396 



THE DEVELOPMENT OF THE CHICK 



to almost eliminate the stroma, a condition that lasts up to the 

 twelfth day, at least, after which the quantity of the stroma 

 increases again with the ingrowth and enlargement of the 



blood-vessels. 



As the testis increases in size it projects more from the surface 

 of the Wolffian body, and folds arise above and below it as well 

 as in front and behind, that progressively narrow the surface 



s.6. 



FIG. 227. Section through the gonad of a chick in the middle of the fifth 



day. Indifferent stage. The sexual cords have reached the germinal 



epithelium; the primitive ova are appearing in the cords. (After Semon.) 



c T., Connective tissue, germ. Ep., Germinal epithelium. M. ep., 



Epithelium of the mesentery, pr. O., Primitive ova. s. C., Sexual cords. 



of apposition, which in this way becomes gradually reduced to 

 form the hilum of the testis, through which the sexual cords pass 

 to the neighboring renal corpuscles (cf. Figs. 221 and 222). 



As the testis is attached to the anterior portion of the Wolffian 

 body, the latter may be divided in two portions, an anterior 



