with air when the nostrils are closed. The marks of distinction between the true seals (Phocidæ) and the sea-lions (Otariidæ) are very clear. The most obvious mark is the, ears: the true seals have no external ear; the sea-lions have ears that can be seen very plainly.
Hence is derived the scientific name of the family, which 
Fig. 3.—The Hooded Seal (Stemmatopus cristatus). signifies having ears, or eared. The whole external appearance and the structure of their limbs are also different. The true seal has hardly any neck; his head and trunk, closely connected, are short, while his loins are of full length; his body is so round that his little hands can hardly touch the ground; the hands themselves are closely bound up with the body, so that hardly more than from the wrist out is free; and the hind-feet, connected with the tail, are stretched out backward. The confinement of his limbs unfits him for movement on the land, and his progress is nothing more than a series of awkward bumps and wriggles, in which the body is never raised from the ground. His situation is very different in the water, where he can use his toes like the blades of a screw-propeller, work his body to the right or left, up or down, at pleasure, rise to the surface or dive to the bottom, and, his hands furnishing him an excellent system of steerage, direct his movements with admirable precision.
The sea-lion, having a head with pointed ears, "looking like the head of a dog with his ears cut off," large eyes, whiskers, a long neck, and a body raised upon its hind and fore limbs several inches from the ground, appears upon the land more like a land animal, while it is fully as much at home in the water as the seal. It is much more at home on the land, where its whole body is singularly lithe and flexible, and it can run nearly as fast as a man can, and get along better in a thick bush, can climb rocky ledges and steep, slippery banks. Both in water and on land it assumes a great variety of attitudes. Dr. Murie, describing its motions, says: "At one moment the entire body presents a long, cylindrical, tapering cone; in another the body seems foreshortened, and the head and neck thrust out turtle-fashion, to a length as astonishing as unexpected to any visitor who may chance to be near; at other times the chest and abdomen become deep, and laterally flattened, while the back is arched like that of a defiant cat. And so, waking and sleeping, walking or swimming, there is a ceaseless change of relation in the figure and proportion of the parts. This
