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 olecrenon processes peint 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 suddeniy projected fyorm 
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- 
inents of the lower portion of the body, reseinbling very much 
the movements of a shrimp propelling itself by its tail. We 
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 deseribed 
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 threading 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 
