EMBRYOLOGY OF THALASSEMA MELLITA 238 



TEXT-FIGURE lo. 



Optical sections of early stages illustrating the origin and fate of the rudimentary 

 cells. A, two rudimentary cells as first budded off at the surface ; pg, polar glob- 

 lales, one inside a cross cell and another within the cleavage cavity. B, the same 

 two rudimentary cells sinking toward the cleavage cavity. (7, a much later stage, 

 in which a large number of rudimentary cells are found within the cleavage cavity 

 and lying on the endodermal cells. D, a still later stage showing the rudimentary 

 cells inside the endodermal cells and undergoing dissolution. E, various stages in 

 the degeneration of the rudimentary cells. 



