GEOMYS. CRATOGEOMYS, 311 
Fic. 56. GEOMYS ARENARIUS. 
No. 36114 U.S. Nat. Mus. Coll. Nat. size. 
UPPER TOOTH ROW. LOWER TOOTH ROW. 
Enlarged 7 times, Enlarged 7 times. 
Color. Above drab brown, lined with black; under parts and 
feet white. 
Measurements. Total length, 258; tail vertebra, 88; hind foot, 
33. Skull: basal length, 37.5—-40.5; Hensel, 34-37; zygomatic width, 
24-28; interorbital breadth, 6—7; length of upper molar series, 7.5—8; 
length of single half of mandible, 27—28.5. 
63. Cratogeomys. Powerful Pocket Gophers. 
Cratogeomys Merr., Mon. Geom., N. Am. Faun., No. 8, 1895, p. 
150, pls. and figs. Type Geomys merriamt Thomas. 
Upper incisor with a single groove, usually open; upper premolar 
with three enamel plates, posterior absent; shaft convex forward; 
upper and lower premolars subequal in length. First and second 
upper molar with one enamel plate each, posterior absent. Last 
upper molar with a deep sulcus on outer side, none on inner. Skull: 
a depression extends obliquely across squamosals from root of zygoma 
