SEX-COKDS AND SPERMATOGONIA IN CHICK 



401 



amoeba. They or rather their ancestors, the primordial germ- 

 cells, had this power in their early history, and it may ha\'e b(HMi 

 in abeyance during their sojourn in the germinal epithelimn and 

 sex cords, only to be assumed again at this time. Color is lent 

 to this theory by the fact that frequently, at this stage, the end 

 of the spermatogonium turned toward the basement mem- 



A". .XT , 





Fig 6 Portion of a transverse section through the left testis of a chick 3 

 days old. This section shows a seminiferous tubule containing spermatogonia 

 and supporting cells. The spermatogonia are next the basement membrane and 

 have a definite polarity — nucleus near the central portion of the tubule and 

 mitochondrial crescent at the basement membrane. The supporting cells are 

 descendants of the peritoneal cells. 



brane is pointed, as if it were forcing its way in that direction 

 between the intervening cells (fig. 5). 



The cords, although forming a network, are again beginning 

 to have a definite orientation, that is, they run obliquely from 

 the germinal epithelium towards the remains of the Wolffian 

 bodv. 



