A New Rodent Genus from Mexico. 



279 



plumbeous at base; fore and hind feet white ; outer side of hind legs 

 dusky to ankles ; eyes surrounded by a narrow rin^; of black ; white of 

 upper lip reaching up on sides of nose half way to eye ; tail sharp]}- 

 bicolor; dusky above, white below, and at tip all round. 



Cranial and dental ckaraclers. — The cranial and dental characters have 

 been so fully given in the generic 

 diagnosis and are so well shown in 

 the accompanying drawings tliat 

 it will be unnecessary to describe 

 them further unless a second spe- 

 cies is discovered. 



Measurements. — Type specimen, 

 (^ ad.: total length, 247 ; tail verte- 

 brae, 121 ; hind foot, 29. Average 

 of 6 specimens from tyjie locality: 

 total length, 244; tail vertebne, 121; Q- 

 hind foot, 29. 



Geographic distribution. — Speci- 

 mens of this remarkable animal ^"^ 

 were collected by Mr. Nelson in the 

 higlier parts of the Sierra Madre in the western corner of the State of 

 Zacatecas, and about 100 miles farther south in the same range, near 

 Bolailos, Jalisco. Another series was obtained in a detached range, east 

 of the Sierra ]Madre, near Plateado, Zacatecas. INIr. Nelson informs me 

 that the animals were usually found a]:)out ledges or other rocky places 

 in the pine forest, at an altitude of 8,000 feet or upwards. Near Plateado 

 specimens were secured along the upper edge of the oak belt, where the 

 oaks mix with the lower edge of the pines. None were found at lower 

 altitudes. 



15.— SkuU oi Nehouia neoiomodon. 

 X 1%. 



