The Life of the Fish 



15 



out nerves of motion and receives nerves of sense. Everything 

 that is done by the fish, inside or outside, receives the attention 

 of the Httle branches of the great nerve-cord. 



The Fish's Nest. — The sunfish in the spawning time will 

 build some sort of a nest of stones on the bottom of the eddy, 

 and then, when the eggs are laid, the male with flashing eye and 

 fins all spread will defend the place with a good deal of spirit. 

 All this we call instinct. He fights as well the first time as 

 the last. The pressure of the eggs suggests nest-building to 

 the female. The presence of the eggs tells the male to defend 

 them. But the facts of the nest-building and nest protection are 

 not very well understood, and any boy who can watch them and 

 describe them truly will be able to add something to science. 



