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 
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.) 
e 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 (ef. 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 
