CONTROL OF SEX BY FOOD IN ROTIFERS 295 



males to be produced whereas a superabundance of this same 

 green diet, produced in the jars by the addition of fresh cul- 

 ture media, caused in some experiments as high as 95 per cent of 

 male-producing females to appear. 



3. In mass cultures of Diaschiza sterea living in stable tea 

 water at room temperature the diet of Polytoma caused only 

 females to be produced but when the rotifers were transferred to 

 bouillon water containing an abundant diet of Chlorogonium 

 many males were produced. 



4. In mass cultures of Diaschiza sterea living in stable tea water 

 at room temperature the diet of stable tea reared Polytoma 

 paused only females to be produced but a diet of a bouillon reared 

 Chlorogonium which had been washed and was added to the 

 filtered stable tea water caused many males to be produced, thus 

 showing that it was the diet and not the change of culture 

 water that caused males to be produced. 



5. In mass cultures of Diglena catellina at room temperature 

 the diet of Polytoma caused only females to be produced but a 

 diet of miscellaneous green flagellates caused many males to be 

 produced. 



6. In mass cultures of Pedalion mirum a scanty diet of miscel- 

 laneous green flagellates caused nearly all female-producing fe- 

 males to be produced whereas a superabundant diet of the same 

 green flagellates, produced in the jars by the addition of fresh 

 culture media, caused in some experiments as high as 90 per 

 cent of male-producing females to be produced. 



7. In mass cultures of Brachionus pala a scanty diet of pure 

 cultures of Chlamydomonas pulvisculus caused nearly all female- 

 producing females to be produced whereas a superabundance of 

 this same Chlamydomonas diet, produced in the jars by adding 

 fresh culture media, caused in many experiments as high as 90 

 per cent of male-producing females to be produced. 



8. The colorless diet of Polytoma causes female-producing 

 females to be produced and the green diets of Chlamydomonas, 

 Chlorogonium, or miscellaneous green flagellates causes male-pro- 

 ducing females to be produced. 



