FORM REGULATION IN CERIANTHUS. 



Each of the remaining ten pieces was also divided by a trans- 

 verse cut into two pieces A and B, but in this case the cut was 

 made near the oral end of the piece (Fig. 5), so that A repre- 



\J 



FIG. 4. 



V 

 FIG. 5. 



sents one sixth of the body-length from the region just aboral 

 to the oesophagus, while B is the whole remaining portion of the 

 body. These pieces constitute Series 55. 



In this manner four sets of ten pieces each were obtained. 

 The oral ends of pieces 54A and 55A represent approximately 

 the same level in the body of the individuals from which they 

 were taken, while their aboral ends lie at very different levels ; 

 moreover, the pieces 54A are about four times as long as 5 5 A. 

 The oral ends of the pieces 546 and 55B are at very different 

 levels, while their aboral ends are the aboral ends of the parent 

 bodies ; 556 is about four times as long as 546. 



In 54A and 54B we have pieces differing widely in size and 

 with oral ends at very different levels ; the same is true of 55 A 

 and 556, but the relations of size are reversed. 



The comparative study of the regeneration of those four sets 

 of pieces should afford data regarding the rapidity and amount 

 of regeneration at different levels of the body and in pieces of 

 different sizes. 



December 19 : Four days after section : 



