THE URINOGENITAL 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 
LOZ. 
Fic. 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. 1. z., Inner zone of nephrogenous tissue (metanephric). n. t. o. 
z., Outer zone of the nephrogenous tissue. Symp. Gn., Sympathetic gang- 
lion 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. 
