3 14 C. M. CHILD. 



the parent body, regenerate with equal rapidity except at the end 

 of the experiment, although pieces 54 A are about four times as 

 long as pieces 55 A. The oral ends of pieces 556, which repre- 

 sent a region of the parent body further aboral than those of 



54 A and 55 A, regenerate less rapidly than these, although the 

 pieces are about equal in size to 54 A and four times as long as 



55 A. And finally, the pieces 546, whose oral ends represent a 

 region near the aboral end of the parent, do not regenerate at all. 



As regards the aboral ends of the pieces only 54A and 55 A 

 need be considered, since no regeneration occurs at the aboral 

 end of a piece when this represents the aboral end of the parent- 

 body, as is the case in 546 and 556. In 54A and 55A the dif- 

 ference in the rapidity and amount of regeneration at the aboral 

 ends is marked; in 5 5 A, where the aboral ends of the pieces 

 represent a region oral to the middle region of the parent-body 

 the aboral regeneration was much greater than in 54A, where 

 the aboral ends represent a region near the aboral end of the 

 parent-body, even though the pieces 54A were four times as 

 long as 5 5 A. 



From all of these facts it is evident that the rapidity and amount 

 of regeneration decrease as the cut surface, either oral or aboral, 

 approaches the aboral end of the parent-body, and that the size 

 of the piece has no marked influence, at least within the limits 

 of size of the present experiment. That the size of the piece 

 does, however, affect the final result in some degree is shown by 

 the condition of pieces 54A and 55A at the end of the experi- 

 ment 37 days after section ; while no differences between the two 

 sets were noted earlier it was found at this time that the smaller 

 pieces 55A were falling slightly behind the larger 54A. Here 

 then a slight influence of size is noticeable, though only in the 

 later stages of the experiment. As will be shown later this re- 

 sult is confirmed by other cases. In pieces above a certain min- 

 imal size regeneration is not influenced by the size, except in the 

 later stages. 



SERIES 35. 



October 20, 1902. In this case after removal of disc and 

 tentacles a single specimen was cut into four pieces, A, B, C, D 

 as shown in Fig. 6. The piece B was much smaller than the 



