Page:Natural History (1848).djvu/134

124 In their aquatic habits, their fishlike form, their smooth bodies, gradually tapering and terminating in a broad horizontal fin, their total want of posterior limbs, and the contraction of the anterior into flippers or swimming paws, the resemblance to the last named animals is very manifest. But the resemblance is almost confined to external characters; the whole internal structure, as Professor Owen has shewn, differing very widely from that of the carnivorous Cetacea; so that, to use the words of this. eminent physiologist, ‘‘ the amount of variation is as great as well could be in animals of the same class, existing in the same great deep. The junction of the Dugongs and the Manatees with the true Whales cannot therefore be admitted in a distribution of animals according to their organization. With much superficial resemblance, they have little real or organic resemblance to the Walrus, [with which they were associated by Linnzeus,] which exhibits an extreme modification of the amphibous carnivorous type. I conclude, therefore, that the Dugong and its congeners must either form a group apart, or be joined, as in the classification of M. de Blainville, with the Pachyderms, with which they have the nearest affinities, and to which they seem to have been more immediately linked by the now lost genus Dinotherium."

The food of the Manatidæ consists of sea-weeds, the grass of rivers, and other aquatic herbage: for the digestion of which they are furnished with a stomach divided into several sacs. They have no canine teeth: the molars are compound or semi-compound, with plain or furrowed crowns: the genus Rytina has no molars, but their place is