634 



REPRODUCTIVE ORGANS. 



projecting part and permitting the escape of the ovum. The wall 

 of the follicle, theca folliculi, is a condensed layer of the stroma, 



Membrana 

 granulosa. 



Discus 

 proligerus. 



Ovtun. 



Germinal vesicle. 



Blood-vessel. 



FIG. 418. Section of fully developed Graafian follicle from injected ovary of pig; 

 X 50 (Bohm and Davidoff ). 



and is itself divisible into an outer layer of fibrous connective 

 tissue, tunica externa, and an inner, tunica internet, which is charac- 



_, terized by the presence of 

 ^~x -'l^i^L blood-vessels and of cells. 



Within the theca is the mem- 

 brana granulosa or stratum 

 granulosum, which is com- 

 posed of several layers of 

 small polyhedral cells. In 

 one portion of the membrana 

 granulosa the cells are very 

 numerous, constituting the 

 discus proligerus, in which 

 the ovum lies embedded. 

 The cells of the discus pro- 

 ligerus which are in contact with the ovum are arranged radially, 

 constituting the corona radiata (Fig. 422). Between the discus 

 proligerus and the membrana granulosa, except at the point where 

 the two are in contact, is a cavity, the antrum, which is filled with 



FIG. 419. Ovary with mature Graafian 

 follicle about ready to burst (Ribemont- 



