154 



American Fisheries Society 



In filling, the common run of gravel from two inches down is 

 used, the larger rock serving to bear the superimposed weight, 

 while the smaller holds the eggs in place. Much sand in the 

 gravel is not desirable and large or small rock alone is not satis- 

 factory; with one the interstices are too great, while the other 

 works into the consistency of soup. Some of the larger sized gravel 

 should be placed under the partition to provide free passage for 

 the water, and two inches of the mixture on the remainder of the 

 bottom. Some soft eggs, at the rate of one part of eggs to ten of 

 gravel, are then gently and evenly distributed by hand and 

 sprinkled with water to settle them into the crevices, and gravel 

 and eggs added alternately until the box is full to within two inches 

 of the top of the lower side. The remainder of the lower side 

 should be filled with the mixture, and the upper side with fine 

 gravel to within two inches of the top. This fine gravel acts as a 

 filter and excludes debris. 



Fry Hatching Container (A. Robertson). 



