THE RABBIT 



451 



Veins. 



Each superior vena cava is formed by the union of 

 a subclavian vein from the shoulder and fore- 

 limb, an external jugular from the surface of 

 the head, and an internal jugular from the brain. The 

 right superior vena cava receives also an azygos vein from 

 the walls of the chest. The external jugular is larger than 



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Fig, 329. — Diagrams of the venous system. 

 A , of a dogfish ; B, of an amphibian ; C, of a rabbit. 



The main system in grey ; the system of the lateral and anterior abdominal veins 

 in black ; the inferior vena cava in white. The hepatic portal system is omitted. 

 1, Entry to heart ; 2, left superior vena cava or precaval or ductus Cuvieri ; 3, left 

 internal jugular or anterior cardinal ; 4, left external jugular or inferior jugular, 

 or sub-branchial ; 5, left subclavian ; 6, left posterior cardinal ; 6', position of 

 same in a newt ; in the frog the posterior cardinals are absent ; in the rabbit 

 the portion shown by dots is wanting ; 6", right azygos vein representing right 

 posterior cardinal in a mammal ; &", left azygos vein ; 7, left deep lateral vein ; 

 7', pelvic ; 7", anterior abdominal, representing both deep laterals fused ; 8, 

 renal portal; 9, caudal (wanting in frog); 10, external iliac or femoral; 11, 

 internal iliac or hypogastric ; 12, inferior vena cava or postcaval : 13, junction 

 between azygos veins. 



the internal and lies nearer the surface in the neck. The 

 inferior vena cava is a large median vessel which lies beside 

 the dorsal aorta. It receives the following veins : (i) The 

 internal iliacs or hypogastrics from the back of the thighs, 

 (2) the external iliacs from the inside of the thighs, (3) the 

 ilio-lumbars from the hinder part of the abdominal walls, 

 (4) the genital veins, (5) the renal veins, (6) the large hepatic 



