236 PINNIPEDIA. 



body on either side of the short tail, the soles of the 

 feet being opposed, and their dorsal surfaces conse- 

 quently turned outward. The result of this structure 

 on the motions of the animal are very striking. On dry 

 land, a Seal usually makes no use whatever of its limbs ; 

 resting on its belly, it throws itself forward by the 

 action of the pectoral and abdominal muscles in a series 

 of most ludicrous spasmodic plunges or bounds, but as 

 will be seen hereafter, the fore-feet are sometimes called 

 into play by some species to drag the body forward. In 

 the water the hind limbs only are used as propellers, the 

 flippers being only used to balance the body or to change 

 its position ; as Prof. Huxley remarks, " the fore limbs 

 are applied against the sides of the thorax, and the 

 hinder moiety of the body being very flexible, the con- 

 joined hind limbs and tail are put to the same use as the 

 caudal fin of a cetacean." For a more detailed account of 

 the motions of Seals on land and in the water, we may 

 refer our readers to a paper on the mechanism of flight 

 and swimming, by Dr. J. B. Pettigrew, in Vol. XXVI. 

 of the " Transactions of the Linnaean Society," and to 

 one on Ph. grcenlandica, by our friend Dr. Murie, in the 

 Zoological Society's " Proceedings " for 1870. 



The second family (Trichechidae) of the sub-order 

 consists, as far as is known, of a single genus and 

 species, distinguished by the enormous developement of 

 the canine teeth in the adult. The Walrus is a native of 

 the Arctic regions, and only visits our coasts as an acci- 

 dental straggler. In many respects it may be regarded 

 as intermediate between the Phocidce and Otarid&y par- 

 ticularly in its quadrupedal gait and in its manner of 

 swimming, but these and other points in its history will 

 be considered hereafter. 



The third family (Otaridce) is distinguished by the 



