Page:Natural History (1848).djvu/114

104 a semi-lunar form. The body is lengthened, gracefully tapered, with a regular outline. Most of the species have a dorsal fin.

The genera of this Family are the most carnivorous, and, though of small or moderate size, the most cruel of the Order. They are scattered in all seas, and frequently ascend rivers. One genus (Inia) is even known to inhabit the mountain lakes of Peru, the fountains of the Amazon, a thousand miles from the sea.

The genus before us is furnished with teeth far exceeding in number those of any other of the Mammalia. The average number, (for it is not uniform even in a given species) is about ninety in each jaw. They cannot be arranged in a formula, as they are all of the same character, and can neither be called incisors, canines, nor molars; they are slender, conical, and pointed, those of one jaw fitting into the interspaces of the other; and hence are adapted for seizing only. The jaws which are thus armed, project in the form of a slender beak, which is separated from the forehead by a groove: the forehead rises abruptly, and is full and rounded. There is a fin on the back.

The Common Dolphin (Delphinus delphis, .) is familiar to fishermen and mariners, being found abundantly around the British shores, and all over the Atlantic and Mediterranean. Its beautiful and graceful form, the extraordinary fleetness with which it darts through the waters, its agile gambols and leaps, and its social habits, render it attractive to every voyager. They are