of lesser characters.

Oxen, antelopes, sheep and goats agree in having hollow horns of
material similar to that of which hair and nails are formed, permanently
fixed upon the skull in all but one species; none of them have more than
the two middle digits functionally developed, one on each side of the
axis of the leg; none have the lower ends remaining of the meta-podial
bones belonging to the two accessory digits; and none have either
incisor or canine teeth in the upper jaw.

From animals so constructed we may first take out goats and sheep, in
which the female horns are much smaller than those of males, and in some
species are even absent. In nearly all of them the horns are noticeably
compressed in section, either triangular or sub-triangular near the
base, and are directed sometimes outwardly from the head with a circular
sweep; at others with a backward curve, often spirally. The muzzle is
always hairy; there is no small accessory column on the inner side of
the upper molars, found always in oxen and in some antelopes; the tail
is short, and scent glands are present between the digits of some or all
the feet.

Now, as to the perplexing animals popularly known as antelopes. No
definition could be framed which would include them all in one group,
for every subordinate character seems to be present in some and absent
in others, so that the most that can be done with this vast assemblage
is to arrange its contents in series of genera, which may or may not be
called sub-families, but which probably correspond in some degree to
their real affinities. We can only say of any one of them that it is an
antelope because it is not a sheep, nor a goat, nor an ox. They concern
us here only to be eliminated, for they are not American, our prong-buck
having a sub-family all to itself, as we shall see later, and the
so-called "white goat" being usually regarded as neither goat nor truly
antelope.

Within the limits of the real bovine animals, four quite distinct types
may be made out, chiefly by the position of the horns upon the skull and
by the shape of the horns themselves. There are also differences in the
relations of the nasal and premaxillary bones, the development of the
neural spines of the vertebrae, and the hairy covering of the body.

In the genus _Bos_ the horns are placed high up on the vertex of
the skull, which forms a marked transverse ridge from which the hinder
portion falls sharply away. The horns are ne