Internal Characteristics and Size 



Was the 



117 



halving of the body volume 

 a "hemi-haploid"? 



"mutant" race 



3. Endomixis and Rhythms 



Endomixis was identified at its discovery as a nu- 

 clear reorganization which occurred periodically, in 

 step with transient decreases of fission rate. Since 



116 124 132 140 H8 156 164 172 180 188 



Body length in micra 



Figure 33. Distribution of body lengths in a clone of Paramecium cauda- 

 tum, comparing the original line a with mutant line b. Culture a-\-b grew 

 from individuals of both lines in one dish. Culture be represents line b 

 after conjugation had intervened. (Redrawn from Jcllos, '21). 



most changes of fission rate have proven to involve 

 changes of adult size, it was natural to look here too 

 for changes of size. This was done by Erdmann ('20) 

 by fixing large numbers of individuals at known days 

 of an endomictic "cycle" and measuring them. 



Size between endomixes. Under the prevailing con- 

 ditions of culture endomixis occurred approximately 

 every thirty days. The results, in three lines belong- 

 ing to two clones, are shown in figure 34. For com- 



