FISSION RATE OF STYLONYCHIA PUSTULATA 



461 



selection is considerably larger than for the first, 0.024 genera- 

 tion; and further it suggests the conclusion that if direct selection 

 were practiced long enough a greater difference might be 

 established. 



TABLE 3 



Experiment 1-B: Actual number of generations per ten lines per ten-day period 

 for the fifty fast lines and fifty slow lines subjected to reversed selection {'fast' 

 lines selected noiv for slow fission, 'sloiv' lines for fast fission) 



Reversed selection. Table 3 gives the actual number of fis- 

 sions of the fifty fast and slow lines under reversed selection. 

 Again the lines of each set are divided into groups of ten each. 



Table 3 shows that reversed selection has made the average 

 fission rate of the fifty slow lines faster than the average fission 

 rate of the fifty fast lines. Now, as pointed out above, if the 

 observed difference in fission rate is hereditary and has resulted 

 from selection this result might logically be expected to follow 

 from reversed selection. The net result of both phases of this 



