BUDDING TENTACLES OF GONIONEMUS. 



245 



means of a secreted adhesive substance as suggested by Perkins. 1 

 At the edges of this pad is present the collar-like expansion of 

 the ectoderm which is characteristic of this structure normally. 

 Indeed, the shape, size and contents of these cells, as well as their 

 method of staining and general appearance, is almost exactly the 

 same as in the normal pad. Thus there seems little doubt that 

 there was originally present here a functional suctorial pad. So 



FIG. 6. 



far as we can tell from the sections the pad might have formed after 

 the bud began its development, though this is very unlikely, since 

 in such case the function would be quite limited. Indeed the pad 

 would lose its power of functioning normally if the bud increased 

 in size to any extent. The ectoderm of the bud is thrown into 

 the folds or ridges, which are characteristic of the normal tenta- 

 cles, and nematocysts are limited to these ridges (cf. figures). 



1 " The Development of Gonionema Murbachii,' 1 '' Proc. Acad. Nat. 6V/., Phila- 

 delphia, p. 764, 1902. 



