Life Cycle of Hydatma Senta 



ZZ3 



The starved lines show a decidedly lower percentage of male- 

 producers in the drainage water, but in the well-fed lines there is 

 practically no difference. It is not clear whether this disagree- 

 ment is due to chance, and indicates that the drainage water has 

 no effect; or whether the more distant relationship of the parents 

 of the well fed lines is responsible for the failure to show different 

 percentages in these lines. 



Experiment IX. The influence of substances found in the 

 food cultures, as distinguished from the flagellate used as food, 

 was tested as follows: An old culture, which had been made up 

 with spring water, and which had been rejected about ten days 

 before, was filtered through a Berkefeld filter. The filtrate was 



TABLE X 



Showing the number of male- and female-producers in the progeny of five sister individuals ofHydatina senta, 

 one line being reared in spring water, the others, in various concentrations of the filtrate from old food 

 cultures. 



THE JOURNAL OF FXPEEIMENTAL ZOOLOGY, VOL. 8, NO. 3. 



