270 



DAVID DAY WHITNEY 



Experiments with Brachionus pala and a mixed diet of miscellaneous green flagel- 

 lates showing that when the flagellates were caused to be very abundant by the 

 addition of fresh culture media the percentage of the male-producing female roti- 

 fers was very high and the percentage of the female-producing female rotifers 

 was very low but when no fresh culture media was added and the flagellates occurred 

 only in moderate nutnbers the percentage of male-producing females was very loxv 

 and the percentage of the female-producing females was very high. 



W 



1915 



April 



CULTURE WATER 



15 cc. bouillon 

 135 cc. tap water 

 mixed green protozoa 

 15 cc. bouillon added 



15 cc. bouillon added 



15 cc. bouillon added 



15 cc. bouillon added 

 15 cc. bouillon added 



15 cc. bouillon added 

 15 cc. bouillon added 



Total 



99 



20 

 60 

 IS 

 28 

 70 

 95 

 95 

 200 

 200 



65 



97 



100 



70 

 100 

 100 



1218 



6^9 





 

 2 



12 

 30 

 5 

 5 

 1 

 1 



35 

 3 







30 



100 







224 



%cf 9 











10 



30 



30 



5 



5 



0.5 



0.5 



35 

 3 

 



30 



50 







W 



March 



15 cc. bouillon 

 135 cc. tap water 

 mixed green protozoa 

 15 cc. bouillon added 

 15 cc. bouillon added 



15 cc. bouillon added 

 15 cc. bouillon added 



Total 



200 



200 

 200 



SO 



70 

 99 







200 

 2 



20 



30 

 1 



849 



253 



50 

 1 



20 



30 

 1 



