48 



Regulation of Size in Unicellular Organisms 



in Actinosphaerium there are evident internal hetero- 

 geneities; in this species the heterogeneity is in the 

 number of nuclei. 



45 



40 



35 



JO 



£25 



CD 



CD 



-^20 

 EE 



15 



fO 







0.6 



0.8 1.0 1.2 \A 1.6 IB 



Body volume in million cubic micra 



20 



Figure 20. Distribution of adult body volumes at 26.5° in Colpoda, feeding 

 on Chlorogonium. CI Nov. 1-3 ; CII Jan. 3-5 ; CIII Jan. 30, four genera- 

 tions after hatching from four permanent cysts. The vertical lines indicate 

 the means for the groups. (From Adolph, '29). 



In general the lowest variabilities were found among 



