THE MAMMALS 



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fin-like flippers fitted for swimming, and the hind limbs 

 are flattened and directed backward. Most of the pinni- 

 peds are inhabitants of the colder parts of the ocean. 

 The seals especially are much sought after for their fur 

 and they have consequently decreased considerably in 

 numbers, so that it has been found necessary to protect 

 their breeding places by law. 



The most exclusively aquatic of the mammals are the 

 Cetacea which include the whales, dolphins, porpoises 



PIG. 178. Habitat group of Steller's sea lions showing large male, 

 females and young. (Prom a group in the museum of the California 

 Academy of Sciences.) 



and their allies. The whales are by far the largest 

 of the mammals, the largest whale, the sulphur bottom 

 of the Pacific Ocean, reaching a length of ninety-five 

 feet and a weight of two hundred and ninety-four 

 thousand pounds. The general form of a whale is 

 more or less like that of a fish; the fore legs are modified 

 into flattened flippers and the tail is expanded, but it 

 differs from the tail of a fish in being flattened horizontally 

 instead of vertically. The hind limbs of whales have al- 

 most disappeared, being represented by minute rudiments 



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