358 SPLANCHNOLOG Y. 



OVARY. 



The ovaries, being the analogues of the testes, are the ultimate 

 organs of generation in the female. They are ovoid, similar in 

 shape to, but smaller than the testicles, and are situated in the 

 sublumbar region of the abdomen, being suspended from its roof, 

 a little behind the kidneys ; they are attached anteriorly to the 

 broad ligament of the uterus, behind and below the Fallopian 

 tubes. In addition to this connection, they are attached at their 

 inner end to the uterus by a muscular cord, the ligament of the 

 ovary, and by their rounded outer end to the fimbriated extremity 

 of the Fallopian tube ; they are also supported by their blood- 

 vessels, which enter anteriorly at a depression called the hilus. 

 An ovary possesses an external serous investment from the 

 peritoneum ; and beneath is the dense fibrous tunica albuginea, 

 resembling that of the testicle, which encloses the stroma, a firm 

 reddish-white vascular substance, consisting for the most part of 

 connective tissue, and apparently continuous with the external coat. 

 Within are numerous small, round ovisacs or Graafian vesicles, 

 which consist of two coats, an external vascular and an inner one, 

 the ovi-capsule, lined by a granular and so-called epithelial layer, 

 the membrana granulosa. The granular cells of which this 

 is composed accumulate at one part of the vesicle forming the layer 

 (cumulus proligerus"), in which is embedded a small, round vesi- 

 cular body, the true ovum. The Graafian vesicle contains a fluid 

 secreted by the cells, and this fluid increases in quantity as the 

 vesicle develops, and at the same time the latter gradually 

 approaches the surface of the ovary, the intervening stroma be- 

 coming absorbed. Ultimately the wall of the ovary and the 

 Graafian vesicle give way, the ovum escapes into the Fallopian 

 tube, and is by it conveyed into the womb, the remains of the 

 vesicle being converted into a yellow mass, the corpus luteum, 

 which shortly becomes a small puckered cicatrix. 



The ovum or egg is in the higher animals microscopic, being 

 about T^TJ- of an inch in diameter. It is a cell, possessing all 

 the characteristics of such ; the cell wall is called the zona 

 pellucida, vitelline or yelk membrane, which contains a proto- 

 plasm called the vitellus or yelk ; the nucleus of the cell is known 

 as the germinal vesicle, the nucleolus as the germinal spot. 

 The arteries are derived from the utero-ovarian. 



