35 



cernible. 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 emitting off of the core of endoderm which filled 

 it. Its appearance is as represented by figure 18, an isth- 

 mus of clear elastic ectodermal tissue (ect.) uniting the 

 bud to the parent. By rapid centrifugal growth the bud be- 

 comes sausage-shaped, and as long as the diameter of the 

 polyp. Soon after the bud reaches the stage shown in fig- 

 ure 19 it becomes detached from the polyp. In only one in- 

 stance was I 3o fortunate as to see this process taking 

 place. In this individual the bud was drawn out into a 

 long finger-like body, its distal end drooping almost to 

 the ground. Soon the ectodermal isthmus began to stretch 

 out and dwindle in diameter until it was mei'ely a thin stem 

 of transparent protoplasm (Fig. 20). The bud seemed to be 

 reaching out and trying to free itself from the limitations 

 of the connection with the parent. This stretching of the 

 isthmus was bi'ought about by constriction of the tubular 

 ectoderm, as if by circular muscle-fibres. When this 

 stretching had gone on until the isthmus was a quarter as 

 long as the entire bud, (Fig. 20), it be/':an to grow still 



