Balæna mysticetus, Linn. The Greenland Right Whale.—Averages from 50 to 60 feet in length; has the head very large, and about a third of the entire length; the baleen long; 54 vertebræ and 13 pairs of ribs. The colour a dark grey, with the lower jaw and throat white. It is almost invariably found close to the polar ice-fields, although it occasionally goes as far south in winter as 46° N. lat. Its occurrence on various parts of the coast of Great Britain has been reported, but not satisfactorily proved.
Balæna biscayensis, Eschricht. The Atlantic Right Whale.—Averages from 40 to 50 feet in length, and has a much shorter head than the last-named species, not more than a fourth of its entire length. The baleen is short; the angle of the mouth depressed below the eyes. No description of the skeleton has yet been published. The colour uniform black. In all probability most of the Right Whales which have come into British waters have been of this species, which has a much more southern range than the Greenland Whale.
Family Balænopteridæ.
Genus Megaptera, Gray.
Characterized by the possession of a low dorsal fin, and very long flippers (hence the name), the latter about a fourth or even a third of the entire length, with undulating edges. The head is broad and flat; the tail broad and deeply forked. The skin of the throat and belly pleated.
Megaptera boöps (Fabricius). Hump-backed Whale.—The average length of this species is from 45 to 50 feet. It has 53 vertebrae and 14 pairs of ribs. The head is larger in proportion than that of the Rorqual; the tail broad and deeply forked. The skin of the throat and belly is disposed in longitudinal pleats or folds. The general colour is black above, black and white beneath; the flippers entirely white; the baleen black. It is found between 62° and 66° N. lat., whence it moves southwards at the approach of winter. At least two authenticated instances of its occurrence on our shores are on record. One was cast ashore near Newcastle; another was taken in the estuary of the Dee.
Genus Balænoptera, Lacépède.
Agrees with the genus Megaptera in having a low dorsal fin, and the skin of the under parts pleated; but differs amongst other
