PINNIPEDS. 207 



PINNIPEDS. 



The Seals and Walruses are the only Pinniped or fin- 

 footed Carnivores. Their entire organization is adapted 

 for an aquatic life. Both the fore and hind limbs are 

 modified into paddle or flipper-like organs; the upper 

 parts of which are enclosed with the same integument as 

 the body, while the elongated feet or flippers are cov- 

 ered with a skin resembling india rubber. The feet have 

 great power of expansion and the five toes are completely 

 connected with web. The first and fifth toes on the hind 

 feet are stouter and longer than the three middle toes; 

 and the skin covering on all the feet terminates in large 

 lobes projecting beyond the extremity of the bones, and 

 is thick and ribbed on the exposed parts, to "prevent it 

 from being injured by abrasions, when brought into vio- 

 lent contact with the rocks or ice. These animals all have 

 very short tails, and are further characterized by the 

 absence of rudimentarj^ collar bones and the presence of 

 large protruding eyes by which they are enabled to 

 secure accuracy of vision under the water. 



Seals are the only pinnipeds that come within the scope 

 of this work, as the Walruses can hardly be considered 

 as fur-bearing animals. Seals have either thirty-four or 

 thirty-six teeth, but none of them show the flesh tooth, 

 always found in the jaw of the fissiped or true Carni- 

 vores. The number of incisors is invariably reduced 

 below the typical pairs in each jaw, some Seals having 

 only two pairs in each jaw, and none having more than 

 three pairs in the upper, and two pairs in the lower jaw. 

 They all have five cheek teeth in each jaw, the first four of 

 which belong to the pre-molar system. A marked pecul- 

 iarity of the teeth, is a groove in the upper incisors, into 

 which the sharp lower incisors fit so as to form a vice 

 from which it is impossible for a fish to escape. The milk 

 teeth are of no real use to these animals, and are fre- 

 quently shed by them before birth. 



