The Seal family forms a still nearer approach to the land quadrupeds, as here hind feet begin to make their appearance. The shortness of these extremities renders their movements upon land generally awkward and slow, but they make up for this deficiency by an uncommon activity in the water. Their body, tapering fish-like from the shoulders to the tail, their abundance of fat, the lightness of which is so favourable to swimming, the position of their feet, admirably formed for rowing, paddling, and steering, their whole economy, in a word, is calculated for the sea. Although citizens of two worlds, their real element is evidently the water, from which their food is exclusively derived. [Illustration: Female Dugong of Ceylon. (From Sir J. Emerson Tennent's Work on Ceylon.)] [Illustration: Skeleton of Seal.] Seals are found in almost all seas, but they particularly abound on the coasts of the colder regions of the earth, and diminish in size and numbers as they approach the torrid zone. Small seals are found near Surinam, but the giants of the family, the huge, sea-elephant, the sea-lion, the sea-bear, belong exclusively to those higher latitudes which the sun visits only with slanting rays, or where the winter forms a dreary and continuous night. [Illustration: The Seal.] How wonderful to see the desolate coasts of the icy seas peopled by such herds of great warm-blooded mammalia! But there, where the dry land produces only the scantiest vegetation, the bountiful sea teems with fishes, affording abundance to the hungry seals. The _Merlangus polaris_ and the _Ophidium Parryii_ in the northern hemisphere, as well as the _Nothothenia phocæ_, which Dr. Richardson discovered off Kerguelen's Land, seek in vain to escape from the pursuit of the seals in the hollows and crevices of the pack-ice; and these small fish, in turn, fare sumptuously upon the minute crustaceans and molluscs with which those cold waters abound. Thus animal life, but sparingly diffused over the barren land, luxuriates in the sea, where we find one species preying upon the other, until at last, at the bottom of the scale, we come to creatures so small as to be invisible to the naked eye. [Illustration: Esquimaux in his Kayak.]