TUSKS OP THE WALRUS. 139 



of sand-worms, starfish, shrimps, and the shells Tri- 

 dacnoe and Cardia, vulgarly called clams and cockles. 

 I believe they also eat submarine algae or sea-weeds, 

 and Scoresby mentions having found the remains 

 of young seals in their stomachs ; but I imagine 

 the latter case to be an unusual one, as the seal is 

 a much more active animal in the water than the 

 walrus, and I have never met with any one else who 

 had observed it. 



The tusks of the walrus are not an extra pair of 

 teeth, but simply an enlargement and modification 

 of the eye-teeth, produced, as I believe, by the ne- 

 cessity the animal has for long tusks, in order to 

 obtain his food in the way he does. 



They are very firmly and strongly imbedded, for 

 about six or seven inches of their length, in a mass 

 of very hard and solid bone, forming the front of 

 the animal's head. This bony protuberance is the 

 size of a man's skull, and through it runs the pas- 

 sage by which the animal breathes, the blow-holes 

 lying between the roots of the tusks. The part of 

 the tusks which is imbedded in the head is hollow, 

 but is mostly filled up with a cellular bony sub- 

 stance containing much oil ; the remainder of the 

 tusk is hard and solid throughout. 



The calf has no tusks the first year, but the sec- 

 ond year, when he has attained to about the size 

 of a large seal, he has a pair about as large as the 

 canine teeth of a lion ; the third year they are 

 about six inches long. 



