258 Chcas. W. and G. T. Hargitt. 



Figs. 30-37. Aurelia flavidula. Sections of developing eggs. X 715. 



Fig. 30. Very early stage of gastrulation. Yolk bodies present in all cells. In 

 the cleavage cavity is a coagulated liquid. 



Fig. 31. The invagination is nearly completed. The cells of the invagination 

 are few in number and nearly cubical; some of these cells dividing. 



Fig. 32. An oblique section giving the appearance of a cell ingression. This 

 is only apparent, for such an ingression does not occur. 



Fig. 33. Invagination completed and the blastopore closing, the entoderm 

 layer already being separated. 



