PONDS. 31 



till she has deposited all her ova, which sometimes takes two 

 weeks. 



There may be from twenty to fifty trout in the race spawn- 

 ing at one time, and all, or nearly all, of the spawn will be found 

 perfectly impregnated and fully matured, so that they will all 

 hatch, if taken out every three days, or once a week, and placed 

 in hatching boxes. 



To take the spawn from the lower screens, first take out two 

 of the upper screens with what gravel is upon them ; then re- 

 move the lower ones, and wash the spawn off into a large pan 

 of water carefully, and replace one set behind you, and then 

 take up one set at a time and place back, until all are returned. 

 Should any spawn remain in the gravel, by raising the screen up 

 and down a few times they will drop down through the inter- 

 stices. The race must be kept well covered during the time of 

 spawning, all persons must be kept away, and the fish disturbed 

 as little as possible. 



By this method the spawn are all saved, are perfectly ma- 

 tured, are all impregnated, and will all hatch ; the young will be 

 perfect, few or none will die, as their sac food is complete, and 

 they will be strong and healthy when they commence seeking 

 food for themselves. It is much less work to take the spawn 

 than by handling, and no parent trout are lost. 



The spawning race above described answered its 

 purpose perfectly in making the fish spawn naturally, 

 and also lessened trie work of getting the eggs. 



The tending of the races, nevertheless, required 

 considerable labor and exposure. This latter objec- 

 tion was ingeniously surmounted by Mr. A. S. Collins,' 

 the partner of Seth Green, in a modification of the 

 Ainsworth Races, known by the name of the Roller 

 Spawning Box. 



I give a description below, written by the inventor. 



