This interesting animal differs in many important respects from the Common Otter, and in all such points shows an approximation to the structure of the Seals. It is a large animal, about three feet long, not counting the tail, which is about a foot more. Its fur is dark brown, both on the upper and lower surfaces, and presents a frosted or silvered appearance, owing to the fact that the long stiff hairs, which differ greatly from those of the under-fur, are grey or colourless at the tip. The head is very short, the snout naked; the eyes extremely small, and placed low down on the sides of the head, and the whiskers are short, but stout and stiff, and mostly directed downwards; altogether there is something very Seal-like about the face. The fore-limbs and feet are small, the paws rather Cat-like in their rounded form, and the claws are quite hidden by the hair. The hind feet, on the other hand, are flat and expanded, being no less than six inches long by four broad, and webbed like a Duck’s feet, or a Seal’s flippers; they differ, however, from the Seal’s, in the fact that the toes increase in length from the inner to the outer side; both above and below they are covered with dense fur, which quite hides the short, stout claws. The skull is, both in its cranial and facial portions, much shorter in comparison with its width than in the ordinary Otters; its base is extremely broad, and both upper and lower jaws bear on each side only eight teeth, so that there are altogether thirty-two teeth, or four less than in the Common Otter.[193] This diminution in number is brought about, as will be seen from the formula below, by reducing the upper premolars from four to three, and the lower incisors from three to two on each side. The form of the grinders differs altogether from what we have found, not only in the Mustelidæ, but in all the Land Carnivores. Their grinding surfaces present no sharp cusps, or jagged cutting edges, as in most Carnivorous forms; neither are they provided with numerous small tubercles and ridges, as in the Bears; but the surface of each is raised into a small number of rounded eminences, reminding one of the “roches moutonnées” of a glacial district, or, as Dr. Coues remarks, differing from the teeth of ordinary Carnivores, as water-worn pebbles differ from fresh-chipped angular pieces of rock. [Illustration: UNDER VIEW OF SKULL OF SEA OTTER. (_After Coues._)] The Sea Otter is found in the North Pacific, chiefly in the regions of Kamstchatka and Alaska, and extends as far south as California.