Page:Natural History (1848).djvu/117

Rh length; and furnished with many stout, conical teeth, somewhat flattened: the upper jaw contains either none, or a few which do not penetrate the gums. They are destitute of baleen. The blow-holes have but a single orifice; situated at the top of the broad muzzle.

As the present genus, which includes only two or perhaps three known species, constitutes the whole Family, it is needless to repeat the distinctive characters already given. We shall confine ourselves, therefore, to a description of the best defined species, the Sperm Whale (Physeter macrocephalus, ).

It is not to any extraordinary development of the brain of this animal, nor even of the skull, that the immense bulk of the head is owing; the jaws in- deed are greatly lengthened, but the brain is very smail, and seated at the back of the head, the whole anterior part forming a huge cavity, known to whalers as the “case,” which is not enclosed by bone, but by a thick, tendinous, elastic skin, and lined with a beautiful, glistening membrane. This cavity is filled with a clear oil, sometimes to the amount of ten barrels, which after death cools into the granulated substance, well known, when purified, as spermaceti.

The coat of blubber, contained in the texture of the skin of the body, produces an oil, which is much valued, for its clearness, and other qualities, and is known as sperm-oil. These two products form the principal object of the Sperm-whale fishery; a pursuit which, from the remote distance