ABSENCE OF THE INFEKIOR CAVA BELOW THE DIAPHRAGM. 9 



right, concerning the termination of which it is impossible to 

 say anything certain.^ It probably joined the main vein just 

 after it passed behind the aorta to the right. An ascending 

 branch empties into it from below at this point (fig. 3). It has 

 a remnant of the 10th intercostal, and there is a hint of the 

 point of entrance of the 9th. This ascending branch is broken 

 off opposite the 10th. Left intercostal veins enter the main 

 vein opposite the lower four thoracic vertebrse. Of the upper 

 left ones nothing is known. The vessels of the kidneys are as 

 follows: On the right, an artery leaves the aorta just to the 

 right of the origin of the superior mesenteric, and presently 

 divides into three branches, of which the lowest is much the 

 largest. This last goes to the kidney at about the middle, 

 while the two smaller ones go to the top, or perhaps to the 

 suprarenal capsule. Another artery leaves the aorta about 2'5 

 cm. lower, and runs straight out to the kidney, which it enters at 

 the hilum, rather below the middle. The renal vein leaves the 

 kidney at the top of the hilum in front of the superior artery, 

 and behind the inferior one. It is soon joined by a smaller 

 branch from the upper part of the kidney, which passes in front 

 of the lower branches of the upper renal artery. This probably 

 anastomosed with some other detached veins. This system 

 is presumably connected with the broken ascending vein already 

 mentioned that opened into the main vein after it had entered 

 the right chest. The renal vein, receiving on the front of the 

 spine an ascending vein (figs. 1 and 3), that shall be discussed 

 later, passes behind the aorta, opposite the upper part of the 2nd 

 lumbar vertebra, to empty into the main trunk. 



On the left the renal system is more simple. There are two 

 arteries, each arising nearly opposite its fellow, but a little 

 lower. The upper enters the kidney at the top of the hilum in 

 front of the vein, and the other at the lower end of the hilum 

 and behind the vein. The renal vein joins the main trunk at a 

 higher level than the right one. It is formed by three branches, 

 uniting just before its end. The ureter is behind the vessels. 

 The ascending lumbar veins on the left (figs. 1 and 2) are 

 represented by a single long trunk running along the pedicles 



1 In fiff. 3 the intercostals appear to empty into the azygos ; bnt in fact the 

 vessel referred to is hidden by it. 



