Inheritance of Size 



67 



the mean size gradually came back to the original size, 

 and then stayed there. 



Reynolds ( J 23) found the variability in diameter of 

 shells in a clone of Arcella polypora considerably 

 greater among individuals which had an abnormality 



Generations 



Figure 29. Restoration of mean shell size in the progeny of 13 individuals 

 of a clone of Arcella dentata which were rendered uninucleate by cutting the 

 body and shell into two. In each of the 13 lines the progeny became bi- 

 nucleate again between the zero and first generations by the process of 

 forming and casting off an empty shell. (Data of Hegner, '20b). 



of shape than among normally shaped individuals of 

 the same clone. He supposed that the abnormally 

 shaped individuals were descended from a parent 

 which was in reality two unseparated or fused individ- 

 uals. The variability was then due to variation of 



