THE TRUE FISHES. 





dence on this point is wholly circumstantial, but it is nevertheless conclu- 

 sive. When eels are placed in land-locked ponds, they grow large, but tb 

 numbers never increase. This, of course, points to the conclusion that all 

 the eels of fresh waters must have been born in the sea, and it farther 

 explains the fact that until the completion of the Wellancl Canal no • 

 were found in the great lakes above Niagara Falls. Tin; young in their 



Fig. 296. — Common eels (Anguilla vulgaris). 



upward migrations reach this harrier, but cannot pass it. Says 

 s! F. Baird: "In the spring and summer the visitor who enters nnd 

 sheet of water at the foot of the falls will he astonished at I «i 



numbers of young eels crawling over the slippery rocks, and 

 the seething whirlpools. An estimate of hundreds of *agon-loa< 

 in the course of the perilous journey referred to, would hardly 



