158 Bulletin American Museum of Natural History. (Vol. XVI.

darker than the,males, especially on the neck and shoulders, but
have the grayish white areas of the males replaced by nearly pure
white.

Rangijer montanus, in late September pelage, may be de-
scribed in general terms as a black Caribou, with the neck and
shoulders, especially in the males, much lighter than the body
and limbs; while R. osbornt, in corresponding pelage, is a
brown Caribou, with much more white on the rump and pos-
terior ventral surface, and the whole neck and shoulders, as
well as the back and limbs, much lighter than in R. montanus.

The specimens of R. montanus are without measurements,
but the species is apparently about the same size as R. osbornt,
as shown by the measurements of the skull given above.

In addition to the marked contrast in color, there are strik-
ing differences in the size and form of the antlers in the two
forms, the antlers of R. montanus being of the typical Wood-
land Caribou type, and in their relative shortness and much
branched character recall strongly the antlers of R. terrenove,
but they are much lighter and more slender than in that spe-
cies. They have the same abrupt upward curvature of the
main beam, in contrast with the much longer and heavier and
more depressed backward-sweeping main beam seen in R.
osbornt.

The nearest known relative of R. osborni is R. stoner from
the Kenai Peninsula, which, however, is a differently colored
animal, with the rostral portion of the skull much shorter and
broader, and other important cranial differences. The antlers
also differ greatly in the two species, the antlers of R. stoner
more resembling those of the Barren Ground and Greenland
species.