THE VEINS 399 



mary vein, which runs along the inner surface 

 of the thoracic wall. 



b, The left anterior vena cava returns blood from the 



left side, by veins corresponding to those open- 

 ing into the right vena cava. At the base of the 

 heart, it runs transversely across the dorsal 

 surface of the left auricle, to open into the left 

 border of the right auricle. 



To see the opening of the left vena cava into the auricle, 

 lift up the, apex of the heart and turn it forwards. 



c, The posterior vena cava returns blood from the pos- 



terior part of the body, including the liver. 



It is formed by the union of the two iliac 

 veins a short distance behind the liver. The vein, 

 so formed, runs forwards through the substance 

 of the right lobe of the liver, close to its dorsal 

 surface : it receives the hepatic veins as it leaves 

 the liver, and then runs forwards as a short wide 

 vessel to open into the posterior surface of the 

 right auricle. 



Turn the heart forwards, to expose the posterior vena cava 

 as it enters the right auricle. Follow it back through the 

 liver, slitting it up and washing out the contained blood. 

 Note the openings of the hepatic veins, and follow them with 

 a seeker into the liver. Follow thj2 vena cava back, behind 

 the liver, to the point where it is formed by the union of the 

 right and left iliac veins. 



2. The veins of the kidneys. 



The veins in connection with the kidneys are 

 rather complicated, and are best dissected in specimens 

 injected from the femoral vein. Their relations may, 

 however, be determined by slitting them open and 

 following them with a seeker. 



The kidneys are a pair of three-lobed bodies, 

 attached to the ventral surface of the ilia, immediately 

 behind the lungs. 



