134 THE BIOLOGY OF STENTOR 



morphological disarrangements without chemical additives, as 

 when reversing the single primordium site often if not always 

 precludes the formation of an anlage (p. 197). 



Oral regeneration is thus often the preferred phenomenon for 

 study because by oral ablations we can induce at will the bio- 

 chemical and epigenetic processes involved in primordium forma- 

 tion. But there is no reason to suppose that the fundamental 

 features of anlagen development in regeneration are different from 

 those in the more autonomous performances of division and re- 

 organization. Instead, it is perhaps reasonable to suppose that 

 from the means providing for the basic requirement for reproduc- 

 tion by division were developed the capacities for reorganization 

 and regeneration which seem far less significant for survival of 

 the species. 



