RECONSTITUTION IN DISARRANGED STENTORS 231 



dominance of one or the other or may result in equiUbrium, with 

 the striping of both halves retained and interpenetrating. A fine 

 and unnoticeable difference might swing the balance one way or 

 the other. When the cell was so cut that the ratio of anterior half 

 to posterior was about 3 : 2, Uhlig found that dominance was 

 exerted by neither part and doublets resulted which could divide 

 and produce more doublets. He states that then each primordium 

 site '' reorganized " completely, but perhaps he also observed what 

 seems to me to be the case : that there is an extension of each half 

 of the original primordium site as it penetrates through the stripes 

 of the other half. He interpreted the various responses as an 

 interaction between the head-tail gradient and the transverse or 

 circumferential gradient in stripe width. For instance, when only 

 the posterior end of the cell is rotated, its circular gradient in the 

 immediate neighborhood of the steepest end of the tail-to-head 

 gradient is apparently obliterated. 



Experiences wdth this type of operation will have a bearing on 

 the analysis of axial gradients in Stentor. From a more general 

 standpoint it is shown that stentors have still further resources, in 

 the selective resorption or interpenetration of stripes, for the 

 reconstitution of their normal form and pattern. 



