No. 492] 



POL YODON SPA TH ULA 



763 



lakes was found to be "running" although I examined from ten 

 to twenty on almost every day from April 1st until May 13th, 1905. 



A number of males and females were from time to time placed 

 in a large wire-netting ])en, with the object of keeping them until 

 they reached the spawning condition. Some of these lived in the 

 pen for four or hve days but rarely longer, althougli the pen was 

 twenty feet square and rested on the bottom of the lake. The 

 larger ones are especially difficult to keep in conliiieiucnt. The 

 eggs of the confined females soon began to degenerate and sol'ien. 

 like those of the lake-females mentioned above. 



After April 10th, 1905, the Mississippi River began to lise and 

 river-fish were taken in Lake Washington after April 14th; seveivd 

 of these females on dissection w^ere found to have spawned. The 

 ovaries contained only a few defective egus still attacluMl to the 

 membranes of their ventral border. The anal K^gioii \\ ;is inflamed 



made it practically certain that these fishes had dc})<)sitrd (Iump e<rMs 

 inanonnal manner. 1 then coneluded thai the laruv fat lake-fi.^i 

 was unable to .paun in the s,ill u;,ttT.. and thai it. c^u^ u.'iv 



of th(- matmv <mv^ had anpaivntly .pawned M.mr linir hefoiv. 

 Thrx dM„l>dr., .paune.l nr'ar the innmh of thi. Wa\..„ ^^ hi,-h \\a. 

 Mbo.n .ixtx milr. distant, and ^^ith thr ,isin- uat.T thr^ lu-gan to 



depleted of th.-ir .(..ck of Polyodon by .seinhig and are not agJili 



