MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 219 



RENAL PORTAL. 



The Renal Portal system is formed by the bifurcation of the 

 Caudal Vein, C, PI. 11. This arises at the end of the tail 

 and runs in the haemal arches of the caudal vertebrae ventral to 

 the caudal aorta. Jvcst posterior to the cloaca the caudal vein 

 bifurcates, each branch passing along the outer side of the cor- 

 responding kidney and giving off numerous vessels, Venae Ai>- 

 VEHENTEs, V. Adv., PI. 11, into these organs. Into the renal 

 portal open the veins from the posterior extremity. 



Each of the four digits of the foot has two veins, one on either 

 side; these two veins usually unite and form short and some- 

 what larger vessels, which join to form a still larger trunk on the 

 dorsum of the foot. This latter vessel runs across the distal end 

 of the extensor digitorum muscles near the proximal end of the 

 digits. This transverse vein receives also a number of small 

 vessels which come from the tarsus. From the outside of the 

 foot this vein is continued towards the body as the Postekioe 

 Tibial Vein^ Fbl., PI. 11, which courses upwards, and near the 

 knee joint it bends gradually and passes over the knee to the 

 flexor surface of the leg. Above the knee it is continued as the 

 Femoral Vein (Sciatic?), Sci., PI. 11; this passes over the 

 hip joint and unites with the Pelvic Vein, Pel., PI. 11, about 

 10 mm from the point of union of the latter and the renal 

 portal. 



I am aware that this differs from the usual description of the 

 veins in Amphibia. Most authors describe the femoral as divid- 

 ing into two branches, a pelvic and iliac ; but no such division 

 could be made out in any of the specimens studied. The angle 

 of union between the femoral and pelvic and the size of the pel- 

 vic precludes, it seems to me, such description. 



Just below the knee the posterior tibial receives a branch 

 which comes from the median side of the leg. Midway between 

 the knee and the hip the femoral receives a considerable branch 

 from the ventral side of the thigh and from about the knee joint. 

 Just before the femoral joins the pelvic vein it receives two small 



