LEPOKIDvE— LEPCS AMERICANUS ET VAES. 323 



General remarks on Lepus americanus and its varieties. 



Lepus americanus differs from the other Varying Hares in its much 

 smaller size and relatively shorter ears, as well as in the size and proportions 

 of the skull. Aside from its white winter pelage, it also differs much from 

 all the other Hares of this continent in color, proportions, and in cranial char- 

 acters, and from most of them, moreover, in size. 



Of its four geographical varieties {americanus, virginianus, toashingtoni, 

 and bairdi), var. bairdi seems to be the most strongly marked. Var. ame- 

 ricanus is the northern tbrm, with a softer and longer winter pelage, more 

 heavily-clothed ears and feet, with the white of the surface invading the 

 pelage to a considerable depth, and with a duskier, duller-tinted summer 

 pelage. By gradual stages, however, it shades into var. virginianus, its south- 

 ern representative on the Atlantic coast, which has the whiteness of the 

 winter pelage restricted to the surface, only partially concealing the color of 

 the under fur, and in which the summer pelage is of a brighter or redder 

 tint. Var. washingtoni is the southern Pacific coast form, known at pres- 

 ent only from the region about Puget's Sound. In summer pelage, it is rather 

 more rufous even than var. virginianus, but by no differences as yet discov- 

 ered is it always distinguishable from the latter form. Like virginianus, it 

 is a southern representative of americanus, with which it insensibly inter- 

 grades. Var. bairdi occupies an intermediate geographical position, and 

 may be regarded as an alpine form. Its distinguishing features are in the 

 summer pelage the prevalence of black, the white under-fur, and white feet, 

 and in winter the tendency to an entire whiteness of the under-fur. It shows, 

 however, decided intergradations with the northern form, as well as with the 

 two southern forms, with which it essentially agrees in size and proportions. 

 So far as at present known, there is no very marked variation in size with 

 locality throughout the wide region inhabited by the varieties of L. ame- 

 ricanus. 



Geographical Distribution. — Lepus americanus, in some of its forms, 

 occupies the wooded portion of the whole northern half of the continent, 

 extending southward in the Rocky Mountains as far, at least, as New Mexico ; 

 its southern limit of distribution coinciding very nearly, apparently, with the 

 isotherm of 50°. On the Pacific coast, the species is represented in var. 

 washingtoni as far south as the head of the Willamette River; in the interior, 



