322 



GENERAL ZOOLOGY 



coast, which grows to be about two feet in length. The 

 most famous of the rays are the torpedoes, so called from 



Fig. 163. Photograph of a shark 

 American Museum of Natural History 



their power of giving an electric shock. One species is 

 sometimes' found on the eastern coast of the United States. 



Economic Importance 

 of Sharks. In some 

 lands, sharks, and es- 

 pecially their fins, are 

 considered a delicacy. 

 Some species are used 

 in producing leather 

 for the manufacture 

 of novelties. The sha- 

 green, used in the arts 

 for polishing woods 

 and for ornamental 

 work, is made from 

 the skin of sharks. 

 Their livers produce 

 oils, and the bodies are fig. 164. Photograph of a skate 



used in the manufac- 

 ture of fertilizer. But these uses do not offset the damage 

 with which the sharks are charged. They destroy great 



