CHAPTER XIV 



CAKNIVOEA {continued) PINNIPEDIA (SEALS AND WALRUSES) 



CKEODONTA 



SuB-UuDER 2. PINNIPEDIA 



This group includes the Seals, Sea -Lions, and Walruses,^ all 

 aquatic and, for the larger part, marine creatures. Being aquatic 

 they have to some extent acquired a fish-like form, though not 

 so completely as have the Whales and even the Sirenia. This 

 is most complete so far as the group is concerned in the Seals, 

 where the hind-limbs have become soldered to the tail and are 

 inefficient as walking legs, where the external ears have vanished, 

 and where the general shape of the body is tapering and thus 

 iish-like. The Walruses and Sea-Lions are less modified in this 

 direction ; in the latter (not in the former) the external ear, 

 though small, is persistent, and the hind-limbs are capable of 

 being used as organs of progression upon dry land. The general 

 characters applicable to the Carnivora, given upon a previous 

 page, apply to the Pinnipedia. 



The characters confined to the Pinnipedia as a whole are 

 mainly these : — The greater part of the limbs are enclosed 

 within the skin, the hands and feet are fully \yebbed, and 

 there is a tendency for the nails to disappear, and for the 

 phalanges to increase in number — characters which are clearly 

 not diagnostic of the order but correlated with an aquatic 

 life, since they reappear, and are indeed exaggerated, in the 

 Cetacea. The teeth are peculiar in that the milk dentition is 

 feeble and is early shed. This, as it were, undue emphasis upon 

 one of the two sets of teeth is another likeness to the Wliales, 



" For tile genera of rinnipedia see Mivart, Proc. Zool. Soc. 1885, p. 484. 



