COLUMBA. 365 
crescentic and has a thin outer wall, its inner wall being 
formed of the thick wall of the left ventricle. 
The venous system consists of two complete parts—(r) 
the two pulmonary veins which are short and lead directly 
from the lungs to the d/¢ auricle, and (2) the systemic 
system which leads into the right auricle. There is no 
Fig. 258.—VENTRAL VIEW OF THE VENOUS SysTEM OF 
THE PIGEON. (Ad nat.) 
Vertebral. External Jugular. 
Brachial. 
y— Pectoral. 
Precaval. Aperture to Right 
Auricle, 
Left Lobe of Liver. 
Postcaval. 
Right Lobe of Liver. 
Anterior Lobe 
of Kidney. 
Renals. 
Portal. 
Gastric. 4 . 7 B- Femoral. 
. Middle Lobe of 
Anterior Kidney. 
Mesenteric. 
B‘Sciatic. 
Posterior Lobe 
of Kidney. 
— Internal Iliac. 
Posterior Mesenteric. 
Renals. 
Caudal. 
The lobes of the liver are drained by hepatic veins, and the left hepatic receives a 
long epigastric from the omentum, seen hanging down the centre. 
Sinus venosus, but three large veins converge together to. 
open into the auricle. Two are paired and anterior and 
are called the pvecavals; the other one is median and 
posterior, called the ostcaval. 
The precavals are formed of three large veins, the 
jugular from the head and neck, the érachial from the 
wing and the fectora/ from the flight-muscles. The two 
