1 68 THE HAUNTS OF LIFE 



like many other animals, probably die after the 

 eggs are safely deposited, for none of them 

 ever reappear at the coasts or in the rivers 

 after spawning. 



There are only a few species of eel which 

 enter fresh water ; the great majority of the 

 family spend their whole lives in the sea, many 

 of them in deep water. Moreover, some in- 

 dividuals, even of the common eel, do not enter 

 the rivers, but probably remain about the 

 estuaries till it is time to return to deeper 

 water. 



On the other hand, some yellow eels do not 

 return to the sea. They may have settled down 

 in ponds which they found it easy to reach 

 when they were little elvers, but difficult to 

 escape from later, or they may lack the impulse 

 to migrate. Such eels may live a long time 

 and grow to a great size, but they never 

 produce eggs. 



All these facts justify the conclusion that the 

 common eel is descended from ancestors which 

 were entirely sea-fish, and that it has taken to 

 a fresh-water life. Whether it will go farther 

 in the same direction, we have no means of 

 knowing. 



We have followed this story at some length, 



