22 DOMESTICATED TROUT. 



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



Fig. 



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 takin, 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 

 Ainslrth Screens, and the improvement conststs - new and 

 convenient method of collecting the eggs. A double row ol 

 coa s" i- screens (three meshes to the inch), -£'« .>" ™-^!'; 

 each wo feet square, are put together in one frame, e.g^' f«' ^J 

 ■fot . These screens are to be filled with coarse g--'' -f f^ 

 eggs pass through as in Ainsworth's Screens. ""^ 'te e 

 kL endless apron of fine wire-cloth, passmg over rollers at he 

 To ends of th 'box. This apron is about one i-h beneath e 

 upper screen, and is kept fiom saggtng by small cross-bars, 

 rorresponding to the division of the upper screen. 



Trercrostbars are supported by, and, when the rollers ar 

 turned slide on, an inch-square strip naded to the s,de of the 

 box. A imilar trip, one inch above, supports the larger screens. 



