136 



1855. Neotoma ^micropus, Baird, Proc. Acad. Nat. Sci., Phila., vii, 1855, 

 333; M. N. A., 1857, 492; U. S. and Mex. Bouad. Surv., ii, pt. 

 ii, 1859 ; Mamm,, p. 44. 



Specific Characters. — Length about 6 inches ; tail about 6; hind foot 1.50; 

 skull averaging 2 inches. Tail scani-hairy, bicolor, grayish and whitish. 

 Adults with general body colors of Norway Rats, but more fulvous on 

 the sides; white below; young grky or slate color. Tubercles blackish; 

 toes and palms flesh-colored ; tips white ; back of hands and the feet 

 snowy white. 



Distribution. — Found in southern United States and northern Mexico; 

 north to Maryland (Audubon), New York (Bell), Massachusetts (Gibbs), 

 Dakota, Illinois, Kansas, and Arkansas (Coues) ; identified in Ohio by 

 Dr. Byrnes, who, as I am informed by Mr. Langdon, "captured a speci- 

 men that was abandoned near New Philadelphia, Ohio." 



Professor M. V. B. Knox, of Baker University, Kansas, states that the 

 species is common along streams in middle and western Kanias, where 

 they build nests by piling up sticks and pieces of bark to the height of 

 two or three feet, often about the base of a tree or stump. In these piles 

 they construct a nest of dried leaves and grass. 



Genus Hesperomys Waterhouse. 



Hesperomys is a tribal rather than a generic name, including, according 

 to Dr. Coues, in North America, Vesperimus, Onychomys, Oryzomys, Ocheto- 

 don, Sigmodon, and Neotoma, with as many South American genera or 

 sub-genera besides. The same author says : " In our comparative ig- 

 norance of South American forms, we shall not venture upon any diag- 

 nosis or description of the full genus Hesperomys." 



Sdb-genub Vespeeimus Coues. 



= Musculus, Raf , ^m. Month. Mag., iii, 1818, 446. 



= Hesperomys, Baird, Mam. N. A., 1857, 458. 



= Vesperimits, Coues, Proc. Acad- Nat. Sci.. Phila., 1874, 178 (type Mus 



leucopus). 

 < Hesperomys, of North American writers. 

 > Oalomys, Aud. & Bach., Quad. N. A., ii, 1851, 303. 



Sub-generic Characters. — Of medium and small size, lithe form, and 

 quick movement; eyes large and prominent; ears rounded, large, thin, 

 scant-pilous, antitragus evident but not valvular ; claws weak ; hind legs 

 and feet long, the latter with six large conical tubercles ; hind feet naked 

 or scant-furred on posterior third; tail terete, slender, closely .hairy. 



