160 NOTES ON THE ANATOMY OF A SEAL — SOMMERS. 



cular development of these organs, along with the strength of 

 the claws, renders them adaptable for climbing. The seal raises 

 its own weight out of the water by means of its fore limbs ; it 

 uses them also, when on land, as a means of progression. While 

 moving in the water they are at rest, held tightly against the- 

 body ; upon the ice or solid surface the palmar surfaces of the- 

 anterior flippers are underneath. The tips of the fingers approach 

 from side to side, and the olecranon processes point outward. 

 The posterior limbs under like conditions are not brought into 

 use, they trail out behind, their edges resting upon the support. 

 They may be said to be practically useless as organs of locomo- 

 tion on land, but their shape and structure eminently fits them 

 for swimming. They present broad, flattened surfaces to the- 

 water, the regular contraction of the extensor muscles of the leg- 

 and foot causes the latter to flatten and spread ; by contraction 

 and relaxation of the hip and thigh muscles the thighs are- 

 drawn towards the abdomen and then suddenly projected from 

 it ; the broad feet striking the water, drives the animal's body- 

 forward by a succession of jumps. The seal moving in the 

 water does not swim smoothly like a fish ; on the contrary, the- 

 propulsion is due to successive arching and straightening move- 

 ments of the lower portion of the body resembling very much 

 the movements of a shrimp propelling itself by its tail. Wa 

 must not forget that the hind limbs of the seal are somewhat in 

 the condition of those of a human being, whose legs being en- 

 closed in a bag, with his feet free, the only movement he could 

 accomplish would be that of leaping, by drawing his thighs- 

 towards the abdomen, throwing his body, forward from the soles 

 of his feet. The hummocky motion of the seal on land described 

 by many, is due to their being used in such a way as described 

 above ; but as the soles of their feet cannot be brought upon the 

 ground or ice, the animal rests upon his knees or heels, and 

 attempts to use them as the moving point. The natural condi- 

 tion of the organ renders them facile in treading water, but 

 makes them awkward and inefficient for like purposes on land 

 or ice. 



Of the whole family, the sea lions are the only ones that can 



