MICROTUS. 11)5 



390. pauperrimus. (Arviio/a), Cooper, Amer. Nat., vol. 11, 1868, 



P- 535- 



Ty/>e locality. Plains of the Columbia, near Snake river, Wash- 

 ington. 



Geogr. Distr. " Eastern Washington and Oregon, central Idaho 

 and north slope of the Uinta Mountains, Utah, in transition zone." 



Gdil. Char. Small; ears small, nearly hidden in hair; feet hairy; 

 tail very short. Skull: small, flat, broad and depressed anteorbit- 

 ally; nasals short; incisive foramina extend beyond the anterior 

 plane of the first molars. 



Color. Upper parts gray tinged with buffy, and lined with black; 

 under parts whitish buff. Tail above gray, below whitish buff. Feet 

 whitish. 



Measuremtnts. Total length, 116; tail vertebr;e, 20; hind foot, 

 16; ear, 8. 



291. curtatus. (ArvUola), Cope, Proc. Acad. Nat. Scien. Phil., 



1868, p. 2. 



Type locality. Pigeon Spring, Mount Magruder, Nevada. 



Geogr. Distr. Eastern California north of Death Valley, western 

 Nevada; limits of range not known. 



Genl. Char. Size very small; tail and hind feet very short; ears 

 prominent. Anterior lower molar with three internal and two exter- 

 nal triangles, and one posterior triangle. Tail shorter than hind 

 foot. 



Color, .\bove light grayish brown; beneath white; feet white. 

 Tail above grayish brown, beneath white. 



^feasurcments. Total length, 118; tail vertebrae, 19; hind foot, 

 18; ear, 11. 



292. pallidus. {Arvicola), Merriam, Amer. Nat., 1888, p. 703. 

 7)/c locality. Fort Buford, North Dakota. 



Geogr. Distr. North Dakota, Montana north to Calgarj', 

 Alberta. 



Genl Char. Size medium ; tail very short, pencil long ; ears 

 well haired, medium. 



Color. Above pale buffy gray mixed with black; beneath white, 

 plumbeous base of fur visible. Tail indistinctly bicolor. 



Measurements. Total length, 121-133; tail vertebr;c, 20-23; foot, 

 18-18.25; ear from crown, 5-6. 



C. Pedomys, 



Palate normal; third lower molar without closed triangles; claws 

 small, those of front feet always shortest; plantaj tubercles, 5; first 



