770 



GENERATION. 



The ova here present an epithelial covering and are embedded in a mass of 

 the epithelial lining of the follicle, the membrana granulosa, this mass being 

 called the discus or cumulus proligerus. 



At or near the period of their maturity the Graafian follicles present 

 several coats and are filled with an albuminous liquid. The mature follicles 



\ v ., L->^; ,' '..'/, ^-'7/A 



\ 



FIG. 276. Portion of a sagittal section of the ovary of an old bitch (Waldeyer). 



a, ovarian epithelium ; b, b, ovarian tubes ; c. c. younger follicles ; d, older follicle : e. discus proligerus, 

 with the ovum ; /, epithelium of a second ovum in the same follicle ; 0, fibrous coat of the follicle ; 

 h. proper coat of the follicle ; i, epithelium of the follicle (membrana granulosa) : k, collapsed, 

 atrophied follicle : I, blood-vessels ; in. TO, cell-tubes of the parovarium. divided longitudinally and 

 transversely ; y, tubular depression of the ovarian epithelium, in the tissue of the ovary ; z, begin- 

 ning of the ovarian epithelium, close to the lower border of the ovary. 



project just beneath the surface and form little, rounded, translucent eleva- 

 tions. The smallest follicles are near the surface, and as they enlarge, at 

 first they become deeper, as is seen in Fig. 276, becoming superficial only as 

 they approach the condition of fullest distention. 



Taking one of the largest follicles as an example, two fibrous layers can 

 be distinguished ; an outer layer, of ordinary connective tissue, and an inner 

 layer, the tunica propria, formed of the same kind of tissue, with the differ- 

 ence that as the follicle enlarges the inner layer becomes vascular. The 



