Bui.. U. S. B. F., 1908. 



Plate CXLVII. 



^■■'^A 



Artilicial ^pa\vllillJ; jh 



crway, used ill cuUvirc of raiiiliow trout at the Wytheville (Virginia) station. 



Iiitciiur ut" a typical tiuvil lialulu 



