The ovaries are supplied with blood by the spermatic arteries, which are of course considerably shorter in the female; they pass between the two layers of the broad ligament to the ovarium, assuming there a beautifully convoluted arrangement, very similar to the convoluted arteries of the testis. These vessels traverse the ovary nearly in parallel lines, forming numerous minute twigs, which have an irregular knotty appearance from their tortuous condition, and appear to be chiefly distributed to the Graafian vesicles. The external covering of the ovaries is formed by peritoneum, which here receives the name of _Inducium_; it envelopes the parenchymatous tissue of the gland called _stroma_, which is a dense laminar cellular tissue of a reddish colour; its external portion which is in contact with and firmly adherent to the indusium, is condensed into a species of covering of a firm structure and whitish colour, and is called the _tunica albuginea of the ovary_. In the substance of the stroma are embedded a number of vesicles of various sizes, which, although previously described by Vesalius and Fallopius, have been called Graafian vesicles, after De Graaf. These do not commonly become visible until the seventh year, from which period they gradually enlarge until puberty, when the ovaries increase in size, become softer and more vascular, and one or two of these vesicles may be observed to be larger, more developed, and projecting considerably from the surface of the gland. The proper capsule of the Graafian vesicle is composed of two layers. The outer is formed of dense cellular tissue, in which are ramified many blood vessels; the inner layer is thicker, softer, and more opaque than the preceding, to which it is closely united, and from which it receives vascular twigs. _Ovum._ The contained part or nucleus of the vesicle of De Graaf consists of, first, a granulary membrane, enclosing, secondly, a coagulable granular fluid; thirdly, connected with the granulary membrane on one side is a circular mass or disc of granulary matter, in the centre of which is embedded, fourthly, the ovum. This disc, called by Baer the _proligerous disc_, presents in its centre on the side towards the interior of the vesicle, a small rounded prominence, called the _cumulus_, and on the opposite side a small cup-like cavity hollowed out in the cumulus. The cavity is for the reception of the ovum.[1] [Illustration: _Diagram of a section of the Graafian Vesicle and its contents, showing the situation of the Ovum._ _a_ The granulary membrane. _b_ The proligerous disc. _c_ Ovum. _d_ The inner and outer walls of the Graafian vesicle. _e_ Indusium of the ovary. _From T. W. Jones._]