ifi'il Torrey: Regeneration of Hydranth and Holdfast. 



213 



shown in the development from the egg, where the plan accord- 

 ing to which the peduncles arise, one or two at a time, is so like 

 that followed by the tentacles, that they arc only distinguished 

 from (lie latter by their larger size, later origin, and cavity. 



The development of the peduncles in the regenerating adult 

 and in the embryo is the same in all essential features, involving 



Fig. 10. — Regeneration of segment of column, showing gonosomal pedun- 

 cles building just distal to proximal tentacles. X 12. 



Fig. 11. — Two sections of young peduncle developing on regenerating 

 column, a is median, showing endoderm only, with clear evagination. 



Fig. 12. — Longitudinal section of body wall through edge of perisarc. 



a distinct evagination of the endodermic epithelium (fig. 11). 

 The only noteworthy difference, which applies equally well to the 

 tentacles, is the greater rapidity of development in the regenerat- 

 ing stem. 



For the sake of simplicity, the discussion has been concerned, 

 up to this point, with the development of the hydranth (and the 

 associated gonosome) on stems cut in the distal naked region; 



