TOWARD A GENETICS OF STENTOR 315 



their regeneration possibilities. Nevertheless, this combination 

 should be attractive for further studies because of the great 

 difference in size together with general similarities in other respects. 



Nucleated cells and cell parts were grafted to obtain mixtures 

 of widely varying proportions of coeruleus and of a polymorphus 

 strain which was grass-green with abundant symbiotic Chlorella. 

 The general result was that successful oral redifferentiation 

 occurred only when there was a preponderance of one species of 

 nucleus in a preponderance of its own type of cytoplasm. The 

 more nearly the two types of cells approached equality the less 

 successful w^as oral reorganization, and instead existing feeding 

 organelles were promptly resorbed. When both species were 

 represented in the cytoplasm but with the nucleus from poly- 

 morphus only, some oral differentiation occurred and the indications 

 are therefore that there is a conflict between the nuclear compo- 

 nents such that polymorphus nucleus is more effective when acting 

 on a mixture alone. 



In spite of incompatibilities in regard to oral differentiation, 

 mixtures of coeruleus and polymorphus in any proportion showed 

 very good shape reconstitution as manifested by the realignment 

 of cells and cell parts to form a single, conical stentor shape 

 (Fig. 89B), and was better than that of enucleated grafts of either 

 species. This suggests that reorientation of the cortical pattern is 

 either a more generalized function in which species differences are 

 not prominent or makes less precise demands on nucleo- 

 cytoplasmic interaction. Were the cytoplasm less specific than 

 the nucleus, as appears, this would substantiate present-day 

 conceptions (Monne, 1948). 



In these quantitatively varying combinations of coeruleus and 

 polymorphus it was also found that any considerable admixture of 

 coeruleus cytoplasm resulted in the ejection of chlorellae from the 

 fusion mass, and it should be added that uniform distribution of 

 the symbionts throughout showed there was complete mixture of 

 the endoplasm. Hence coeruleus cytoplasm appears to be anti- 

 thetical to the entertainment of the symbionts. Correspondingly, 

 admixture of polymorphus cytoplasm resulted in depigmentation 

 of coeruleus. 



Similar results in regard to pigmentation have been found in 

 recent tests in which nucleated coeruleus was fused with a smaller 



