452 H. S. JENNINGS AND K, S. LASHLEY 



non-conjugant members of split pairs, were cultivated for twenty- 

 four (or twenty-one) days, with extraordinary precautions for 

 keeping the conditions uniform in all the lines. The two members 

 of gi^'en pairs or split pairs were kept in separate moist chambers 

 and handled separately. 



Unfortunately, for reasons set forth in my former paper ('13), 

 in but a comparatively small number of cases were descendants of 

 both members of pairs or split pairs propagated. Where this 

 was done, however, two lines of propagation were retained from 

 each member. The results are so extremely marked that the 

 number of lines thus obtained turns out to be amply sufficient 

 for solving the problem in which we are here interested. 



The question for answer is: Do the progeny of the two members 

 of a pair give evidence of biparental inheritance, in case all the 

 conjugants are originally derived from a single parent? In other 

 words, are the progeny of the two members of the pairs more 

 aUke than they would have been if their parents had not conju- 

 gated together, but had conjugated with other individuals? 



To answer this question for the rate of reproduction, which 

 was the character studied, we must determine (1) whether the 

 progeny of the two members of a pair that have conjugated show 

 any unusual likeness in their rate of reproduction ; and (2) whether 

 this degree of hkeness occurs also in the members of the split 

 pairs. If we find such an unusual likeness in the members of the 

 pairs, and not in those of the split pairs, this will show it to be the 

 result of conjugation. 



An inspection of the Hotals' for the numbers of fissions of the 

 diverse lines during the entire experiment, as given in tables 34 

 and 35 of my paper on the Effects of Conjugation (this Journal, 

 vol. 14, page 385) will show at once that there is a most striking 

 resemblance in rate of fission between the progeny of the two 

 members of the pair; and that this resemblance is nearly or quite 

 lacking in the case of the members of the split pairs. To bring 

 this out clearly, it will be well to give here a table showing the 

 total numbers of fissions in both cases. The period of time was 

 for the pairs twenty-four days; for the split pairs twenty-one days; 

 from each member (a and 6) of a pair or split pair there was kept 



