ORDER VI. PACHYDERMATA.
( Thick-skinned Animals.)
This Order contains animals, which, while they have certain features in common, warranting their association, present so much diversity in detail, as to lack the apparent unity and completeness which other similar groups possess. By the aid, however, of fossil genera and species, unknown in a living state, many blanks are filled up, and links are supplied, by which the creatures of this Order are arranged in a more regular and complete series. In no other Order of Mammalia have the discoveries of organic remains been so copious and so important as in the present.
The Pachydermata are, for the most part, animals of large size, and many are of gigantic proportions. They are generally also uncouth and clumsy in form, and heavy in their motions. The name, which Cuvier selected to distinguish the Order, describes a peculiarity, most obvious in the great tropical genera, but more or less observed in all, the thickness of their skin. In the Whales we saw the skin greatly thickened, in order to hold in its tissues the blubber or surface-fat: in some of the Pachydermata, as the Hogs and Hippopotamus, there is, in like manner, a tendency to the deposition of a thick layer of fat on the surface of the body, but it is beneath, and not within, the integuments. ‘The skin is usually dense and leathery in its consistence; its external appear-
