Marriner. — On the Anatomy of Hyla aurea. 261 



II. Right Anterior Vena Cava. 



This vein and its branches correspond to the left. 



III. Posterior Vena Cava (fig. 2, p.v.c.). 



This is a large median vein, returning blood from the kidneys 

 and reproductive organs. It is formed by five or more pairs 

 of renal veins, and then runs forward amongst the viscera, 

 through the liver, on to the sinus venosus. Just after emerging 

 from the liver a pair of hepatic veins join it. 



The pulmonary veins are a pair of small veins, and are often 

 very difficult to see. They return blood from the lungs, and 

 run along its inner side to the heart, where they unite, and open 

 into the left auricle. 



Portal Systems. 

 A. Renal Portal System. 



The large femoral vein (fig. 2, /.), which comes up the leg, 

 bifurcates as it enters the body-cavity. The ventral branch 

 forms a portion of the hepatic portal system — namely, the 

 left pelvic vein. The dorsal branch runs along the dorsal body- 

 wall to the lower end of the kidney and joins it on its outer 

 margin. This branch is the left renal portal vein (fig. 2, r.p.), 

 and on its way is joined by two smaller veins. The left 

 sciatic vein (fig. 2, sc.) brings blood from the back of the thigh, 

 and, coming in from the inner side of the leg, joins the renal 

 portal about half-way between its commencement and its junc- 

 tion with the kidney. 



The left ileo-lumbar (fig. 2, i.l.) is the name I have given to 

 a medium-sized vein bringing blood from the dorsal body-wall. 

 It commences up near the arms, and runs down more or less 

 parallel with the backbone, and about 10 mm. away from it, until 

 it is near the lower end of the kidney, when it turns in and joins 

 the renal portal just after it leaves the femoral. 



The left lumbar vein (fig. 2, lum.) is a vein bringing blood 

 from the dorsal body-wall by several branches, and after uniting 

 to form a single vein it joins the renal portal vein about half- 

 way along its length, and on its outer margin. 



The right side of the renal portal system is similar to the 

 left. 



B. Hepatic Portal System. 



The anterior abdominal (fig. 1, a.a.v., and fig. 2, a.a.v.) is a 

 median vein running on the under-surface of the ventral body- 

 wall from the pelvic girdle to the liver. It is made by the union 

 of the pelvic veins (fig. 2, pel.), which are the ventral branches 

 of the femoral veins. It runs forward along the ventral body- 

 wall until over the liver, where it runs down and breaks up into 



