LIFE CYCLE OF HYDATINA SENTA 



127 



would have any noticeable effect on the proportion of male-pro- 

 ducers, but the experiment was nevertheless made. This ether- 

 soluble residue was dissolved in 125 cc. of distilled water, giving 

 a clear solution, and a Hne of rotifers was reared through four 

 generations in it. The residue after ether-extraction was like- 

 wise dissolved in 125 cc. of distilled water and boiled, making a 

 brown solution not apparently different from the original manure 

 culture, and a sister line of rotifers was reared in the solution. A 

 third line was reared as control in spring water. Table 23 shows the 

 result. * 



TABLE 23 



Showing the mimher of male- and female-producers in the progeny of three sister indi- 

 viduals of Hydatina senta, one line being bred in a solution of the ether-soluble 

 part of an old food culture, one line in the part insoluble in ether, the third in 

 spring water. 



The experiment was so brief that the difference in the propor- 

 tion of male-producers between the line in spring water and that 

 in the ether-soluble part of the filtrate may mean nothing. The 

 chance of obtaining any result from such a minute ether-soluble 

 residue did not seem to warrant a more extensive experiment, 

 especially since the part of the manure solution not soluble in 

 ether had the same effect as the entire manure solution had in 

 other experiments. 



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

 of the manure solution was obtained in a manner similar to the 

 ether-extraction above. The portion soluble in absolute alcohol 

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



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 10, NO. 2 



