half-cylinder working in a deep glenoid fossa of
corresponding form. The brain varies much in size and form, but the
hemispheres are never destitute of convolutions. The stomach is always
simple and pyriform; the caecum is either absent or short and simple;
and the colon is not sacculated or much wider than the small intestine.
Vesiculae seminales are never developed, but Cowper's glands may be
present or absent. The uterus is two-horned, and the teats are abdominal
and variable in number; while the placenta is deciduate, and almost
always zonary. The clavicle is often absent, and when present never
complete. The radius and ulna are distinct; the scaphoid and lunar of
the tarsus are united; there is never an os centrale in the adult; and
the fibula is distinct.

The large majority of the species subsist chiefly on animal food, though
many are omnivorous, and a few chiefly vegetable-eaters. The more
typical forms live altogether on recently-killed warm-blooded animals,
and their whole organization is thoroughly adapted to a predaceous mode
of life. In conformity with this manner of obtaining their subsistence,
they are generally bold and savage in disposition, though some are
capable of being domesticated, and when placed under favourable
circumstances exhibit a high degree of intelligence.

I. FISSIPEDIA

[Illustration: FIG. I.--Left upper sectorial or carnassial teeth of
Carnivora. I, _Felis_; II, _Canis_; III, _Ursus_. 1, anterior, 2,
middle, and 3, posterior cusp of blade; 4, inner cusp supported on
distinct root; 5, inner cusp, posterior in position, and without
distinct root, characteristic of the _Ursidae_.]

The typical section of the group, the Carnivora Vera, Fissipedia or
Carnassidentia, includes all the existing terrestrial members of the
order, together with the otters and sea-otters. In this section the
fore-limbs never have the first digit, or the hind-limbs the first and
fifth digits, longer than the others; and the incisors are 3/3 on each
side, with very rare exceptions. The cerebral hemispheres are more or
less elongated; always with three or four convolutions on the outer
surface forming arches above each other, the lowest surrounding the
Sylvian fissure. In the cheek-series there is one specially modified
tooth in each jaw, to which the name of "sectorial" or "carnassial" is
applied. The teeth in front of this are more or less sharp-pointed and
compressed; the teeth behind broad and tuberculate