310 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
marked contrast with the mixed white and brown winter pelage of specimens 
from the Eastern States: and even the specimens from the highest northern 
localities, though pure white at the surface, are fulvous and then plumbeous 
beneath. These specimens agree, however, in this character with winter 
specimens from Fort Bridger, Fort Benton, and the Bitter Root Valley, 
which, from the locality, I have referred to var. bairdi, and are in no way 
distinguishable from them. I have also included specimens from “Koko- 
youkuk, R. Am.”, in changing pelage, in this series, which they seem to 
approach quite strongly. 
The skins of var. washingtoni vary in length of body from 15.25 to 
18.50 inches, eight specimens giving an average of 16.68, or about one inch less 
than the average of var. virginianus, and half an inch more than specimens 
from the northern districts of the fur countries, or var. americanus. The ear 
fully equals, and the hind foot scarcely falls short, of the length of the same 
parts in var. virginianus from Massachusetts. The single fully adult skull 
fully equals the average of eastern examples. The measurements given in 
Table XIX are taken wholly from the skins, many of which are unfilled and 
evidently much shrunken. The measurements of the skulls (Table XX), as 
before stated, are mainly from more or less immature specimens. The pro- 
portions are not essentially different from those of eastern specimens of cor- 
responding age, and the ears and tarsi are fully equal to these parts in var. 
virginianus, instead of being shorter, as has been supposed. 
Var. BAIRDI. 
Rocky Mountain Varying Hare. 
Size and proportions same as those of the other varieties of americanus. 
Winter pelage sometimes wholly snowy-white to the base, as in the Arctic 
Hare; generally with the outer white zone extending much deeper than in 
any other form of americanus, with the middle zone much paler, varying from 
a faint shade of fulvous to a delicate salmon tint, and the basal plumbeous 
zone greatly reduced in extent, and lighter-colored. In summer, above pale 
grayish-brown and black, the black being often the prevailing tint; under-fur 
whitish, sometimes almost pure white, with the middle brown zone of the 
other forms obsolete; under parts (excepting the pectoral region) and the feet 
pure white; general color of the ears black, washed more or less with whit- 
ish, and with a very broad conspicuous white border. 
In different specimens, the color of the dorsal aspect in summer varies 
