PRIMORDIUM IN RELATION TO STRIPE PATTERN 187 



In four instances it has been observed that the primordium 

 curved in a paradoxical direction, the posterior end bending 

 tow^ard the wide-stripe area instead of the narrow. Two cases are 

 shown in Fig. 48. They remain entirely unexplained. 



One of the most remarkable relationships between the stripe 

 pattern and oral anlage development is found in cases of reversed 

 asymmetry. For these are always correlated with a reversed 

 position of wide- and narrow-stripe areas (Tartar, 1956b, c). My 

 best case is shown for the first time in Fig. 49. This was from a 



Fig. 49. Reversed asymmetry in »S. coeruleus. After rotating 

 left half on right and anterior half on posterior, stripe pattern 

 reconstituted with stripes graded in opposite direction from 

 normal. The primordium appears in the l.s.c. but coils into the 

 fine-line zone which is now to the animal's left. Macronuclear 

 chain is also on reversed side from normal. Fair but incomplete 

 mouthparts formed and specimen reorganized four times 

 without achieving an adequate oral differentiation. 



Specimen of coeruleus which had been '* drawn and quartered ", 

 i.e., the anterior half was first rotated 180° on the posterior, then 

 the animal was cut longitudinally and the left half rotated on the 

 right. Naturally, this operation resulted in great disturbance of the 

 cortical stripe pattern and when realignment was achieved the area 

 bearing widest stripes lay to the right instead of to the left of the 

 fine-line zone. Correspondingly, the anlage coiled in the reversed 



