190 



GENITAL GLANDS 



outwards into the germinal epithelium, while the epithelial strands grow inwards, 

 so that we have an interlocking of epithelial and connective tissues. In the early 



epitheliun 



oocutes 



FIG. 240. SECTION OF THE OVABY OF A HUMAN FCETUS OF THE SEVENTH MONTH. 

 (Figs. 239 and 240 from Felix and Biihler, Hert wig's Handbuch der Entwickelungslehre.) 



stages, a narrower cortical zone, in which the epithelial strands are closely pressed 



together and separated by a very small amount of connective tissue, is distin- 

 guished from a central medul- 

 lary zone in which, owing to 

 the increase in the vascular 

 stroma, the primary genital cords 

 are more definitely marked off 

 from one another (fig. 239) . This 

 medullary portion of the paren- 

 chyma is gradually reduced as 

 the cortical zone increases in 

 thickness, and the medullary 

 cords are reduced to a few 

 epithelial strands, in which ova 

 are no longer to be seen. The 

 body of the ovary is formed 

 from the cortical zone. The 

 epithelial columns (egg-tubes of 

 Pfliiger) become separated, then 

 cut up, by the growth of the 

 stroma, into cell-islands con- 

 taining one or more primitive 

 ova ; these again into smaller 

 groups or nests of cells, until 

 ultimately the primitive follicles 

 are isolated, each containing 

 a single ovum surrounded by a 



layer of follicular cells (fig. 241). From these the Graafian follicles are formed. 



This process, by which the stratum germinativum of the ovary is formed, goes 



FIG. 241. SECTION OF THE OVABY OF A NEWLY BOBN 

 CHILD. (Waldeyer.) Highly magnified. 



a, Germinal epithelium dipping in at b, to form an 

 ovarian tube ; c, c, primordial ova lying in the germ- 

 epithelium ; d, d, longer tube becoming constricted so as 

 to form nests of cells ; e, e, larger nests ; /, distinctly 

 formed follicle with ovum and epithelium ; g, g, blood 

 vessels. 



