I9II] 



A. Franklin Shull 



185 



TABLE 8. 



Showing the numher of male- and female-producers in the progeny of two 

 sister individuals of Hydatina senta,one line being bred in spring water, the other 

 in a Solution of urea. A and B are separate experiments. 



the three salts seemed to make a repetition of the experiment with 

 any one of them unnecessary. 



Experiment 2^. Ammonium hydroxid. On July 6, 1910, 

 a female from the same pure line as those of the preceding experi- 

 ment was placed in a Solution of ammonium hydroxid, made by 

 diluting strong NH4OH to 5000 times its volume with Great Bear 

 spring water. Its progeny for thirteen generations were bred in 



