LEPORIDAIi—LEPUS AMERICANUS VAR. BAIRDI. rod bl 
from pale _yellowish-gray to yellowish-brown, varied with black. The hairs 
have a very long black tip, with a narrow subterminal bar of yellowish- 
brown, of varying intensity; thence to the base black. The effect of the 
long black tips is to give a much greater prevalence of black over the other 
tints than is seen in the other forms of americanus, imparting a general sooty 
tint to the whole upper surface. In some specimens, the black is quite the 
prevailing tint, especially over the rump, which region, in some specimens, 
is wholly black, varied with white by the white under fur showing through 
the surface color. The feet are wholly white, and there are generally a 
few white hairs on the back—traces, doubtless, of the winter pelage. The 
anterior part of the body above and the head are more or less rufous, this 
tint being most developed on the upper surface of the head. The white 
under-fur (varying in different specimens from white to grayish-white) always 
shows through the surface color more or less,and is conspicuous on the slightest 
disarrangement of the pelage. In one specimen only (No. 11099, from Lewis 
Lake, Wyoming Territory) is there a very decided trace of the yellowish 
zone that terminates the under-fur in the other forms of Lepus americanus. 
Typical examples in summer pelage of this peculiarly interesting form 
give the impression of its being thoroughly distinct from any other form of 
americanus; but comparison of a series of specimens from the original locality 
of L. bairdi with others from the Red River district reveals a decided tendency 
to intergradation between these forms. The most prominent distinctive fea- 
tures of var. bairdi in summer pelage are its pure white under-fur, the long 
black tips of the hairs, and the white feet, and in winter the tendency of 
the pelage to become pure white to the base. Some of the summer speci- 
mens from the Red River district and from Fort Rae (northern shore of 
Great Slave Lake) also have white feet, and the pale yellowish-gray of the 
back is also strongly varied with black, and the under-fur is simply dusky, 
without the fulvous termination. Again, occasional specimens of bazrdi 
have the fulvous apical zone of the under-fur slightly developed. Var. 
bairdi, in its blackish-gray dorsal surface and white under-fur, bears a strong 
resemblance to summer specimens of L. ¢imidus var. arcticus, from the Arctic 
coast; but the great disparity in size and the differences in the skulls forbid 
the supposition of any very close affinity between them. 
The few measurements obtainable from the considerable series of skins 
before me (mostly in a very bad state) are presented in the following table. 
The length varies from 15.50 to 18.00 inches, but on one or two of the 
