310 GEOMYIDJE. 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 



half crescent 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 



jugal Macrogeomys 3 26 



b." Zygomatic arch normally complete 



without jugal Zygogeomys 330 



B. Upper incisors without median grooves Thomomys 332 



62. Geomys. Pocket Gophers. 



Qeomys Rafin., Am. Month. Mag., n, No. i, 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, i, 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 bullae elongate, somewhat acute anteriorly, not greatly inflated; 

 basioccipital very broad posteriorly ; pterygoid fossa wide ; fore claws 

 immensely developed; mammae, three pair, two inguinal, one pectoral. 



308. arenarius (Geomys), Merr., Mon. Geom., N. Am. Faun., No. 8, 



1895, P- J 39- Elliot, Syn. N. Am. Mamm., 1901, p. 219. 

 SAXD-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. 



