32 DOMESTICATED TROUT. 



Fig. I is a spawning box, with a portion of the side removed. 



Fig. i. 

 A is a double row of coarse wire screens; B apron of fine wire cloth; D a 

 screen ; F a screen. 



Roller Spawning Box. 



For taking the naturally impregnated eggs of Brook Trout, Salmon, 

 etc. (Patent of A. S. Collins.) 



In the Roller Spawning Box the principle used is that of the 

 Ainsworth Screens, and the improvement consists in a new and 

 convenient method of collecting the eggs. A double row of 

 coarse wire screens (three meshes to the inch), eight in number, 

 each two feet square, are put together in one frame, eight feet by 

 four. These screens are to be filled with coarse gravel, and the 

 eggs pass through as in Ainsworth's Screens. Under these 

 is an endless apron of fine wire-cloth, passing over rollers at the 

 two ends of the box. This apron is about one inch beneath the 

 upper screen, and is kept from sagging by small cross-bars, 

 corresponding to the division of the upper screen. 



These cross-bars are supported by, and, when the rollers are 

 turned, slide on, an inch-square strip nailed to the side of the 

 box. A similar strip, one inch above, supports the larger screens. 



