2 20 THE SALAMANDER 



easily found from the posterior aspect of the subclavian vein, between 



this vessel and the post-cardinal vein. 



T}\Q post-cardinal vein (v.card.p.) lies very close to the oesophagus, 

 round which it passes, and is the most posterior of the veins entering 

 the ductus Cuvieri. It is only likely to be confused with the internal 

 jugular, but it is more posterior than this vessel and more mesial, 

 while its direction is slightly po5tero-dors?i\ as compared with the 

 obliquely antero-dorsal direction of the internal jugular. 



A rather tough connective tissue enclosing lymph spaces sur- 

 rounds the whole of the venous complex just described, and, as the 

 walls of the vessels are very thin, considerable care must be exercised 

 in cleaning them to avoid rupture. 



The ducts of Cuvier are often referred to as the pre-caval veins, 

 but in view of the persistence of the post-cardinal veins in a functional 

 condition, and the retention at the same time of their primitive con- 

 nexions, it would seem preferable to call the vessel formed by the 

 union of the post-cardinal vein with the derivative of the anterior 

 cardinal vein (the internal jugular) the ductus Cuvieri. 



8. Description of the Veins. 



For descriptive purposes the venous system may be divided into 

 groups according to distribution and function as follows:^ 



Veins entering the Heart direct. 



Veins of the Head. 



A. Internal Jugular (see footnote). 



B. External Jugular. 



Veins of the Trunk and Viscera. 



A. Post-caval. 



B. Post-cardinals. 



C. Subclavian. 

 Veins of the Lungs. 



Veins of the Portal Systems. 

 Hepatic Portal System. 



A. Abdominal Vein. 



B. Portal Vein. 

 Renal Portal System. 



A. Caudal Vein. 



B. Common Iliac Veins. 



C. Pelvic Veins. 



'^ The veins of the cranial cavity, factors of the internal jugular, are described at the 

 end of the present section under 'Vessels of the Brain'. 



