symmetrical, rather small, narrow, and upright; lateral hoofs also; small.
Both sexes generally provided with horns, which are large and spreading
in the males, but, except in one case, small and upright in the females -,
those of males directed at first outwardly from the sides of the head, with
the upper border convex at starting, and then generally forming a circular
or spiral curve, with the tips pointing outwards; in section generally more
or less distinctly triangular, and the surface, of which the colour is usually
some shade o f yellowish-olive or brown, in most .cases marked by fine
parallel transverse wrinkles. Pelage usually consisting of close, short,
stiff hair, which may be elongated into a ruff on the chest and throat, and
in one instance is long and shaggy on the whole of the throat, chest, and
front surface of the fore-limbs; coloration usually some shade of rufous,
brown, or tawny, becoming lighter on the under-parts, and in some cases
with blackish markings between the dark and light areas and on the limbs.
Upper molar teeth with tall, narrow crowns, on the inner side of which
there is no additional small column comparable to that of the oxen. When
face-glands are developed, the skull has shallow pits below the eyes for
their reception, but only very small unossified vacuities. Cannon-bones in
both limbs relatively long and slender, and thus quite unlike those of
either the oxen or the musk-ox.
As additional characters of the skeleton, it may be mentioned that the
skull is broadest across the sockets of the eyes, which are fairly prominent
but not distinctly tubular ; below these it narrows suddenly, and thence
tapers gradually to the muzzle ; the planes of the forehead and the occiput
(the latter of which includes the parietal bones) meet one another nearly
at a right angle, the true occiput being almost flat.
Although very closely connected with the goats, the relationship of
the sheep to other members of the family Bovidce is still very obscure.
They appear to be an essentially modern group, possibly even o f later
origin than the oxen, as it is doubtful whether they are represented in the
Siwalik deposits of India, where remains of the latter are abundant. That
they have no intimate relationship with the oxen, may be considered fairly
certain ; and it seems more than doubtful i f they have any very near
kinship with the musk-oxen, from which they differ markedly in the
structure of the horns and in the form of the cannon-bones. Antelopes, so
far as our present knowledge goes, are among the oldest of the hollowhorned
ruminants, and since the gazelles and their allies have molar teeth
of the same general structure as those of the sheep, it is possible that
the latter may be a gjpecialised offshoot from the ancestral stock of the
former.
From the point of ,view of the systematic naturalist sheep form an
excessively difficult group to deal with. In the first place, several of the
local forms are so similar to one another that it is almost impossible to
decide whether thejgfshould be regarded as species or races. And, in the
second place, the more aberrant members of the group exhibit so many
characters, common to the goats that it becomes a question whether, on the
one hand)Jt would not be advisable to include both sheep and goats in a
single genus, or whether, on the other, the sheep themselves might not be
divided into at least three genera. As a compromise, three distinct subgenera,
or groups, of wild sheep are here recognised. In addition to these,
the various breeds of domestic sheep (Ovis aries^y which form the type of
the whole genus, are perhaps entitled to constitute a fourth and typical
group. Here it may be mentioned that the ancestral form of these
domestic breeds, which differ from all the wild species save the arui by
the length of the tail, is at present totally unknown, so that no detailed
mention o f the typical group is made in the present work. The woolly
character of the pelage, which forms such a marked feature in the European
breeds of sheep, might seem another feature distinguishing all the domesticated
kinds from the wild species. This, however, is not the case, since
many of the domesticated breeds belonging to less civilised tribes, like