VIII.] 



THE VENOUS CIRCULATION. 



211 



Fig. 64. 



SuY-4, 



SuV 



Diagram of the Venous Circulation of the Chick after the Commence- 

 ment of Respiration by means of the Lungs. 



IF. wing- vein, /.jugular vein. Su. V. superior vertebral vein. These unite 

 together on each side to form the corresponding superior vena cava. 

 L. V. pulmonary veins. V. C. I. vena cava inferior. IIP. hepatic veins. 

 P. V. portal vein. 31. mesenteric veins. At U. and O.f. are shewn the 

 points at which the umbilical and omphalo-mesaraic veins originated 

 previous to their becoming obliterated at the commencement of respiration. 

 Co. V. connecting vessel between the branches of the portal vein and the 

 vena cava inferior. It is called the coccygeo-mesenteric vein, and unites 

 the cross branch connecting the two hypogastrics with the mesenteric 

 vein. It is represented in the figure in a purely diagrammatic manner. 

 The ductus venosus has become obliterated. The three venae cavse fall 

 independently into the right auricle and the pulmonary veins into the 

 left auricle. 



14—2 



