256 



Notes on the Wolffian Body of Hio;lier Mammals 



4. Blood-Vessels of Wolffiax Body of Embryo Pig. 



The arteries of the Wolffian body in an embryo 40-80 mm. in length 

 arise from the lower half of the aorta. Their nnmber varies from five 

 to eight. They run in a slant direction posteriorly across the lower 

 part of the kidney and enter the Wolffian body at its medial border. 

 Entering the organ here they break np into branches which pro- 

 ceed to the glomeruli. The position of the latter in the organ has 

 been described. It is shown again in Fig 12. Each arterial branch 



Fig- 14 



- V 



Fig iZ. 



Fig. 12. Thick transverse section of Wolffian body of a pig's embryo 4.5 mm. long. 

 Ttie blood vessels are injected. The arteries, veins and glomeruli can readily be 

 distinguished. 



FigT 13. Ventral aspect of Wolflian body of a pig's embryo 45 mm. long, showing 

 the surface veins and the arteries entering the organ. 



Fig. 14. Cross section of Wolffian body, kidney, and sexual gland, showing the 

 .relation of their veins. 



Fig. 1.5. Three tubules from a thick section of the Wolflian body of embryo pig 

 45 mm. long, showing the capillary plexuses in the walls. 



may supply one or more glomeruli; or, on the other hand, one glomer- 

 ulus may receive several branches from one artery. The afferent 

 arterial branches break up to form the large plexus of capillaries making 

 up each glomerulus. No definite arrangement of these capillaries can 

 be made out. The glomeruli are many times as large as those of the 

 permanent kidney. From each glomerulus there arise two or more 

 efferent arteries. These usually proceed from the side opposite the 

 entry of the afferent vessels. As many as five of these are often seen 

 in a thick section. They run out radially from the glomeruli and form 

 networks of capillaries around the Wolffian tubules. From these the 

 veins arise, as shown in Fig. 12. 



