, and with numerous and complex convolutions.
There is a very short caecum; the kidneys are divided into numerous
distinct lobules. There are no Cowper's glands. Teats two or four,
abdominal. No clavicles. Tail always short. Eyes large and exposed, with
flat cornea. The nostrils close by the elasticity of their walls, and
are opened at will by muscular action.

The members of this group are aquatic, spending the greater part of
their time in the water, swimming and diving with great facility,
feeding mainly on fish, crustaceans and other marine animals, and
progressing on land with difficulty, but always coming on shore for the
purpose of bringing forth their young. They are generally marine, but
occasionally ascend large rivers, and some inhabit inland seas and
lakes, as the Caspian and Baikal. Though not numerous in species, they
are widely distributed over the world, but occur most abundantly on the
coasts of lands situated in cold and temperate zones.

As mentioned in the article CREODONTA, the true seals (_Phocidae_),
together with the walruses, may be directly descended from the primitive
Creodont Carnivora. The eared seals, on the other hand, show signs of
affinity with the bears; but as they are of earlier geological age than
the latter, they cannot be derived from that group.

Seals.

The true seals (family _Phocidae_) are the most completely adapted for
aquatic life of all the Pinnipedia. When on land the hind-limbs are
extended backwards and take no part in progression, which is effected
by a series of jumping movements produced by the muscles of the trunk,
in some species aided by the fore-limbs. The soles of the feet are
hairy. There is no pinna to the ear, and no scrotum, the testes being
abdominal. The upper incisors have simple, pointed crowns, and vary in
number in the different groups. All have well developed canines and
5/5 teeth of the cheek series. In those species of which the
milk-dentition is known, there are three milk molars, which precede
the second, third, and fourth permanent molars; the dentition is
therefore p. 4/4, m. 1/1, the first premolar having as usual no milk
predecessor. The skull has no post-orbital process and no alisphenoid
canal. The fur is stiff and adpressed, without woolly under-fur.

In the typical group, or subfamily _Phocinae_, the incisors are 3/2.
All the feet have five well-developed claws with the toes on the
hind-feet sube