314 



COMPARATIVE MORPHOLOGY OF VERTEBRATES 



veloped, there being a subclavian vein entering the Cuvierian duct, 

 and occasionally a brachial vein which may empty into the sinus 

 venosus. In the amphibia a cutaneus magnus vein (fig. 343), 

 coming from the skin of the trunk, may enter the subclavian, while 

 in all tetrapoda the subclavian, after leaving the Hmb, receives a 

 superficial cephalic and an axillary vein, the latter changing its name 

 in the appendage to the brachial vein. In the hind limb the com- 



mie. 334. — A , venous system of Ceratodus, dorsal view, after Spencer; 5 , of a urodele, 

 ventral view, aft, abdominal vein; av, venae advehentes; b, brachial; c, caudal; cd, 

 Cuvierian duct; ej, external jugular; h, heart; hp, hepatic portal; ij, inferior jugular; 

 j, jugular; il, iliac; I, liver; Ic, lateral cutaneous; m, mesonephros; p, postcava; pc, post- 

 cardinal; r, venae revehentes; s, subclavian; t, testes. 



mon iliac vein is formed by the union of the femoral and sciatic 

 (ischiadic) veins, as well as the h3T)ogastric (internal iliac) vein 

 already referred to. 



In the classes above fishes (dipnoi, amphibia and amniotes) a new 

 vein, the postcava (vena cava inferior) appears. This arises in part 

 from scattered spaces, in part as a diverticulum of the sinus venosus 

 and the hepatic veins, and grows backward, dorsal to the liver, 

 until it meets and fuses with the right subcardinal vein (figs. 332, 



