38 BOMBAY DUCKS 



have lost not only their sight, but even their eyes. 

 Man's tail became useless to him, so has disappeared. 

 The whale's legs were no longer needed when it took 

 to an aquatic life ; they were, therefore, transformed 

 into fins. 



Thus it is probable that, if the tails of the mouse 

 and the rat served no useful purpose, these animals 

 would long ago have been reduced to the state of the 

 guinea-pig. What, then, is the use of the tail in each 

 case ? This is, indeed, a problem. These creatures, 

 being nocturnal in their habits, do not afford the 

 naturalist many opportunities of watching them. 

 Nevertheless, they move in such a rapid, silent, 

 mysterious way that it is more than possible that the 

 long supple tail assists them during locomotion. 



