Seals and Walruses. 101 



The large-headed sperm whales are often as much 

 as sixty to eighty feet long. One third of the whole 

 length is formed by the head, whose anterior bones, 

 enormously dilated, are hollowed into a chamber" 

 which contains the substance called spermaceti, used 

 in making ointments and cosmetics. These whales 

 possess from fifty to sixty large conical teeth in the 

 lower jaw, and therein differ from the baleen whales, 

 which in some cases possess small embryonic teeth 

 that disappear early and are replaced by the whale- 

 bone plates. The common porpoises, bottle-noses, 

 and dolphins have numerous simple teeth in both 

 jaws, and the narwhal has one enormous front tooth 

 which sometimes grows to a length of 5^ or 6 feet, 

 forming a horizontal tusk. Whales are the largest of 

 animals, and have been seen over ninety feet in 

 length. 



62. Order 8, Pinnipedia. This small order con- 

 sists of the seals and walruses, and forms a connecting 

 link between the whales on the one hand and the bears 

 on the other. They are aquatic, fish-eating, hair-clad 

 mammals, with four fin-like limbs, each provided with 

 five webbed digits. The hind-limbs are stretched 

 horizontally backwards on the same line as the tail, 

 to which they are very closely united. They have 

 roundish heads provided with numerous sensitive 

 bristles, large eyes, and loosely united facial bones. 

 They have valvular nostrils, no external ears, simple 

 stomachs, and large venous cavities to hold the 

 impure blood while respiration is suspended during 

 diving. 



Most seals are marine, but some live in fresh- 



