This image shows a section through a mature cat ovary.  The ovary consists of four layers. The very thin, darkly staining germinal epithelium is the outermost covering, immediately beneath which is a pinkish, somewhat thicker layer of fibrous tissue called the tunica albuginea.  Most of the mass of the ovary is divided into an outer cortex and an inner medulla.  The stroma (which is found in both the cortex and medulla) is the region of connective tissue deep to the tunica albuginea into which follicles and blood vessels are embedded.  In this large view of the ovary you can see several  stages of follicular development, the earliest of which are the primordial follicles.  These structures are located in clusters in the cortical (outer) stroma, very near the tunica albuginea.  A primordial follicle consists of a primary oocyte surrounded by a single layer of flat follicular cells.  The cortex of the ovary contains many primordial follicles, which may eventually  develop into mature Graffian follicles.