CHAP, viii.] OEGANS OF EESPIEATION AND SECEETION. 249 



blood-vessels, and some muscular fibres. It lias an outer epithelial 

 covering, and contains embedded vesicles of various sizes — called 

 Graafian foUldes — containing the ova, or true female sexual 

 product. 



In the stroma of the ovary there is but little fibrous connective 

 tissue. It is made up mainly of large spindle-shaped cells,* which 

 surround the Graafian follicles, being arranged concentrically about 

 them. 



Upon dividing the ovary, vesicles of various sizes are seen within, 



Fig. 119.— Portion of the Section of thk prepared Cat's Ovary, represented in the 



PRECEDING FKiDRE, .MORE HIGHLY MAGNIFIED. 



1. Outer covering of the ovaiy. 



2. Fibrous stroma. 



3. Superficial layer of fibro-uuclear substance. 

 3'. Deeper parts of the same. 



4. Blood-vessels 



.5. Ovigerms forming a layer near the surface. 



0. One or two of the ovigenns sinking deeper, 

 and lieginniug to enlarge. 



7. One of the ovigerms fuitlier ileveloped, now 

 euch)sed by a i)rolongation of tlie fibrous 

 stroma, and consisting of a small Graaliaii 



follicle, within which is situated the oxmn 

 covered liy the cells of the tliscus proligerus. 



8. A follicle further advanced. 



S'. Another which is irregularly compressed. 



9. The greater part of the largest foUicle— iii 



which tlie following parts are seen : o, 

 cells of tlie membrana granulosa lining the 

 follicle ; h, the reflected iJortion, named 

 iliscus pjroligerus ; c, vitellus or yelk jiart of 

 tlie oviun, surrounded by the zona pellucida ; 

 d, germinal vesicle ; c, germinal spot. 



and these are much more numerous in the very young animal than 

 in the adult. 



These vesicles, or " Graafian foUiclcs,^' are naturally spherical or 

 oval, and have three coats. The first and most external of these, 

 the tunic of tlie ovisac, or tunica fibrosa, is a fibrous, vascular 

 membrane, containing oval nuclei, but destitute of oil globules. 

 The second coat is the ovisac, formed of connective tissue, rounded 

 cells, and minute oil globules. The third coat (if it should be 

 really recognized as distinct) is the membrana granulosa, consisting 



See Klein and Noble Smith's Atlas of Histologj-. 



