250 I5ULLETIX OF THE UNITED STATES FISH COMMISSION. 



the "collector," into which the fish are dravrn by the lowering of the 

 water in the pond, and c a valve which controls the flow of the water 



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Fig. 1. — A carp pond built in a meadow. 

 through the discharge pipe m. I) is a wide, shallow drain, having 

 branches, d d d d, by means of which all of the water is led into the 



