igii] 



A. Franklin Shull 



187 



TABLE 10. 



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

 sister individuals of Hydatina senta, one line being bred in dilute ammonium 

 hydroxid Solution, the other in spring water. 



1910, frort! one of the groups in other experiments in progress at 

 that time. One was placed in a Solution of Liebig's beef extract, 

 the other in spring water. The beef extract was dissolved in 

 spring water, and a i per cent. Solution kept in stock. This stock 

 Solution w'as boiled once or twice a day to prevent the growth of 

 bacteria, and in the intervals was set in the cool water of a spring. 

 Loss by evaporation was restored with distilled water. The stock 

 Solution was diluted with Great Bear spring water when ready to 

 be used. In the first experiment, Table 1 1, A, a 0.03 per cent. Solu- 

 tion was used for the first two generations, a 0.04 per cent. Solu- 

 tion thereafter. In B, a female was removed from the line in 

 beef extract in A to spring water, so that here also the strength 

 of the beef extract is 0.04 per cent., the line in the extract being 

 the last part of the corresponding line in A. 



In both experiments the number of male-producers was much 

 smaller in the beef extract than in the spring water. 



