MEROGONY AND REGENERATION IN RENILLA. 



22 I 



changes in parts already completely formed. Interesting results 

 can doubtless be obtained by the further study of these changes. 

 2. The above case not only shows a reversal of polarity but 

 proves that regeneration may take place anterior to the budding 

 zone. A similar result \vas also given in several cases where the 



O 



peduncle was removed by section posterior to the budding zone ; 

 but this only occurs when the section is not far removed from 

 the budding zone. 



In at least one such case it is certain that the section was out- 

 side the normal limits of the budding zone, the colony having 



y 



D 



FIG. j. A, outline of young colony with three pairs of buds, showing plane of 

 section. , posterior piece after forty-eight hours, with new axial polyp forming; a 

 new peduncle had formed on the anterior piece. C, the same nine days later, with 

 nearly perfect axial polyp and new bud on the left side. I), new axial polyp and 

 pair of buds regenerated from the anterior end of a peduncle, cut off behind the bud- 

 ding zone from a young colony with seven pairs of buds ; five days after operation. 



seven buds on each side. In two days a new axial polyp was 

 well under way at the anterior end of the severed peduncle. In 

 five days this polyp was well developed, with short tentacles and 

 mesenterial filaments, while a pair of symmetrically placed buds 

 had appeared in the same position as in the young colonies (Fig. 

 3, D]. A condition was thus attained essentially similar to that 

 of the young colonies developed .from the egg (cf. Fig. i), 

 though the peduncle was of course greatly exaggerated in 



