ONYCHOMYS. PEROMYSCUS. 123 



three-fourths of tail much obscured by whitish hairs, nearly obsolete: 

 ears less densely clothed than in the remaining forms of O. torridus, 

 and without a well defined dusky spot; whiskers mostly white or 

 colorless: under parts, feet and end of tail, white. 



Afcasurfrnenls. Total length, 157: tail vertebra', 57: ear from 

 crown, 16: hind foot, 22; skull, 26 by 13.7. (Mearns, 1. c.) 



157. fuiiginosus. {Onvc/wmys), Merr., N. Am. Faun., No. 3, 1890, 

 p. 60. 



Type locality. Tank lava beds, northeast of San Francisco Moun- 

 tain, Arizona. 



Cifogr. Dis/r. Painted Desert and high mesas, northeastern 

 Arizona. 



(jtnl. Char. Size rather large: tail and liintl feet short; ears 

 rather large with lanuginous tufts at base scantily developed; pelage 

 coarser than in the O. mt-lanophrxs group. 



Color. Above blackish slate, darkest along the middle of the 

 back, faintly tinged with fulvous on the sides: under parts white, the 

 hairs of the belly plumbeous at base. Tail dusky above, except the 

 terminal fourth which is whitish like the under side; a ring of dusky 

 surrounds the base of the tail. The color of the upper parts is more 

 extended than in any of the known forms. It completely covers the 

 sides, coming down to the belly, from which it is separated by a very 

 sharp line of demarcation; it also completely covers the posterior 

 and outer aspects of the hind legs to the ankles, where it ends ab- 

 ruptly. 



Measurements. Total length, 160: tail vertebra-, 47; hind foot, 

 21.5. Ear from crown, 12.5: ear to anterior root, 16. (Merriam, 1. c. ) 



46. *Peroniyscus. 



I. Illi; M. -^-3 = 16. 

 I— 1 .'—.1 



Peromyscus. Gloger, Handb. und Hilfsb. Naturgeschichte, 1842, p. 



95- Type. Cricetus myoides, Gapper; = /'. americanus, Kerr. 

 Calomys. Aud. & Bach., Quad. N. Am., 1851, 11, p. 303 (nee. 



Waterh. P. Z. S., 1837, p. 21.). 

 Vespcrimys. Coues, Proc. Acad. Nat. Scien. Phil., 1874, p. 178. 

 Baiomys. True, Proc. U. S. Nat. Mas., 1894, 16, p. 758. 

 Trinodontomys. Rhoads, Proc. Acad. Nat. Scien. Phil., 1894, 



P- 257- 

 Size moderate, eyes rather prominent: face ratiier long, nose 

 pointed. Ears thin, rather rounded, in some species very large. 



' The members o( this genus require a very careful and strict revision, for many of them 

 probablv should more properly grace the list of synonyms than hold a specific or sub-specific rank. 



