A MARINE animal, differing from all the cetacea, to which it belongs, in not having any teeth, properly so called, and in being armed with a horn of seven or eight feet in length, which projects from the head. This horn is white, spirally twisted throughout its whole length, and tapering to a point: it is harder, whiter, and more valuable than the ivory of the elephant, and was formerly in high repute for its supposed medical properties: small ones may be sometimes seen set with an elegant head as a walking-stick, and large specimens have been employed as bed-posts. The animal itself is from twenty to forty feet in length, and is occasionally found with two horns; indeed, there is always the germ of a second horn both in the male and female, though it is rarely developed in the former, and never in the latter, from which we may conjecture that the females trust entirely to the males for their defence, as we know is the case with several of the mammalia. When there is only one horn, it is always on the left side of the head; and when there are two, the horn on the left side is always larger than the other. This animal chiefly inhabits the arctic seas, and its food is said to consist of the smaller kinds of flat fish and other marine animals; its horn is useful in breaking away the ice when it wants to come up to breathe. The blubber supplies a small quantity of very fine oil, and the Greenlanders are very partial to the flesh. [Illustration: THE MANATEE, (_Manatus Australis_,)] ALSO called the Sea Cow, is a great deal smaller than the other cetacea just described, and differs from them in its diet, which consists entirely of marine plants. It haunts the coasts and estuaries of South America, and measures nine or ten feet in length; its head is comparatively small, its jaws are furnished only with grinding-teeth, of which it has thirty-two, its skin is provided with a good many scattered bristles, and its flippers, or fins, with four small nails. This animal not unfrequently raises its head and shoulders out of the water, when it is said to have some resemblance to a human being, and it is probable that the distant view of a nearly related species, the _Lamantin_, which inhabits the shores of Africa, may have given the ancients their first notion of the Mermaid. The Manatee is captured with harpoons, and its flesh is said to be very good eating. When salted and dried it will keep for a year. It also furnishes an excellent oil, and its skin is used for making harness and whips. The Dugong (_Halicore Dugong_) is a very similar animal, inhabiting the eastern seas. It grows to a length of eighteen or twenty feet. § II. _Cartilaginous Fishes._ [Illustration: THE STURGEON, (_Acipenser sturio_,)]