qual, the first and fifth not greatly exceeding the
others in length, the interdigital membrane not extending beyond them.
In the genus _Halichoerus_ the dentition is i. 3/2, c. 1/1, p. 4/4, m.
1/1; total 34. Molars with large, simple, conical, recurved, slightly
compressed crowns, having sharp anterior and posterior edges, but
without accessory cusps, except sometimes the two hinder ones of the
lower jaw. With the exception of the last one or two in the upper jaw
and the last in the lower jaw, all are single-rooted. Vertebrae: C. 7,
D. 15, L. 5, S. 4, Ca. 14. Includes only one species _H. grypus_, the
grey seal of the coasts or Scandinavia and the British Isles.

In _Phoca_ the dental formula is as in the last, but the teeth are
smaller and more pointed. Molars with two roots (except the first in
each jaw). Crowns with accessory cusps. Vertebrae: C. 7, D. 14-15, L.
5, S. 4, Ca. 11-14. Head round and short. Fore-feet short with five
strong, subcompressed, slightly curved, subequal, rather sharp claws.
On the hind-feet the claws much narrower and less curved. The species
of this genus are widely distributed throughout the northern
hemisphere, and include _P. barbata_, the bearded seal; _P.
groenlandica_, the Greenland seal; _P. vitulina_, the common seal; _P.
hispida_, the ringed seal of the north Atlantic; _P. caspica_, from
the Caspian and Aral Seas; and _P. sibirica_, from Lake Baikal. (See
SEAL).

The members of the second subfamily, _Monachinae_, have incisors 2/2;
and the molars two-rooted, except the first. On the hind-feet the
first and fifth toes greatly exceeding the others in length, with
nails rudimentary or absent. In the genus _Monachus_, the dentition is
i. 2/2, c. 1/1, p. 4/4, m. 1/1; total 32. Crowns of molars strong,
conical, compressed, hollowed on the inner side, with a
strongly-marked lobed cingulum, especially on the inner side, and
slightly developed accessory cusps before and behind. The first and
last upper and the first lower molar smaller than the others.
Vertebrae: C. 7, D. 15, L. 5, S. 2, Ca. 11. All the nails of both fore
and hind feet very small and rudimentary. Represented by _M.
albiventer_, the monk-seal of the Mediterranean and adjacent parts of
the Atlantic, and the West Indian _M. tropicalis._

The other genera of this section have the same dental formula, but are
distinguished by the characters, of the cheek-te