68 



ZOOLOGY 



SECT. 



into the stroma of the ovary, in which it becomes imbedded, the 

 small cells forming a Graafian follicle (foil.) which encloses it. 

 Soon spaces filled with fluid appear among the follicle cells (Fig. 

 1226, A, sp.), and these eventually coalesce to form a single cavity. 



Jbrov 



vrv 



II. V 



jell 



FIG. 1225. Part of a sagittal section of an Ovary of a new-born child, bl. v. blood-vessels ; 

 foil, strings and groups of cells derived from the germinal epithelium becoming developed 

 into follicles ; </. cp. germinal epithelium ; in. ingrowing cord of cells from the germinal 

 epithelium ; pr. OP. primitive ova. (From Hertwig, after Waldeyer.) 



This cavity, which in some Mammals is crossed by strings of cells, 

 separates an outer layer of the follicle cells the membrana 

 granulosa (mem.) from the mass cumulus proligerus (disc.) 



caps. 



ov 



disc 



Fio. 1226. Two stages in the development of the Graafian follicle. A. with the folli- 

 cular fluid beginning to appear ; B, after the space has largely increased, caps, capsule ; 

 disc, cumulus proligerus ; me tub. iiiemhrana granulosa ; or. ovum : sv space containing 

 fluid. (After Hertwig.) 



surrounding the ovum, except on one side where they coalesce. 

 A basement membrane is formed externally to the follicle 

 cells, and the stroma around this becomes vascular, and forms 



