New Mice from Mexico and Guatemala. 



125 



Characters. — Size small; ears large; tail enormously elongated and 

 moderately haired ; fur long and soft ; color grayish-fulvous. 



Color. — Upper parts gray anteriorly, becoming more and more suffused 

 with olivaceous-fulvous to the rump, which is pale fulvous; hack slightly 

 darkened by black hairs, but no dark dorsal area: nose gray, with a 

 small whitish deck on extreme tip; ring round eve dusky ; under parts 

 butty-whitish, becoming huffy on pectoral region and whitish on chin, 

 lips, and sides of nose; wrists dusky; fore feet white; front of ankles 

 and upper two-thirds of metatarsus dusky; rest of hind feet, toes, and 

 sides of ankles white ; tail dusky, indistinctly paler below. 



Cranial characters. — Skull small; rostrum short and narrow ; zygomata 

 squarely but narrowly spreading anteriorly, the outer sides strongly con- 

 vergent anteriorly ; frontals narrow interorbitally without trace of supra- 

 orbital bead; braincase broad and rather flat; interparietal narrow; 

 audital bulla? small. 



Measurements. — Type specimen: Total length 249; tail vertebrae 155; 

 hind foot 24. 



Fig. 20. — Skull of Megadontomys /ho, nasi (X 1%). 

 See page 115. 



