GENERATIVE ORGANS OF THE FEMALE 



179 



muscular fibres. It is covered by a layer of small columnar epithelium- 

 cells (germinal epithelium, fig. 216, a], between which are here and 

 there to be seen a few larger spheroidal cells, with large round nuclei 

 (primitive ova, fig. 218, c). In the young subject the epithelium may 

 occasionally clip down into the subjacent stroma. 



The stroma is beset with vesicles of different sizes, the smallest 



FIG. 216. SECTION OF THE OVAUY OF AN ADULT BITCH. \ 5 



, germ-epithelium ; b, egg-tubes ; c, c, small follicles ; d, more advanced follicle ; e, discus pro- 

 ligerus and ovum ; /, second ovum in the same follicle (this occurs but rarely) ; g, outer 

 tunic of the follicle ; h, inner tunic ; i, membrana grauulosa ; k, collapsed retrograded 

 follicle ; I, blood-vessels ; m, m, longitudinal and transverse sections of tubes of the paro- 

 varium ; y, involuted portion of the germ-epithelium of the surface ; z, place of the transi- 

 tion from peritoneal to germinal or ovarian epithelium. 



being near the surface of the organ, the larger ones placed more deeply 

 in the stroma, although, as they increase in size, they may again tend 

 to approach the surface. 



These vesicles are the Graafian follicles. Each Graafian follicle 



N2 



