FISSION RATE OF STYLONYCHIA PUSTULATA 



463 



This experiment is simply a connecting link between part 

 one and part three of Experiment 1. There is a slight increase 

 in the difference between the average number of generations 

 produced by the fast and slow lines during the first and second 

 ten-day periods. The fourth and fifth ten-day periods of figure 



I , 



I I 



I . 



Fig. 3 Polygon of the average number of generations produced, per line, 

 by the fast and slow selected sets of lines of Experiment 1, while the two were 

 undergoing selection in opposite directions; averaged for ten-day periods. The 

 polygon shows this average for each of all the 13 consecutive ten-day periods 

 of Experiment 1. The continuous line shows the average for the fast lines, the 

 broken one the average for the slow lines. The ordinates give the average 

 number of generations produced and the abscissae the number of days since the 

 beginning of the experiment — the successive ten-day periods. 



3 show the average number of generations per line per ten-day 

 period for this part of the first experiment and its first three 

 ten-day periods show it for the first part; while figure 4 is the 

 curve of the daily differences between the average number of 

 generations produced by each fast and each slow line during 

 these two ten-day periods. 



