DISSECTION OF THE PELVIS. 



365 



2. The Stroma is composed of fibrous connective tissue with some 

 bundles of non-striped muscular tissue. Some coarser strands start 

 from the bottom of the ovulation fossa, and diverge radially towards the 

 periphery of the organ. In the softer greyish parenchyma between these 

 strands the Graafian follicles are situated, the smaller ones being found 

 towards the centre of the organ, and the larger near the surface. A 

 layer of condensed stroma without any Graafian follicles lies beneath the 

 surface epithelium, and is sometimes termed the tunica albiiginea of the 

 ovary. 



Fig. 51. 



Section of Cat's Ovary, magnified (from Schron). 



1. Outer covering of the ovary ; 2. Fibrous stroma ; 3. Superficial iayer of iibro-nuclear substance ; 

 3'. Deeper parts of the same ; 4. Blood-vessels ; 5. O vi-sacs forming a layer near the surface ; (J. One 

 or two of the ovi-saes sinking deeper and beginning to enlarge ; 7. One of the ovi-sacs farther 

 developed, now enclosed by a prolongation of the fibrous stroma, and consisting of a small Graafian 

 follicle, within which is situated the ovum covered by the cells of the discus proligerus ; S. A follicle 

 farther advanced ; 8'. Another which is irregularly compressed ; 9. The greater part of the largest 

 follicle, in which the following parts are seen ; a. Cells of the tunica granulosa lining the follicle ; 

 b. The reflected portion named discus proligerus ; c. Vitellns or yelk part of the ovum, surrounded 

 by the zona pellucida ; d. Germinal vessicle ; e. Germinal spot. 



3. The Graafian Follicles, or Ovi-sacs. — These are vesicular bodies for 

 the maturation and extrusion of the ova. A large-sized follicle possesses 

 the following parts : — 



a. The wall of the follicle, composed of an inner delicate tunica 

 propria, and an outer layer — the tunica fibrosa — derived from the 

 surrounding stroma. 



b. The Memhrana Granulosa.— -Thia forms an epithelial lining to the 

 wall of the follicle, and consists of several layers of cells. At one point 



