S4 



rins of tentacles, as in figure, and interradially , i.e., 

 at the end of a radius which bisects the angle between two 

 tentacles (Fig. 19), Never more than a single bud appeared 

 at one time on any polyp. 



All three body-layers of the parent are involved in 

 the formation of a bud (Fig. 16). The cells of both ecto- 

 derm and endoderm multiply rapidly in the region of the 

 wall of the polyp where the bud is about to be formed. The 

 endoderm pushes out as a rounded protuberance covered by 

 the ectoderm in a layer of constant thickness. A thin sup- 

 porting lamella of mesogloea lies between the two. As the 

 bud increases in size it bulges out at its base, around the 

 stalk which connects it with the polyp, and it also devel- 

 ops rapidly at the tip of the free end. In this way it be- 

 comes pear-shaped (Fig. 17). As the drawings indicate, the 

 ectoderm is of the same thickness in the bud as in the pa- 

 rent polyp (Fig. 16, ect.); indeed, so nicely regulated is 

 the rate of growth of the two tissue-layers that the thick- 

 ness of the ectoderm dees not change appreciably during the 

 entire grov/th of the bad, previous to its detachment. The 

 cells of this latter layer are iri-egular, loosely constitu- 

 ted, and coarsely granular, and their walls are hardly dis- 



