GROWTH AND DIVISION 77 



Stops at ''indifferent" striping (Fig. i6b). The latter blockage is 

 probably not because the indifferent component is not in a "state 

 of division" since Weisz (1951b) had shown that, although removal 

 of patches of ectoplasm in the path of the presumptive furrow still 



D 



Fig. 16. Pertaining to the fission line (S. coenileus). 



A. Continuation of furrow formation in the non-oral half of 

 divider cut longitudinally at stage 4. Note how pigment granules 

 withdraw from the middle of granular stripes and accumulate 

 posteriorly. 



