1910] 



Torrey: Regeneration of Hydranth and Holdfast. 



215 



on the characteristics of the covered ectoderm, and the edge of 

 the perisarc is established a1 the usual proportional distance 

 from the hydranth. If the piece is small, and tends to return to an 

 embryonic condition, this is the proportional distance character- 

 istic of the embryo. If it is long, so thai very slight changes in 



Fig. 13. — Hydranth developing in region of cut made just distal to oral 

 edge of perisarc. Proximal tentacles appearing just below latter, gonosome 

 buds just above. 



Fig. 14. — Same hydranth as in fig. 13, twenty-one hours later. 



form would produce the adult proportions, the adult ratio of 

 naked to covered stem is approximated. 



When the stem is cut obliquely, the process of regeneration 

 differs with the obliquity of the wound. A number of stems were 

 cut, so that the planes of the wounds made angles with the axes 

 of the stems varying from thirty to ninety degrees. It was found 



