110 Regulation of Size in Unicellular Organisms 



Assortation of size. Pearl ('07) discovered that 

 Paramecia that were conjugating with one another 

 were more alike in size than were random pairs either 

 of other coniugants or of non-conjugants (figure 32). 



70 







5 10 15 20 25 



Difference of lengths in percent 



Figure 32. Assortation of lengths among conjugating as compared with 

 non-conjugating Paramecium caudatum. A, conjugating pairs ; B, conjugat- 

 ing individuals paired at random; C, non-conjugating individuals paired at 

 random. In each case 101 pairs were measured. (Data of Pearl, '07, pp. 

 257-259). 



