58 



Regulation of Size in Unicellular Organisms 



dividual's body substance is actually furnished by the 

 parent. For whereas the germ cells of most multicel- 

 lular organisms furnish a negligible amount of actual 



80 



120 160 200 240 280 320 



Body volume of their quadruplet progeny 



360 



Figure 25. Correlation of body volumes between parents and their off- 

 spring in Colpoda. Body volumes are in thousand cubic micra. The co- 

 efficient of correlation is +0.561. The frequency curve for parents, which 

 belongs on the ordinate scale, is transferred to the abscissae for easier 

 comparison with the curve for the progeny. Means are indicated by vertical 

 lines. (From Adolph, '29). 



material to the developed offspring, unicellular organ- 

 isms receive material which is usually half of the quan- 

 tity contained in the adult. It is, probably, this ma- 



