310 GEOMYIDZ:. GEOMYS. 
a.’/”’ Skull short, rounded; mesethmoid 
higher than long, lower edge entering PAGE 
between wings of vomer posteriorly. .Pappogeomys 320 
b.’” Skull elongate, flat; mesethmoid a 
haliicrescettt so. suc fs beer Orthogeomys 322 
b. Upper premolar with four enamel plates. 
a.’ Posterior plate restricted to inner half..... Heterogeomys 325 
b.’ Posterior plate restricted to inner third. 
a.’’ Zygomatic arch not complete without 
juga ee ta eRe eae ae eee Macrogeomys 326 
b.” Zygomatic arch normally complete 
Without jilgal\s s-. se lea eae) eee Zygogeomys 330 
B. Upper incisors without median grooves......... Thomomys 332 
62. Geomys. Pocket Gophers. 
l=, P=; M. 
o—— 
3 
rte ir = 
= 20. 
tw lGo 
Geomys Rafin., Am. Month. Mag., 1, No. 1, 1817, p. 45. Type 
Geomys pinetis Raf. =Mus tuza Ord, 1815. 
Saccophorus Kuhl, Beitr. Zool. und vergl. Anat., 1820, p. 65. 
Pseudostoma Say, Long’s Exped. Rocky Mts., 1823, 1, p. 406. 
Ascomys Licht., Abhand. K. Acad. Wiss. Berl., 1825, p. 20, fig. 2. 
Upper incisors grooved along the middle; first and second upper 
molars with two enamel plates each, posterior one complete; root of 
inferior incisor slightly protuberant; zygomata widest anteriorly; 
posteriorly but little greater than mastoid breadth; parietals ridged; 
audital bull elongate, somewhat acute anteriorly, not greatly inflated ; 
basioccipital very broad posteriorly; pterygoid fossa wide; fore claws 
immensely developed; mamme, three pair, two inguinal, one pectoral. 
308. arenarius (Geomys), Merr., Mon. Geom., N. Am. Faun., No. 8, 
1895, p. 139. Elliot, Syn. N. Am. Mamm., rgor, p. 219. 
SAND-LOVING PocKET GOPHER. 
Type locality. El Paso, El Paso County, Texas. 
Geogr. Distr. From Juarez, State of Chihuahua, Mexico, north to 
Las Cruces, and Valley of Upper Rio Grande from El Paso, and west 
to Deming, New Mexico. 
Genl. Char. Size medium, tail long, well haired, except tip; color 
pale. Skull: no sagittal crest; prominent knob at distal end of 
squamosal arm of zygoma; interparietal truncate posteriorly on plane 
of lambdoid suture; occiput moderately bulging. 
