328 MACROGEOMYS. 
KEY TO-THE, SPEGLES: 
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 cx amo ate oe nee VU. 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 
[tical Besa races eee ne aoe has ce een eee M. costaricensis 330 
b. Upper parts plumbeous, beneath paler; roots 
of maxilla and squamosals not meeting above 
Waal ko Ae eee ee oe Bons cae ae re M. cherrit 330 
328. heterodus (Geomys), Peters, Monatsb. K. Preuss. Akad. Wiss. 
Berl., 1864, p. 177, pls. and figs. 
Irazu PocKEeT GOPHER. 
Type locality. Costa Rica. Locality unknown. 
Geogr. Distr. Trazu 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, ro—14; length of upper molar series, 14-15; length of 
mandible, 44-45. 
329. dolichocephalus (Macrogeomys), Merr., N. Am. Faun., No. 8, 
1895, p. 189, pls. and figs. 
NARROW-HEADED POCKET GOPHER. 
Type locality. San José, 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 
