MAMMALS OF THE MEXICAN BOUNDARY. 



461 



Description. — Form stout. Average measurements of four adults 

 (3 males and 1 female): Length, 111 mm.; tail vertebra', 70. .'J: ear 

 from crown, 11.7; length of hind foot, L7.2; skull (fig. 114), 21 by 11.2. 

 Pelade long and soft; tall and ears rather hairy. Above yellowish 

 gray, with the hairs ringed with darker, and broadly pointed with 

 blackish in the median dorsal area; sides more fulvous; chest some- 

 times with a small rust-colored spot ; feet, and under surface, white, 

 the hairs gray at base; tail bicolored, drab above and white below; 

 ears externally drab, mixed with a few reddish and hoary hairs, inter- 

 nally scantily coated with reddish hairs, which form a tuft at ante- 

 rior base of ear; whiskers colorless, reaching to shoulders. 



Fig. 114.— Reithrodontomys megalotis. Skull, n, doesal view; b, ventral view, 



C, LATERAL VIEW. 



Remarks. — The above description of this small mouse is based on 

 four adults, taken near the type-locality, April 7 to 29, 1892. Typical 

 megalotis was found by us at only two points: A single specimen was 

 taken east of the Mimbres Valley, in New Mexico, near Monument 

 No. 15, about 50 miles west of the initial Monument; and three were 

 afterwards taken at the Upper Corner Monument, about 100 miles 

 west of the Rio Grande, and almost due north of Janos — the place 

 where the species was first discovered by Dr. C. B. Kennedy, of the 

 old Mexican Survey, under Major Emory. We did not succeed in 

 getting any more specimens of the genus Reithrodontomys until the 

 survey party reached the Colorado River, whence it was abundant 

 to the edge of the Pacific Ocean. 



