FIELD BOOK OF MAMMALS 



dirty whitish to pale buff, sometimes with white on chin. 

 Winter pelage unknown, but probably very pale. Total 

 length, males, 7.2 inches, females, 6.6; tail vertebrae, males, 

 2.0 inches, females, 2.0; hind foot, males, .9 inch, females, 

 .9. Found on "Snake River Plains, southeastern Idaho." 

 (Bailey) 

 Pygmy Pocket Gopher. — Thomomys pygmcBUs Merriam. 



Smallest Pocket Gopher of the genus Thomomys; ears small; 

 color a rich brown. Upperparts (summer) a uniform rich 

 hazel-brown; nose slaty, dusky patch about ear reduced; 

 feet and tail whitish to buffy; underparts dull ochraceous, 

 only rarely with white on chin or breast. Winter pelage 

 paler than summer, brown more buffy. Total length, males, 

 and females, 6.7 inches; tail vertebra?, 2.0 inches; hind foot, 

 .9 inch. Found in "Southwestern Wyoming and south- 

 eastern Idaho (Transition Zonej." (Bailey) 



Fossor Group 



Characterized by mammae in five pairs (inguinal, 2-2; 

 pectoral, 3-3.) 



Colorado Pocket Gopher. — Thomomys fossor Allen. 



Medium in size, dark and dull in color; ears large, fur long 

 and soft. Upperparts (summer) dull dark brown varying 

 occasionally to rich chestnut; blackish on nose, face, and 

 about ear; whitish on feet, tip of tail, often on chin and 

 occasionally on chest; underparts buffy to ochraceous. 

 Winter pelage duller and grayer. Total length, males, 8.8 

 inches, females, 8.8; tail vertebras, males, 2.7 inches, females, 

 2.5; hind foot, males, 1.3 inches, females, 1.16. Found in 

 "Mountains of western Colorado, extreme southern Wyom- 

 ing, northern New Mexico, eastern and southern Utah, and 

 northwestern Arizona." (Bailey) 



Fort Bridger Pocket Gopher. — Thomomys hridgeri Merriam. 

 Large in size, dark in color, with large and prominent ears. 

 Upperparts (summer) rich brown, warm in tone; dusky 

 brown on nose and face; considerable black about ear; feet 

 and tail grayish, the latter with brownish tinge and some- 

 times white-tipped; underparts dark buffy to dull ochra- 

 ceous, sometimes with white on chin. Winter pelage dull, 

 dark brown above, washed with buffy below. Total length, 

 males, 9.5 inches, females, 9.1; tail vertebrae, males, 2.8 

 inches, females, 2.y\ hind foot, males, 1.36 inches, females, 

 1.33. Found in "Southwestern Wyoming and southeastern 

 Idaho (Transition Zone)." (Bailey) jj 



Uinta Pocket Gopher. — Thomomys uinta Merriam. ■ 



Almost indistinguishable from fossor externally, but skull ^ 

 shorter and wider. Upperparts (summer) dull dark brown ; 

 dusky on nose and face, blackish on ear and back of ear; 

 underparts buffy to ochraceous. Winter pelage duller and 



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