ISO 



HIGH SCHOOL ZOOLOGY. 



Walrus, etc., towards the reduction in number of the incisor 

 teeth j the canines are rarely tusk-like, and the extrenaities are 

 converted into flijjpers, the hinder ones being turned backwards 

 parallel with the short tail (Fig. UG). The seals proper are those 



J CO «: l^-^J 



Fig. 116.— Skeleton of Seal, 

 vc. cervical, vd. dorsal, vl. lumbar, s. sacral, vca. caudal regions of vertebral column • 

 h. humerus; r. radius; c. carpus ; me. metacarpus; ph. phalanges; sc. scapula ; co' 

 ribs. 



which are least adapted for locomotion on land ; the walruses and 

 sea-lions, on the other hand, can raise themselves off the ground 

 by the aid of their limbs, and the flippers of the sea-lions even 

 have divisions, corresponding to the toes. As a rule there is 

 no external ear, the head is rounded, and the cylindrical body 

 diminishes in girth towards the tail. 



Of the three families distinguished, that containing the eared-seals 

 (Otaria;), is nearest such Carnivora as the sea-otter, the structure of 

 the flippers and their habits suggesting a less perfect adaptation to an 

 aquatic life than we meet with in the seals proper. In most of the 

 species the coat is formed of stiff, bristly hairs alone, but in several, 

 such as the Alaska inr-seals (Calloi-hi7ms ursina), the bristles are scarcer, 

 and there is a thick, soft under- wool. These skius, when dried and the 

 bristles removed, yield the valuable seal-skin furs, bnt the skin of the 

 seal is also sought after for other purposes, and the blubber of all the 

 species yields a valuable oil. Some of the Otarise, such as the California 

 sea-lion {Euinetopias Sttlkri), reach the large size of fifteen feet. The 

 other species are smaller. 



