Page:Popular Science Monthly Volume 20.djvu/641
who takes the world exactly as he finds it; and who, upon principle, abstains at once from unfounded affirmations, unsupported judgments, and unanswerable questions. His business, as he conceives it, is to regulate his life, and help others to regulate their lives, by realities; and a thing to be a reality to him does not need to be a stone-wall.
By W. H. LARRABEE.
THE sea is inhabited by three families of mammalian animals, which, though they may be so "very like a whale" as to have been sometimes spoken of together as cetaceans, are quite distinct in their structure and habits, and show evidences of distinct origin. They are the cetaceans, including the whales, dolphins, and porpoises; the pinnipeds, including the seals, sea-lions, and walruses; and the sirenians, including the manatees and dugongs. The affinities of the cetaceans are not exactly known, but it is certain that they are creatures of a very different sort from the animals of the other two classes; the pinnipeds are closely allied to the bears, dogs, and cats. Both these classes are carnivorous. The sirenians are herbivorous pachyderms, whose nearest analogies must be sought among the hogs, tapirs, and particularly in the hippopotamus.
The manatee, or sea-cow, is the most widely diffused of the sirenians, and, being American, has the first claim to consideration. Its various species are found along the coasts and in the rivers and inland lakes of tropical America; the length of the entire opposite coast of Africa, around the Cape; and as far north up the Mozambique coast as the Zambesi River; in the upper Niger River; in Lake Tchad; in the East African Lake Shirwa; and in the Tana Sea, in Abyssinia. Agassiz has termed the animal the modern representative of the dinotherium, and it is most probably the creature which Columbus mistook for a mermaid. It grows to be sometimes as long as seventeen or twenty feet, but generally, not more than from eight to twelve feet, and to weigh from one to three or four tons, having a body the shape of an elongated barrel, slightly flattened above and below, with two fore-limbs, but no sign of hinder extremities, and an horizontally flattened or spatulate tail of about one fourth the extent of the body. Its skin is much like that of the hippopotamus, and is very sparsely covered with hair. Its fore-limbs are set far forward, are more free in their motions than those of the cetaceans, and may be used as claspers, flexed over the chest, for swimming or dragging the animal along the bottoms, or up the banks of the rivers in which it feeds, and to assist in the prehension of food. The finger-bones may be felt