THICK-SKINNED ANIMALS. PACHYDERMATA. "Beside him stalks to battle, The huge earth-shaking beast- The beast who hath between his eyes. MACAULAY'S "LAYS OF ANCIENT ROME." THE animals of the present Order are, in their general habits, herbivorous. One of their most obvious characteristics is the toughness and great thickness of the skin; from this peculiarity the scientific name for the order has been derived. Most of the species belong to the torrid zone; but none are found in Australia. The Elephant, both of India and of Africa-for there are two species-has been celebrated for his strength, docility, inoffensive habits, and usefulness to man; and the term. "half-reasoning Elephant," which has been applied to him by the poet, indicates that remarkable sagacity of which so many well-authenticated anecdotes are told. The food of the Elephant, when in a state of nature, consists not merely of leaves, but of the twigs and branches of trees. It is needful, therefore, that he should have teeth fitted to grind down the woody fibre, and with some power of renewal which would make up for the continual wearing away. The teeth are, therefore, composed of three sub stances of different degrees of hardness; this causes the surface to wear away in an unequal manner, and hence the property which makes a millstone most valuable is secured. The arrangement to make good what a mechanic would call "the wear and tear" of the apparatus is not less effectual. The teeth are ever growing, not as in the gnawing animals (page 217), by the deposit of fresh matter at the base, but by enormous molar teeth in the course of its life, or twentyfour in all, never more than two are seen in each jaw at the same time. The Hippopotamus or "River-horse" (Fig. 226), whose bulk is scarcely inferior to that of the elephant, is peculiar to Africa; but the Rhinoceros (Fig. 206), of which there are seven species, is distributed through both Asia and Africa. The wild Boar of Europe, and the Peccaries of America, are examples of families belonging to the present order. Related by peculiarities of structure to the Elephant, the Rhinoceros, and the Hog, is the Tapir. The species represented in the annexed figure (Fig. 227) is a native of America, and is about the size of a calf of six months old. Its most remarkable feature consists in the prolongation of the nose into a moveable proboscis, which extends several inches beyond the mouth, and is capable of being moved at will in various directions. The Tapir is found in every part of South America, from the straits of Magellan to the Isthmus of Darien; it is extremely inoffensive, and never attacks either man or beast, except in self-defence, or under circumstances of great provocation. The family to which the Horse belongs is universally distributed, either in a wild or a domesticated state. The wild Asses extend from Siberia to Egypt; and the different species of Zebra (Fig. 228) throughout central and southern Africa, some inhabiting the plains, others selecting the mountains. The species of the present order which are most remark THESE animals are distinguished by their fish-like form, their flat horizontal tail, and by the anterior extremities being in the form of fins. They were divided by Cuvier into two families-those that live on vegetable, and those that live on animal food. The latter group is divided into |