3-28 MACROGEOMVS. 



KEY TO THE SPECIES. 



A. Audital bulla rounded on outer side; no white 



patch on head. PAGE 



a. Upper parts sepia brown ; skull short, broad . . . M. heterodus 328 



b. Upper parts chocolate brown anteriorly, buffy 



posteriorly M. dolichocephalus 328 



c. Upper parts dark seal brown, nearly black." M. cavator 329 



d. Upper parts dusky chocolate brown, uniform . . . .M. pansa 329 



B. Audital bulla flattened on outer side; white 

 patch on head. 



a. Upper parts dark brown, beneath whitish; 

 roots of maxilla and squamosal meeting above 



jugal M. costaricensis 330 



b. Upper parts plumbeous, beneath paler; roots 

 of maxilla and squamosals not meeting above 



jugal M. cherrii 330 



328. heterodus (Geomys), Peters, Monatsb. K. Preuss. Akad. Wiss. 



Berl., 1864, p. 177, pis. and figs. 

 IRAZU POCKET GOPHER. 



Type locality. Costa Rica. Locality unknown. 



Geogr. Distr. Irazu Range, and possibly other parts of Costa Rica. 



Genl. Char. Size large; upper incisor with a deep narrow groove 

 on inner side of median line; large naked nasal pad; tail naked, as 

 are also the feet, except a few hairs on toes; no external ears; in- 

 cisors in front orange. Skull large, short; frontal broad, flat, concave 

 between orbits, with deep notches in front of postorbital processes, 

 which are large; zygomata wide; jugal broad; nasals wedge-shaped; 

 pterygoids U-shaped, truncate posteriorly. 



Color. Above hair brown; remaining portions of body and the 

 muzzle soiled gray, this hue reaching well up on side of rump, and 

 also covering base of tail. 



Measurements. Total length, 325; tail, 65; hind foot, 41. Skull: 

 basal length, 58-60; Hensel, 51.2-55; zygomatic width, 42.5; inter- 

 orbital width, 10-14; length of upper molar series, 14-15; length of 

 mandible, 44-45. 



329. dolichocephalus (Macrogcomys}, Merr., N. Am. Faun., No. 8, 



1895, p. 189, pis. and figs. 

 NARROW-HEADED POCKET GOPHER. 



Type locality. San Jose, Costa Rica. 



Geogr. Distr. Range unknown. 



Genl. Char. Size large, similar to M. heterodus, but darker. 

 Skull long and narrow; zygomata narrow, the breadth but slightly 



