•2i-l FISHES 



of the greatly elongated and enlarged pectoral fins (Fig. 

 158). By means of vigorous, quick strokes of the tail and 

 enlarged tail fin, the fish is able to jump from the water 

 into the air. Then the large pectoral fins are spread and 

 the fish floats on the air somewhat as a man hoyna by a 

 parachute. It is asserted that some of the larger species 



Fig. 158. — Flving fish. 



actually vibrate the pectoral fins, thus producing a real 

 flight capable of prolonged duration. 



The bony fishes, for the most part, have large, conspicuous 

 eyes, without eyelids, but covered with a thin, transparent 

 skin. There are some, however, that live in the caves and 

 underground streams of Illinois, Indiana, Kentuck}', 

 Tennessee, and AlaJ^ama, that have rudimentar}' eyes, — 

 so rudimentary that in two or three species, at least, they 

 are wholly valueless as organs of vision. The l:iodies of 

 these fishes are colorless and translucent. One species 

 lives in the Mammoth Cave of Kentucky. 



The eels are bony fishes with long, cylindrical bodies 

 bearing small inconspicuous scales. The common eel 

 (Fig. 159) is found on both coasts of the Atlantic ami in 

 the rivers, lakes, and streams of the eastern United States, 



