HATCHING TKOUT 147 



the little fish is enabled to keep more easily his gill- 

 covers open and breathe. In fact the shell, dragging 

 at the edge of the gill-covers, pulls them open and 

 thus gives assistance to a safe delivery. If the little 

 creatures were to emerge head first the shell would 

 most likely press itself against the gill-covers, close 

 them, and either smother the fish or leave it so weak 

 that death would surely follow in a little while. Be 

 this as it may, it is nevertheless a fact that the issuance 

 of a fish in any other manner than tail foremost is 

 indicative of premature or improper hatching, with 

 early death as a result. 



As the fry emerge, they fall through the long 

 meshes in the trays to the bottom of the trough 

 which at this time contains no gravel or sand. 

 They are then gathered daily, or oftener, by 

 means of a feather and scap-net, placed in pans 

 of water and transferred to troughs previously 

 made ready for them, the bottoms of which are 

 covered with fine, well washed gravel. It is 

 important that the gravel be not sharp, but 

 water-worn and smooth, so that the delicate 

 covering of the yolk-sac cannot be injured by 

 the wrigglings of the little fish. When a suf- 

 ficient supply of good gravel is secured, it 

 should be carefully preserved from year to 



