CHAPTER XXV. 



OVARY AND PAROVARIUM. 

 BY W. WALDEYER. 



THE ovaries (Eierstocke) are as widely distributed through the 

 animal kingdom as the process of sexual reproduction itself. 

 If their structural characters be in many cases of such extreme 

 simplicity that it is scarcely possible to speak of them as 

 special organs, the structure of the female germ is nevertheless, 

 with perhaps the solitary exception of the Porifera, always 

 associated with a remarkably complex arrangement of cells 

 developed in a special region of the body, thus forming a 

 contrast to the mode in which the buds and germs of a 

 sexual propagation are formed. 



In the ovaries the eggs are formed, and here they ripen, 

 become invested with special protecting membranes, and often 

 remain for years. As a general rule, the more highly developed 

 is the entire organism, the more complex also is the structure 

 of the ovary. 



In the three highest classes of the Vertebrata, Mammals, 

 Birds, and Reptiles, and probably also amongst the Sharks^ 

 on which, however, I have myself made no observations, the 

 mature ovary possesses, as its essential constituents, (1) the 

 epithelium of the ovary, or germ-epithelium ; (2) the egg- or 

 Graafian-follicles, in which (3) the ova are contained. These 

 structures are supported and connected by an extremely 

 vascular stroma of connective tissue, containing also muscles 

 and nerves. 



We shall, in the first instance, discuss the arrangement and 



