114 



DAVID DAY WHITNEY 



ments shown in diagrams in a former paper the production of 

 male-producing females practically ceased at the low points of 

 depression in the curves where the food supply was scanty. 



In sunlight Chlamydomonas being a green organism gives off 

 oxygen in the process of photosynthesis but in darkness no photo- 

 synthesis takes place and consequently no oxygen is given off. 

 According to Shull and Ladoff one would expect many male- 

 producing females to be produced in sunlight and Chlamydo- 



Diagram 4 Brachionus militaris. Experiment 3 of table 4. Showing the 

 production of a high percentage of male-producing females when the food of 

 colorless flagellates was increased by the addition of bouillon. B indicates the 

 addition of bouillon. 



monas with the accompanying excess of oxygen but no male- 

 producing females would be expected to be produced in darkness 

 and Chlamydomonas with no excess of oxygen. In some of these 

 experiments in table 5, 84 per cent of male-producing females 

 were produced in sunlight with oxygen and 76 per cent of male- 

 producing females were produced in darkness without oxygen. 

 This production of such a high percentage of male-producing 

 females in darkness without an excess of oxygen would seem to 

 indicate that oxygen is not the factor that causes this production 

 of male-producing females. 



