EELS. 89 



scarcely any have pelagic habits, but many eater or live in fresh 

 waters communicating with the sea. They are spread over all the 

 temperate and tropical seas. The genus of Herrings proper 

 (Clupea) includes more than sixty species, of which several are 

 extremely common on our coasts, viz. the Herring (Clupea harengus) 

 of immense commercial value, the Sprat (C. sprattus), the Shad 

 (C.alosa&nd C.finta), and the Pilchard_or Sardine (C. pilchardus) . 

 The " Mossbanker " (C. menhaden) is common on the Atlantic 

 coasts of the United States. The economic value of this fish is 

 surpassed in America only by that of the Gadoids, and derived 

 chiefly from its use as bait for other fishes, and from the oil 

 extracted from it. Albula and Elops reach a size of three feet, but 

 are not esteemed as food. The largest species of the whole family 

 is the Tarpon (Megalops thrissoides) [a specimen of which is 

 exhibited on the top of the case], from the Tropical Atlantic, 

 exceeding a length of five feet, and excellent eating. 



The Chirocentridce and Notopteridee (Case 22 b) are small families, [Case 

 inhabiting, the former the Indian Ocean, the latter fresh waters of 

 the East Indies and West Africa. 



The Gymnotidce (Case 22 b) are eel-like freshwater fishes from 

 Tropical America, of which the best known is the Electric Eel 

 (Gymnotus electricus, fig. 76) ; it is the most powerful of electric 



Fig. 76. 



Electric Eel (Gynmotus electricus). 



fishes, growing to a length of six feet, and extremely abundant in 

 certain localities of Brazil and the Guianas. The electric organ 



22 6.1 



