394 THE FEMALE KEPKODUCTIVE OKGANS 



THE CORTEX of the ovary likewise contains a vascular stroma 

 and also large numbers of ova which are in all stages of develop- 

 ment, from the genetic cells of the germinal epithelium up to the 

 more mature germ cells, contained within epithelial sacs and 

 known as Graafian follicles. During the menstrual epoch the 

 ovaries also contain peculiar yellowish bodies, corpora lutea> result- 

 ing from the rupture of the largest Graafian follicles, a phenome- 

 non which marks the climax of the process of ovulation. 



The stroma of the ovarian cortex is a connective tissue structure 

 which contains relatively few elastic fibres and, except near the 

 medulla, very little if any smooth muscle. It is, however, abun- 

 dantly supplied with connective tissue cells of large size, most of 

 which are ovoid, fusiform, or even considerably elongated in shape. 

 Many of these cells closely simulate smooth muscle on superficial 

 examination, but are readily distinguished by careful study, espe- 

 cially if specimens are prepared by the various differential staining 

 methods. 



In the vicinity of the Graafian follicles the stroma is specially 

 rich in cellular elements and is otherwise modified to form a con- 

 centric coat for each of these bodies. This coat, the tkeca foUicuU, 

 consists of (a) an outer layer, or tunica externa, composed chiefly 

 of connective tissue whose interlacing bundles are concentrically 

 disposed, (#) an inner layer, tunica interna, which is peculiarly 

 rich in large ovoid cells, and (c) an innermost membrana propria, 

 upon which the epithelial cells of the follicle directly rest. 



At the surface of the ovary the cortical stroma forms a dense 

 layer of fine connective tissue fibres whose delicate bundles inter- 

 lace in a close-meshed network. This layer, which immediately 

 underlies the germinal epithelium at the surface of the ovarian 

 cortex, is known as the tunica albuginea. It differs greatly in 

 thickness in different mammalian species, in different individuals 

 of the same species, and even in different portions of the same 

 ovary. Its deeper surface blends insensibly with the underlying 

 stroma of the cortex. 



The general appearance of the ovary varies according to the 

 number, size, and stage of development of its ova and Graafian 

 follicles. At birth the cortex is packed with large numbers of 

 newly formed ova, all of which are in approximately the same 

 stage of development. During childhood the formation of larger 

 follicles goes forward at an unequal rate, some ova rapidly ap- 

 proaching maturity, others apparently remaining almost stationary, 



