442 H. S. JENNINGS AND K. S. LASHLEY 



We carried out this operation for the second ten-day period 

 (April 8 to 18). There were 346 cases where pairs could be made 

 up in this way, giving a total of 173 pairs. The numbering in 

 the original experiment was not the same as in table 51, since nine 

 of the original 250 pairs were lost by accident; the numbering had 

 therefore to be altered to close up the gaps. Hence the computa- 

 tations were not based on comparing the odd and succeeding even 

 lines in table 51, though the latter would presumably give a simi- 

 lar result. 



The coefficient of correlation between the odd numbered line 

 a (or 6), and the even numbered line a (or h) lying adjacent to it 

 in the moist chambers was, for these 346 lines but 0.0117 ± 0.0363 

 That is, there was no correlation whatever. The evidence is 

 therefore strong that this adjacence in position has nothing to 

 do with the production of correlation in the previous experiments, 

 where a and h were adjacent. 



All together, the result of this experiment, with its 482 lines, 

 excludes the possibility that the correlation observed in former 

 experiments was without significance owing to the small numbers 

 employed ; or owing to any possible similarity in the environmental 

 conditions of the two members of pairs. The correlation is 

 certainly real, and due to some intrinsic special similarity between 

 the animals that have conjugated. 



The data of table 51 show many other relations of extreme 

 interest, bearing on inheritance; on the possible origin of heritable 

 variations; on the fate of the diverse lines of exconjugants; on 

 changes in reproductive power with the lapse of time, and many 

 other points, some of them of great importance for a full interpre- 

 tion of the significance of conjugation. But in order not to com- 

 plicate the present paper, which deals mainly with the general 

 question of whether conjugation produces biparental inheritance, 

 it appears best to reserve the analysis of these matters for a later 

 paper on variation and inheritance of these animals. We shall 

 therefore take up here only matters which bear upon the question 

 whether conjugation actually does result in biparental inheri- 

 tance. 



