4 CHARACTERS OF PINNIPEDIA. 



processes swollen, but not salient, and without distinct alisphe- 

 noid canals. Anterior limbs smaller than the posterior, the first 

 digit little, if any, longer than the next succeeding ones, all 

 armed with strong claws, which are terminal. Hind feet ca- 

 pable of moderate expansion, short ; digits (usually) all armed 

 with strong claws, and without terminal cartilaginous flaps. 

 Femur with no trace of the trochanter minor.. .REPTIGRADA.* 

 III. Without external ears. Postorbital processes wanting, or very 

 small. Incisors variable (f, f , or f ). Deciduous dentition not 

 persistent beyond foetal life .. PhotidcB. 



The Pinnipeds present a high degree of cerebral develop- 

 ment, and are easily domesticated under favorable conditions. 

 They manifest strong social and parental affection, and defend 

 their young with great persistency and courage. They are car- 

 nivorous (almost without exception), subsisting upon fishes, 

 mollusks, and crustaceans, of which they consume enormous 

 quantities. The Walruses and Eared Seals are polygamous, 

 and the males greatly exceed the females in size. The ordinary 

 or Earless Seals are commonly supposed to be monogamous, and 

 there is generally little difference in the size of the sexes. The 

 Walruses and Eared Seals usually resort in large numbers to 

 certain favorite breeding grounds, and during the season of re- 

 production leave the water, and pass a considerable period upon 

 land. The Earless Seals, on the other hand, with the exception 

 of the Sea Elephants, do not so uniformly resort to particular 

 breeding grounds on land, and leave the water only for very 

 short intervals. They usually bring forth their young on the 

 ice, most of the species being confined to the colder latitudes. 

 Only one of the various species of the Pinnipedia appears to 

 be strictly tropical, and very few of them range into tropical 

 waters. As a group, the Pinnipeds are distinctively character- 

 istic of the Arctic, Antarctic, and Temperate portions of the 

 globe, several of the genera being strictly Arctic or Subarctic 

 in their distribution. The Walruses are at present confined 

 mainly within the Arctic Circle, and have no representatives 

 south of the colder portions of the Northern Hemisphere. The 

 OtariidcB and PJiocidce, on the other hand, are abundantly 

 represented on both sides of the equator, as will be noticed 

 more in detail later. 



* For the suggestion of the terms Grcssigrada and Eeptigrada I am indebted 

 to my friend Dr. Elliott Coues. 



