MALE-PRODUCTION IN HYDATINA 



525 



TABLE 2 



A comparison of the effectiveness of a 60 per cent oxygen mixture and a 4-0 per cent 

 oxygen mixture in increasing male-production in the rotifer Hydatina senta. 

 The tests covered the same period of three months, but were made on 

 alternating days 



March 6 



March 13 



March 18 



March 23 



April 4 



April 10 



April 13 



April 17 



April 25 



May 2 



May 9 



May 19 



June 4 



June 8 



Total 



Percentage of 



cf 9 ' 



March 11 

 March 15 

 March 20 

 March 27 

 April 7.. 

 April 11.. 

 April 14.. 

 April 20. . 

 April 28.. 

 May 5.. 

 May 12.. 

 May 30. . 

 June 5.. 

 June 12. . 



a^ 



1 



6 

 



12 

 1 

 

 1 

 3 

 1 



17 

 1 

 

 3 

 



46 



25 

 22 

 25 

 11 



4 

 14 

 30 

 38 

 44 

 23 



1 

 10 

 34 



6 



287 



13.8 



40 PER CENT 

 OXYGEN 



0) o 



1 



2 

 3 



35 

 



17 

 2 

 3 

 5 



12 

 

 

 3 

 



83 



27 



38 



21 



2 



6 



9 



29 



45 



37 



17 



17 



23 



22 



19 



312 



21.0 



the difference between these two ratios is probably significant or 

 not. 



Amount of oxygen dissolved from atmosphere and from Euglena 



After repeated tests had shown that the increase of male-produc- 

 tion in rotifers reared in oxygenated water was no mere accident, 

 it became a pertinent question whether, and to what degree, the 

 increase of male-production among rotifers fed upon green organ- 

 isms is dependent upon the liberation of oxygen in photosynthe- 

 sis. As a preliminary problem, it was necessary to discover how 

 nearly the amount of oxygen dissolved from the air-oxygen mix- 

 tures described in this paper and in that of Shull and Ladoff 



