Vol. VI. December, /<?oj. No. i 



BIOLOGICAL BULLETIN. 



FORM REGULATION IN CERIANTHUS, II. 



THE EFFECT OF POSITION, SIZE AND OTHER FACTORS UPON 

 REGENERATION. ( Continued. ) 



c. M. CHILD. 



II. DISCUSSION OF RESULTS. 

 Tlic Factor of Position. 



In the experiments described above, which were selected from 

 a large number, the effect of position on regeneration has ap- 

 peared in every case. Considering first the effect of position on 

 the rapidity of regeneration, we 'find that in each series the 

 rapidity of regeneration is dependent on the position which the 

 piece occupied in the parent body, a decrease in the rapidity of 

 regeneration occurring with increasing distance from the oral 

 end. This relation holds for the aboral ends of pieces as well 

 as for the oral ends, though the regenerative phenomena at the 

 aboral ends are in most cases less sharply defined than at the 

 oral ends. Further analysis is possible in such series as 54 and 

 55. The oral ends of the two sets of pieces 54*4 and $$A are 

 situated at approximately the same level of the body, but the 

 aboral ends of the pieces 54/4 are much nearer the aboral end of 

 the parent body than those of 55^4. The data given above for 

 this series show very clearly that the rapidity of regeneration at 

 the oral ends of both sets of pieces was equal, except in the final 

 stages, while at the aboral ends it was much greater in the shorter 

 pieces, i. e., those in which the aboral cut surface was near the 

 oral end of the parent body. From these experiments we may 

 conclude that the two ends of a piece regenerate independently of 

 each other, at least to a certain extent, the result depending in 

 each case on the level which a particular cut surface occupied in 

 the parent body. 



Near the aboral end the regenerative capacity is reduced nearly 



