428 



H. S. JENNINGS AND K. S. LASHLEY 



TABLE 42 



Experiment 1. Average difference in fission rate between the members of pairs, as 

 compared with the average difference between the 'females' of different pairs; and 

 also between the 'males' of different pairs. The most rapidly reproducing member 

 of a pair is designated 'female'; the slower one 'male'. Based on data of table 29 

 of the paper on the effect of conjugation, {page 379). 



between the members of pairs cannot be considered evidence of 

 sexual differentiation. For this difference is actually less than 

 that between individuals taken at random ; and not more than that 

 between individuals that would, on the sexual theory, have to be 

 considered members of the same sex. 



Biparental inheritance? 



Thus in studying the question of sexuaUty, we have come upon 

 a matter that is of much interest quite independently of this 

 question. The fact that the progeny of two individuals which 

 have conjugated resemble each other more than do those of two 

 individuals taken at random would seem to indicate that they 

 must inherit from both the conjugants. If this be the case, we 

 have here the first evidence that has been presented of biparental 

 inheritance in Protozoa, and particularly in connection with 

 that form of conjugation in which both the conjugants continue to 

 reproduce. 



Analysis of the experimental results 



From this point of view we may examine the facts further. 

 Since in Experiment 1, as we have seen, the two strains derived 

 from a pair resemble each other in rate of reproduction more than 



