THE URIXOGEXITAL SYSTEM 



383 



duct is situated near the dorso-lateral edge of the mesonephros, 

 and the opening of a collecting tubule into it is shown in Figure 

 220. The renal corpuscles are situated next the median face of 

 the Wolffian body. The space between the tubules is occupied 



';7.f.o.z. 



Mh'tr 



-3.?V 

 iVJ). 



apmm 



Gon.l 



Fig. 221. — Transverse section through the metanephros, mesonephros, 

 gonads and neighboring parts of an 8-day chick, 

 bl. v., Blood vessels (sinusoids). B. W., Body-wall. col. T. M't'n., 

 Collecting tubules of the metanephros. M. D., Miillerian duct. M's't., Mesen- 

 tery, n. t. i. z., Inner zone of nephrogenous tissue (metanephric). n. t. o. 

 z., Outer zone of the nephrogenous tissue. Symp. Gn., Sympathetic o^ang- 

 hon of the twenty-first spinal ganglion. V. C, Centrum of vertebra. Other 

 abbreviations as before. 



almost entirely by a wide vascular network of sinusoidal char- 

 acter; that is, the endothelial walls of the vessels are moulded 

 directly on the basement membrane of the tubules without any 

 intervening connective tissue. The circulation is described in the 

 chapter on the vascular system. 



