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122 ance is frequently rough and coarse, thinly clothed with bristly hairs, or almost entirely naked.

The food of these animals is exclusively vegetable: various grasses and aquatic herbage; the thick and succulent plants of tropical plains; bulbous and farinaceous roots; and the young twigs of trees, afford them variety of nutrition. The stomach, however, is either simple, or, where compound, is not capable of the process of rumination. The molar teeth are compound, often triple, with flattened crowns: in many, there is a peculiar development of the canines or incisors into curved and projecting tusks. The muzzle is frequently produced into a projecting proboscis, as in the Elephants, Tapirs, and in a less degree in the Hogs; or into a lengthened and flexible upper lip, as in most of the Rhinoceri.

Being destitute of clavicles, the fore limbs of the terrestrial Pachydermata have not the freedom and mobility necessary to constitute them organs of climbing, or of seizing and holding prey, or of dealing and warding blows in conflict. ‘The limbs are simply organs of motion, and of support; hence they assume the form of pillars, more or less perpendicular; and their extremities, though divided as to the skeleton into distinct toes, are so encased in the common integuments as to be undivided externally, except that the last joints of the toes are encased in hollow, box-like hoofs. In the first family, the link which connects the present Order with the preceding, the hind limbs are wanting, and the fore limbs resemble the swimming paws of the Whales; the extremities of the toes, however, being marked by small horny claws.

The torrid zone, and those regions which are