THE COMMON SEAL. 135 



and a common quadruped ; the head is like that of a dog ; 

 the arms, which are destitute of collar-bones, are so hid 

 beneath the skin of the body that only the wrists and hands 

 appear, and they are then so short that they can scarcely be 

 advanced forward at all. But what they lose in extent they 

 gain in power. They are admirably adapted for swimming, 

 and serve also for seizing or holding. The fingers have an 

 intervening membrane, but they can be separated so as to 

 diminish or increase the surface of the paws. In all the 

 species, the fingers can be distinguished through the paw, 

 and in most the nails appear at the termination ; but in one 

 group of seals there is this difference, that the membrane or 

 web extends beyond the nails, not joined, but hanging down 

 in the water like broad leathern strips, which the sailors 

 call " flippers." The face is provided with strong whiskers 

 placed on each side of the mouth and at the corner of the 

 eye, communicating with nerves of considerable size, and the 

 slightest impression produces sensation. 



The ground color of the hair or skin of the common seal, 

 when the animal is alive and dry, is a pale whitish-gray, 

 with a very slight tinge of yellow. When just out of the 

 water and wet, the color is ash ; after death, and as seen in 

 museums, the ground color is pale yellowish-gray, the oil 

 having penetrated the skin and rendered the hair of a more 

 yellow hue. The fur of seals is very smooth, and abun- 

 dantly lubricated with an oily secretion. There is generally 

 an inner coating of rich fur, through which grow long hairs, 

 forming an outer covering. Another adaptation to aquatic 

 life and a cold climate is the layer of fat under the skin, 

 from which the oil is obtained, and serving, as in the case 

 of the whale, not only for support when food is scarce, but 

 protection from the cold, besides rendering the whole body 

 lighter. The respiration of the seal differs considerably 

 from what has been observed in most animals : the nostrils 

 are habitually closed, instead of being uniformly opened. 



