THOMOMYS. 333 
Upper incisors without median sulcus, but with a fine marginal 
groove, not, however, always present; root of inferior incisors form- 
ing a protuberance on outside of condylar ramus; zygomata wider 
posteriorly than mastoid diameter of skull; audital bulle inflated: 
basioccipital narrower in the middle than bulle at same place. 
pterygoid fossa rather short, and wide posteriorly; upper molars 
with exterior edge of crown acute; lower molars with interior edge 
acute; fore claws moderately developed. 
Fic. 64. THOMOMYS ATROVARIUS. 
No. 13769 Am. Mus. Nat. Hist. Coll. Nat. size. 
Eye vOetnE ore ClIESVAND SUBSEECIES. 
A. Upper incisors without median grooves; fore 
claws weak. 
a. Upper parts yellowish brown or fulvous. 
a.’ Under parts yellowish white, tinged with ee 
TOULOUSE) \e ot... Meee... T.fulvus 334 
Be’ Undemeessbulit, cu... . ceed... om LT. jf. ante a3s 
e Underieemes reddish fulvousgevg i... -- iy). aliccoldiee'3s 
b. Upper parts tawny brown, beneath tawny 
a. A ne a T.f. nigricans 335 
Cimvpper paresi@atk mars brown.......:... T.f.antermedius 336 
d. Upper parts grayish brown and _ blackish, 
ipemeathveraniSi Witte)... et ee T. martirensis 336 
