250 



THE SEALS. 



Eskimo and the Europeans. The animal 

 attains a length of only 6y% feet at most. In 

 early years it is of a uniform gray colour, 

 somewhat darker on the back. Gradually the 

 dark colour increases, and in adult animals it 

 forms on the back two large patches resemb- 

 ing a saddle. The second digit of the fore- 

 flipper is longer than the others. Ice-fields 

 are the favourite resort of this species. 



The species of the Caspian Sea, the Sea of 

 Aral, and Lake Baikal all belong to this group. 



THE WALRUS OR MORSE 



(TRICHECHUS ROSMARUS-PL. XV.). 



This enormous creature, which attains a 

 length of from 20 to 23 feet and a weight 

 of 3300 Ibs., forms a family by itself. It 



Fig. 130. Tl 



land Seal (Phoctigr&jilandica). page 249. 



inhabits the ice-covered waters of the Arctic 

 Ocean. The thick and unshapely body is 

 very massive behind, the neck relatively thin, 

 the head small. The tail is rudimentary, the 

 thick lips set with stiff whiskers, each hair 

 of the thickness of a raven's quill. The 

 nostrils are situated on the highest part of 

 the blunt muzzle. The eyes are small. 

 The thick loose skin has a smooth covering 

 of bristly hair, which in the young animal is 

 brown, in adults yellowish, and in old animals 

 is disfigured by numerous scars and naked 

 patches. The end of the snout and the soles 

 of the feet are naked. 



The dentition is different from that of all 

 other seals. In the upper jaw are to be seen 

 two straight massive tusks, obliquely cut 

 away on the outer surface. These project 

 far beyond the lips and may attain a length 



of 2 feet and a weight of 17 or 18 Ibs. The 

 incisors are altogether wanting, both in the 

 upper and lower jaw. The flat molars, with 

 crowns blunted by use and single roots, are 

 set so far within the mouth that they lie 

 partly between the canines, along the border 

 of the palate, which is hollowed out so as to 

 form a groove. The number of these molars 

 may be as low as three in each half of the 

 jaw. In the female the canines are much less 

 developed. In those cases in which the den- 

 tition is reduced to the very lowest there are 

 in each half of the jaw only three or four 

 teeth, the first of which, considered to be a 

 premolar, gets worn away on both sides, while 

 the other three, which would thus be regarded 

 as true molars, get worn away obliquely. The 

 milk dentition is more in accordance with the 

 carnivorous type. It exhibits three incisors 



