768 PROCEEDINGS OF THE ACADEMY OF [DeC, 



The first indication of the appearance of a bud upon any indi- 

 vidual polyp was a rounded eminence upon the hydrocaulus (fig. 

 2), It was usually located at a level about half-way between the 

 base of the polyp and the ring of tentacles, as in the figure, and 

 interradially — i.e., at the end of a radius which bisects the angle 

 between two tentacles (fig. 6). Never more than a single bud 

 appeared at one time upon any polyp. 



All three body-layers — ectoderm, endoderm and mesogloea — of 

 the parent are involved in the formation of the bud. The cells 

 of both ectoderm and endoderm midtiply 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 (fig. 3). A 



Fig. 3. Fig. 4. 



Same bud eight hom-s old. Bud one day old. 



thin supporting 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 Avith the polyp, and it also develops rapidly 

 at the tip of the free end. In this vmj it becomes pear-shaped 

 (fig. 4), As the drawings indicate, the ectoderm is of the same 

 thickness in the bud as in the parent (fig. 3). Indeed, so nicely 

 regulated is the rate of growth of the two tissue-layers that the 

 thickness of the ectoderm does not change appreciably during the 

 entire growth of the bud, previous to its detachment. The cells of 

 the endoderm are irregular, loosely constituted and coarsely granu- 

 lar, and their vvalls are hardly discernible. No cavity exists in 

 the bud until considerably later. The endoderm of the bud now 

 becomes separated from that of the parent, by the constriction of the 

 ectoderm and the cutting off of the core of endoderm which filled 

 it. Its appearance is as represented in fig. 5, an isthmus of clear 

 elastic ectodermal tissue uniting the bud to the parent. By rapid 



