494 



JENNINGS— HEREDITY IN PROTOZOA. 



[April 24, 



of each was killed and measured. Later, on March 7, twenty indi- 

 viduals were taken anew from each of these thirteen lots, brought 

 again with elaborate precautions into the same culture fluid, kept 

 under the same conditions and allowed to multiply, part till March 

 13, part till March 19, when other samples were killed and measured. 

 From our previous extensive experience with i and g (Table XXIII. , 

 page 488) and with five lines of Tables XXIV. (page 491), we can 

 be assured that two sets of measurements taken at such intervals 

 will give us reliable data as to the existence of any considerable 

 lasting differences among the different lines. The results of the 

 measurements of the thirteen different sets are given in classified 

 form in Table XXV. 



Table XXV. 

 Mean Dimensions in Microns, of tlie Thirteen Sets Described in the Text, 

 after Cultivation under the Same Conditions, February 21 to February 

 26, and March 7 to March 13 {or March ig). (The conditions before; 

 and in intervening periods were essentially the same, but elaborate pre- 

 cautions were taken for the periods specified). All are from the con- 

 jugating culture M, of January 29, save the last two sets. 



Examination of this table shows that lines derived from different 

 conjugating pairs or different ex-conjugants do differ from each 

 other at the same periods in the life cycle, even though living under 



