BIPARENTAL INHERITANCE IN PARAMECIUM 415 



Calkins^ experiments 



Calkins in his paper of 1902 gives some statistics bearing on 

 this matter. In liis table 3 he gives records for the progen}^ of 

 40 pairs of conjugants, 24 being 'exogamous/ 16 'endogamous.' 

 These were not all taken nor cultivated at the same time, so that 

 it is doubtful how far we should attempt to use them for our pres- 

 ent purposes. However, some of the facts may be given, in order 

 to show an}' relation they may have to our problem. Calkins 

 notes that a large proportion of the hues die out before the tenth 

 day. We may then select this period for examination. It is 

 found from Calkins' table that by the end of the tenth day 40 of 

 the 80 hnes derived from the 40 pairs have died out. Here we 

 have m = 80; ?i = 40. The most probable number of pairs is 

 found, by our formula (1) or (2), to be 10. The actual number of 

 pairs dead is 14. Thus in this case, as in those described by jMiss 

 Cull, the number of pairs dead, and the number of pairs living, 

 is greater than would be expected ; not less, as the theorj^ of sexual 

 differentiation demands. 



At the end of one month but five lines were living, out of the 

 80. Among those li\'ing there were no pairs ; this was to be 

 expected on any theory. 



The data given by ' Calkins perhaps hardly warrant farther 

 analysis for our present purposes. 



Experiments of the author 



In my paper on the Effect of Conjugation in Paramecium ('13), 

 which immediately precedes the present one, I have given an 

 account of a number of experiments which yield data for attack- 

 ing our present problem. I will here analyze these data, refer- 

 ring to the paper just mentioned for all details not bearing directly 

 upon the question now in hand. I shall refer to the experiments 

 by the numbers given to them in the paper cited. 



