400 THE DEVELOPIMENT OF THE CHICK 



the ovary of a fledgling of Numenius arciiatus three or four days 

 old. The germinal epithelium covers the surface and is continu- 

 ous with the ovigerous strands projecting far into the stroma. 

 The strands are broken up in the stroma into nests of cells; 

 next the germinal epithelium are found characteristic primi- 

 tive ova, but in deeper situations the primitive ova are larger 

 and each is accompanied by a group of epithelial cells, which are 

 distinctly differentiated as granulosa cells of young folHcles in 

 the deepest. Thus the young follicles arise by separation of 

 nests of cells from the ovigerous strands within the stroma; 

 each nest includes a young ovocyte and a group of epithelial 

 cells which arrange themselves in a single layer of cuboidal cells 

 around the ovocyte. On each side of the free border of the ovary 

 the embryonic state persists, and it is not known whether this 

 condition is maintained permanently, as in some reptiles, or 

 not. 



The atrophy of the Wolffian body is much more complete in 

 the female than in the male; no part of it remains in a functional 

 condition, but the part corresponding to the epididymis of the 

 male remains as a rudiment, known as the epoophoron. It has 

 almost the same structure in young females as in young males, 

 but the rete cords uniting it with the ovary do not become tubular. 

 A rudiment of the non-sexual part of the Wolffian body is also 

 found in the hen between ovary and kidney in the lateral part of 

 the mesovarium; it has been named the paroophoron. 



Development of the Genital Ducts. The Wolffian Duct. The 

 origin and connections of the Wolffian ducts have been already 

 sufficiently described. In the male they are connected with the 

 seminiferous tubules by way of the epididymis, vasa efferentia, 

 and rete, and function as vasa deferentia exclusively, after de- 

 generation of the mesonephros. Subsequently they become 

 somewhat convoluted, acquire muscular walls and a slight ter- 

 minal dilatation. The details of these changes are not described 

 in the literature. In the female the Wolffian duct degenerates; 

 at what time is not stated in the literature, but presumably along 

 with the Wolffian body. 



The Mullerian Duct. The Miillerian duct, or oviduct, is laid 

 down symmetrically on both sides in both male and female em- 

 bryos; subsequently both right and left Mullerian ducts degen- 

 erate in the male; in the female the right duct degenerates, the 



