MALE-PRODUCTION IN HYDATINA 



147 



TABLE 16 

 Showing number of male-producers (d' 9 ) and female-producers (9 9) in two lines 

 ■ of Hydatina, one reared in water in ordinary air, the other in water saturated 

 with an atmosphere of which 60 per cent was oxygen 



families. Table 17 records all these groups of successive male- 

 producers in both lines. The average size of these groups in 

 the air line is 3.26, in the oxygen hne only 2.40. The male- 

 producers are distributed more uniformly through the families 

 in the oxj^gen Hne than in the control. In this connection, see 

 also table 15, and the discussion of it under Experiment 17. 



This difference in the distribution of the male-producers is 

 also seen if, instead of recording the generations separately, as 



