436 H. S. JENNINGS AND K. S. LASHLEY 



of fissions being recorded. The records were then grouped by ten- 

 day periods, and the number of fissions in these periods were made 

 the units in analyzing the results. 



We have thus for each of the 482 strains (so far as they lived 

 through), four records, of the number of fissions for four succes- 

 sive ten-day periods, extending from March 30 to May 8, 1912. 



These records are given in table 51, which will be found in the 

 Appendix. Tliis table contains everything that might be dis- 

 tributed in a great number of correlation tables, and at the same 

 time shows much that would not appear in such tables. From it, 

 anyone who so desires can construct tables or repeat the compu- 

 tations on which the results hereafter are based, in order to test 

 their accuracy. Further, we hope that table 51 may serve as a 

 storehouse of material, from which independent study can be 

 made by others on the problems of reproduction and inheritance 

 in these organisms. We shall ourselves make much farther use of 

 it, in papers to appear on inheritance in Protozoa. 



Distribution of survivals and deaths among the members of pairs 



We may first examine the question as to whether the two mem- 

 bers of pairs tend to have the same, or a different, fate, so Jar as 

 mortality is concerned. Is there a tendency for one to die and the 

 other to live, or are their fortunes alike? 



The pertinent data for the four periods of table 51 and for a 

 subsequent period of twenty-one days, are given in table 44. 

 Since the periods of table 51 do not begin till seven days after 

 conjugation, we have in table 44 the data as to the deaths for 

 five periods, of respectively seventeen, twenty-seven, thirty-seven, 

 forty-seven, and sixty-eight days after conjugation. For the 

 first four periods the data are extracted from table 51 ; for the fifth 

 period of sixty-eight days, the data of table 44 are independent 

 of table 51. 



The understanding of table 44, which condenses the results of a vast 

 amount of work, will be facilitated by the following explanation of the 

 various entries. 



The total number of strains at the beginning was 482; or for the lower 

 half of the table, where 8 pairs are omitted, 466. Columns (2) and (6) 



