in these animals, which consist of separate or fused bones terminated
by the usual three joints of the finger, on the last of which is placed
the hoof.

[Illustration: Bones of a Pig's foot. (See also Appendix C.)]

The two halves are always symmetrical, and from this we may affirm
that it is the thumb and not the little finger which is absent, for
we know that, counting from the knuckles, our fingers have three
joints, whereas the thumb has only two; so in the digits of the
_Artiodactyla_ are three joints at the end of each metacarpal. In
the pig the metacarpals of the fore and little fingers are produced
from the carpus or wrist, or, as is popularly termed in the case of
these animals, the knee. They are more attenuated in the chevrotians
or deerlets, of which our Indian mouse-deer is an example; in the
_Cervidae_ they are more rudimentary, detached from the carpus, and
are suspended free and low down, forming the little hoof-points
behind; and a little above the proper hoofs in these the two large
metacarpals are more or less joined or fused into one bone, and they
are still more so in the camel, in which the fore and little finger
bones are entirely absent. In the giraffe and prong-horn antelope
they are also wanting. The hind feet are similarly constructed.[32]

[Footnote 32: See notes in Appendix C.]

Of the non-ruminantia we have only the Suidae--the peccaries
belonging to America, and the hippopotami to Africa.

FAMILY SUIDAE--THE HOGS.

These have incisors in both jaws, which vary in number, the lower
ones slanting forward. Their canines are very large and directed
outwards and upwards in a curve, grinding against each other to a
sharp edge and fine point. Their metacarpal bones are four in number,
and are all distinct, in which respect they differ from the peccaries,
in which the central metacarpals and metatarsals are fused into a
solid bone. The hogs have a prolonged snout, flexible at the end,
with a firm cartilaginous tip, with which they are enabled to plough
up the ground in search of roots. They have also a very keen sense
of smell. The normal dentition of the true hogs is as follows:--

Inc., 6/6; can., 1--1/1--1; premolars, 4--4/4--4; molars, 3--3/3--3
= 44.

[Illustration: Dentition of Wild Boar.]

The hogs, unlike other pachyderms, are noted for their fecundity.

_GENUS SUS_.

Incisors, 4/6 or 6/6; the lower ones slanted; the canines large and
curved outwards and upwards; molars tu