FRESH WATER ANIMALS 213 



South America and Africa. The ancient ganoids all live in 

 lakes and rivers except for some large sturgeons and garfish 

 which, however, spawn only in fresh water. All trout and 

 salmon spawn exclusively in streams and ponds, though salmon 

 and some trout live mostly in the sea. The brook trout in the 

 north live in the sea in winter, at least along the coast, but 

 in the south stay always in fresh water, as do the land-locked 

 salmon in the lakes of Maine. The Pacific salmon, lea\'ing 

 the river of their birth when very young, do not return until 

 their full maturity, when they spawn and die. The common 

 eel does the reverse and spawns only in the deep sea southwest 

 of the Bermudas, the American and European eels together. 

 Some fresh water fishes in the tropics also spawn only in the 

 sea, though near the land. 



IMost of the fishes of fresh water are closely related to others 

 in the sea, some very closely, like the sharks and sting-rays 

 found in a few localities about the Caribbean Sea. Some are 

 quite distinctive, but scarcely demand consideration here. 



Of curious fishes we should note the fresh water flying-fishes 

 of Guiana and west Africa, the electric eels of South America 

 and electric cat-fishes of Africa, corresponding to electric skates 

 and other fish at sea. 



The most ferocious of the fresh water fishes are the cannibal 

 fishes of the South American rivers; others are found in Africa. 

 These are not large, but they hunt in packs and have teeth 

 like razors. They are very good to eat. To catch them you 

 first bait your hook, then heave a large rock in the w^ater; 

 the splash attracts them; they think that it is you. Then 

 you throw your line in and if there are any within hearing 

 distance you are soon rewarded. 



Along fresh water shores the conspicuous plants are flowering 

 plants of many types, partially submerged, like pickerel-weed, 

 or floating, like duck-weed, or immersed. There are no "sea- 

 weeds," though there are numerous other sorts of algae, and 

 there are some aquatic ferns and mosses. 



Suspended in the water of the larger deeper ponds and lakes 



