The Frog: A Representative Vertebrate 67 



subclavian carries blood from the arm, the superficial muscles, and 

 the skin. 



The posterior vena cava has its beginning when the many veins 

 from the kidneys and reproductive organs join. 



EXTERNM. XIGULAR 



SCIATIC 



Fig. 17. — The venous system of the bullfrog. 



Those veins carrying blood to the kidneys make up the renal 

 portal system. Blood from the jemoral and sciaiic veins of the legs 

 and the dorsal lumbar from the back passes into the renal portal vein 

 which terminates in the capillaries of the kidney. After being filtered 

 in the kidney, this blood returns to the heart by means of the renal 

 veins and the posterior vena cava. 



