454 



JENNINGS- HEREDITY IN PROTOZOA. 



[April 24, 



same cultures. Conjugation does not occur till a certain stage of 

 growth has been reached, and the conjugants do not include speci- 

 mens undergoing the changes preparatory to fission. The conjugants 

 would then fall in those portions of the growth curve that are nearly 

 straight ; that is, there would be in these little variation due to growth. 



Table XVI. 

 Coefficients of Variation. 



Pearl (1907) has already shown that the observed variability of con- 

 jugants is less than that of random samples of the same culture. I 

 have made extensive studies of conjugants and find the same thing. 

 Details regarding the relation of conjugation to variation and heredity 

 are to be taken up in a later communication ; here I give merely the 

 coefficients of variation for certain cases, as compared with those of 

 random samples. 



Table XVII. 



Coefficients of Variation for Conjugants, as compared with those for random 

 samples of non-conjugants of the same culture. 



On comparing the coefficients of variation in conjugants, as given 

 in Table X\^II., with those for specimens beginning fission (Table 

 XVI.), and those for specimens at definite ages (Table X.), it is 

 found that in the conjugants the variation is not so small as it is in 

 specimens at definite growth stages. This shows clearly that nothing 

 is required to explain the low variation of conjugants, save the fact 

 that a certain number of growth stages (the earlier and later ones) 



