MAMMALIA, 427 
The genus Phocena, Porpoises, is easily recognisable by the shortness 
of the snout, which can scarcely be distinguished from the forehead. The 
jaws, however, are elongated, and very distinct from the skull when the 
soft parts are removed, which in the living condition give to the head and 
snout that roundness which distinguishes this genus. The porpoises live 
associated in large numbers, and sometimes ascend rivers far from the sea. 
Their food consists of fishes and molluscs, which they consume in large 
quantities. P. communis is the most common species met with in the 
Kuropean seas, and is often caught by fishermen. A species very much 
related to it, and with which it has been confounded until very lately, is 
peculiar to the American shore of the Atlantic (P. americana). It differs 
from the former in having the teeth grooved on the broad faces near the 
summit, so as nearly to divide them into three lobes, whilst in P. communis 
they are smooth. The dorsal fin is serrated and tuberculous. The largest 
species of this genus, the common grampus, P. orca (with some authors 
Orca communis), measures from twenty to twenty-four feet in length, with 
a body of proportional bulk. The snout is very short, the dorsal fin very 
high, the teeth large and in small number, eleven in each side of both jaws, 
conical and a little bent backwards. Those near the extremity of the lower 
jaw are worn off first. The upper part of the body is black, the lower white, 
and a white oblong spot above the eyes. Found in the Mediterranean and the 
Atlantic. The P. gladiator, or sword grampus, is remarkable for its dorsal 
fin, which is higher than the body itself under it. The skull is vaulted, the 
snout depressed, very obtuse, and the lower jaw a little longer than the 
upper one. ‘This species lives in Davis's Straits, on the coasts of America 
and Spitzbergen, in troops of from six to eight. The P. globiceps, also large 
and bulky, has a snout still shorter and more rounded, and a large triangular 
dorsal. The number of teeth varies very much; in adult specimens each 
jaw has from eighteen to twenty-six of them. Their form is conical, 
slightly curved inwards at their tip. This species keeps the open seas, but 
was once seen at the mouth of Charles River, between Boston and Charles- 
town (Mass.). A similar species, P. 7zssoana, is found in the Mediterranean, 
and has a snout still shorter, a character which has led some naturalists to 
place it in a special genus, Globicephalus, which included those porpoises 
with a round and more or less spheroidal head. Some other species of 
Phoczena are described in systematic works. 
The genus Delphinapterus includes only one species as far as known, the 
beluga or white whale, whose characters consist in the absence of a dorsal 
fin, instead of which it has only a kind of longitudinal projection on the 
back. The head is proportionally small, spheroidal, and the snout truncated, 
or rather rounded off. Both jaws are equal, and furnished with nine or ten 
small teeth, blunt at the top, but unequal and distinct from each other. 
The D. beluga is a native of the northern seas, the Arctic, and especially 
of Hudson’s Bay and Davis’s Straits. 
The genus Oxypterus is known only from vague information. Rafinesque 
established it for a species from the seas of Sicily, calling it O. mongitor?. 
According to Quoi and Gaimard (Voyage de ]’Uranie, Zool., p. 86, pl. ii., 
631 
