8  19.0  6.0  7.8  0.9  15.4  7.3
Min.   207  50  28  30.5  12.8  22.7  18.6  5.8  7.4  0.5  14.7  7.0
Max.   240  66  30  34.8  15.5  23.0  19.6  6.2  8.1  1.5  17.8  7.7

_T. t. levis_, 2; topotypes
Av.    203  65  27  28.1  11.1  19.2  17.7  6.1  6.9  0.8  13.0  6.8
Min.   199  61  26  28.0  10.6  18.9  17.5  5.8  6.6  0.6  12.8  6.6
Max.   206  70  27  28.2  11.6  19.5  17.9  6.4  7.2  1.0  13.2  7.0
----------------------------------------------------------------------


=Thomomys bottae= (Eydoux and Gervais)

_Thomomys bottae_ is a southern species that, within the Great Basin,
reaches the most northern limits of its distribution in Utah. The
animals of this species inhabit the lower valleys, and with the
exception of the Oquirrh Mountains, inhabit also the mountains in that
part of the state west of the central mountain ranges. The specific
characters are: Sphenorbital fissure present; incisive foramina
posterior to infraorbital canal; anterior prism of P4 rounded;
interparietal relatively small; lambdoidal suture straight in region of
interparietal, in Utah specimens.


=Thomomys bottae aureiventris= Hall

     _Thomomys perpallidus aureiventris_ Hall, Univ. California
     Publ. Zoöl., 32:444, July 8, 1930; Univ. California Publ.
     Zoöl., 37:3, April 10, 1931.

     _Thomomys bottae aureiventris_ Goldman, Proc. Biol. Soc.
     Washington, 48:156, October 31, 1935.

_Type._--Male, adult, skin and skull, No. 43980, Museum of Vertebrate
Zoölogy, University of California; Fehlman Ranch, 3 mi. N Kelton, 4,225
ft., Box Elder County, Utah; September 27, 1929; collected by Louise
Kellogg; original number 451.

_Range._--Northwestern Utah, and extreme western Utah as far south as
the southern end of the Deep Creek Mountains.

_Diagnosis._--Size medium (see measurements); claws on front feet
small. Color: Near Cinnamon on dorsal and ventral surfaces; inguinal
region, front and hind feet and distal third to half of tail white;
nose, cheeks and postauricular patches grayish black. Skull: Moderately
angular and ridged; zygomatic arches nearly parallel with sides of
skull; jugals vertical; marked thickening at union of jugal and
zygomatic process of maxilla; greatest zygomatic breadth at anterior
part of arches; interpterygoid space lyre-shaped; ventral margin of
jugal concave dorsally; nasals long and denticulate distally; parietal
ridges bowed in at two places, at coronal suture and at middle of
interparietal; paroccipital processes extremely well developed; dorsal
frontomaxillary suture usually straight.

_Comparisons._--From near topotypes of _Thomomys bottae centralis_,
_aureiventris_ differs as follows: Size larger; tail shorter; hind foot
longer; claws on front feet shorter. Color: Slightly darker on upper
parts, but with greater extension of white on ventral surface. Skull:
Zygomatic breadth greater; greatest width across zygomatic arches at
anterior rather than posterior region; zygomatic arches thicker at
union of jugals and zygomatic processes of maxillae; dorsal
frontomaxillary suture less convex medially; mastoid breadth greater;
extension of premaxillae posterior to nasals less; interpterygoid space
lyre-shaped rather than V-shaped.

From topotypes of _Thomomys bottae albicaudatus_, _aureiventris_ can
be distinguished by: Size larger; hind foot longer. Color: Markedly
lighter throughout, Cinnamon as opposed to near (13''''_n_) Black.
Skull: Larger in all but three measurements taken; extension of
premaxillae posterior to nasals less; alveolar length of upper molar
series shorter; zygomatic arches widest anteriorly rather than
posteriorly; thickening at union of jugal and zygomatic process of
maxilla markedly greater; interpterygoid space lyre-shaped as opposed
to V-shaped; lacrimal processes more globose at tips.

_Thomomys bottae aureiventris_ can be readily distinguished from _T. b.
bonnevillei_, _sevieri_, _wahwahensis_, and _convexus_ by larger size
in all measurements taken and darker coloration. The same differences
obtain in comparison with _T. b. tivius_ and _stansburyi_ except that
_aureiventris_ is much lighter colored. See comparisons under those
forms.

_Remarks._--_T. b. aureiventris_ has one of the most extensive ranges
of any race of _T. bottae_ occurring in Utah. The range extends from
the valleys of the northwest corner of the state south along the
extreme western margin of the state approximately to the southern end
of the Deep Creek Mountains. This ascribed range practically bounds the
northwest and western margins of the great salt desert in Box Elder and
Tooele counties. As far as known, this great waste area harbors no
members of the Geomyidae. Pocket gophers were available from four
localities in addition to the type locality. In these four localities
all of the animals were intergrades. The three specimens from Queen of
Sheba Canyon, Deep Creek Mountains, although smaller than
_aureiventris_ in every measurement taken, resemble it in color and
general configuration of the skull. The animals from Trout Creek and
Ibapah at the southern end of the range, although referred to
_aureiventris_, are intermediate between it and _centralis_. In color
and measurements they more closely resemble _centralis_, but the skulls
closely resemble those of _aureiventris_. The skulls show some slight
characteristics of _bonnevillei_, the form to the east, which indicate
an early relationship between the two. Specimens from the east side of
Tecoma Range, adjacent to Pilot Peak, although referred to
_aureiventris_ are intergrades between it and _centralis_. Although
this locality is nearer the type locality of _aureiventris_ than any of
the other record stations, the animals show the maximum departure from
topotypes in morphological features. In color they approach
_centralis_, and agree with it in one-half of the measured characters.
The general configuration of the skull and a majority of the critical
diagnostic characters, for example, jugal thickening, are more nearly
as in _aureiventris_. From the above remarks it is readily understood
that this subspecies is extremely variable.

     _Specimens examined._--Total, 55, distributed as follows:
     _Box Elder County_: Fehlman Ranch, 3 mi. N Kelton, 4,255
     ft., 8 (7, M. V. Z.); Utah-Nevada Boundary, E Side Tecoma
     Range, 4,300 ft., 12. _Tooele County_: Ibapah, 5,000 ft.,
     21. _Juab County_: Queen of Sheba Canyon, W side Deep Creek
     Mountains, 5,600 ft., 11.


=Thomomys bottae robustus= new subspecies

_Type._--Male, adult, skin and skull, No. 2726, Museum of Zoölogy,
University of Utah; Orr's Ranch, Skull Valley, 4,300 ft., Tooele
County, Utah; June 19, 1938; collected by S. D. Durrant; original
number 1583.

_Range._--Skull Valley, Tooele County, Utah.

_Diagnosis._--Size medium (see measurements); tail short; hind foot
short. Color: In a series of 24 animals, upper parts vary from Pale
Smoke Gray (4 specimens) through Cinnamon Buff (19 specimens) to Dark
Mouse Gray (1 specimen). The Cinnamon Buff color is considered to be
typical. Color grading to lighter on underparts; postauricular patches
small and grayish black; front and hind feet and distal part of tail
white. Skull: Small, flat and heavily ridged; nasals short; zygomatic
arches heavy and widely spreading, widest posteriorly at union of jugal
and squamosal; union of jugal and zygomatic process of maxilla
thickened, with a ventrally directed spinous process in sixty percent
of the specimens; occasionally there is a second process, also directed
ventrally at union of jugal and zygomatic process of squamosal;
zygomatic arches convex dorsally; deep dorsal depression present in
frontal bones in mature specimens; lacrimal processes prominent,
projecting well above the arch at the anteromedial angle of the orbit;
interpterygoid spaces V-shaped; tympanic bullae well inflated
ventrally; upper incisors short, and pale; when placed on a flat plane
the dorsal surface of the skull is nearly parallel to the substratum;
space enclosed within the zygomatic arches nearly quadrangular.

_Comparisons._--From topotypes of _Thomomys bottae aureiventris_,
_robustus_ can be distinguished as follows: Size smaller; tail and hind
foot shorter. Color: Lighter throughout. Skull: Smaller, more heavily
ridged and more nearly flat; nasals shorter; rostrum relatively wider
and shorter; zygomatic arches shorter and relatively more widely
spreading with greatest width posteriorly as opposed to anteriorly;
junction of jugal and zygomatic process of maxilla not as prominent;
_aureiventris_ shows no spinous process at this junction; lacrimal
processes larger and projecting farther dorsally; enclosed space within
zygomatic arches roughly quadrangular as opposed to triangular;
mastoidal part of tympanic bullae less exposed; sphenorbital fissure
smaller; interpterygoid space V-shaped rather than lyre-shaped; palatal
pits smaller and shallower; tympanic bullae smaller, but more inflated
ventrally; basioccipital averaging relatively wider; molars smaller;
upper incisors shorter, smaller and cadmium yellow as opposed to orange
yellow.

Comparisons of _robustus_ with topotypes of _Thomomys bottae
albicaudatus_ show the following: Size smaller. Color: Lighter
throughout; postauricular patches smaller and lighter. Skull: Smaller,
more compact and more nearly flat; rostrum shorter and more nearly
straight; lacrimal processes larger, projecting higher above the
anteromedial angle of the orbit; parietal ridges uniformly heavier;
mastoid width actually as well as relatively wider; zygomatic arches
heavier and relatively much wider (males 76.2 percent of basilar
length, females 73.8 percent as opposed to males 73.8 percent and
females 73.5 percent); union of jugal and zygomatic process of maxilla
uniformly more thickened; spinous process at jugal-maxillary suture
present; zygomatic arches much more concave on ventral surface; uniform
deep depression present in mature adults, between frontal processes of
premaxillae, and anterior interorbital region of frontals; extension of
premaxillae posterior to nasals less; sphenorbital fissure more
constricted; tympanic bullae more inflated ventrally, extending well
ventrad of basioccipital; palatal pits shallower and smaller; molars
smaller; upper incisors shorter, narrower and paler (see comparison of
_aureiventris_).

From near topotypes of _Thomomys bottae centralis_ from 1 mile east of
Garrison, Millard County, Utah, _robustus_ differs in: Size smaller;
tail and hind foot shorter. Color: Lighter, terminal bands of hair
cinnamon, but because more black in underfur the animals appear darker;
postauricular patches smaller and lighter. Skull: Shorter, more nearly
flat and much more heavily ridged; nasals shorter; rostrum shorter and
wider; lacrimal processes larger and projecting higher above
anteromedial angle of orbit; zygomatic arches heavier, shorter, more
angular and actually as well as relatively wider; jugals thicker; angle
between maxillary plate and rostrum less obtuse; spinous process at
jugal-maxillary suture present; extension of premaxillae posterior to
nasals less; parietal ridges much more pronounced; looked at from
above, space enclosed within zygomatic arches more quadrangular in
shape as opposed to roughly triangular; tympanic bullae more inflated
ventrally; molars smaller; upper incisors shorter, narrower and paler.

The characters that distinguish _robustus_ from topotypes of _Thomomys
bottae wahwahensis_ are: Size slightly smaller. Color: Darker
throughout. Skull: Rostrum longer and narrower; nasals longer;
zygomatic arches wider and longer; lacrimal processes larger and
projecting higher above anteromedial angle of the orbit; parietal
ridges more roughened; tympanic bullae much larger and more inflated
ventrally; supraoccipital higher; middorsal depression in frontals
present. For comparisons with _Thomomys bottae bonnevillei_ see account
of that form.

The remaining forms from the Bonneville Basin, namely, _Thomomys bottae
sevieri_, _convexus_, _tivius_ and _stansburyi_ are all easily
distinguished from _robustus_. Specimens of _sevieri_ are paler,
smaller in every measurement taken, and the skulls are weaker and less
angular. All specimens of _convexus_ are paler, the skulls are more
convex dorsally and narrower, with less ridging and angularity. Both
_tivius_ and _stansburyi_ are small dark forms, with weak, smooth,
small skulls as compared with _robustus_ which is light colored and has
compact, ridged and angular skulls.

_Remarks._--Twenty-three specimens were obtained at a small isolated
spring. Critical study of animals taken only a few miles to the east
prove them to be so different as to be referable to another subspecies,
_albicaudatus_. _T. b. robustus_ is an endemic form in this desert
valley. The variable color is noteworthy but difficult to explain in an
isolated population as small as this one. All five of the gray animals
are females of which four are lactating adults. The affinities of this
subspecies are with _albicaudatus_ to the east, but enough time has
elapsed since isolation to enable them to differentiate.

     _Specimens examined._--Total, 23, from the type locality.


=Thomomys bottae minimus= Durrant

     _Thomomys bottae minimus_ Durrant, Proc. Biol. Soc.
     Washington, 52:161, October 11, 1939; Marshall, Journ.
     Mamm., 21:154, May 14, 1940.

_Type._--Male, adult, skin and skull, No. 263942, U. S. National Museum
(Biological Surveys Collection); Stansbury Island, Great Salt Lake,
Tooele County, Utah; June 25, 1938; collected by William H. Marshall;
original number 141.

_Range._--Known only from the type locality.

_Diagnosis._--Size small (see measurements); tail relatively long.
Color: Upper parts Pinkish Buff, darker on head; underparts Pale
Pinkish Buff; front and hind feet white; nose, chin and postauricular
patches black. Skull: Long, slender and nearly devoid of ridges;
braincase moderately inflated; interparietal quadrangular; zygomatic
arches weak, widest in temporal region, but neither widely spreading
nor angular; nasals straight and truncate posteriorly; extension of
premaxillae posterior to nasals relatively great; tympanic bullae
moderately inflated; palatal pits deep; rostrum short but narrow;
interpterygoid space moderately lyre-shaped; upper incisors narrow;
molars light.

_Comparisons._--Compared with topotypes of _Thomomys bottae
albicaudatus_, _minimus_ differs as follows: Size markedly smaller;
claws on front feet shorter and weaker. Color: Markedly lighter
throughout, being Pinkish Buff as contrasted with near (13''''_n_)
Black. Skull: Smaller in every measurement taken; slender, smooth, weak
and nonangular as opposed to ridged, robust, wide and angular;
zygomatic arches much weaker and not so widely spreading posteriorly;
ascending processes of premaxillae much narrower; extension of
premaxillae posterior to nasals less; interpterygoid space moderately
lyre-shaped as opposed to V-shaped; dentition lighter.

Topotypes of _minimus_ differ from those of _Thomomys bottae
aureiventris_ as follows: Size markedly smaller. Color: Lighter
dorsally and no "gold color" on underparts. Skull: Markedly smaller in
every measurement taken; weak, smooth and slender as opposed to ridged,
angular and robust; zygomatic arches weak and widest posteriorly rather
than heavy and widest anteriorly; no great thickening at region of
union of jugal and zygomatic process of the maxilla; jugals more nearly
straight rather than concave laterally; interpterygoid space not so
markedly lyre-shaped; dentition lighter.

The races nearest geographically to _minimus_ are _Thomomys bottae
nesophilus_ and _T. b. stansburyi_. For comparisons see accounts of
those forms.

_Remarks._--This subspecies is the smallest of all the races of
_Thomomys bottae_ occurring in Utah. As far as known it is endemic to
Stansbury Island, and since the Pleistocene Lake Bonneville attained
its highest level has remained on that part of Stansbury Island that
was above this high level. (See comments under _nesophilus_.) The sandy
nature of the soil and the desert conditions of the area that has since
been exposed at lower levels apparently do not constitute a favorable
environment. Unlike _nesophilus_ from Antelope Island, this form does
not have its affinities with _albicaudatus_, the valley form of the
adjacent mainland, but does show affinities with _stansburyi_, the
nearest mountain form on the mainland. This is easily understood when
one realizes that Stansbury Island is only an isolated part of
Stansbury Mountain that projects northward as a peninsula into Great
Salt Lake. The history of Stansbury Island with reference to isolation
of _minimus_ parallels that of _nesophilus_ on Antelope Island. See
discussion under _nesophilus_.

     _Specimens examined._--Total, 5, as follows: _Tooele
     County_: Stansbury Island, Great Salt Lake, 5 (U. S. N. M.).


=Thomomys bottae nesophilus= Durrant

     _Thomomys bottae nesophilus_ Durrant, Bull. Univ. Utah, 27
     (No. 2):2, October, 1936; Marshall, Journ. Mamm., 21:156,
     May 14, 1940.

_Type._--Male, adult, skin and skull, No. 1136, Museum of Zoölogy,
University of Utah; Antelope Island, Great Salt Lake, Davis County,
Utah; April 20, 1935; collected by S. D. Durrant; original number 761.

_Range._--Known only from the type locality.

_Diagnosis._--Size medium (see measurements); claws on front feet long.
Color: Upper parts Cinnamon Buff; lighter below; sides Pinkish Buff
interspersed with gray; pectoral and inguinal regions Cinnamon; nose
grayish black; postauricular patches black. Skull: Interparietal
wedge-shaped; tympanic bullae small; dorsal surface of lambdoidal
prominence 3 mm. wide rather than developed as a crest; jugals nearly
straight; zygomatic arches strongly rectangular.

_Comparisons._--Compared with topotypes of _Thomomys bottae
albicaudatus_, _nesophilus_ is of approximately the same size, but
differs as follows: Claws on front feet longer. Color: Lighter
throughout; tail white terminally, but much darker at base;
postauricular patches smaller. Skull: Interparietal wedge-shaped as
opposed to roughly quadrangular; lambdoidal eminence more of a crest
than a ridge; tympanic bullae smaller; jugals more nearly straight;
zygomatic arches more nearly rectangular.

From topotypes of _Thomomys bottae aureiventris_, _nesophilus_ differs
in: Size smaller; claws on front feet longer. Color: Darker throughout;
postauricular patches larger. Skull: Heavier, more massive; zygomatic
arches more robust and convex laterally rather than concave;
interparietal wedge-shaped rather than roughly quadrangular; braincase
more nearly flat; tympanic bullae markedly smaller; upper molariform
series longer; molariform teeth wider and heavier; interpterygoid space
V-shaped rather than lyre-shaped.

The race nearest geographically to _nesophilus_ is _T. b. minimus_ from
Stansbury Island, Great Salt Lake. It can easily be distinguished from
_minimus_ by the following features: Size much larger; claws on front
feet longer and thicker. Color: Darker throughout; postauricular
patches larger and with more admixture of buff colored hairs. Skull:
Larger in every measurement taken; wide and robust as opposed to narrow
and slender; zygomatic arches more widely spreading and angular;
braincase more nearly flat; tympanic bullae actually larger, but
relatively smaller; lambdoidal eminence flat-topped rather than a
crest; interparietal wedge-shaped as opposed to quadrangular; teeth
larger.

_Remarks._--The affinities of _nesophilus_ of Antelope Island are
unquestionably with _albicaudatus_ of the eastern and southern
mainland. At the time of this writing (1945), Antelope Island is not
truly an island, but only the tip of a broad peninsula projecting
westward into Great Salt Lake. Nevertheless, the area of occurrence of
_nesophilus_ is effectively isolated by the exposed, sandy lake bottom
that is unsuited to occupancy by pocket gophers. Fluctuations in the
level of the Great Salt Lake have broken and reëstablished this
connection with the mainland many times. Each of the several other
kinds of mammals which are known from both the island and the mainland
show no differentiation on the island. These are kinds (see Marshall,
1940:156), which more freely cross the exposed, sandy lake bottom. I,
myself, have noted tracks of coyotes going to and from the island. The
pocket gopher, _nesophilus_, so far as known is the only mammal which
has developed a subspecies endemic to the island. The beach levels of
Pleistocene Lake Bonneville are well marked on both Antelope Island and
Stansbury Island, which is fifteen miles west of Antelope Island. On
the eastern side of Antelope Island the lower beach levels of this
prehistoric lake are farmed. Although sought for elsewhere on this
island, pocket gophers were found only in the farmed land. On Stansbury
Island there has been no farming, and the endemic pocket gophers,
_minimus_, although sought for elsewhere on that island were found only
above the highest beach levels of the ancient lake. Evidently these
pocket gophers still occupy only that part of Stansbury Island that
projected above water during the greatest height of Lake Bonneville.
Farming on Antelope Island may have developed a more favorable
environment for pocket gophers, thus causing them to move down to the
lower levels from that part of the island that was above water during
Pleistocene times.

     _Specimens examined._--Total, 5, from the type locality.


=Thomomys bottae stansburyi= new subspecies

_Type._--Female, adult, skin and skull, No. 2045, Museum of Zoölogy,
University of Utah; South Willow Creek, Stansbury Mountains, 7,500 ft.,
Tooele County, Utah; July 2, 1937; collected by O. S. Walsh and S. D.
Durrant; original number 1257 of Durrant.

_Range._--Stansbury Mountains, Tooele County, Utah.

_Diagnosis._--Size small (see measurements). Color: Upper parts
Saccardo's Umber, darker on head; sides and underparts Pinkish Buff;
nose, chin and postauricular patches black; front and hind feet and
distal third to half of tail white. Skull: Small, slender, weak and
smooth; zygomatic arches light and not widely spreading; zygomatic
arches actually as well as relatively short; interparietal generally
quadrangular; nasals relatively long and slender; interpterygoid space
narrowly V-shaped; basioccipital fairly wide; tympanic bullae
moderately inflated ventrally; dentition light.

_Comparisons._--Topotypical specimens of _stansburyi_ can be readily
distinguished from those of _Thomomys bottae centralis_, _aureiventris_
and _albicaudatus_ by being smaller in every measurement taken,
particularly those of the skull; the skull is weaker and smoother. In
color _stansburyi_ is like _albicaudatus_ but is much darker throughout
than _aureiventris_ and _centralis_.

Comparisons of topotypes of _stansburyi_ with those of _Thomomys bottae
sevieri_ show them to be of approximately the same size, but to differ
as follows: Color: Darker throughout. Skull: Zygomatic arches shorter;
tympanic bullae less inflated ventrally; zygomatic breadth less;
mastoid breadth greater; width across alveolar processes of maxillae
greater; alveolar length of upper molar series greater; molariform
teeth larger.

Compared with topotypes of _Thomomys bottae minimus_, _stansburyi_ is
seen to be of larger size and darker color throughout, with a skull
that is larger in most every measurement taken, although of the same
slender, smooth, nonangular type.

Among named races of _Thomomys bottae_, _stansburyi_ most closely
resembles tivius, a small, dark, mountain form from central Utah. Size
and color are almost the same but _stansburyi_ differs in: Tail
shorter; hind foot averaging slightly longer. Skull: Generally larger
in every measurement taken; zygomatic arches shorter; width across
alveolar processes of maxillae greater; zygomatic arches more widely
spreading, and widest in extreme posterior region rather than in region
of jugal-squamosal suture.

_Remarks._--The Stansbury Mountains are separated from the Oquirrh
Mountains by the Stockton Bar, and from the Onaqui Mountains, which are
in reality a continuation of the Stansbury Mountains, by only a low
pass. Pocket gophers from Clover Creek, Onaqui Mountains and Little
Valley, Sheeprock Mountains, although intergrades between _robustus_
and _albicaudatus_ are dark in color like _stansburyi_. These
intergrades are large, dark colored, and have heavy, ridged, angular
skulls. It appears that _stansburyi_ is a mountain subspecies derived
from _albicaudatus_ of the valley. It would be instructive to
artificially transplant gophers from mountains to valleys, and _vice
versa_, so as to reveal what effects if any on the animals' morphology
the environment might have in one or a few generations. Gophers are
well known to be very plastic, and such an experiment as suggested
might call for modification of the view, held here, that the
differential features of gophers from South Willow Creek and, say,
Bauer, are hereditary.

     _Specimens examined._--Total, 11, from the type locality.


=Thomomys bottae albicaudatus= Hall

     _Thomomys perpallidus albicaudatus_ Hall, Univ. California
     Publ. Zoöl., 32:444, July 8, 1930; Univ. California Publ.
     Zoöl., 37:3, April 10, 1931.

     _Thomomys bottae albicaudatus_ Goldman, Proc. Biol. Soc.
     Washington, 48:156, October 31, 1935; Durrant, Bull. Univ.
     Utah, 28 (No. 4):5, August 18, 1937.

     _Thomomys perpallidus aureiventris_ Hall, Univ. California
     Publ. Zoöl., 37:3, April 10, 1931.

_Type._--Male, adult, skin and skull, No. 43971, Museum of Vertebrate
Zoölogy, University of California; Provo, 4,510 ft., Utah County, Utah;
October 17, 1929; collected by Annie M. Alexander; original number 506.

_Range._--From the area between the Great Salt Lake and the Wasatch
Mountains south along the western margin of the central mountains of
the state to the Sevier River, in Juab County, west into Tooele County
to the Onaqui and Sheeprock mountains.

_Diagnosis._--Size medium (see measurements); claws on front feet
medium. Color: Upper parts near (13''''_n_) Black, grading over sides
and flanks to Pinkish Cinnamon on underparts; chin, nose, top of head
and postauricular patches black; front feet, hind feet and distal third
to half of tail white. Skull: Angular and ridged; zygomatic arches
moderately wide spreading, widest posteriorly; paroccipital processes
weak; zygomatic processes of maxillae convex anteriorly; lacrimal
processes small and peglike; jugals convex dorsally on ventral surface;
nasals short, rounded distally and truncate proximally; parietal crests
bowed in, in two places; interpterygoid space broadly V-shaped.

_Comparisons._-For comparisons of _albicaudatus_ with _Thomomys bottae
aureiventris_ and _centralis_ see accounts of those forms.

Topotypes of _albicaudatus_ are dark colored and can be distinguished
from those of _Thomomys bottae birdseyei_, _tivius_, _stansburyi_ and
_contractus_ which are also dark forms, by larger size and larger, more
robust skulls (see accounts of those forms). It can be distinguished
from the remainder of the known subspecies of _Thomomys bottae_ in Utah
by darker color and by cranial details (see accounts of those forms).

_Remarks._--The range of _albicaudatus_ is larger than that of any
other race of _Thomomys bottae_ limited to Utah. Specimens are
available from thirty localities which represent widely varied habitats
and environments. This subspecies consists of many highly variable
local populations, and the marginal populations intergrade freely with
adjacent races. In many populations, it is really difficult to
recognize the relationships on account of the great variation, and one
is frequently tempted to name some of them as distinct. Careful study
of the large number of specimens has enabled me to recognize diagnostic
characters common to all of these variable populations. The animals
range from large and dark at the north to small and light at the south.

The Jordan River bisects Salt Lake County from north to south. Pocket
gophers were taken at nine places east of the river, and at three
places west of it.

Gophers from Salt Lake City and environs (east of the river) vary in
color from almost black to dark cinnamon. Specimens from Draper, which
locality is likewise east of the river, are uniformly lighter, but also
vary in color. The skulls of animals from both localities are
indistinguishable from each other and closely resemble those of
topotypes. Specimens from the west side of the river, from Riverton,
two miles west of Murray and Rose Canyon, Oquirrh Mountains, all are
lighter in color than topotypes. The color varies from darkest at the
north at Murray to lightest at the south at Riverton. This is exactly
the reverse of what would be expected since Riverton is the locality
geographically nearest to the type locality, Provo. The skulls are
quite uniform and are all referable to _albicaudatus_. The Jordan River
may be one factor which causes this lack of uniformity between the
animals from the two sides of the river. Davis (1939:56-57) states that
rivers are not barriers to movement of pocket gophers where the river
completely freezes over and has the ice covered with thick snow.
Although the Jordan River does occasionally freeze over, it is never
frozen for more than a few days at a time, and snow in this area does
not last for long periods. The material at hand indicates that the
gophers from both sides of the river are referable to the same
subspecies _albicaudatus_. The animals from the east side of the river
are in the aggregate of characters the most typical of _albicaudatus_
of any in the entire range. Those from the west side of the river,
although definitely referable to _albicaudatus_ do show some
intergradation with _Thomomys bottae robustus_, the subspecies to the
west.

The specimens from Bauer, Tooele County, are relatively uniform in
color, and are considerably lighter than topotypes of _albicaudatus_.
Their upper parts vary from Sepia to Saccardo's Umber as compared with
near (13''''_n_) Black of the topotypes. The sides and underparts are
lighter, due primarily to much less black in the underfur. They average
slightly longer in total length, but shorter in hind foot. All cranial
measurements are slightly smaller than in topotypes of _albicaudatus_.
The shape of the skull closely resembles that of _albicaudatus_,
although the rostrum, nasals, upper incisors and posterior tongues of
the premaxillae tend to be narrower. This narrowness indicates
intergradation with _Thomomys bottae stansburyi_, the race nearest to
the west. These animals are in the majority of characters referable to
_albicaudatus_.

Bauer is situated in extreme western Tooele Valley at the foot of
Stockton Bar, a low pass between the Stansbury and the Oquirrh
mountains. This valley lies to the west of the aforementioned Jordan
River. Although these gophers are definitely referable to
_albicaudatus_ they are more unlike topotypes than are the animals from
Riverton.

The specimens from Settlement Canyon, Oquirrh Mountains, Tooele County,
show the same characteristics as those from Bauer.

In a large series of animals from St. John, in Rush Valley, Tooele
County, the upper parts vary from black, even darker than topotypes of
_albicaudatus_, to Tawny Olive, and the underparts vary from black
through Cinnamon Buff to Pinkish Buff. Most of the animals are Cinnamon
Buff. Although variable they approach _albicaudatus_ in color. The
total length, tail and hind foot of males are longer than in topotypes
of _albicaudatus_; females differ in the same direction but only
slightly. In both sexes the zygomatic breadth is less, but the mastoid
breadth is greater than in _albicaudatus_. In size and shape of the
lacrimal processes, and the great thickening of the jugal at the
maxillo-jugal suture they approach _robustus_. They are much larger,
however, and in the majority of characters are referable to
_albicaudatus_.

What has just been said relative to the animals from St. John applies
also to those from Clover Creek in the Onaqui Mountains of Tooele
County. At the latter locality the tendencies towards _robustus_ are
accentuated. This is to be expected, since this locality is midway
between St. John and the type locality of _robustus_. All characters
considered, these animals are all referable to _albicaudatus_.

The animals from Little Valley, Sheeprock Mountains, Tooele County,
resemble _albicaudatus_ in color. They vary on the upper parts from
near (1) Sepia to Clay Color, and ventrally from nearly black to
Pinkish Buff. They are markedly smaller in every measurement taken,
except zygomatic and mastoidal breadths, and extension of premaxillae
posterior to nasals. This relatively greater breadth indicates
intergradation with _robustus_ to the west. These gophers are smaller
in most measurements than any other population referred to
_albicaudatus_. This is understandable because gophers from mountains
usually are smaller and have weaker, smoother skulls than animals from
low lands. Although approaching _robustus_ in size and in some
aforementioned cranial details, the aggregate of characters including
color, make these animals referable to _albicaudatus_.

The animals from Fairfield, Utah County, are closer geographically to
the type locality of _albicaudatus_ than any other series, but
morphologically are the least like topotypes. At first glance one is
struck with the differences. They are uniformly Clay Color above, with
Cinnamon Buff sides and flanks and Pinkish Buff underparts. Their color
closely approaches that of _robustus_ to the west which has Cinnamon
Buff on the upper parts. Examination of eleven measurements of males
and the same number for females, shows that the animals are nearest to
_robustus_ in two measurements, to _albicaudatus_ in 12, distinct in 7
and intermediate in one. The general appearance of the skull is
intermediate between that of the two above mentioned forms. The
differences from _albicaudatus_ in size and color may be correlated
with the differences in soil at Fairfield and Provo. At Fairfield the
soil is light-colored clay, but at Provo it is sandy and darker.
Although they are intergrades between _robustus_ and _albicaudatus_,
the animals are referred to the latter race. Utah Lake and its outlet,
the Jordan River, make a partial barrier between populations at
Fairfield and at the type locality at Provo. During Pleistocene times,
when Lake Bonneville was present it formed a complete barrier. Enough
time has evidently elapsed since the disappearance of this lake to
allow _albicaudatus_, the mainland form, to expand its range to the
west. Intergradation has taken place, with the result that the animals
from Fairfield, although unstable, agree with the mainland form,
_albicaudatus_, in a majority of their characters.

Pocket gophers were taken at four localities from north to south in
eastern Juab County. They range in color from Ochraceous Tawny on the
upper parts and Cinnamon Buff on the underparts to shades that are
slightly lighter. All are much lighter than topotypes of
_albicaudatus_. The general configuration of the skull is the same as
that of _albicaudatus_, and this is especially true in the females. In
the narrower rostrum and weaker dentition they approach _contractus_,
but are distinctly lighter colored. Hall (1931:3) referred one specimen
from Nephi, Juab County, to _Thomomys bottae aureiventris_. Since that
time _Thomomys bottae lenis_ which has some affinities with
_aureiventris_ has been described (see account of _contractus_). The
large series now available from Nephi and nearby localities do show
some intergradation with _lenis_, in that four characters are more as
in _lenis_ and _contractus_ and seven characters are more as in
_albicaudatus_. Although differing markedly in many respects from
topotypes of _albicaudatus_ they fit the aforementioned concept of this
subspecies, and are being treated as a variable local population of it.

Provo is the locality listed for specimens which were available to
naturalists from 1875-1877. To these specimens the following names were
applied: _Thomomys talpoides bulbivorus_ Coues (1875:256; 1877:627) and
_Thomomys talpoides umbrinus_ Coues and Yarrow (1875:112). Possibly
these names were applied to the animals currently known as _Thomomys
bottae albicaudatus_ which does occur at Provo. Without the opportunity
to examine the actual specimens, which so far as I know are no longer
in existence, I cannot exclude the possibility that the locality
designation "Provo" was used in a general sense to include pocket
gophers taken a few miles to the eastward of Provo, where it is known
that pocket gophers of only the species _Thomomys talpoides_ (current
terminology) occur.

     _Specimens examined._--Total, 239, distributed as follows:
     _Davis County_: Bountiful, 4,500 ft., 1. _Salt Lake County_:
     Salt Lake City and environs, 4,300 ft., 51; 2 mi. W Murray,
     4,300 ft., 6; Riverton, 4,300 ft., 11; Draper, 4,500 ft., 7;
     Rose Canyon, Oquirrh Mountains, 5,650 ft., 4. _Tooele
     County_: Bauer, 4,500 ft., 30; Settlement Creek, Oquirrh
     Mountains, 6,500 ft., 1; St. John, 4,300 ft., 28; Clover
     Creek, Onaqui Mountains, 5,500 ft., 15; Vernon, 4,300 ft., 2
     (U. S. A. C.); Little Valley, Sheeprock Mountains, 5,500
     ft., 20. _Utah County_: Fairfield, 4,800 ft., 24; Provo,
     4,400 ft., 20 (8, B. Y. U.; 12, M. V. Z.). _Juab County_:
     Neff Farm, 4 mi. N Nephi, 5,000 ft., 2 (1, R. H.); Nephi,
     5,000 ft., 1 (M. V. Z.); 2 mi. S Nephi, 4,700 ft., 14; 7 mi.
     SW Nephi, 6,000 ft., 2.


=Thomomys bottae bonnevillei= new subspecies

_Type._--Male, adult, skin and skull, No. 3576, Museum of Zoölogy,
University of Utah; Fish Springs, 4,400 ft., Juab County, Utah; June 8,
1940; collected by S. D. Durrant; original number 1955.

_Range._--Known only from the type locality.

_Diagnosis._--Size medium (see measurements); claws on front feet
small. Color: Entire dorsal surface Warm Buff; sides near (_e_)
Cinnamon Buff, underparts near (16") Pale Pinkish Buff; inguinal
region, front and hind feet and distal part of tail white: top of head,
nose and cheeks grayish black; postauricular patches small and grayish
black; ears small, pointed and with heavily pigmented pinnae. Skull:
Angular, short and wide; nasals of medium length, narrow proximally but
widely flared distally; interparietal small; lambdoidal suture concave
towards the interparietal; zygomatic arches uniformly widely spreading;
interpterygoid space widely V-shaped; extension of premaxillae
posterior to nasals long; lambdoidal crest well developed.

_Comparisons._--From topotypes of _Thomomys bottae aureiventris_,
_bonnevillei_ differs as follows: Size smaller, hind foot shorter.
Color: Upper parts and sides lighter; underparts pale buff rather than
"gold." Skull: Shorter and relatively wider; rostrum wider and heavier;
zygomatic arches relatively wider and more massive, with greatest width
posteriorly instead of anteriorly; interpterygoid space widely V-shaped
rather than lyre-shaped; thickening at union of jugal and zygomatic
process of maxilla less developed; anterior palatine foramina larger;
nasals shorter and more markedly flared distally; zygomatic breadth
relatively, and mastoidal breadth actually, wider; extension of
premaxillae posterior to nasals greater; tympanic bullae more inflated
ventrally; upper incisors wider.

From near topotypes of _Thomomys bottae centralis_, from 1 mile east of
Garrison, Millard County, Utah, _bonnevillei_ differs as follows: Size
smaller; hind foot and tail shorter. Color: Generally darker above and
lighter below; top of head darker; postauricular patches smaller and
lighter. Skull: Shorter and wider (zygomatic breadth expressed in
percent of basilar length being, in males, 74.5 in _bonnevillei_ and
71.5 in _centralis_); interpterygoid space more widely V-shaped;
interparietal smaller, and more triangular; nasals shorter and much
more dilated distally, as well as more constricted proximally; lacrimal
processes smaller and less globuse at tips; temporal fossae larger;
braincase and entire dorsal surface of skull more nearly flat;
lambdoidal suture convex posteriorly as opposed to nearly straight;
tympanic bullae more inflated ventrally.

Comparisons of _bonnevillei_ with the type and type series of _Thomomys
bottae wahwahensis_ show them to be of approximately the same size, but
to differ as follows: Color: Slightly darker above and lighter below;
postauricular patches smaller and lighter. Skull: Larger in every
measurement taken, except breadth of rostrum which is smaller; skull
not as flat; tympanic bullae more inflated ventrally; nasals and
rostrum longer; extension of premaxillae posterior to nasals greater;
interparietal smaller and more triangular; zygomatic arches more bowed
out laterally; jugals heavier; interpterygoid space more widely
V-shaped; upper incisors less massive.

The characters that distinguish _bonnevillei_ from _Thomomys bottae
albicaudatus_ are: Size smaller. Color: Markedly lighter throughout.
Skull: Shorter and wider; mastoid and zygomatic breadths greater;
rostrum narrower but shorter; angle between rostrum and zygomatic
processes of maxillae less; interparietal smaller and more triangular;
extension of premaxillae posterior to nasals greater; upper incisors
shorter, narrower and more recurved.

_T. b. bonnevillei_ is indistinguishable in color from _Thomomys bottae
convexus_, but differs from it in the following features: Size larger
in nearly every measurement taken. Skull: Flattened dorsally as opposed
to convex; zygomatic arches longer and weaker; jugals more nearly
perpendicular; tympanic bullae larger; upper incisors longer; alveolar
length of upper molar series the same, but molars narrower; rostrum
longer but nasals shorter; extension of premaxillae posterior to nasals
greater.

Topotypes of _bonnevillei_ can be distinguished from those of both
_Thomomys bottae tivius_ and _stansburyi_ by being larger in every
measurement taken, by markedly lighter color throughout, and by ridged,
massive, angular skulls rather than smooth, weak, nonangular skulls.

The races closest geographically to _bonnevillei_ are _Thomomys bottae
robustus_ and _T. b. sevieri_. Compared with topotypes of _robustus_,
_bonnevillei_ differs in: Size larger. Color: Lighter throughout.
Skull: Larger, although not as compact; zygomatic arches more widely
spreading; jugals lighter; lacrimal processes not as prominent;
zygomatic processes of maxillae not as robust; nasals more flared
distally; extension of premaxillae posterior to nasals greater;
alveolar length of upper molar series longer; molars larger; upper
incisors longer, wider and darker in color; when placed ventral side
down on a surface, the dorsal face of a skull of _robustus_ is
approximately parallel to the surface, whereas one of _bonnevillei_
dips down in the occipital region.

_T. b. sevieri_ can be easily distinguished from _bonnevillei_ by being
smaller in every measurement taken, darker in color, and by small,
weak, smooth skulls as opposed to large, robust, ridged skulls.

_Remarks._--Fish Springs, where _bonnevillei_ occurs is a marshy area
south of the barren, salt-desert country of western Utah. The source of
water is springs at the base of the north end of the Fish Springs
Mountains. Only the moist area supports pocket gophers. Specimens from
Trout Creek, Juab County, twenty-five miles to the southwest are
intergrades between _bonnevillei_ and _aureiventris_, and are referred
to the latter subspecies. The country between Fish Springs and Trout
Creek in 1937 and 1940 lacked pocket gophers; it was of the playa and
sand type. Probably _T. b. bonnevillei_ was derived from _T. b.
aureiventris_, a western mainland form of Pleistocene Lake Bonneville,
through isolation and subsequent differentiation morphologically. The
moist soils at Cane Springs, seven miles south of Fish Springs, had no
pocket gophers when visited in 1940.

     _Specimens examined._--Total, 11, from the type locality.


=Thomomys bottae centralis= Hall

     _Thomomys perpallidus centralis_ Hall, Univ. California
     Publ. Zoöl., 32:445, July 8, 1930.

     _Thomomys bottae centralis_ Goldman, Proc. Biol. Soc.
     Washington, 48:156, October 31, 1935; Hall and Johnson,
     Proc. Utah Acad. Sci. Arts and Letters, 15:121, 1938.

_Type._--Male, adult, skin and skull, No. 41688, Museum of Vertebrate
Zoölogy, University of California; 2-1/2 mi. E Baker (1-1/4 mi. W
Nevada-Utah boundary on 39th parallel), 5,700 ft., White Pine County,
Nevada; May 30, 1929; collected by E. Raymond Hall; original number
2683.

_Range._--Extreme western Utah, in Millard, Beaver and Iron counties.

_Diagnosis._--Size medium (see measurements); tail long; claws on front
feet long. Color: Near Cinnamon Buff on upper parts, darker in
middorsal region, grading to Pinkish Buff on underparts, more
accentuated in pectoral and inguinal regions; nose, cheeks and
postauricular patches grayish black; front and hind feet and distal
half of tail white. Skull: Robust and moderately ridged; zygomatic
breadth about the same for entire length of arches; jugals vertical
posterior to middle; moderate thickening present at region of
maxillo-jugal suture; interpterygoid space narrowly V-shaped; dorsal
frontomaxillary sutures convex medially; lacrimal processes globose and
well developed; nasals long and with distal denticulations;
paroccipital processes well developed.

_Comparisons._--Compared with topotypes of _Thomomys bottae
albicaudatus_, _centralis_ differs as follows: Size larger; tail
longer; claws on front feet longer. Color: Lighter throughout, Cinnamon
Buff as opposed to near (13''''_n_) Black. Skull: Basilar length and
length of nasals greater; zygomatic breadth less; zygomatic arches
thicker at region of maxillo-jugal sutures; interpterygoid space more
broadly V-shaped; dorsal frontomaxillary sutures convex medially as
opposed to straight; paroccipital processes more developed; zygomatic
arches approximately the same width throughout as opposed to widest
posteriorly.

For comparisons with _Thomomys bottae aureiventris_ see account of that
form.

_T. b. centralis_ can be distinguished from _Thomomys bottae
bonnevillei_, _robustus_, _sevieri_ and _convexus_ by larger size
throughout and generally darker color (see accounts of those forms).
From _Thomomys bottae stansburyi_ and _tivius_, _centralis_ differs in
larger size throughout and lighter color (see accounts of those forms).

_Remarks._--_Thomomys bottae centralis_ has one of the most extensive
ranges of any of the known races of _T. bottae_. The eastern limits
extend into extreme western Utah. Specimens from Utah for the most part
are intergrades between _centralis_ and _aureiventris_, the race to the
north. Some minor intergradation is also noted between _centralis_ and
_sevieri_ and _bonnevillei_, the races to the east. Intergradation is
the expected condition because the animals belonging to _centralis_ are
at the extremes of their range in this area. The greater affinities of
these animals with _aureiventris_ is to be expected because both
_aureiventris_ and _centralis_ are forms of the western mainland of the
Pleistocene Lake Bonneville; while the races to the east, although
closest geographically, were isolated from the gophers of the western
mainland during prehistoric times by this lake. They are still isolated
and enough time has elapsed so that only vestiges of morphological
intergradation exist between _centralis_ and these eastern forms. Two
specimens from Cedar City, Iron County, are intergrades between
_Thomomys bottae wahwahensis_, _centralis_ and _planirostris_. Their
skulls are slightly convex as in _planirostris_, and the rostrum is
short and wide as in _wahwahensis_. In shape of the zygomatic arches,
length of the nasals, and color, they resemble _centralis_ to which
they are here referred.

     _Specimens examined._--Total, 49, distributed as follows:
     _Millard County_: 1 mi. SE Gandy, 5,000 ft., 15 (M. V. Z.);
     White Valley (Tule Spring), 60 mi. W Delta, 4, (3 in R. W.
     Fautin Vertebrate Collection); Robison Ranch, 5,300 ft., (on
     Hendry Creek) Simonsons Ranch, 4,596 ft., 2 (M. V. Z.); 1
     mi. E Garrison, 5,000 ft., 21; 5 mi. S Garrison, 5,400 ft.,
     5 (M. V. Z.). _Iron County_: Cedar City, 2 (M. V. Z.).


=Thomomys bottae sevieri= new subspecies

_Type._--Female, adult, skin and skull, No. 2530, Museum of Zoölogy,
University of Utah; Swasey Spring, House Mountains, 6,500 ft., Millard
County, Utah; May 16, 1938; collected by S. D. Durrant; original number
1380.

_Range._--Known only from the type locality.

_Diagnosis._--Size medium (see measurements); claws on front feet short
and weak; ears short; tail relatively long. Color: Upper parts Pinkish
Buff, grading over sides to Pale Pinkish Buff on underparts; nose, top
of head, chin and cheeks grayish black; postauricular patches small and
grayish black; front and hind feet and distal two-thirds of tail white.
Skull: Small, weak and smooth; rostrum narrow; nasals narrow, not
markedly flared distally; zygomatic arches weak, not angular, and of
"graceful" contour; lacrimal processes small; characteristic dorsal
depression present in region of sagitto-coronal suture; mastoid and
zygomatic breadths narrow; occiput narrow and high; braincase well
inflated; paroccipital processes small and smooth; interpterygoid space
narrowly V-shaped; tympanic bullae small, but well inflated ventrally;
alveolar length of upper molar series short; molars small; upper
incisors short, but narrow.

_Comparisons._--From topotypes of _Thomomys bottae aureiventris_,
_sevieri_ differs as follows: Size smaller. Color: Lighter throughout,
no "gold" on underparts. Skull: Much smaller in every measurement
taken, less massive and not angular; zygomatic arches weaker and widest
posteriorly rather than anteriorly; union of jugal and zygomatic
process of maxilla not greatly thickened; interpterygoid space narrowly
V-shaped rather than lyre-shaped; pterygoid hamulae shorter and weaker;
tympanic bullae smaller, but markedly more inflated ventrally;
dentition smaller and weaker.

From near topotypes of _Thomomys bottae centralis_, _sevieri_ can be
distinguished by the following features: Size markedly smaller. Color:
Lighter throughout. Skull: Markedly smaller in every measurement taken,
weaker and smoother; zygomatic arches weaker, less angular and more
"graceful"; rostrum shorter, but narrower; lacrimal processes smaller;
tympanic bullae smaller, but more inflated ventrally, being triangular
in shape as opposed to ovate and with anteromedial margin decidedly
pointed; pterygoid hamulae smaller and weaker; dentition smaller and
weaker.

_T. b. sevieri_ can readily be distinguished from _Thomomys bottae
albicaudatus_ by the following features: Size smaller in every
measurement taken. Color: Markedly lighter throughout. Skull: Smaller,
and weaker; rostrum shorter and narrower; ascending processes of
premaxillae narrower; extension of premaxillae posterior to nasals
shorter; posterior tongues of premaxillae narrower; dentition much
lighter.

Comparisons of _sevieri_ with topotypes of _Thomomys bottae
wahwahensis_ show them to be of approximately the same size, but to
differ as follows: Hind foot longer; ear shorter. Color: Slightly
darker. Skull: Smaller, weaker, less ridged; zygomatic breadth less;
zygomatic arches markedly less angular; mastoid breadth less; rostrum
much longer and narrower, not as blunt nor flattened; tympanic bullae
much larger and more inflated ventrally; braincase vaulted as opposed
to flattened.

From topotypes of _Thomomys bottae bonnevillei_, _sevieri_ differs in:
Size smaller throughout. Skull: Smaller in every measurement taken,
weaker, smoother and less angular; dentition smaller and weaker.

Topotypes of _sevieri_ are easily distinguished from those of _Thomomys
bottae robustus_ by smaller size, and smaller, markedly weaker skull
which is less angular and ridged.

Among named races of _Thomomys bottae_, _sevieri_ is closest
geographically to _convexus_, but differs from it as follows: Size
larger; hind foot longer. Skull: Smaller in every measurement taken;
nasals shorter and not so flaring distally; rostrum weaker, narrower
and not so depressed; zygomatic arches markedly weaker and less
angular; lacrimal processes smaller; supraoccipital narrower and
higher; paroccipital processes weaker; tympanic bullae smaller;
dentition markedly weaker.

Topotypical specimens of _sevieri_ can be readily distinguished from
those of _Thomomys bottae tivius_ by Pinkish Buff instead of Mummy
Brown on upper parts. Tympanic bullae larger and markedly more
inflated; nasals longer; zygomatic and mastoidal breadths greater;
rostrum longer and more depressed; upper incisors longer and wider;
molariform teeth smaller. The skulls of _sevieri_ resemble those of
_tivius_ more closely than those of any other subspecies.

_Remarks._--The House Mountains in western Millard County are
surrounded by desertlike terrain that is seemingly unsuited to pocket
gophers. In these mountains, gophers were sought in vain at several
localities, including Antelope Springs which superficially appeared
suitable for the animals. Pocket gophers were found only at the type
locality, Swasey Spring, which is well above the highest level of the
Pleistocene Lake Bonneville. _T. b. sevieri_, like _T. b. minimus_ on
Stansbury Island, Great Salt Lake, appears to remain only on land that
was an island when Lake Bonneville was at its highest level.

     _Specimens examined._--Total, 10, from the type locality.


=Thomomys bottae convexus= Durrant

     _Thomomys bottae convexus_ Durrant, Proc. Biol. Soc.
     Washington, 52:159, October 11, 1939.

_Type._--Male, adult, skin and skull, No. 2482, Museum of Zoölogy,
University of Utah; E side Clear Lake, 4,600 ft., Millard County, Utah;
May 20, 1938; collected by S. D. Durrant; original number 1401.

_Range._--Westcentral Utah in Delta Valley.

_Diagnosis._--Size medium (see measurements). Color: Upper parts and
sides Pinkish Buff, purest on sides; underparts Pale Pinkish Cinnamon;
inguinal and pectoral regions Pale Pinkish Buff; nearly all specimens
have white on perineal region; nose grayish black; front feet, hind
feet and distal third to half of tail white; postauricular patches
black. Skull: Braincase moderately convex on dorsal surface; rostrum
strongly depressed, giving the entire dorsal surface of the skull a
"rocker-shape"; zygomatic arches heavy, short and widely spreading,
widest posteriorly; upper incisors recurved, short and wide; molariform
teeth large; alveolar length of upper molar series long; palatal pits
deep; tympanic bullae moderately inflated ventrally; mastoidal breadth
actually as well as relatively wide.

_Comparisons._--Compared with topotypes of _Thomomys bottae
wahwahensis_, _convexus_ is of approximately the same color, but
differs as follows: Size smaller; tail, hind foot, and ear shorter.
Skull: Rostrum longer, narrower and more depressed; skull convex rather
than flat; nasals longer, and convex rather than flat; tympanic bullae
larger; zygomatic arches shorter and more massive; molariform teeth
larger.

From topotypes of _Thomomys bottae centralis_, _convexus_ differs in:
Size smaller; tail and hind foot shorter. Color: Uniformly lighter,
more white in perineal region. Skull: Smaller, more convex; rostrum
shorter, wider and more depressed; zygomatic arches shorter and
heavier; mastoidal breadth actually, as well as relatively wider;
tympanic bullae more inflated ventrally; upper incisors shorter and
wider.

Comparatively, topotypes of _convexus_ can be distinguished from those
of _Thomomys bottae aureiventris_ by: Size smaller; tail and hind foot
shorter. Color: Darker on upper parts; no "gold" on underparts. Skull:
Smaller and more nearly flat; rostrum shorter and more depressed;
zygomatic arches shorter, heavier and widest posteriorly rather than
anteriorly; interpterygoid space V-shaped as opposed to lyre-shaped;
upper incisors shorter, narrower and more recurved.

Topotypical specimens of _convexus_ differ from those of _Thomomys
bottae nesophilus_ as follows: Size smaller; tail and hind foot
shorter. Color: Uniformly lighter throughout, Cinnamon Buff as opposed
to Pinkish Buff. Skull: Smaller; rostrum heavier, shorter and more
depressed; zygomatic arches shorter, heavier and not so widely
spreading; no widening of supraoccipital as in _nesophilus_; upper
incisors shorter and more recurved.

When compared with topotypes of _Thomomys bottae albicaudatus_,
_convexus_ shows the following differences: Size smaller; tail and
hind foot shorter. Color: Markedly lighter throughout. Skull: Smaller,
more convex and compact; rostrum shorter, heavier, more depressed and
compact; zygomatic arches shorter and more robust; upper incisors
shorter and more recurved.

_Thomomys bottae tivius_ is the race closest geographically to
_convexus_. From it, _convexus_ can be readily distinguished by: Size
larger; tail shorter; hind foot longer. Color: Markedly lighter
throughout. Skull: Much heavier and more compact, weights of skulls of
males and females of the two subspecies being 2.4 grs., 1.6; 1.6, 1.2,
respectively; rostrum heavier, wider and more depressed; zygomatic
arches shorter, and more massive; upper incisors shorter, wider and
more recurved; molariform teeth larger.

For comparisons with _Thomomys bottae lenis_, _contractus_, _sevieri_,
_bonnevillei_, and _robustus_ see accounts of those forms.

_Remarks._--_T. b. convexus_ is limited to the area around Clear Lake
in Millard County. This lake is surrounded by areas of loose, shifting
sand and flat areas of barren alkali. The lake is fed by springs which
flow from lava outcroppings on its eastern side. As far as discernible,
the only area populated by pocket gophers (1938) was that adjacent to
the lake where vegetation had trapped the sand. The factor which limits
the extension of range of this subspecies probably is plant food. Also,
the soil is mechanically poor for burrowing, since it caves in easily
and burrows were found only in the sand where salt grass (_Distichlis
stricta_) had trapped and stabilized it. Burrows were found from the
edge of the water back as far as this grass persisted.

     _Specimens examined._--Total, 17, from the type locality.


=Thomomys bottae tivius= Durrant

     _Thomomys bottae tivius_ Durrant, Bull. Univ. Utah, 28 (No.
     4):5, August 18, 1937.

_Type._--Female, adult, skin and skull, No. 1827, Museum of Zoölogy,
University of Utah; Oak Creek Canyon, 6 mi. E Oak City, 6,000 ft.,
Millard County, Utah; September 14, 1936; collected by S. D. Durrant;
original number 1100.

_Range._--Limited to the Cañon Mountains, Millard County.

_Diagnosis._--Size small (see measurements). Color: Upper parts Mummy
Brown, grading through Cinnamon on the sides to Pale Cinnamon on the
underparts; cheeks Cinnamon; postauricular patches black; distal third
to half of tail white. Skull: Small, weak; zygomatic arches weak, not
widely spreading, widest posteriorly; tympanic bullae large;
interpterygoid space V-shaped; nasals short, usually simple distally,
but with some denticulations in some specimens; palatal pits deep;
palate narrow; paroccipital processes small; incisors, both upper and
lower, narrow; molariform teeth small.

_Comparisons._--Topotypes of _tivius_ differ from those of _Thomomys
bottae albicaudatus_ as follows: Size markedly smaller in every
measurement taken. Color: Lighter, Mummy Brown as opposed to near
(13''''_n_) Black. Skull: Smaller, slenderer and weaker; zygomatic
arches weak and not widely spreading as opposed to massive and wide
spreading; nasals and rostrum narrower and shorter; extension of
premaxillae posterior to nasals shorter; tympanic bullae smaller;
molariform teeth smaller.

For comparisons with _Thomomys bottae stansburyi_ and _T. b.
contractus_ see accounts of those forms.

The four subspecies _tivius_, _albicaudatus_, _stansburyi_, and
_contractus_ are the darkest in color of all the _Thomomys bottae_
occurring within the state.

_Remarks._--This small, dark subspecies is limited to the Cañon
Mountains in eastern Millard County. Apparently it is a mountain
derivative of _Thomomys bottae contractus_ which occurs in the valleys
to the east and west of these mountains. Intergradation is noted with
animals from the valleys on either side. For further comments on
distributional problems of this type see remarks under _Thomomys bottae
stansburyi_.

     _Specimens examined._--Total, 12, from the type locality.


=Thomomys bottae contractus= new subspecies

     _Thomomys perpallidus albicaudatus_ Hall, Univ. California
     Publ. Zoöl., 37:3, April 10, 1931.

     _Thomomys bottae albicaudatus_ Durrant. Bull. Univ. Utah, 28
     (No. 4):4, August 18, 1937.

_Type._--Male, adult, skin and skull, No. 1851, Museum of Zoölogy,
University of Utah; Scipio, 5,315 ft., Millard County, Utah; September
17, 1936; collected by S. D. Durrant; original number 1125.

_Range._--Extreme eastern Millard and Beaver counties, Utah.

_Diagnosis._--Size medium (see measurements). Color: Upper parts
Cinnamon Buff, mixed with black giving a color of Dresden Brown; sides
between Cinnamon Buff and Pinkish Buff; underparts Pinkish Buff, purest
on inguinal and pectoral regions; postauricular patches medium in size
and black; ears covered with black hairs; nose, chin, cheeks and top of
head dusky; front feet, hind feet and distal third to half of tail
white; proximal part of tail covered all around with buff-colored
hairs. Skull: Long, slender, moderately ridged and convex transversally
at proximal ends of nasals; nasals long; rostrum long and narrow;
posterior ends of nasals truncate or shallowly emarginate; ascending
processes of premaxillae slender; extension of premaxillae posterior to
nasals long; zygomatic arches neither robust nor widely spreading;
interparietal subquadrangular; supraoccipital extending horizontally
well behind lambdoidal suture instead of dropping off abruptly to the
foramen magnum; interpterygoid space moderately V-shaped in some
specimens, but somewhat lyre-shaped in others; tympanic bullae large
and truncate anteriorly; upper incisors long and narrow; molariform
teeth small and light.

_Comparisons._--Compared with topotypes of _Thomomys bottae
albicaudatus_, _contractus_ differs as follows: Tail longer. Color:
Lighter throughout. Skull: Slenderer, less ridged and angular; rostrum
narrower; zygomatic and mastoidal breadths less; ascending processes of
premaxillae narrower; posterior tongues of premaxillae narrower;
posterior ends of nasals less truncate; zygomatic arches weaker, less
angular, and less widely spreading posteriorly; interparietal larger;
paroccipital processes weaker; interpterygoid space not as widely
V-shaped; upper incisors longer and narrower; molariform teeth smaller.

Topotypes of _contractus_ can be distinguished from those of _Thomomys
bottae convexus_ by the following: Size larger, tail longer; hind foot
larger. Color: Darker throughout. Skull: Longer, narrower, and not as
massive; top of skull moderately, as opposed to strongly, convex;
nasals arched rather than straight; zygomatic arches neither as widely
spreading, angular nor massive; space enclosed within zygomatic arches
longer; interparietal larger; interpterygoid space more narrowly
V-shaped; upper incisors longer and narrower; molariform teeth much
lighter.

Comparisons of topotypes of _contractus_ with near topotypes of
_Thomomys bottae centralis_ show them to be approximately the same
size, but to differ as follows: Color: Darker throughout. Skull:
Shorter and slenderer; rostrum narrower; region between posterior
tongues of premaxillae narrower and more convex transversally; nasals
more truncate; zygomatic breadth less, but arches relatively more
widely spreading posteriorly; interparietal larger; interpterygoid
space generally narrower; upper incisors longer and narrower;
molariform teeth smaller.

Topotypes of _contractus_ differ from those of _Thomomys bottae
aureiventris_ as follows: Size smaller; tail longer; hind foot shorter.
Color: Darker throughout. Skull: Shorter but slenderer; rostrum
narrower; nasals shorter but slenderer, and more truncate posteriorly;
extension of premaxillae posterior to nasals longer; zygomatic arches
weaker and less angular; zygomatic processes of maxillae weaker and
with no marked thickenings at union of maxilla and jugals;
interparietal larger; interpterygoid space more generally V-shaped;
upper incisors longer and narrower; molariform teeth smaller.

Compared with topotypes of _Thomomys bottae planirostris_, _contractus_
differs in: Size smaller throughout. Color: Darker, more black and less
Cinnamon in pelage. Skull: Smaller in every measurement taken; rostrum
narrower; nasals arched instead of flat; zygomatic arches neither
angular, massive nor widely spreading; upper incisors narrower;
molariform teeth markedly smaller and weaker.

Topotypes of _contractus_ differ from those of _Thomomys bottae
levidensis_ in larger size, darker color and longer, slenderer skulls.

Among named races of _T. bottae_, _contractus_ is closest
morphologically to _tivius_. It differs from it as follows: Size larger
throughout. Color: Lighter throughout. Skull: The same general shape
and proportions, but larger in every measurement taken; rostrum longer
and narrower; extension of premaxillae posterior to nasals longer;
posterior tongues of premaxillae narrower.

_Remarks._--Fifteen animals from Oak City are intergrades between
_contractus_ and _tivius_. Intergradation with _lenis_ is also shown in
some specimens by the widely spreading zygomatic arches. In the
majority of characters including the diagnostic long, slender, narrow
rostrum they are more like _contractus_ to which they are here
referred.

Nine animals from Beaver were considered by Hall (1931:3) and Durrant
(1937:4) to be intergrades between _Thomomys bottae albicaudatus_ and
_Thomomys bottae centralis_. Restudy of these specimens in the light of
additional material now shows them to be intergrades between _T. b.
centralis_, _T. b. planirostris_ and _T. b. contractus_. The majority
of these animals are intermediate in color between _centralis_ and
_contractus_, but a few have the reddish cast of _planirostris_. The
shape of the nasals is characteristic of _planirostris_, while the
zygomatic arches are as in _centralis_. In the remainder of the
diagnostic characters they are like _contractus_ to which they are here
referred.

Strong affinities exist between _albicaudatus_, _tivius_ and
_contractus_. All three of these races probably stemmed from a dark
form which formerly inhabited the eastern mainland of the Pleistocene
Lake Bonneville. At present, _tivius_ is isolated on the Cañon
Mountains in eastern Millard County, while the range of _albicaudatus_
and _contractus_ have been separated by that of _lenis_. _T. b. lenis_
has the majority of its affinities with _aureiventris_ which is an
inhabitant of the western mainland of this ancient lake. An
understanding of the history of the Sevier River Valley will probably
clarify this distribution of pocket gophers.

     _Specimens examined._--Total, 39, distributed as follows:
     _Millard County_: Oak City, 5,000 ft., 15; Scipio, 5,315
     ft., 15. _Beaver County_: Beaver, 6,000 ft., 9 (M. V. Z.).


=Thomomys bottae lenis= Goldman

     _Thomomys townsendii lenis_ Goldman, Proc. Biol. Soc.
     Washington, 55:75, June 25, 1942.

     _Thomomys perpallidus aureus_ Moore, Journ. Mamm., 10:259;
     November 11, 1931.

_Type._--Male, adult, skin and skull, No. 264805, U. S. National Museum
(Biological Surveys Collection); Richfield, 5,308 ft., Sevier County,
Utah; March 11, 1928; collected by A. W. Moore; X-catalogue number
28835 (after Goldman, type not seen).

_Range._--Sevier River Valley from Piute County north to southwestern
Juab and northeastern Millard counties, Utah.

_Diagnosis._--Size large (see measurements). Color: Upper parts
Cinnamon Buff mixed with black in middorsal region; sides, flanks,
forearms, thighs and underparts Pinkish Buff; inguinal region, front
feet, hind feet, underpart of tail and end of tail white; postauricular
patches small and dusky; chin, cheeks, nose and top of head dusky.
Skull: Largest of Utah gophers, massive and angular; nasals long and
denticulate distally; rostrum long and relatively narrow; zygomatic
arches widely spreading and heavy throughout; jugals nearly vertical;
zygomatic processes of maxillae heavy and flaring out abruptly from
base of rostrum; union of zygomatic process of maxilla and jugal
greatly thickened; extension of premaxillae posterior to nasals long;
posterior tongues of premaxillae relatively narrow; lacrimal processes
small; pterygoid hamulae long; interpterygoid space moderately
V-shaped, tending to be somewhat lyre-shaped in some specimens;
tympanic bullae somewhat flattened, only moderately inflated ventrally;
upper incisors long and narrow; molariform teeth actually large, but
relatively small.

_Comparisons._--Topotypes of _lenis_ can be distinguished from those of
_Thomomys bottae tivius_, _convexus_, _contractus_, _albicaudatus_,
_levidensis_, _centralis_ and _aureiventris_ by the following markedly
greater average measurements of males: Total length, 250 mm.; length of
nasals, 15.5; zygomatic breadth, 28.3; mastoid breadth, 22.5; and
length of rostrum, 18.3. Other distinguishing characters are: Zygomatic
arches more widely spreading; length of zygomatic processes of maxillae
greater; and relatively longer, narrower rostrum.

_Remarks._--Twenty-one animals obtained from Lynndyl, Millard County,
are all intergrades between _lenis_ and _aureiventris_. They are like
_aureiventris_ in the shape of the zygomatic arches, and in the bowing
of the parietal crests. Slight intergradation with _centralis_ is
indicated by color and the shape of the nasals. The transverse arching
of the posterior part of the rostrum is indicative of some relationship
with _contractus_. In six other characters studied they most closely
approach _lenis_ to which they are here referred.

Large size is the distinctive feature of _Thomomys bottae lenis_. The
skulls are the largest of any species or subspecies of _Thomomys_ found
in Utah. In total length, however, these animals are no longer than the
extremes found in other named races. When Goldman (1942:75) described
this race as new, he referred it to the species _Thomomys townsendii_,
but remarked that the animal from Richfield was different enough from
any other form then named to merit probably full specific status. I
know of no character other than size to separate _Thomomys townsendii_
from _Thomomys bottae_, and since intergradation has been shown to
exist between these alleged _townsendii_ from Richfield and animals
from extreme western Utah known to belong to the species _bottae_,
_lenis_ is here arranged as a subspecies of _Thomomys bottae_ which
name has priority over _Geomys townsendii_.

The range here ascribed to this race is the Sevier River Valley from
Piute County as far downstream as the town of Lynndyl which is near the
eastern mainland of Pleistocene Lake Bonneville. The Sevier River
continues farther out into Delta Valley ultimately to empty into Sevier
Lake, which at present is adjacent to the area that formerly
constituted the western mainland of the aforementioned ancient lake.
This watercourse may have provided a migration route in ancient times,
during the fluctuations of Lake Bonneville, whereby the animals
formerly of the western mainland were able to come far eastward. The
animals from Lynndyl which are intergrades between _lenis_, an eastern
mainland form, and _centralis_ and _aureiventris_ which are western
mainland forms of Lake Bonneville lend support to this hypothesis.

     _Specimens examined._--Total, 26, distributed as follows:
     _Millard County_: Lynndyl, 4,796 ft., 21. _Juab County_: U.
     B. (= Yuba) Dam, 5,000 ft., 1. _Sevier County_: Salina,
     4,575 ft., 1; Richfield, 5,308 ft., 3. (U. S. N. M.).


=Thomomys bottae levidensis= Goldman

     _Thomomys bottae levidensis_ Goldman, Proc. Biol. Soc.
     Washington, 55:76, June 25, 1942.

     _Thomomys perpallidus aureus_ Bailey, N. Amer. Fauna, 39:75,
     November 15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85,
     April, 1922; Bull. Univ. Utah, 17 (No. 12):100, June, 1927.

_Type._--Male, adult, skin and skull, No. 191962, U. S. National Museum
(Merriam Collection); Manti, 5,500 ft., Sanpete County, Utah; December
6, 1888; collected by Vernon Bailey; original number 427 (after
Goldman, type not seen).

_Range._--San Pitch River Valley, Sanpete County, Utah.

_Diagnosis._--Size small (see measurements). Color: Upper parts and
sides Cinnamon Buff, finely mixed with black along median line of back;
underparts Pinkish Buff; nose, cheeks and chin grayish black;
postauricular patches fairly large and grayish black; front and hind
feet white (examples from type series badly stained); tail light buff
but apparently white distally (the color of these specimens has
apparently changed with age). Skull: Small, fairly robust; basilar
length short; zygomatic arches weak, but widely spreading; tympanic
bullae small; nasals short and simple distally; ventral margin of
jugals convex dorsally; extension of premaxillae posterior to nasals
relatively as well as actually long; posterior tongues of premaxillae
relatively wide.

_Comparisons._--Topotypes of _levidensis_ differ from those of
_Thomomys bottae absonus_ as follows: Size smaller. Color: Lighter
throughout. Skull: Shorter, weaker and less ridged and angular, but
relatively wider.

Compared with topotypes of _Thomomys bottae albicaudatus_, _levidensis_
differs as follows: Size smaller in every measurement taken. Color:
Markedly lighter throughout. Skull: Smaller in every measurement taken;
width relatively greater; skull smooth, weak and nonangular as opposed
to ridged, robust and angular.

For comparisons with _Thomomys bottae lenis_ and _contractus_ see
accounts of those forms.

_Remarks._--The range here ascribed to _levidensis_ is the San Pitch
River Valley, which gradually merges southward into the Sevier River
Valley. The latter valley in this area is inhabited by pocket gophers
that belong to another subspecies, _lenis_. Nephi Valley to the west of
San Pitch River Valley is inhabited by animals belonging to the
subspecies _albicaudatus_. No known specimens show intergradation
between _lenis_ and _levidensis_, but intergradation between _lenis_
and _albicaudatus_ is noted in the Nephi Valley animals (see account of
_albicaudatus_). Superficially _levidensis_ resembles _absonus_ in size
and color, but the skulls closely resemble those of _albicaudatus_,
except for size in which they are smaller in all measurements. _T. b.
albicaudatus_ is the most variable subspecies of _T. bottae_ occurring
in Utah, and additional material from the Sevier River Valley between
San Pitch River Valley and Nephi Valley may show _levidensis_ to be
only a local variant of the highly variable subspecies, _albicaudatus_.

     _Specimens examined._--Total, 6, from the type locality.


=Thomomys bottae osgoodi= Goldman

     _Thomomys perpallidus osgoodi_ Goldman, Journ. Washington
     Acad. Sci., 21:424, October 19, 1931.

     _Thomomys bottae osgoodi_ Goldman, Proc. Biol. Soc.
     Washington, 48:156; October 31, 1935.

     _Thomomys perpallidus aureus_ Bailey, N. Amer. Fauna, 39:75,
     November 15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85,
     April, 1922; Bull. Univ. Utah, 17 (No. 12):100, June, 1927.

_Type._--Male, adult, skin and skull, No. 158530, U. S. National Museum
(Biological Surveys Collection); Hanksville, Wayne County, Utah;
October 20, 1908; collected by W. H. Osgood; original number 3701
(after Goldman, type not seen).

_Range._--Eastern Utah in the valleys of the drainage of the San
Rafael, Dirty Devil and Price rivers.

_Diagnosis._--Size medium (see measurements). Color: Upper parts near
(_e_) Pale Ochraceous Buff, definitely yellow in appearance; sides Pale
Ochraceous Buff; entire underparts white, with a wash of Light Buff in
the pectoral and inguinal regions; top of head, nose, cheeks, and chin
dusky; postauricular patches grayish black; front feet, hind feet and
distal part of tail white. Skull: Fairly robust but narrow; zygomatic
arches concave medially in mid-jugal region; skull moderately convex
dorsally, due to swelling in region of base of rostrum; lambdoidal
suture situated well ahead of posterior margin of skull, with
supraoccipital forming a side shelf at posterior part of skull;
interpterygoid space narrowly V-shaped; tympanic bullae well inflated
ventrally; basioccipital short; nasals rounded posteriorly; molariform
teeth large.

_Comparisons._--Topotypes of _osgoodi_ differ from those of _Thomomys
bottae absonus_ as follows: Size generally smaller. Color: Lighter
throughout, more yellowish in appearance as opposed to buffy. Skull:
Smaller in all measurements, except length of nasals, mastoid breadth,
and alveolar length of upper molar series which are larger; rostrum
shorter but relatively wider; zygomatic arches more robust and concave
medially; palate wider; supraoccipital more bulging posteriorly;
tympanic bullae more inflated ventrally; molariform teeth larger.

For comparisons with _Thomomys bottae aureus_ and _T. b. dissimilis_
see accounts of those forms.

_Remarks._--The animals here referred to _osgoodi_ are remarkably
uniform in color, but vary widely in cranial details. Specimens from
Carbon County are not typical and when more material becomes available
it may prove that these animals from the northern part of the range of
_osgoodi_ will merit separation and naming. The specimens from Emery
County are not typical but resemble _osgoodi_ more than do the animals
from Carbon County.

The range here ascribed to _osgoodi_ is in that part of the eastern
Utah desert that is bounded on the east by the Green and Colorado
rivers, on the west by the high mountains of central Utah, on the north
by the Book Cliffs and on the south by the Dirty Devil River. This area
is an uninviting wasteland in which there are relatively few roads and
little water. In addition, it is greatly cut up by washes and gullies
which contain water only during a few weeks of the year. The
continuation of this area of wasteland southward beyond the Dirty Devil
River is inhabited by pocket gophers belonging to the subspecies
_absonus_. If specimens were available they would undoubtedly show
intergradation to exist between _osgoodi_ and _absonus_.

     _Specimens examined._--Total, 14, distributed as follows:
     _Carbon County_: 1-2 mi. N Spring Glen, 6,150 ft., 2; Spring
     Glen, 6,200 ft., 2; 2 mi. E Spring Glen, 6,200 ft., 1.
     _Emery County_: Price River, 2 mi. SE Woodside, 4,600 ft., 2
     (C. M.); Green River, 4,080 ft., 5 (M. V. Z.). _Wayne
     County_: Hanksville, 2 (U. S. N. M.).


=Thomomys bottae howelli= Goldman

     _Thomomys bottae howelli_ Goldman, Journ. Washington Acad.
     Sci., 26:116, March 15, 1936.

_Type._--Female, adult, skin and skull, No. 25684, U. S. National
Museum (Biological Surveys Collection); Grand Junction, 4,600 ft., Mesa
County, Colorado; November 7, 1895; collected by A. H. Howell; original
number 493 (after Goldman, type not seen).

_Range._--In the valleys of eastern Utah, east of the Green River and
north of the Colorado River.

_Diagnosis and Comparisons._--Inasmuch as there is but one specimen,
the holotype known, and as it was impossible to study it, the following
diagnoses and comparisons are from Goldman, (1936:116).

"_General characters._--A rather large, pallid subspecies with a broad,
flattened cranium. Similar to the palest specimens of _Thomomys bottae
aureus_ of the San Juan River Valley, southeastern Utah, in color, but
underparts more thinly overlaid with buffy white, and cranial
characters, especially the broad, flat braincase, distinctive.
Approaching _Thomomys bottae osgoodi_ of the Fremont River Valley,
Utah, in color, but much larger and skull widely different.

"_Color._--Type (winter pelage): Upper parts in general between tilleul
buff and pale olive buff (Ridgway 1912), somewhat darkened on head by a
mixture of cinnamon buff and brown; a few inconspicuous dusky-tipped
hairs along median line of back; muzzle dusky; ears and postauricular
spots deep, contrasting black; underparts thinly overlaid with buffy
white, the hairs becoming pure white to roots on inguinal region;
thighs pure white to roots all around; feet white; tail buffy whitish,
slightly paler below than above.

"_Skull._--Similar in general to that of _T. b. aureus_, but braincase
conspicuously broader and flatter; zygomata more widely spreading;
nasals shorter; premaxillae more attenuate posteriorly; interparietal
larger; audital bullae more rounded and fully inflated anteriorly;
incisors short, as in _aureus_, but less strongly recurved. Compared
with that of _T. b. osgoodi_ the skull is much larger, with flatter
braincase, shorter nasals, and posteriorly narrower premaxillae."

_Remarks._--Six specimens, in the Carnegie Museum from 10 miles north
of Moab, Grand County, Utah, were available for this study. They are
not typical of _howelli_ as it is diagnosed by Goldman (_loc. cit._).
They appear to be intergrades between _howelli_ and _osgoodi_ in
cranial characters, but more closely resemble _howelli_, particularly
in the flat, widened, low braincase. In color, some specimens seem to
intergrade toward _aureus_.

The range ascribed to this form in Utah appears to be one of the most
natural ones within the state since it is bounded by the Green and
Colorado rivers which have formed deep rocky gorges in this region.

     _Specimens examined._--Total, 6, as follows: _Grand County_:
     10 mi. N Moab, 6 (C. M.).


=Thomomys bottae wahwahensis= Durrant

     _Thomomys bottae wahwahensis_ Durrant, Bull. Univ. Utah, 28
     (No. 4):4, August 18, 1937.

_Type._--Male, adult, skin and skull, No. 1750, Museum of Zoölogy,
University of Utah, Wah Wah Springs, 30 mi. W Milford, 6,500 ft.,
Beaver County, Utah; July 22, 1936; collected by S. D. Durrant;
original number 989.

_Range._--Westcentral Utah, in Wah Wah Mountains, and Pine Valley to
the west of these mountains.

_Diagnosis._--Size medium (see measurements). Color: Upper parts
Pinkish Buff; underparts Pale Pinkish Buff with considerable admixture
of gray; inguinal and pectoral regions Pale Pinkish Buff; nose and
cheeks grayish black; postauricular patches small and black; front
feet, hind feet and distal one-third to one-half of tail white. Skull:
Flat dorsoventrally; rostrum short and wide; premaxillae broad and
heavy; nasals short and straight, with no arching as viewed laterally;
tympanic bullae small; space enclosed within zygomatic arches short
antero-posteriorly; alveolar length of upper molar series short;
molariform teeth small.

_Comparisons._--From topotypes of _Thomomys bottae centralis_,
_wahwahensis_ differs as follows: Size smaller in every measurement
taken. Color: Lighter, Pinkish Buff as opposed to Cinnamon Buff. Skull:
Rostrum wider, shorter and more nearly flat; nasals straight as opposed
to moderately convex; tympanic bullae smaller and less inflated
ventrally; zygomatic arches more widely spreading and angular;
molariform teeth smaller; extension of premaxillae posterior to nasals
less.

From topotypes of _Thomomys bottae albicaudatus_, _wahwahensis_ differs
as follows: Hind foot shorter. Color: Lighter throughout, Pinkish Buff
as opposed to (13''''_n_) Black. Skull: Smaller and more nearly flat;
rostrum shorter, wider and more nearly flat; nasals straight as opposed
to convex; zygomatic breadth less but mastoid breadth greater; tympanic
bullae smaller, and less inflated ventrally; extension of premaxillae
posterior to nasals less; molariform teeth smaller.

From topotypes of _Thomomys bottae aureiventris_, _wahwahensis_ differs
in the following features: Size smaller; hind foot shorter. Color:
Lighter throughout, no "gold" on underparts. Skull: Smaller in nearly
every measurement taken; rostrum shorter and relatively wider;
zygomatic arches more angular and relatively more widely spreading;
nasals shorter and more nearly flat; thickening at union of jugal and
zygomatic process of maxilla less; interpterygoid space V-shaped as
opposed to lyre-shaped; tympanic bullae much smaller, and less inflated
ventrally; molariform teeth much smaller.

Topotypes of _wahwahensis_ can be easily distinguished from those of
_Thomomys bottae tivius_ by their markedly larger size in every
measurement taken, lighter color, and larger, more robust and more
nearly flat skull.

For comparisons of _wahwahensis_ with _Thomomys bottae sevieri_,
_robustus_, _bonnevillei_ and _convexus_ see comparisons under those
forms.

Among the named races of _Thomomys bottae_, _wahwahensis_ definitely
has its affinities with _planirostris_ from Zion National Park. Both
possess flat skulls with wide, short rostra. It differs from the latter
in: Size smaller in every measurement taken. Color: Lighter throughout.
Skulls: Nasals and rostrum shorter and more nearly flat; tympanic
bullae markedly smaller; alveolar length of upper molar series shorter;
molariform teeth markedly smaller and weaker.

_Remarks._--Wah Wah Springs, the type locality of _wahwahensis_, are on
the summit of a low pass in the Wah Wah Mountains in the desert of west
central Utah. The surrounding valleys, for many miles, as far as my
investigations show, are not inhabited by pocket gophers, except the
Desert Range Experiment Station of the United States Forest Service in
Pine Valley to the west of these mountains. There, pocket gophers were
obtained which are intergrades between _centralis_ and _wahwahensis_.
In five out of seven characters investigated these gophers resemble
_wahwahensis_, to which they are here referred. Study of the topography
reveals the probable means by which the animals reached this valley.
The long axis of the Wah Wah Mountains is north and south, but a
westward arm forms the northern boundary of Pine Valley. Around springs
in this westward projecting arm workings of pocket gophers were found.
With the development of water at the Desert Range Experiment Station,
and subsequent improvement of forage, these animals probably came down
into the valley from the springs to the north.

The terrain between the Desert Range Experiment Station in Pine Valley
and Snake Creek (where _centralis_ occurs) to the west is not inhabited
by pocket gophers at present. This area, however, forms part of the
southwest mainland of Pleistocene Lake Bonneville, which mainland in
times past was probably suitable for pocket gophers. Since the close of
the Pleistocene, aridity has rendered most of it unfit for pocket
gophers, and they remain only in isolated areas where suitable
environments still persist.

     _Specimens examined._--Total, 18, distributed as follows:
     _Millard County_: Desert Range Experiment Station, United
     States Forest Service, Sec. 9, T. 25 S, R. 17 W, Salt Lake
     Base Meridian, 6. _Beaver County_: Wah Wah Springs, Wah Wah
     Mountains, 30 mi. W Milford, 6,500 ft., 12 (2, M. V. Z.).


=Thomomys bottae dissimilis= Goldman

     _Thomomys perpallidus dissimilis_ Goldman, Journ. Washington
     Acad. Sci., 21:425, October 19, 1931.

     _Thomomys bottae dissimilis_ Goldman, Proc. Biol. Soc.
     Washington, 48:156, October 31, 1935.

     _Thomomys perpallidus aureus_ Bailey, N. Amer. Fauna 39:75,
     November 15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85,
     April, 1922; Bull. Univ. Utah, 17 (No. 12):100, June, 1927.

_Type._--Female, adult, skin and skull, No. 158526, U. S. National
Museum (Biological Surveys Collection); E slope Mount Ellen, Henry
Mountains, 8,000 ft., Garfield County, Utah; October 15, 1908;
collected by W. H. Osgood; original number 3677 (after Goldman, type
not seen).

_Range._--Known only from the type locality.

_Diagnosis._--Size small (see measurements). Color: Upper parts Light
Buff, grading over sides to nearly white on underparts; underparts
lightly washed with Pale Buff, more marked in inguinal and pectoral
regions; postauricular patches grayish black; nose, chin, cheeks and
top of head dusky; front feet, hind feet and distal half of tail white.
Skull: Small and weak; zygomatic arches long, but lying close to skull,
giving it a slender appearance; supraoccipital markedly projecting
posteriorly from lambdoidal suture; rostrum relatively long and narrow;
nasals long; tympanic bullae well inflated ventrally, with a median
ventral ridge; pterygoid hamulae weak; interpterygoid space narrowly
V-shaped; upper incisors short and light in color; molariform teeth
relatively large.

_Comparisons._--Comparison of one topotype of _dissimilis_ with
topotypes of _Thomomys bottae aureus_ shows it to differ as follows:
Size smaller throughout. Color: Lighter dorsally and on sides, pale
buff as contrasted with rich ochraceous; underparts more buffy. Skull:
Smaller in every measurement taken; zygomatic arches markedly less
widely spreading; braincase narrower and more vaulted; tympanic bullae
with a median ventral ridge as opposed to smooth; pterygoid hamulae
slenderer; interpterygoid space narrowly V-shaped as opposed to
U-shaped; upper incisors smaller and lighter in color.

Compared with topotypes of _Thomomys bottae absonus_, _dissimilis_
differs in the following features: Size smaller in every measurement
taken. Color: Lighter throughout. Skull: Smaller in every measurement
taken, except alveolar length of upper molar series which is greater;
skull narrower and weaker; zygomatic arches weaker and less widely
spreading; tympanic bullae more ridged on ventral surface and shorter
(more rounded) in antero-posterior measurement; upper incisors shorter
and narrower; molariform teeth larger.

_Thomomys bottae dissimilis_ resembles _T. b. osgoodi_ more than any
other subspecies but differs in: Size smaller throughout. Color:
Slightly darker dorsally. Skull: Smaller in every measurement taken,
and slenderer; rostrum relatively longer; zygomatic arches weaker, and
less widely spreading, more converging anteriorly; tympanic bullae less
rounded, more ridged medioventrally; upper incisors shorter but
narrower; molariform teeth smaller.

_Remarks._--The Henry Mountains, in eastern Garfield County, are in the
Colorado River drainage. The surrounding country is desertlike and cut
by gullies and washes with sheer escarpments and precipitous draws. The
type locality of _dissimilis_ is possibly in an isolated area. Only
three specimens were available to Goldman when he named _dissimilis_.
He commented on the close resemblance to _osgoodi_ which inhabits the
country to the north. I have examined only one of the three specimens
available to Goldman. Although I can see the characters that he
mentioned, I am not fully convinced that _dissimilis_ is separable from
_osgoodi_. Two specimens from Escalante, Garfield County, are referred
to _absonus_, but they show intergradation with _dissimilis_.

     _Specimens examined._--One (U. S. N. M.) from E slope Mount
     Ellen, Henry Mountains, 8,000 ft., Garfield County.


=Thomomys bottae aureus= Allen

     _Thomomys aureus_ Allen, Bull. Amer. Mus. Nat. Hist., 5:49,
     April 28, 1893.

     _Thomomys bottae aureus_ Goldman, Proc. Biol. Soc.
     Washington, 48:156, October 31, 1935; Benson, Univ.
     California Publ. Zoöl., 40:450, December 31, 1935.

     _Thomomys fulvus aureus_ Goldman, Journ. Washington Acad.
     Sci., 21:417, October 19, 1931; Journ. Washington Acad.
     Sci., 23:464, October 15, 1933.

     _Thomomys perpallidus aureus_ Bailey, N. Amer. Fauna, 39:74,
     November 15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85,
     April, 1922; Bull. Univ. Utah, 17 (No. 12):100, June, 1927.

_Type._--No. 5243/4123. American Museum of Natural History; Bluff City,
San Juan County, Utah; May 12, 1892; collected by Charles P. Rowley
(after Allen, type not seen).

_Range._--All of San Juan County (except extreme southwestern part) and
Grand County east of the Colorado River.

_Diagnosis._--Size large (see measurements). Color: Upper parts
Cinnamon Buff, lighter on sides; underparts generally white, or if
colored at all with only a faint wash of Light Buff; nose and chin
blackish gray; top of head blackish due to admixture of black hairs;
postauricular patches small and dusky; front feet and hind feet white.
Skull: Long, narrow but massive; zygomatic arches not widely spreading,
but heavy; jugals thick, union of jugals and zygomatic processes of
maxillae thickened; rostrum long but wide; top of rostrum convex in
lateral view; ascending processes of premaxillae wide and heavy; nasals
thin proximally; braincase long and narrow; tympanic bullae well
inflated ventrally; alveolar length of upper molar series long; molars
large; pterygoid hamulae heavy; interpterygoid space U-shaped; palate
arched; upper incisors long and wide.

_Comparisons._--Compared with topotypes of _Thomomys bottae osgoodi_,
_aureus_ differs as follows: Size larger in every measurement taken,
except tail which is shorter. Color: Darker throughout except on
ventral surface which is lighter. Skull: Larger, longer and wider;
nasals longer; rostrum wider and longer; zygomatic arches more nearly
straight and heavier; ascending processes of premaxillae wider;
basioccipital longer; interpterygoid space U-shaped as opposed to
V-shaped; tympanic bullae larger; upper incisors longer, wider; molars
larger.

Topotypical specimens of _aureus_ can be distinguished from those of
_Thomomys bottae dissimilis_ by: Size larger throughout. Color: A
trifle darker on dorsal surface. Skull: Larger in every measurement
taken; zygomatic arches heavier and more nearly straight; tympanic
bullae larger and more inflated ventrally; interpterygoid space
U-shaped as opposed to V-shaped; alveolar length of upper molar series
longer; molars larger; upper incisors longer and wider.

Topotypes of _aureus_ differ from those of _Thomomys bottae absonus_ as
follows: Size larger in every measurement taken. Color: Darker
dorsally, Light Ochraceous as opposed to Cinnamon Buff; due to
admixture of gray, _absonus_ has more of a grayish cast. Skull: Larger
in every measurement taken, longer, narrower and more compact;
zygomatic arches heavier; ascending processes of premaxillae wider;
jugals heavier; tympanic bullae larger; interpterygoid space U-shaped
rather than V-shaped; upper incisors longer and wider; molars larger.

From topotypes of _Thomomys bottae planirostris_, _aureus_ can be
distinguished as follows: Size larger; tail shorter. Color: Lighter
throughout. Skull: Larger in every measurement taken except zygomatic
breadth, extension of premaxillae posterior to nasals, and length of
upper molariform series which are less; rostrum longer, wider and more
convex; nasals slightly arched rather than straight; depression absent
rather than present in posterior region of nasals; zygomatic arches not
so widely spreading, but equally heavy.

For comparisons with _Thomomys bottae alexandrae_, see accounts under
that form.

_Remarks._--Topotypes of _aureus_ are among the largest pocket gophers
in the state. They are exceeded in total length only by _T. b. lenis_
and are approached by _T. b. aureiventris_ and _T. b. planirostris_. On
the average they have the longest hind foot, body and ear. The length
of the skull is second only to that of _lenis_ as also is the length
and breadth of the rostrum relative to the basilar length.

From the time of the original description of _aureus_ in 1893 until
1930, all light colored gophers from Utah were referred to that form.
Barnes (1927:100) gives the range of _aureus_ as extending completely
across southern Utah and on the west and east sides as far north as
central Utah. Since 1930, forms named by E. R. Hall, W. H. Burt, E. A.
Goldman and the writer have restricted the range of _aureus_ in Utah to
that part of the state east of the Colorado River.

     _Specimens examined._--Total, 22, as follows: _San Juan
     County_: Bluff, 3,300 ft., 22 (15, M. V. Z.).


=Thomomys bottae birdseyei= Goldman

     _Thomomys bottae birdseyei_ Goldman. Proc. Biol. Soc.
     Washington, 50:134, September 10, 1937.

     _Thomomys perpallidus aureus_ Bailey, N. Amer. Fauna, 39:75,
     November 15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85,
     April, 1922; Bull. Univ. Utah, 17 (No. 12):100, June, 1927.

_Type._--Male, adult skin and skull, No. 161654. U. S. National Museum
(Biological Surveys Collection); Pine Valley Mountains, 5 mi. E Pine
Valley, 8,300 ft., Washington County, Utah; April 10, 1909; collected
by Clarence Birdseye; original number 861 (after Goldman, type not
seen).

_Range._--High mountains and plateaus of southwestern Utah.

_Diagnosis._--Size medium (see measurements). Color: Upper parts
between Cinnamon and Sayal Brown, finely mixed with black in median
dorsal region, grading over sides and flanks to Cinnamon on underparts;
front feet, hind feet, and distal part of tail white; postauricular
patches, chin, cheeks and top of head grayish black. Skull: Depressed
along median line of frontals and posterior ends of nasals; region of
nasofrontal suture concave ventrally; zygomatic arches heavy and widely
spreading, widest posteriorly; posterior ends of nasals straight,
tending to be somewhat rounded in some specimens; extension of
premaxillae posterior to nasals moderate; tympanic bullae moderately
inflated ventrally; basioccipital wide; interpterygoid space widely
V-shaped.

_Comparisons._--Topotypes of _birdseyei_ differ from near topotypes of
_Thomomys bottae virgineus_, from Beaverdam Wash as follows: Size
larger; tail and hind foot longer. Color: Darker throughout, between
Cinnamon and Sayal Brown as opposed to Cinnamon Buff. Skull: Larger in
every measurement taken except extension of premaxillae posterior to
nasals, and length and width of rostrum which are less; skull more
depressed in nasofrontal region; zygomatic arches more widely
spreading; zygomatic processes of squamosals shorter; pterygoid hamulae
longer; tympanic bullae smaller and less inflated ventrally.

Among named races of _T. bottae_, _birdseyei_ most closely resembles
_trumbullensis_ in size, but differs as follows: Hind foot and tail
longer. Color: Lighter throughout; postauricular patches smaller and
lighter. Skull: Larger; mastoid breadth less; zygomatic arches wider
and more widely spreading posteriorly; median frontal depression more
marked; extension of premaxillae posterior to nasals greater; tympanic
bullae less inflated ventrally; molariform teeth larger.

For comparisons with _Thomomys bottae planirostris_ see account of that
form.

_Remarks._--_T. b. birdseyei_ is apparently endemic to the mountainous
area of southwestern Utah in Washington and Iron counties. It
intergrades with _virgineus_ and with _planirostris_ as described in
the account of the latter.

     _Specimens examined._--Total, 8, distributed as follows:
     _Washington County_: Pine Valley, 1 (U. S. N. M.); Pine
     Valley Mountains, 5 mi. E Pine Valley, 8,300 ft., 3 (U. S.
     N. M.); Pine Valley campground, 6,800 ft., 1 (R. H.); 3/4
     mi. E town of Pine Valley, 6,500 ft., 3 (R. H.).

     _Additional records._--_Washington County_: Hebron, 1;
     Mountain Meadows, 2 (Bailey 1915:75).


=Thomomys bottae virgineus= Goldman

     _Thomomys bottae virgineus_ Goldman, Proc. Biol. Soc.
     Washington, 50:133, September 10, 1937.

_Type._--Male, adult, skin and skull, No. 262016, U. S. National Museum
(Biological Surveys Collection); Beaverdam Creek, near confluence with
Virgin River, Littlefield, 1,500 ft., Mohave County, Arizona; October
16, 1936; collected by Luther C. Goldman; original number 67 (after
Goldman, type not seen).

_Range._--Extreme southwestern Utah, in Beaverdam Wash, Washington
County, Utah.

_Diagnosis._--Size medium (see measurements). Color: Upper parts
Cinnamon Buff, finely mixed with black; sides and flanks Pinkish Buff;
underparts Pale Pinkish Buff; front feet, hind feet, and distal part of
tail white; nose, cheeks, chin and top of head grayish black. Skull:
Robust, with moderately wide zygomatic arches; zygomatic processes of
maxillae wide; zygomatic processes of squamosals long; jugals concave
laterally, giving the zygomatic arches the appearance of double bowing;
nasals long; extension of premaxillae posterior to nasals long;
tympanic bullae well inflated ventrally; pterygoid hamulae heavy;
interpterygoid space widely V-shaped; molariform teeth large.

_Comparisons._--For comparisons of _virgineus_ with _Thomomys bottae
planirostris_ and _T. b. birdseyei_ see accounts under those forms.

Topotypical specimens of _virgineus_ can be distinguished from those of
_Thomomys bottae trumbullensis_ as follows: Size smaller. Color:
Lighter throughout. Skull: Zygomatic arches less widely spreading;
jugals more bowed medially; zygomatic processes of squamosals longer;
extension of premaxillae posterior to nasals greater; tympanic bullae
larger and more inflated ventrally; molariform teeth larger.

Compared with topotypes of _Thomomys bottae centralis_, _virgineus_
differs in: Size smaller; tail shorter; hind foot smaller. Color:
Deeper Cinnamon Buff, thus darker in overall appearance. Skull:
Smaller, but relatively wider; zygomatic processes of maxillae heavier;
region of maxillo-jugal sutures thicker; jugals more concave laterally;
tympanic bullae more inflated ventrally; molariform teeth larger.

_Remarks._--This pocket gopher occupies practically the same range in
Utah as the large kangaroo rat _Dipodomys deserti deserti_ Stephens.
Both are found in the Beaverdam Wash. The type locality of _virgineus_
is but a short distance down the Beaverdam Creek at Littlefield,
Arizona. It intergrades with _birdseyei_, the mountain form to the
north and east (see remarks under _birdseyei_). There are evidences of
intergradation with _planirostris_ of the Virgin River Valley above the
narrows of the Virgin River where it cuts through the Beaverdam
Mountains (see the discussion under _planirostris_). There are
intergradational tendencies exhibited towards _centralis_ in some
specimens. Some of the animals are practically indistinguishable in
color and there are intergrading cranial characters in the nasals,
zygomatic arches and tympanic bullae.

     _Specimens examined._--Total, 20, distributed as follows:
     _Washington County_: Beaverdam Wash, 8 mi. N Utah-Arizona
     border, 7; Beaverdam Wash, 5 mi. N Utah-Arizona border,
     2,600 ft., 13.


=Thomomys bottae planirostris= Burt

     _Thomomys perpallidus planirostris_ Burt, Proc. Biol. Soc.
     Washington, 44:38, May 8, 1931.

     _Thomomys bottae planirostris_ Hall and Davis, Proc. Biol.
     Soc. Washington, 47:52, February 9, 1934; Goldman, Proc.
     Biol. Soc. Washington, 48:156, October 31, 1935; Presnall,
     Zion-Bryce Mus. Bull., 2:14, January, 1938; Long, Journ.
     Mamm., 21:176, May 14, 1940.

     _Thomomys perpallidus aureus_ Bailey, N. Amer. Fauna, 39:75,
     November 15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85,
     April, 1922; Bull. Univ. Utah, 17 (No. 12):100, June, 1927;
     Woodbury, Ecological Monographs, 3:193, April, 1933.

     _Thomomys bottae centralis_ Hall and Davis, Proc. Biol. Soc.
     Washington, 47:52, February 9, 1934; Presnall, Zion-Bryce
     Mus. Bull., 2:14, January, 1938.

     _Thomomys perpallidus centralis_ Hall, Univ. California
     Publ. Zoöl., 23:445, July 8, 1930.

     _Thomomys bottae nicholi_ Goldman, Journ. Washington Acad.
     Sci., 28:337, July 15, 1938, type from Shivwits Plateau, 20
     mi. S Wolf Hole (road to Parashonts), 5,000 ft., Mohave
     County, Arizona; Hardy, Ecological Monographs, 15:98,
     January, 1945.

     _Thomomys bottae trumbullensis_ Hall and Davis, Proc. Biol.
     Soc. Washington, 47:52, February 9, 1934.

_Type._--Male, adult, skin and skull, No. 8395, Collection of Donald R.
Dickey; Zion National Park, Washington County, Utah; May 4, 1920;
collected by A. Brazier Howell; original number 2184 (after Burt, type
not seen).

_Range._--Valley of the Virgin River from Zion National Park west to
the Beaverdam Mountains.

_Diagnosis._--Size large (see measurements); tail long. Color: Upper
parts Sayal Brown; underparts between Vinaceous Cinnamon and Cinnamon,
grading to Pinkish Cinnamon in some specimens; nose, chin, cheeks,
postauricular patches, and top of head grayish black; front feet and
hind feet white; tail Pinkish Buff, with distal third white. Skull:
Massive and ridged; nasals straight and flat, simple distally; dorsal
surface of rostrum slightly concave at proximal end of nasals;
zygomatic arches widely spreading, widest posteriorly; zygomatic
processes of maxillae heavy; premaxillae broad and extending far beyond
posterior end of nasals; rostrum wide and heavy; palate slightly
arched; pterygoid hamulae heavy; interpterygoid space V-shaped;
tympanic bullae moderately inflated ventrally, somewhat compressed
laterally; upper incisors long and heavy; molariform teeth large.

_Comparisons._--Compared with topotypes of _Thomomys bottae birdseyei_,
_planirostris_ differs as follows: Size larger, except total length
which averages slightly less in females. Color: Lighter throughout.
Skull: Larger in every measurement taken; more massive; rostrum wider,
longer and more nearly flat; nasals straight and not inflated dorsally
on distal end; premaxillae wider at posterior ends; extension of
premaxillae posterior to nasals greater; zygomatic arches heavier,
especially the zygomatic processes of the maxillae; posterior ends of
nasals more nearly truncate as opposed to generally rounded; tympanic
bullae more nearly flat and relatively smaller; upper incisors longer
and heavier; interpterygoid space more narrowly V-shaped; molariform
teeth much heavier.

Topotypes of _planirostris_ differ from near topotypes of _Thomomys
bottae virgineus_ as follows: Size larger; tail and hind foot longer.
Color: Slightly darker dorsally, but markedly darker ventrally;
postauricular patches smaller and lighter. Skull: Larger in every
measurement taken; skull more massive; nasals flat, neither arched nor
swollen distally; rostrum wider; nasofrontal region flattened or
concave as opposed to convex; premaxillae relatively narrower;
zygomatic arches heavier, especially in the processes of the maxillae;
tympanic bullae smaller and less inflated ventrally; interpterygoid
space generally more narrowly V-shaped; upper incisors longer and
heavier; molariform teeth larger.

From topotypes of _Thomomys bottae trumbullensis_, _planirostris_
differs in: Size larger throughout; tail longer. Color: Much lighter
throughout. Skull: More convex dorsally; rostrum wider and more
depressed distally; extension of premaxillae posterior to nasals
greater; zygomatic arches shorter, and not as widely spreading
posteriorly; interpterygoid space more narrowly V-shaped; tympanic
bullae smaller; upper incisors wider and longer; molariform teeth
larger.

Topotypes of _planirostris_ can be easily distinguished from those of
_Thomomys bottae absonus_ by darker color throughout and markedly
larger size.

_Remarks._--From the synonomy at the beginning of this account one may
note that the animals here ascribed to this subspecies have had nearly
as many subspecific names applied to them as there have been
investigators who have written about them. Although each of the
previous writers had but a small amount of material upon which to base
his opinion, the diversity of opinion as to subspecific status bespeaks
the instability of these animals. The present study is based upon
eighty animals including additional comparative material.

All animals from Zion National Park have the characters pointed out by
Burt (1931:38) in his description of this form. Farther down the
Virgin River Valley towards St. George, however, some very perplexing
problems of intergradation are encountered. St. George and environs may
correctly be thought of as a "melting pot." Each of the fifty-seven
animals studied from this region is an intergrade; some specimens
combine the characters of three subspecies.

As may be seen on the distribution map, three different subspecies of
_Thomomys bottae_ occur in Washington County. Down the river, below St.
George, the race _virgineus_ inhabits the Virgin River Valley below the
narrows of the Beaverdam Mountains. Because these narrows are filled
with water from wall to wall during periods of high runoff, they form
an effective barrier at present to migration of pocket gophers. The
mountains to the north of St. George are inhabited by the dark form,
_birdseyei_. The type locality of _planirostris_ is on the middle
reaches of the Virgin River, in Zion National Park. In addition Mount
Trumbull to the south, in northern Arizona, is the locality of another
subspecies, _trumbullensis_.

Unquestionably the easiest route of migration into the St. George area
is down the Virgin River from Zion National Park; no barrier to gophers
occurs between the Park and St. George. Although the animals from St.
George are all intergrades, the majority of their affinities as would
be expected are with _planirostris_ from Zion National Park. The river
itself is not an impassable barrier for gophers to the north and south
of it, since this stream frequently changes its course, and often
nearly dries up. The Virgin River Valley in Zion National Park is in
the bottom of a relatively deep, narrow canyon which has sheer rock
escarpments. The upper reaches of the river are inhabited by pocket
gophers of another species, _Thomomys talpoides_.

Two specimens from St. George, north of the Virgin River, were
identified as _centralis_ by Hall and Davis (1934:52), but were stated
to be intergrades between _centralis_, _trumbullensis_ and
_planirostris_. Goldman (1938:338) referred twelve specimens from St.
George to _nicholi_, but stated that they intergraded with
_planirostris_. Twenty-six other specimens from three miles southwest
of St. George on the west side of Santa Clara Creek, about one-half
mile above its confluence with the Virgin River and on its north side,
like the topotypes of _planirostris_ were taken in May and have
complete, fresh summer pelage. With the exception of two specimens
which show the ventral color of _virgineus_, these animals are
indistinguishable in color from the topotypes of _planirostris_. A
study of eleven measurements of the males of this series yield the
following data: Like _planirostris_ in four measurements, _birdseyei_
in one, _virgineus_ in one; intergrade between _planirostris_ and
_birdseyei_ in two, _planirostris_ and _virgineus_ in two and
_birdseyei_ and _virgineus_ in one. Corresponding measurements of the
females show the animals to be: Like _planirostris_ in four
measurements, _birdseyei_ in one, _virgineus_ in two; intergrade
between _planirostris_ and _birdseyei_ in two, _planirostris_ and
_virgineus_ in one and _birdseyei_ and _virgineus_ in one. In eight of
eleven measurements the males either are like _planirostris_ or
intergrade towards it, and the females are similarly allied to
_planirostris_ in seven out of eleven measurements. In none of the
measurements was either sex referable to _trumbullensis_.

Intergradation was noted in still other cranial details. In the heavy,
relatively straight zygomatic arches, a majority of the skulls resemble
those of _planirostris_, although some show the elongated zygomatic
processes of the squamosals that are characteristic of _virgineus_.
Some skulls show a tendency toward _birdseyei_ in the widely spreading
posterior regions of the zygomatic arches. The nasals for the most part
are as in _planirostris_. Intergradation between all three subspecies
is shown in the extension of the premaxillae posterior to the nasals.
Some skulls show the lateral concavity of the jugals which is
characteristic of _virgineus_. The tympanic bullae are variable but on
the average are intermediate between those of _planirostris_ and
_birdseyei_, but more as in the latter. The size of the pterygoid
hamulae is like that of _planirostris_, but the shape of the
interpterygoid space is more like that of _birdseyei_. The size of the
molariform teeth is as in _birdseyei_. The incisors are intermediate
between those of _planirostris_ and _birdseyei_, but more like those of
_birdseyei_.

Eighteen specimens from St. George and its environs, on the north side
of the Virgin River, agree with the twenty-six specimens just
described, except that they show more evidence of intergradation with
_birdseyei_ in slightly darker color, length of hind foot, length of
nasals and alveolar length of the upper molar series.

One specimen from three miles south, two from two miles southwest,
another from four miles southeast of St. George, and four immature
animals from Short Creek Road south of the town of Virgin, all on the
south side of the Virgin River, are darker than topotypes of
_planirostris_ and show intergradation with _trumbullensis_ to the
south. In size they are likewise closer to the latter race. They
intergrade with _trumbullensis_ in the size and shape of the zygomatic
arches and tympanic bullae. In the majority of cranial details,
however, they are like _planirostris_ to which they are here referred.

One specimen, a skin only, from Danish Ranch, 5 miles northwest of
Leeds, north of the Virgin River is an intergrade in size and color
between _birdseyei_ and _planirostris_, but referable to the latter.

Three specimens from the East Entrance, and three from near the east
entrance to Zion National Park are much darker than topotypes of
_planirostris_. All of these animals are in worn pelage, thus allowing
a great amount of the black underfur to show, which gives a markedly
darker color. The unworn hair is only slightly darker than that of the
topotypes. The cranial details prove these animals to be intergrades
between _planirostris_ and _trumbullensis_. They resemble
_trumbullensis_ in size of tympanic bullae, extension of the
premaxillae posterior to the nasals and shape of the nasals. The
majority of the cranial details are as in _planirostris_ to which they
are here referred.

When Goldman (1938:337) named _Thomomys bottae nicholi_ from northern
Arizona he referred twelve specimens from St. George, Washington
County, Utah, to his newly named race. He noted that the animals from
this region intergrade with _planirostris_. I have had occasion to
study one-fourth of the material available to Goldman for his original
description of _nicholi_. For his specimens listed as from St. George,
the exact locality of capture, which is so essential in this
distributional study, was not given. All of the specimens that I have
seen from the Biological Surveys Collection are from the south side of
the Virgin River, while St. George itself is on the north side. As
noted earlier in this account there are differences between the gophers
from the two sides of the Virgin River in this area. Those from the
north side are intergrades between _birdseyei_, _planirostris_ and
_virgineus_, while those from the south side are intergrades between
_planirostris_ and _trumbullensis_.

Goldman (_loc. cit._) mentioned several times that the skulls of
nicholi were nearly indistinguishable from, or closely resembled those
of, _trumbullensis_. Color was the only truly diagnostic character
mentioned by Goldman. My study reveals the same differences and
likenesses found by Goldman, but I consider color alone insufficient
basis in this instance for establishing a new subspecies, and regard
_Thomomys bottae nicholi_ as a synonym of the earlier proposed name,
_Thomomys bottae trumbullensis_.

The animals from the south side of the Virgin River, labelled as from
St. George, Washington County, heretofore referred by Goldman to
_nicholi_, are intergrades between _trumbullensis_ and _planirostris_
and along with other specimens from the same place are referable to the
latter race.

     _Specimens examined._--Total, 68, distributed as follows:
     _Washington County_: Danish Ranch, 5 mi. NW Leeds, 1; Zion
     National Park, 2 (M. V. Z.); Grotto Camp, Zion National
     Park, 4,300 ft., 6 (N. H. M. S. D.); Springdale, 3,400 ft.,
     4 (K. U.); near Short Creek Road, S town of Virgin, 4 (R.
     H.); St. George, N Virgin River, 2,950 ft., 21 (4, M. V. Z.;
     8, R. H.; 9, N. H. M. S. D.); Santa Clara Creek, 3 mi. SW
     St. George, 2,800 ft., 26; St. George, S Virgin River, 5 (2,
     M. V. Z.; 3, U. S. N. M.); 2 mi. SE St. George, 2,950 ft., 2
     (N. H. M. S. D.); 3 mi. S St. George, 1 (C. M.); 4 mi. SE
     St. George, S Virgin River, 1 (R. H.); 6 mi. S St. George,
     2,700 ft., 6 (K. U.). _Kane County_: East Entrance Zion
     National Park, 5,725 ft., 3 (N. H. M. S. D.); near East
     Entrance Zion National Park, 5,500 ft., 3 (N. H. M. S. D.).

     _Additional records._--_Washington County_: Zion National
     Park, 22; Washington, 7 (Burt, 1931:39); St. George, 5;
     Santa Clara, 2 (Bailey, 1915:75).


=Thomomys bottae absonus= Goldman

     _Thomomys perpallidus absonus_ Goldman, Journ. Washington
     Acad. Sci., 21:425, October 19, 1931.

     _Thomomys bottae absonus_ Hall and Davis, Proc. Biol. Soc.
     Washington, 47:52, February 9, 1934; Goldman, Proc. Biol.
     Soc. Washington, 48:156, October 31, 1935.

     _Thomomys perpallidus aureus_ Bailey, N. Amer. Fauna, 39:75,
     November 15, 1915; Barnes, Bull. Univ. Utah, 12 (No. 15):85,
     April, 1922; Bull. Univ. Utah, 17 (No. 12):100, June, 1927.

_Type._--Male, adult, skin and skull, No. 250016, U. S. National Museum
(Biological Surveys Collection); Jacobs Pools, Houserock Valley, 4,000
ft., Coconino County, Arizona; June 7, 1931; collected by E. A.
Goldman; original number 23569 (after Goldman, type not seen).

_Range._--Southern Utah in Kane and Garfield counties, in the drainages
of Kanab Creek, Johnson Creek, Paria River and Escalante River.

_Diagnosis._--Size medium (see measurements). Color: Upper parts
Ochraceous Buff mixed with dusky; sides and underparts Light Ochraceous
Buff; chin, nose, cheeks and top of head grayish black; postauricular
patches black mixed with buff; front feet, hind feet, inguinal region
and distal third of tail white. Skull: Nasals relatively long; rostrum
narrow; ascending processes of premaxillae narrow; extension of
premaxillae posterior to nasals short; lambdoidal and sagittal crests
poorly developed; zygomatic arches light; jugals nearly straight;
palate narrow; molariform teeth small.

_Comparisons._--Compared with topotypes of _Thomomys bottae
trumbullensis_, _absonus_ differs in: Size smaller. Color: Markedly
lighter throughout. Skull: Smoother, less angular; zygomatic arches
weak as opposed to robust; nasals more convex as viewed laterally;
extension of premaxillae posterior to nasals less; ascending processes
of premaxillae narrower; palate narrower; palatal pits shallower;
rostrum narrower; molariform teeth smaller.

For comparisons of _absonus_ with _Thomomys bottae aureus_ see account
under that form.

Among named races of _Thomomys bottae_, _absonus_ most closely
resembles _planirostris_, but can be distinguished from the topotypes
as follows: Size markedly smaller. Color: Lighter, more buffy
throughout. Skull: Smaller, less ridged and more nearly flat; nasals
convex as opposed to flat; extension of premaxillae posterior to nasals
less; width of ascending processes of premaxillae less; zygomatic
arches weaker; palate narrower; alveolar length of upper molar series
shorter; tympanic bullae more inflated ventrally; molariform teeth
smaller and lighter.

_Remarks._--One specimen from Kanab is an intergrade between
_trumbullensis_ and _absonus_. The majority of its characters are with
_absonus_ to which it is referred (see Hall and Davis, 1934:52). Two
specimens from Escalante are intergrades between _absonus_ and
_dissimilis_, but are referable to _absonus_.

     _Specimens examined._--Total, 3, distributed as follows:
     _Garfield County_: Escalante, 5,258 ft., 2 (B. Y. U.), _Kane
     County_: Kanab, 4,925 ft., 1 (M. V. Z.).


=Thomomys bottae alexandrae= Goldman

     _Thomomys alexandrae_ Goldman, Journ. Washington Acad. Sci.,
     23:464, October 15, 1933.

     _Thomomys bottae alexandrae_ Benson, Univ. California Publ.
     Zoöl., 40:449, December 31, 1935.

_Type._--Male, adult, skin and skull, No. 250969, U. S. National Museum
(Biological Surveys Collection); 5 mi. SE Rainbow Lodge, near Navajo
Mountain, Coconino County, Arizona; June 16, 1933; collected by E. A.
Goldman; original number 23613 (after Goldman, type not seen).

_Range._--In extreme southwestern San Juan County, Utah. Known only
from Navajo Mountain, probably limited to the area enclosed on the
north by the Colorado and San Juan rivers, on the east and west by
Navajo and Piute canyons, respectively.

_Diagnosis._--Size small (see measurements). Color: Upper parts
Cinnamon Buff, grading over the sides to Pinkish Buff on underparts;
nose and top of head grayish black; hind feet and tail white;
postauricular patches large and dark. Skull: Small and not heavily
ridged; zygomatic arches widely spreading but weak; zygomatic arches
nearly parallel; tympanic bullae moderately inflated ventrally; palate
not arched; interpterygoid space U-shaped; dentition light.

_Comparisons._--Compared to topotypes of _Thomomys bottae absonus_,
_alexandrae_ differs as follows: Size smaller in every measurement
taken. Color: Upper parts Cinnamon Buff as contrasted with Light
Ochraceous Buff. Skull: Smaller in every measurement taken except
interorbital breadth and alveolar length of upper molar series which
are larger; molariform teeth larger.

Among named races of _Thomomys bottae_ occurring in Utah, _alexandrae_
most resembles _T. b. aureus_ to the northeast. It can be distinguished
from topotypes of the latter by: Size smaller in every measurement
taken. Color: Darker throughout. Skull: Smaller, slenderer and more
nearly flat; palate nearly flat as opposed to arched; zygomatic arches
weaker and not so widely spreading; interparietal narrower; tympanic
bullae smaller; dentition weaker.

_Remarks._--Goldman (1933:464) accorded _alexandrae_ full specific
status, because he found no intergradation with other races, from which
he thought _alexandrae_ had been isolated perhaps for thousands of
years by the barriers of the surrounding terrain. Benson (1935:450)
noted resemblances between _alexandrae_ and specimens of _latirostris_
from Keams Canyon, Zuni Well, and Winslow in Navajo County, Arizona (=
_aureus_), and also between _alexandrae_ and _absonus_ from Houserock
Valley, Arizona. He thought that _alexandrae_ is no more differentiated
or isolated than each of several other kinds of desert pocket gophers,
and, therefore, accorded _alexandrae_ only subspecific status, as I,
also, am inclined to do.

     _Specimens examined._--One (M. V. Z.) from Soldier Spring,
     Navajo Mountain, 8,600 ft., San Juan County. Fourteen
     topotypes from Arizona also were examined.


MEASUREMENTS OF ADULT MALES OF THOMOMYS

(In millimeters)

======================================================================
       Total length
       |    Length of tail
       |    |   Length of hind foot
       |    |   |   Basilar length
       |    |   |   |     Length of nasals
       |    |   |   |     |    Zygomatic breadth
       |    |   |   |     |    |      Mastoid breadth
       |    |   |   |     |    |      |     Interorbital breadth
       |    |   |   |     |    |      |     |    Alveolar length of
       |    |   |   |     |    |      |     |    upper molar series
       |    |   |   |     |    |      |     |    |    Extension of premax
       |    |   |   |     |    |      |     |    |    post. to nasals
       |    |   |   |     |    |      |     |    |    |    Length of
       |    |   |   |     |    |      |     |    |    |    rostrum
       |    |   |   |     |    |      |     |    |    |    |     Breadth
       |    |   |   |     |    |      |     |    |    |    |     of rostrum
----------------------------------------------------------------------

_T. b. aureiventris_, 4; topotypes (Hall, 1930:446)
Av.    243  67  32  36.4  14.7  26.5  21.5  6.6  7.9  2.4  ....  ...
Min.   232  59  31  35.3  14.0  25.5  20.9  6.1  7.8  1.8  ....  ...
Max.   253  72  33  37.1  15.3  27.3  22.3  6.9  8.0  3.4  ....  ...

_T. b. centralis_, 9; topotypes (Hall, 1930:446)
Av.    237  75  30  36.3  14.6  25.2  20.7  6.6  8.0  3.2  ....  ...
Min.   215  61  29  34.5  13.9  24.6  19.7  5.8  7.5  2.2  ....  ...
Max.   250  83  32  38.0  15.9  26.1  21.9  7.2  8.7  4.5  ....  ...

_T. b. albicaudatus_, 7; topotypes (Hall, 1930:446)
Av.    228  65  31  35.4  14.0  26.1  20.5  6.6  8.1  3.2  ....  ...
Min.   223  59  29  34.9  13.4  24.9  19.8  6.4  7.8  3.0  ....  ...
Max.   235  72  32  36.1  15.1  27.8  21.1  6.9  8.4  3.8  ....  ...

_T. b. robustus_, 9; topotypes
Av.    222  65  29  34.1  13.6  26.0  20.8  6.4  7.8  2.7  15.7  8.4
Min.   214  59  28  32.6  13.0  25.2  20.0  6.1  7.3  2.0  14.7  8.1
Max.   236  70  31  35.7  14.4  26.7  21.5  6.7  8.2  3.0  17.0  8.8

_T. b. stansburyi_, 5; topotypes
Av.    206  60  28  32.3  12.4  22.4  19.1  6.3  7.6  2.8  14.7  7.5
Min.   198  58  26  30.6  12.0  21.5  18.2  6.2  7.0  2.5  14.1  7.1
Max.   215  68  31  33.4  13.0  23.1  20.1  6.5  8.0  3.0  15.4  7.8

_T. b. nesophilus_, 4; topotypes
Av.    230  69  32  35.3  14.4  25.5  20.4  6.8  8.4  2.5  17.1  8.2
Min.   220  60  30  33.6  14.1  24.9  19.8  6.5  8.2  2.1  16.4  7.6
Max.   242  75  33  36.5  14.8  26.2  21.1  7.1  8.7  2.9  18.4  8.6

_T. b. minimus_, 2; topotypes
Av.    184  60  25  30.7  11.3  21.3  18.7  6.4  7.4  2.5  13.9  7.5
Min.   179  55  24  28.7  10.2  20.2  17.8  6.3  7.3  2.5  12.9  7.0
Max.   189  64  26  32.8  12.5  22.4  19.6  6.4  7.6  2.5  15.0  7.9

_T. b. lenis_, 2; topotypes
Av.    251  80  32  39.7  16.0  28.6  22.6  6.8  8.3  3.4  18.4  8.8
Min.   248  74  31  39.4  15.8  28.4  22.4  6.6  8.2  3.0  17.9  8.6
Max.   255  86  32  29.9  16.2  28.7  22.7  6.9  8.5  3.7  18.8  8.9

_T. b. contractus_, 8; topotypes
Av.    229  74  31  33.3  12.5  23.7  19.1  6.6  7.6  3.0  15.4  7.3
Min.   209  63  28  30.0  10.9  21.4  17.7  6.3  7.2  2.4  13.5  6.5
Max.   255  85  33  37.4  14.5  26.4  20.9  6.9  8.0  3.5  18.2  8.0
----------------------------------------------------------------------


MEASUREMENTS OF ADULT MALES OF THOMOMYS--_Continued_

======================================================================
       Total length
       |    Length of tail
       |    |   Length of hind foot
       |    |   |   Basilar length
       |    |   |   |     Length of nasals
       |    |   |   |     |    Zygomatic breadth
       |    |   |   |     |    |      Mastoid breadth
       |    |   |   |     |    |      |     Interorbital breadth
       |    |   |   |     |    |      |     |    Alveolar length of
       |    |   |   |     |    |      |     |    upper molar series
       |    |   |   |     |    |      |     |    |    Extension of premax
       |    |   |   |     |    |      |     |    |    post. to nasals
       |    |   |   |     |    |      |     |    |    |    Length of
       |    |   |   |     |    |      |     |    |    |    rostrum
       |    |   |   |     |    |      |     |    |    |    |     Breadth
       |    |   |   |     |    |      |     |    |    |    |     of rostrum
----------------------------------------------------------------------

No. 191959 (U. S. N. M.) _T. b. levidensis_, 1; topotype
       222  65  28  33.3  12.7  24.5  19.0  6.5  7.6  3.3  15.1  8.0

_T. b. convexus_, 6; topotypes
Av.    213  59  28  33.1  14.3  24.9  21.7  6.6  8.0  2.6  16.2  8.2
Min.   206  57  27  31.3  13.9  23.8  21.0  6.5  7.7  2.1  15.2  8.0
Max.   233  68  29  35.0  14.6  26.7  22.3  6.8  8.1  2.8  17.2  8.6

_T. b. tivius_, 7; topotypes
Av.    208  69  27  31.5  12.2  22.4  18.4  6.4  7.2  2.4  14.0  7.1
Min.   199  67  25  29.3  11.9  20.6  17.1  6.0  7.0  2.1  13.2  6.5
Max.   227  70  30  34.1  12.8  25.0  19.8  6.6  7.6  3.0  15.0  7.9

_T. b. bonnevillei_, 3; topotypes
Av.    228  70  30  35.4  13.9  26.4  21.8  6.6  8.1  3.7  17.6  8.5
Min.   221  62  30  33.6  13.2  25.4  20.5  6.5  8.1  3.4  16.1  8.2
Max.   236  79  30  37.4  14.9  28.0  22.5  6.7  8.1  4.3  18.1  8.7

_T. b. sevieri_, 3; topotypes
Av.    216  67  30  32.7  12.9  22.9  18.7  6.4  7.2  2.5  15.3  7.6
Min.   210  66  29  31.7  11.8  22.2  18.0  6.2  7.0  1.8  14.5  7.5
Max.   222  68  31  33.5  13.5  23.4  19.3  6.7  7.2  3.0  16.4  7.7

_T. b. wahwahensis_, 4; topotypes
Av.    228  66  29  34.7  13.5  25.5  20.7  6.6  7.3  2.3  15.7  8.7
Min.   210  60  26  33.0  13.1  24.6  20.1  6.5  7.0  2.2  14.9  8.5
Max.   250  78  30  37.6  14.6  27.0  21.4  6.8  8.0  2.5  17.1  9.0

_T. b. planirostris_, 8; topotypes (Burt, 1931:39)
Av.    238  76  32  35.6  13.8  25.9  20.4  6.6  8.5  3.7  ....  8.8
Min.   222  66  31  33.3  12.5  24.4  19.8  6.2  8.2  3.0  ....  8.3
Max.   261  83  34  38.7  15.3  27.6  21.3  7.2  8.9  4.5  ....  9.4

_T. b. birdseyei_, 3; topotypes
Av.    227  64  31  34.9  13.8  26.2  20.9  6.2  8.4  2.6  16.3  8.3
Min.   214  52  30  34.5  13.1  26.0  20.1  6.0  8.1  2.2  16.0  8.2
Max.   243  81  32  35.2  14.1  27.4  21.5  6.5  8.8  2.8  16.9  8.4

_T. b. virgineus_, 5; Beaverdam Wash, 5 mi. N Utah-Arizona Line
Av.    226  68  29  34.6  13.5  25.6  20.7  6.3  8.0  3.0  16.5  8.5
Min.   216  62  27  33.5  12.8  25.0  20.0  6.1  7.6  2.4  15.3  8.3
Max.   235  70  30  34.9  14.4  26.0  21.1  6.6  8.4  3.5  17.4  8.7

_T. b. aureus_, 3; topotypes
Av.    242  68  34  36.6  14.3  25.3  21.4  6.6  8.3  2.4  17.2  8.7
Min.   233  65  32  35.3  13.8  24.6  20.6  6.4  7.7  2.0  16.7  8.3
Max.   251  70  36  37.8  14.9  25.8  22.0  6.8  8.7  2.5  17.9  9.0
----------------------------------------------------------------------


MEASUREMENTS OF ADULT MALES OF THOMOMYS--_Concluded_

======================================================================
       Total length
       |    Length of tail
       |    |   Length of hind foot
       |    |   |   Basilar length
       |    |   |   |     Length of nasals
       |    |   |   |     |    Zygomatic breadth
       |    |   |   |     |    |      Mastoid breadth
       |    |   |   |     |    |      |     Interorbital breadth
       |    |   |   |     |    |      |     |    Alveolar length of
       |    |   |   |     |    |      |     |    upper molar series
       |    |   |   |     |    |      |     |    |    Extension of premax
       |    |   |   |     |    |      |     |    |    post. to nasals
       |    |   |   |     |    |      |     |    |    |    Length of
       |    |   |   |     |    |      |     |    |    |    rostrum
       |    |   |   |     |    |      |     |    |    |    |     Breadth
       |    |   |   |     |    |      |     |    |    |    |     of rostrum
----------------------------------------------------------------------

_T. b. howelli_, 5; 10 mi. N Moab
Av.    213  67  31  33.1  13.5  23.2  20.1  6.5  8.3  2.5  16.1  8.8
Min.   205  64  30  31.8  12.8  22.8  18.9  6.4  8.0  2.3  15.1  8.1
Max.   225  68  32  35.3  14.3  24.1  20.7  6.8  8.8  2.8  17.5  9.4

No. 3094 (U. U.) _T. b. absonus_, 1; topotype
       220  71  29  32.0  13.9  22.6  19.0  6.4  7.0  1.0  15.1  7.2

No. 158529 (U. S. N. M.) _T. b. osgoodi_, 1; topotype
       225  70  29  33.8  13.3  22.7  19.6  6.6  8.4  3.2  16.5  8.3

_T. b. alexandrae_, 1; topotype (Benson, 1935:450)
       205  59  27  33.9  13.7  24.3  19.7  6.5  8.0  ...  15.8  8.1
----------------------------------------------------------------------


MEASUREMENTS OF ADULT FEMALES OF THOMOMYS

(In millimeters)

======================================================================
       Total length
       |    Length of tail
       |    |   Length of hind foot
       |    |   |   Basilar length
       |    |   |   |     Length of nasals
       |    |   |   |     |    Zygomatic breadth
       |    |   |   |     |    |      Mastoid breadth
       |    |   |   |     |    |      |     Interorbital breadth
       |    |   |   |     |    |      |     |    Alveolar length of
       |    |   |   |     |    |      |     |    upper molar series
       |    |   |   |     |    |      |     |    |    Extension of premax
       |    |   |   |     |    |      |     |    |    post. to nasals
       |    |   |   |     |    |      |     |    |    |    Length of
       |    |   |   |     |    |      |     |    |    |    rostrum
       |    |   |   |     |    |      |     |    |    |    |     Breadth
       |    |   |   |     |    |      |     |    |    |    |     of rostrum
----------------------------------------------------------------------

_T. b. aureiventris_, 2; topotypes (Hall, 1930:446)
Av.    212  62  30  32.4  12.9  22.9  19.4  6.7  7.4  2.8  ....  ...
Min.   208  58  29  31.8  12.6  22.5  18.9  6.6  7.0  2.7  ....  ...
Max.   215  65  30  33.0  13.1  23.3  19.8  6.8  7.8  3.1  ....  ...

_T. b. centralis_, 17; topotypes (Hall, 1930:446)
Av.    214  67  29  31.8  12.6  22.1  19.0  6.6  7.6  2.7  ....  ...
Min.   195  55  27  30.5  11.9  21.3  18.2  5.9  7.0  2.0  ....  ...
Max.   229  75  30  33.0  13.8  23.1  20.1  7.1  7.8  3.4  ....  ...

_T. b. albicaudatus_, 4; topotypes (Hall, 1930:446)
Av.    211  64  30  32.5  12.9  22.9  18.8  6.6  7.7  2.7  ....  ...
Min.   199  55  29  31.7  11.9  21.9  18.2  6.1  7.5  2.6  ....  ...
Max.   219  70  32  33.8  13.5  24.0  19.5  6.8  8.0  3.0  ....  ...

_T. b. robustus_, 11; topotypes
Av.    199  61  27  30.6  11.7  22.6  18.8  6.4  7.6  2.6  13.9  7.4
Min.   191  56  22  29.0  10.6  21.0  18.1  6.2  7.1  2.0  12.0  7.1
Max.   207  66  29  31.6  12.2  23.6  19.8  6.7  8.0  2.9  14.7  7.9

_T. b. stansburyi_, 5; topotypes
Av.    202  57  28  31.1  12.1  21.9  18.7  6.5  7.7  2.6  14.5  7.4
Min.   195  56  26  29.9  10.6  21.0  17.8  6.2  7.3  2.3  13.4  6.9
Max.   210  63  30  32.7  12.8  22.4  19.5  6.8  8.0  3.0  15.2  7.7

No. 900 (U. U.) _T. b. nesophilus_, 1; topotype
       210  65  31  31.2  12.3  23.2  19.3  6.9  8.2  2.2  15.2  7.3

_T. b. minimus_, 2; topotypes
Av.    178  56  25  28.2  10.6  19.7  17.4  6.1  7.0  2.3  13.1  6.7
Min.   175  54  24  28.1  10.4  19.6  17.1  6.1  7.0  2.3  13.0  6.5
Max.   181  58  25  28.2  10.8  19.7  17.7  6.1  7.0  2.3  13.2  6.8

_T. b. contractus_, 6; topotypes
Av.    219  68  30  33.1  12.6  23.3  19.5  6.5  7.8  2.6  15.5  7.1
Min.   208  58  29  32.2  12.0  22.2  18.9  6.4  7.6  2.3  14.2  7.0
Max.   225  73  31  34.7  13.3  25.2  20.6  6.7  8.2  3.2  17.0  7.3

_T. b. levidensis_, 4; topotypes
Av.    205  69  26  30.5  11.1  21.7  17.5  6.6  7.5  2.9  14.0  7.0
Min.   194  61  26  29.3  10.6  21.5  17.3  6.3  7.2  2.8  13.0  6.9
Max.   223  73  27  30.8  11.5  21.9  17.9  6.9  7.8  3.2  14.7  7.2
----------------------------------------------------------------------


MEASUREMENTS OF ADULT FEMALES OF THOMOMYS--_Continued_

======================================================================
       Total length
       |    Length of tail
       |    |   Length of hind foot
       |    |   |   Basilar length
       |    |   |   |     Length of nasals
       |    |   |   |     |    Zygomatic breadth
       |    |   |   |     |    |      Mastoid breadth
       |    |   |   |     |    |      |     Interorbital breadth
       |    |   |   |     |    |      |     |    Alveolar length of
       |    |   |   |     |    |      |     |    upper molar series
       |    |   |   |     |    |      |     |    |    Extension of premax
       |    |   |   |     |    |      |     |    |    post. to nasals
       |    |   |   |     |    |      |     |    |    |    Length of
       |    |   |   |     |    |      |     |    |    |    rostrum
       |    |   |   |     |    |      |     |    |    |    |     Breadth
       |    |   |   |     |    |      |     |    |    |    |     of rostrum
----------------------------------------------------------------------

_T. b. convexus_, 11; topotypes
Av.    197  57  27  29.9  12.5  21.7  19.3  6.6  7.7  2.6  14.7  7.4
Min.   182  43  26  27.9  11.2  21.0  18.8  6.2  7.1  2.1  13.3  7.1
Max.   204  63  28  30.9  13.4  22.3  19.8  7.1  7.9  3.1  15.2  7.7

_T. b. tivius_, 5; topotypes
Av.    203  68  27  29.5  11.1  21.1  17.8  6.5  7.2  2.4  13.5  6.8
Min.   192  63  26  28.0  10.5  20.1  17.3  6.3  7.1  2.0  12.7  6.4
Max.   215  74  30  31.3  11.4  22.9  19.0  6.7  7.5  3.0  14.2  7.2

_T. b. bonnevillei_, 7; topotypes
Av.    199  57  28  31.7  11.8  22.2  19.3  6.6  7.7  3.2  14.9  7.3
Min.   184  50  24  29.4  10.1  20.3  18.1  6.4  7.1  2.6  13.5  6.9
Max.   216  66  29  34.3  13.6  24.3  20.3  7.0  8.5  4.1  16.6  7.7

_T. b. sevieri_, 7; topotypes
Av.    205  62  28  30.2  11.8  21.6  18.0  6.4  7.0  2.7  14.2  7.1
Min.   199  54  28  29.4  11.3  20.6  17.7  6.1  6.6  2.1  13.9  6.6
Max.   212  70  29  30.7  12.6  22.1  18.6  6.8  7.4  3.0  14.7  7.6

_T. b. wahwahensis_, 8; topotypes
Av.    185  56  27  28.7  11.3  20.6  17.6  6.3  7.1  2.1  12.6  7.1
Min.   180  50  26  26.3  10.2  19.0  16.5  5.8  6.9  1.1  10.8  6.4
Max.   197  62  29  30.7  12.6  22.0  19.0  6.7  7.8  2.9  14.0  7.6

_T. b. planirostris_, 8; topotypes (Burt, 1931:39)
Av.    215  71  31  32.2  12.4  23.2  18.7  6.5  8.1  3.6  ....  7.9
Min.   205  61  30  31.5  11.8  22.3  18.1  6.4  7.5  2.8  ....  7.5
Max.   228  78  33  33.0  12.9  24.1  19.5  6.7  8.6  4.5  ....  8.1

_T. b. birdseyei_, 3; topotypes
Av.    220  71  29  31.6  11.8  22.7  18.6  6.1  7.4  2.4  14.7  7.5
Min.   217  68  28  31.4  11.0  22.4  18.3  6.0  7.3  1.6  13.3  7.4
Max.   223  75  30  32.0  12.8  23.0  19.1  6.2  7.4  3.0  15.3  7.5

_T. b. virgineus_, 4; Beaverdam Wash, 5 mi. N Utah-Arizona Line
Av.    211  64  29  31.6  12.2  22.6  19.4  5.9  7.5  3.1  15.1  7.3
Min.   202  60  27  31.3  11.3  22.4  18.8  5.8  7.3  2.4  14.4  7.2
Max.   218  68  30  32.1  12.8  22.7  20.0  6.1  7.8  3.7  15.5  7.6

_T. b. aureus_, 3; topotypes
Av.    226  57  31  33.2  13.3  23.8  19.8  6.7  8.2  1.9  15.3  8.2
Min.   217  54  30  32.8  12.5  23.3  19.6  6.4  8.0  1.6  14.5  8.2
Max.   233  64  31  34.0  14.2  24.4  19.8  6.9  8.4  2.0  16.4  8.3

No. 20300 (C. M.) _T. b. howelli_, 1; 10 mi. N Moab
       202  59  28  32.4  12.3  21.1  19.2  6.4  7.9  2.4  15.8  8.3
----------------------------------------------------------------------


MEASUREMENTS OF ADULT FEMALES OF THOMOMYS--_Concluded_

======================================================================
       Total length
       |    Length of tail
       |    |   Length of hind foot
       |    |   |   Basilar length
       |    |   |   |     Length of nasals
       |    |   |   |     |    Zygomatic breadth
       |    |   |   |     |    |      Mastoid breadth
       |    |   |   |     |    |      |     Interorbital breadth
       |    |   |   |     |    |      |     |    Alveolar length of
       |    |   |   |     |    |      |     |    upper molar series
       |    |   |   |     |    |      |     |    |    Extension of premax
       |    |   |   |     |    |      |     |    |    post. to nasals
       |    |   |   |     |    |      |     |    |    |    Length of
       |    |   |   |     |    |      |     |    |    |    rostrum
       |    |   |   |     |    |      |     |    |    |    |     Breadth
       |    |   |   |     |    |      |     |    |    |    |     of rostrum
----------------------------------------------------------------------

No. 158524 (U. S. N. M.) _T. b. dissimilis_, 1; topotype
       188  61  27  28.2  10.1  19.0  16.7  6.1  7.4  2.1  12.8  6.5

No. 158528 (U. S. N. M.)  _T. b. osgoodi_, 1; topotype
       203  61  27  29.6  11.5  ..    18.3  6.9  7.4  2.0  14.0  7.3

_T. b. alexandrae_, 3; topotypes
Av.    205  63  28  30.9  11.8  20.8  17.9  6.4  7.6  1.8  14.1  7.5
Min.   195  57  27  28.7  11.5  20.5  17.2  6.3  7.5  1.5  13.6  7.2
Max.   215  70  29  31.5  12.1  22.2  18.6  6.5  7.7  2.0  14.7  7.7
--------------------------------------------------------------------------




LITERATURE CITED


ALLEN, J. A.

     1874. Notes on the mammals of portions of Kansas, Colorado,
           Wyoming and Utah, Part IV. On the mammals of the Great
           Salt Lake Valley, Utah. Bull. Essex Inst., 6:61-66, 1874.

     1893. Descriptions of four new species of _Thomomys_ with
           remarks on other species of the genus. Bull. Amer. Mus.
           Nat. Hist., 5:47-68, April 28, 1893.

     1893. List of mammals collected by Mr. Charles P. Rowley in
           the San Juan region of Colorado, New Mexico and Utah,
           with descriptions of new species. Bull. Amer. Mus. Nat.
           Hist., 5:69-84, April 28, 1893.

     1896. List of mammals collected by Mr. Walter W. Granger in
           New Mexico, Utah, Wyoming and Nebraska, 1895-1896, with
           field notes by the collector. Bull. Amer. Mus. Nat.
           Hist., 8:241-258, November 25, 1896.

     1905. Mammals from Beaver County, Utah, collected by the
           Museum expedition of 1904. Brooklyn Inst. Mus. Sci.
           Bull., 1:117-122, March 31, 1905.

BAILEY, VERNON.

     1915. Revision of the pocket gophers of the genus
           _Thomomys_. N. Amer. Fauna, 39:1-136, pls. 8, 10 figs.,
           November 15, 1915.

BARNES, CLAUDE T.

     1922. Mammals of Utah. Bull. Univ. Utah, 12 (No. 15):1-176,
           30 figs., April, 1922.

     1927. Utah mammals. Bull. Univ. Utah, 17 (No. 12):1-183, 32
           figs., June, 1927.

BENSON, SETH B.

     1935. A biological reconnaissance of Navajo Mountain, Utah.
           Univ. California Publ. Zoöl., 40:439-455, December 31,
           1935.

BURT, WILLIAM H.

     1931. A new pocket gopher of the genus _Thomomys_ from Utah.
           Proc. Biol. Soc. Washington, 44:37-40, May 8, 1931.

COUES, E.

     1875. Abstract of results of a study of the genera _Geomys_
           and _Thomomys_. Part III. Zoölogy, in explorations of
           the Colorado River of the West and its tributaries,
           explored in 1869, 1870, 1871 and 1872 under the
           direction of the Smithsonian Institution, reported by
           J. W. Powell, Gov't Printing Office, Washington, D. C.,
           1875.

     1877. Monographs of North American Rodents, No. X, Geomyidae,
           pp. 601-629, U. S. Geol. Surv. of the territories,
           Gov't Printing Office, Washington, D. C., 1877.

COUES, E., and YARROW, H. C.

     1875. Report upon the collection of mammals made in portions
           of Nevada, Utah, California, New Mexico and Arizona
           during the years 1871-74. Wheeler's Rept. Expl. W of
           100th Mer. vol. 5, pp. 35-129, 1875.

DAVIS, WILLIAM B.

     1939. The Recent mammals of Idaho. The Caxton Printers, Ltd.,
           Caldwell, Idaho, pp. 1-400, pls. 2, 33 figs., April 5,
           1939.

DURRANT, STEPHEN D.

     1937. Two new gophers from Utah. Bull. Univ. Utah, 28 (No.
           4):1-7, August 18, 1937.

     1939. A new pocket gopher of the _Thomomys quadratus_ group
           from the northern Great Basin region. Bull. Univ.
           Utah, 39 (No. 6):1-6, February 28, 1939.

GOLDMAN, E. A.

     1933. New mammals from Arizona, New Mexico and Colorado.
           Journ. Washington Acad. Sci., 23:463-473, October 15,
           1933.

     1936. New pocket gophers of the genus _Thomomys_. Journ.
           Washington Acad. Sci., 26:111-120, March 15, 1936.

     1938. New pocket gophers of the genus _Thomomys_ from
           Arizona and Utah. Journ. Washington Acad. Sci.,
           28:333-343, July 15, 1938.

     1939. Remarks on pocket gophers, with special reference to
           _Thomomys talpoides_. Journ. Mamm., 20:231-244, May
           14, 1939.

     1942. Three new rodents from southern Utah. Proc. Biol. Soc.
           Washington, 55:75-78, July 25, 1942.

HALL, E. RAYMOND.

     1931. Critical comments on mammals from Utah, with
           descriptions of new forms from Utah, Nevada and
           Washington. Univ. California Publ. Zoöl., 37:1-13,
           April 10, 1931.

HALL, E. RAYMOND, and DAVIS, WILLIAM B.

     1934. Notes on Arizona rodents. Proc. Biol. Soc. Washington,
           47:51-56, February 9, 1934.

HAYWARD, C. LYNN.

     1936. A bibliography of Utah mammalogy; including references
           to names and type localities applied to Utah mammals.
           Utah Acad. Sci. Arts and Letters, 13:122-146, 1936.

     1941. A bibliography of Utah mammalogy; including references
           to names and type localities (first supplement). Great
           Basin Nat., 2:125-136, December 31, 1941.

MARSHALL, WILLIAM H.

     1940. A survey of the mammals of the islands in Great Salt
           Lake, Utah. Journ. Mamm., 21:149-159, 2 pls., 1 map,
           May 14, 1940.

MERRIAM, C. HART.

     1901. Descriptions of twenty-three new pocket gophers of
           the genus _Thomomys_. Proc. Biol. Soc. Washington,
           14:107-117, July 19, 1901.

MILLER, GERRITT S., JR.

     1924. List of North American Recent mammals, 1923. U. S.
           Nat. Mus. Bull., 128, pp. I-XVI, + 1-673, Govt.
           Printing Office, Washington, D. C., March 18, 1924.

SVIHLA, RUTH DOWELL.

     1931. Mammals of the Uinta Mountains region. Journ. Mamm.,
           12:256-266, pls. 1, 1 fig., August 24, 1931.

21-2786




       *       *       *       *       *

Transcriber's Notes


Made minor punctuation corrections, and the following changes:

Page 11: Changed Oquirrah Mountains to Oquirrh Mountains.

Page 15: Changed interptergoid to interpterygoid.

Page 25: Changed acccounts to accounts.

Page 30: Changed distiguished to distinguished.

Page 54: Changed hpyothesis to hypothesis.

Page 57: Changed under parts to underparts.

Formatted Tables to fit width guidelines.

Bold text is shown within =equal signs=.

Italicized text is shown within _underscores_.