80 DUDLEY MEMORIAL VOLUME 



4. As to the possible influence of light on the ratio of male and female 

 prothalli, I wish merely to record the observation that, in my cultures, illumi- 

 nation, increased by revolving the prothalli, seemed to be followed by an 

 increased proportion of female prothalli. I do not care at this time to dis- 

 cuss this observation or to hazard an opinion as to the extent of this possible 

 eiTect of light on plants. 



