1915.] 



GENUS THOMOMYS. 



37 



62. Size medium, hind foot of J" averaging over 26 and under 36. 

 Color brown, mainly ciimamon-hazel, chestnut., or russet. 

 d^. Color dark and rich browns. 

 e^. No conspicuous black on nose and face; hind foot of cT about 30, 



limosus (p. 120). 



e^. Much blackish on nose and face. 



p. Size smaller, hind foot of c? about 27 hesperus (p. 131). 



p. Size larger, hind foot of c? about 29. 



gri. Skull with very small oval interparietal melanops (p. 11'9). 



g^. Skull with large triangular interparietal helleri (p. 126). 



d?. Color light, or bright or dull browns. 

 e^. Ears small but pointed and well formed. 

 p. Color light brown; hind foot of c? about 27. 



g^. Slightly paler; molars lighter fuscus (p. 126). 



g'^. Slightly darker; molars hea\ier loringi (p. 129). 



p. Color duller and darker shades of brown; size larger. 



g'^. Skull A^ery long and narrow; hind foot of <S^ about 29 . saturatus (p. 128). 

 g'^. Skull relatively short and wide. 



h^. Incisors projecting beyond tip of nasals; hind foot of c? 29, 



pryori (p. 104). 



A^. Incisors not projecting beyond tip of nasals. 

 i^. Nasals truncate at posterior tip; hind foot of c? 27, 



quadratus (p. 114). 

 i?. Nasals emarginate at posterior tip; hind foot of c? 28, 



caryi (p. 104). 



e^. Ears relatively long and pointed. 

 p-. Color dull brown. 



g'^. Size larger, hind foot of c? averagirg 33 bridgeri (p. 112). 



g"^. Size smaller, hind foot of c? under 33. 



Bullae large; posterior tip of nasals rounded fossor (p. 111). 



A^. Bullae smaller; posterior tip of nasals emarginate uinta (p. 113). 



p. Color bright, warm browns. 



g^. Size larger, liind foot of male averaging about 30. 



K^. Skull relatively short and wide; interparietal triangular, 



oregomis (p. 117). 

 'h?. Skull long and naiTow; interparietal small and oval. 



i^. Zygomatic arches widest anteriorly douglasi (p. 116). 



i^. Zygomatic arches widest posteriorly yelmensis (p. 118). 



g^. Size smaller, hind foot of about 28 or less. 



A^ Color russet; bullae full and rounded mazama (p. 123). 



Color hazel; bullae relatively small and angular. 



i^. Color dull hazel; braincase very narrow monticola (p. 121). 



i^. Color more yellowish hazel; braincase wider. 

 jK Nasals longer and conspicuously widened anteriorly, 



nasicus (p. 125). 



Nasals shorter and merely cuneate pinetorum (p. 124). 



Color not distinctly brown, but of various shades of ochraceous, tawny, buff, 

 gray, umber, or black. 

 d^. Color strongly ochraceous. 



e^. Incisors projecting conspicuously beyond tip of nasals. 

 Color dark ochraceous, clouded with dusky in winter. 



g^. Size large, hind foot of c? averaging 33 bottae (p. 45). 



Size smaller, hind foot of cJ not over 30. 



A^. Color darker than in hottae minor (p. 51). 



'h?. Color lighter than in hottx diaboli (p. 51). 



