THE URIXOGEXITAL SYSTEM 



389 



co/T. 



si 



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Fig. 225. — Sections of the embryonic metanephros of the chick 

 to show developing tubules. (After Schreiner.) 



A. Nephric vesicle or primordium of secreting tubule (ur t ) 

 and collecting tubule (col. T.); 9 days and 4 hours. 



B. Elongation of nephric vesicle; same embryo. 



C. Indication of renal corpuscle at the distal end of the 

 lormmg tubule. 



D. The secreting tulMile appears S-shaped. 



E. Secreting tubule well formed; 9 days and 21 hours 



i^. Secreting tubule opening into collecting tubule; 11 days 



