Charles F. W. McClure 387 
Owen, and finds that in both animals the left precava opens into the 
auricle in common with the postcava. 
2. The hepatic division of the postcava (H., Text Fig. V), which lies 
within the liver, includes that portion of the vein into which hepatic veins 
open. ‘The hepatic veins open into the postcava by means of three large 
and two or three small branches. The small branches return the blood 
from the caudate lobe of the liver. 
3. The renal division of the postcava (R., Text Fig. V), includes that 
section of the vein which lies between the most caudal of the hepatic veins 
and a point just behind the most caudal of the two renal veins, so as to 
include that portion of the postcava into which the renal veins open. 
The right suprarenal body is firmly attached to the dorsal surface of 
the posteava in this region, and its cranial end is embedded in the 
caudate lobe of the liver. The only direct tributaries which the renal 
division receives are the V. suprarenalis dextra, which opens into the 
dorsal surface of the postcava, and the Vv. renales. 
The right renal vein usually opens into the postcava cranial to the 
left and about opposite the first lumbar vertebra. The left renal vein, 
which hes just caudal to the Truncus coeliacomesentericus, opens into 
the postcava about opposite the second lumbar vertebra. The left supra- 
renal body lies upon the left renal vein into which its vein opens. 
Multiple renal veins, especially on the right side, were frequently met 
with and, in a few cases, the right renal artery was found to cross the 
postcava on its ventral instead of its dorsal surface. 
The first three divisions of the postcava, with the exception of that 
portion into which the renal veins open, occupy a position, as in other 
mammals, on the right side of the body ventrolateral to the aorta and 
at no point come in contact with the latter. At the level of the renal 
veins, however, the postcava bends mediad so as to reach the ventral sur- 
face of the aorta and occupies this position with respect to the aorta as 
far caudad as the Vv. iliace externe. 
4. The postrenal division of the postcava (PR.) consists of that por- 
tion of the vein which lies caudal to the renal veins (V. r.). (See Text 
Figs. V and IX and Fig. 23, Plate V.) Its tributaries consist of 
two or three pairs of Vy. lumbales, the Vv. spermatice interne and the 
Vy. iliace. The caudal end of the azygos vein also joins this division 
of the posteava. Each pair of lumbar veins may open into the posteava 
either as single vessels or by means of a common trunk. The internal 
spermatic veins (V. sp. i.) open into the postcava slightly caudad of a 
point midway between the renal and external iliac veins, the vein of the 
right side being slightly cranial to the left. 
