126 THE STORY OF LIFE IN THE SEAS. 



eludes the many genera of Whales, Porpoises 

 and Dolphins. 



The Eight- whales are distinguished by the 

 enormous size of the mouth and the absence of 

 the little triangular fin in the middle of the back 

 which is found in the other Whales. 



These animals have no teeth in the adult 

 condition, but are provided with a series of 

 plates situated at the sides of the mouth which 

 are used as strainers to catch the small Pteropods 

 and other animals living in the water which 

 pass through the great gape. The plates are 

 composed of a substance called "Baleen," the 

 well-known whale-bone of commerce, they are 

 triangular in shape, and frayed out into a 

 brush-like edge on the side that faces the cavity 

 of the mouth. The Greenland Eight-whale at- 

 tains to a size of fifty feet in length when fully 

 grown, and it is usually found in shoals among 

 the ice floes of the far north. 



In former times many Eight- whales belonging 

 to species allied to the Arctic form occurred in 

 the temperate regions of the Atlantic and Paci- 

 fic Oceans, but in consequence of the valuable 

 fishery they afforded they are now becoming 

 very scarce. 



The largest of all the Whales in fact, the 

 largest existing animal is the Blue-whale, which 

 attains to the enormous length of 86 feet. It 

 spends the winter in the open seas, and ap- 

 proaches the coast of Norway in the spring. 



The Whales, like all the animals of the Class 

 to which they belong, are air-breathers. They 

 are able, however, to hold their breath for a 



