FUSION MASSES OF WHOLE STENTORS 215 



4. Incomplete oral differentiation 



When fifteen or more stentors were grafted together there was no 

 longer adequate mouthparts formation. Primordia were few and 

 unusually long, forming extensive garlands of oral cilia stretched 

 across the mass (Fig. 6ib). There was some indication that the 

 membranelles in these bands were not completely formed, though 

 this has not been ascertained. But it was obvious that formation of 

 mouthparts was inhibited. Since induction of these parts is deter- 

 mined by a normal relation of the anlagen to the axis of the cell, 

 the presence of numerous cell axes running in random directions 

 and cancehng each other in their polar influences may be responsible 

 for the astomatous development of the feeding organelles in large 

 masses. 



5. Absence of fission 



Random masses containing more than five stentors never showed 

 any attempt to undergo fission. This is rather surprising for two 

 reasons. First, the masses are very large and, although increase in 

 size is not in itself invariably stimulative of division, one might 

 expect that a very exaggerated volume could be so. Second, 

 multiple fission would seem to be the easiest way for a mass to 

 resolve its difficulties, yet this does not occur. But when masses are 

 cut into pieces about the size of a normal stentor they promptly 

 regenerate normal singles, a test which shows that no irreversible 

 pathology occurs within large fusion complexes. Faure-Fremiet 

 (1945 a) attributed similar failure in simpler complexes to their 

 heteropolar arrangement, which permits the establishment of no 

 single plane of fission. Whatever the reason, the elimination of the 

 capacity to divide should make the study of fusion masses fruitful 

 in searching for the basis of fission. In this connection one is 

 reminded of an hypothesis by Berglas (1957) that cancerous 

 proliferation might be stopped by capitalizing on the avidity of 

 cancerous cells, causing their overgrowth to such a size that divi- 

 sion is no longer possible. 



6. Tubes and ciliated vacuoles 



In these unique intracellular formations the morphogenetic 

 capacities of Stentor seem to be extended beyond what is ever 

 normally expressed. The tubes extend deep into the endoplasm 



