68. In Oregon 



Thomomys hulhivorns (Richardson) Camas Pocket Gopher 

 From Texas to Ariz. 



Thomomys haileyi Merriam Sierra Blanca Pocket Gopher 



69. Ears small 70. 

 Ears relatively large 72. 



70. Ears pointed; northwestern states 



Thomomys fuscus Merriam Brown Pocket Gopher 

 Ears rounded; southwestern states 71. 



71. Upper incisors definitely grooved; coat yellowish'brown 



Thomomys fulvus (Woodhouse) Tawny Pocket Gopher 

 Upper incisors with no, or very faint, grooves; coat yellowish-gray 

 Thomoynys perpalUdus (Merriam) Desert Pocket Gopher 



72. With five or six pairs of mammae 73. 

 With four pairs of mammae 74. 



73. With six pairs of mammae; color gray; upper incisors distinctly grooved; 



Colo, northward 



Thomomys talpoides (Richardson) Plains Pocket Gopher 

 With five pairs of mammae; color brown; upper incisors very faintly 

 grooved; Colo, and Utah 



Thomomys fossor Allen Mountain Valley Pocket Gopher 



74. Incisor grooves scarcely visible; with considerable white on under side 



and on throat; Sierra Mts. 



Thomomys alpmus Merriam Alpine Pocket Gopher 

 Upper incisors with distinct grooves 75. 



75. Under parts usually buff; central Oregon into Cal. and Nevada 



Thomomys monticola Allen Mountain Pocket Gopher 

 Under parts usually with some irregular white patches; Wash, and north' 

 ern Oregon 



Thomomys douglasii Richardson Columbia Pocket Gopher 



76. Upper incisors each with one groove; no posterior enamel plates on upper 



middle two cheek teeth; Colo, southwards 



Cratogeomys castanops (Baird) Chestnut'faced Pocket Gopher 



Upper incisors each with two grooves; with enamel on front and back of 



upper check teeth; widely distributed over the central and southern 



states 77. 



77. Rarely over nine inches in total length; color dark brown; Kansas to the 



Gulf states 



Geomys hreviceps Baird Southern Prairie Pocket Gopher 

 (and related forms) 

 Adult length ten to twelve inches; color usually chestnut or reddish 

 brown, a few forms dark to slaty 78. 



78. With an easily felt longitudinal ridge (sagittal crest) along top of brain' 



case, especially well developed in males; top profile concave; western 

 Wis. and Ind. to the Rockies 



Geomys hursarius (Shaw) Northern Prairie Pocket Gopher 

 (and related forms) 



511 



