e degree of distinction will be
accorded to, at least, one or two Alaskan forms.

As sheep probably came into America from Asia during the Pleistocene, at
a time when Bering's Strait was closed by land, it might be expected
that those now found here would show relationship to the Kamtschatkan
species (_Ovis nivicola_); and such is indeed the case, while
furthermore, in the small size of the suborbital gland and pit, and in
comparative smoothness of the horns, both species approach the bharal of
Thibet and India, which in these respects is goat-like.

When one considers the poverty of the new world in bovine ruminants, it
seems strange that three such anomalous forms should have fallen to its
share as the prong-horn, the white goat and the musk-ox, of none of
which have we the complete history; two of the number being entirely
isolated species, sometimes regarded as the types of separate families.

The prong-horn is a curious compound. It resembles sheep in the minute
structure of its hair, in its hairy muzzle, and in having interdigital
glands on all its feet. Like goats, it has no sub-orbital gland nor
distinct pit. Like the chamois, it has a gland below and behind the ear,
the secretion of which has a caprine odor. It has also glands on the
rump. It is like the giraffe in total absence of the accessory hoofs,
even to the metapodials which support them. It differs from all hollow
horned ungulates in having deciduous horns with a fork or anterior
branch. There is not the least similarity, however, between these horns
and the bony deciduous antlers of deer, for, like those of all bovines,
they are composed of agglutinated hairs, set on a bony core projecting
from the frontal region of the skull.

It is well known that these horn sheaths are at times shed and
reproduced, but the exact regularity with which the process takes place
is by no means certain, although such direct evidence as there is goes
to prove that it occurs annually in the autumn. Prong-bucks have shed
on eight occasions in the Zoological Gardens at Philadelphia, five times
by the same animal, which reached the gardens in October, 1899, and has
shed each year early in November, the last time on October 22, 1903,[1]
and the writer has seen one fine head killed about November 5 in a wild
state, on which the horn-sheaths were loose and ready to drop off.

[Footnote 1: It is interesting to note that the first pair shed measured
7-1/4 inches, on the anterio