80 



SEVENTH REPORT. 



For comparison with the above the following table of values from 

 Pearson's* note on Simpson's data is introduced. The character is 

 "length of body," and the series included 100 Paramecia. It will be noted 

 that the individuals in our series are considerably larger and somewhat 

 more variable than those in Simpson's series. 



Length of Paramecium, 100 Individuals. 

 Simpson's Data. 



Mean 



Standard Deviation. . . . 

 Coefficient of Variation 



229.050 mikrons 

 19.152 mikrons 

 8.361 % 



The next three distributions (Table III) show the variation in 

 length of the "control" individuals in Experiments 1, 2, and 7. These 

 individuals multiplied in the standard hay-infusion culture medium 

 throughout their lives. The 1,500 individuals whose measurements are 

 recorded in Table III are all the descendants of the same original single 

 ancestor. The other conditions regarding these series are explained 

 above. 



TABLE III. 

 Frequency Distributions. Length of Paramecia of Selected Ancestry. Controls. 

 Class Unit = 10 mikrons. 



These distributions are shown graphically in Figure 2. 

 tion constants are exhibited in Table TV. 



Their varia- 



*Biometrika, VoL I, p. 405. 



