198 THE BIOLOGY OF STENTOR 



grafted transversely across the striping of the host it will rotate in 

 correspondence with the host axis (see Fig. 44B), and even when a 

 stentor is cut in two longitudinally and the halves rotated 180° on 

 each other they often rotate back into their original alignment 

 (Tartar, 1957c), as shown in Fig. 53. Grafted pairs could shift into 

 homopolar orientation from any initial arrangement (Tartar, 

 1954). The original polarity of the components is obviously 

 retained and becomes the basis for their extensive movements 

 with reference to each other in the reorientation (see Fig. 28B). 



Another response which sometimes occurs when patches or 

 sectors are completely reversed is that the misoriented piece 

 becomes resorbed in place (Fig. 53D) (Tartar, 1958b). Commonly 

 the ectopic patch creeps towards the anterior or posterior end of 

 the host where it is gradually resorbed (e). A less drastic expression 

 of this way of resolving the conflict in polarities is observed in the 

 suppression of such pieces, as when early primordium sectors are 

 grafted heteropolar on to regenerating hosts and the anlage then 

 fails to develop, or when the induction of a secondary primordium 

 fails to occur in an additional primordium site implanted in 

 reverse (Tartar, 1958b) as we show in (f) and (g). These cases 

 may be of great interest for their implication that the instigation 

 and support of primordium development involves geometric 

 relationships in the entire cortex and are not solely the result, say, 

 of a substance like RNA being released within the cell and affecting 

 formative loci regardless of how they lie. 



Reversed sectors may not be resorbed but creep to one end of 

 the host and establish new individualities (Tartar, 1956a) clearly 

 demonstrating the autonomous polarity of the implant (h). 

 Alternatively — and most intriguing for the problem of polarity — 

 the patch may remain in place and produce an astonishing 

 disturbance of the form and morphogenesis of the cell (Tartar, 

 1956b). In Fig. 54A is shown one case of four in which regeneration 

 never occurred though the animals survived 6 days — striking 

 instances of inhibition of regeneration apparently due to polar 

 conflicts ; and (b) is an example of the transient chaos which may 

 develop before polar discrepancies are resolved. Nuclear nodes 

 also are often abnormally located, indicating that the overlying 

 ectoplasm guides the movements of the macronucleus. From these 

 extraordinary disturbances it may be inferred that, although the 



