EXTENSIONS 363 



band may incite division, as seems to be the case in stentors. 



In reorganization the old mouthparts are resorbed and the new 

 membranellar bands join with that of the old. Micronuclear 

 mitoses occur during reorganization and regeneration as well as in 

 division. There is no evidence for intranuclear differentiation, for 

 all parts of the macronucleus in Blepharisma as in Stentor were 

 capable at all times of mediating oral regeneration. 



Ablations of other than oral parts does not result in regeneration, 

 but the more of the peristome removed the sooner regeneration 

 follows. Primordium formation is therefore inhibited by existing 

 feeding organelles. Suzuki attributed the possibility of anlage 

 development during division to a release from inhibition by reason 

 of partial dedilferentiation of the existing feeding organelles. 

 Gullet and oral pouch also become vague in dividing stentors, but 

 in both organisms the blurring itself seems to occur only after the 

 primordium is well started. 



Nucleate anterior fragments of Blepharisma behave like longitu- 

 dinal aboral halves of Stentor which also lack the original primor- 

 dium site. Regeneration is usually much delayed yet does occur. 

 Therefore the normal site is not indispensable and all parts of the 

 ectoplasm are equipotent as regards anlagen formation. 



Rotation of the anterior on the posterior half can lead to the 

 formation of doublets and doublet animals could be maintained 

 through a series of divisions lasting a month. Like parts tend to 

 join, as two cytopyges coalesce or tandem membranellar bands join 

 together. Induced reorganization occurs on one side of a doublet 

 when the other side is caused to regenerate, as evident in Suzuki's 

 figure 38DC. Without grafting, induced resorption of primordia 

 could not have been demonstrated, but if one type of induction is 

 possible the other may be likewise, and blepharismas may also pass 

 through states of activation and inhibition. 



Feeding organelles of reversed asymmetry can be produced in 

 Blepharisma. These forms were apparently the result of the 

 influence of a posterior pole at the " wrong " end of the primordium, 

 just as peristomes with mouthparts at both ends were formed when 

 two posterior ends were present. As in all other cases of feeding 

 organelles which are a mirror image of the normal, those in 

 Blepharisma are unable to feed and a self-reproducing biotype 

 with situs inversus cannot be produced. Evidently the posterior pole 



