822 



THE REPRODUCTIVE ORGANS 



[CH. LVIIl. 



The cells in each layer multiply, and are eventually arranged in 

 several strata. The lining epithelium of the follicle is then called 



Fio. 614. View of a section of the ovaiy of the cat. 1, Outer covering and free border of the ovary ; 1', 

 attached border ; 2, the ovarian stroma, presenting a fibrous and vascular structure ; 3, granular 

 substance lying external to the fibrous stroma ; 4, blood-vessels ; 5, ovigerms in their earliest stages 

 occupying a part of the granular layer near the surface ; 6, ovigerms which have begun to enlarge 

 and to pass more deeply into the ovary ; 7, ovigerms round which the Graafian follicle and tunica 

 granulosa are now formed, and which have passed somewhat deeper into the ovary and are surrounded 

 by the fibrous stroma ; 8, more advanced Graafiau follicle with the ovum imbedded iu the layer of 

 cells constituting the proligerous disc; 9, the most advanced follicle containing the ovum, etc.; 9', 

 a follicle from which the ovum has accidentally escaped ; 10, corpus luteum. (Schron.) 



the membrana granulosa, and the heaped mass of cells around the 

 ovum, the discus proligerus. The fluid increases in quantity, the 



A 



FIG. 615. Section of the ovary of a cat. A, germinal epithelium ; B, immature Graafian follicle ; C, 

 stroma of ovary; D, vitelline membrane containing the ovum; E, Graafian follicle showing lining 

 cells ; F, follicle from which the ovum has fallen out. (V. D. Harris.) 



follicle becomes tenser, and finally it reaches the surface of the organ 

 and bursts ; the ovum is thus set free, and is seized by the fringed 



