i8o 



Life Cycle of Hydatina Senta 



[Dec. 



An experiment was started, in which the alcohol-soliible portion 

 of the maniire Solution was obtained in a manner similar to the 

 ether-extraction described. The portion soluble in absolute alcohol 

 was smaller than that soluble in ether. The experiment was dis- 

 continued in the middle of the second generation, hence the de- 

 tailed results are not of value. It may be said, however, that 



TABLE 4. 



Shozving the niimber of male- and fcviale-producers in the progeny of three 

 sister individuals of Hydatina senta, one line being bred in a Solution of the ether- 

 soluble pari of an old food culture, a second line in the part insoluble in ether, 

 the third in spring water. 



the first family reared in the alcohol-soluble portion contained a 

 considerable number of male-producers. 



Experiment 22. Decolorized filtrate. It was noticed in 

 the preceding experiments of this section that those residues which 

 produced the same effect as the unaltered manure Solution were 

 brown like the original; those that had no effect were colorless. 

 To determine whether the substance producing the brown color 

 has any effect on the life cycle of the rotifers, a portion of the 

 filtrate from old food culture was decolorized with animal char- 

 coal. An excess of the charcoal was added to the filtrate, and the 

 mixture boiled eight or ten minutes. It was then filtered through 

 paper, and the volume of water lost by evaporation was restored, 

 the added water being passed through the filter. More charcoal 

 was added to the filtrate, and the boiling repeated. After three or 

 four boilings the filtrate was practically colorless. It was not to 

 be expected that the colored substance was the only one removed 

 by this process for animal charcoal probably carries down most 



