328 SYSTEMATIC ZOOLOGY. 



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large species occur, some weighing 100 pounds or more. 

 Many more species occur in the tropics of Africa and 

 America, and some of these have the scales greatly devel- 

 oped so that they form a bony armor. One African 

 species, like the electrical eel and the torpedo, can give a 

 sharp electrical shock. 



The carp and minnows abound in fresh water, but, 

 excepting as they furnish food for other fishes, they are 

 of little importance; the carp of Europe having a slight 

 value as food for man. The goldfishes of Chinese origin 

 also belong here. 



Much more valuable is the group of trout and salmon, 

 which are among the most important of food-fishes. As a 

 rule these have a soft fin behind the rayed dorsal. The 

 salmon, of which there are one species on the Atlantic 



FIG. 127. Atlantic salmon (Salmo solar}. After Goode. 



(fig. 127) and four on the Pacific coast, live in the sea 

 and enter the rivers to lay their eggs. The whitefish of 

 the lakes are closely allied forms. 



The blindfish of Mammoth Cave should be mentioned 

 here. In this form a life in total darkness has resulted in 

 the degeneration of the eyes, which are buried beneath the 

 skin. 



The savage, swift-swimming pike, pickerel, and muska- 

 longe, the latter reaching a length of eight feet, are, with 

 one exception, confined to America. They are noted for 



