290 THE SIXTH DAT. [CHAP. 



FiQ. 91. 



SuX: 



C^M 



Diagram op the Venous Circulation of the Chick after 

 THE Commencement of Respiration by means of the 

 Lungs. 



W. wing vein. J. jugular vein. Su. V. superior vertebral vein. 

 In. V. inferior vertebral vein. These unite together on each 

 side to form the corresponding superior vena cava. Z.V. 

 pulmonary veins. V.O.I, vena cava inferior. H.P. hepatic 

 veins. P. V. portal vein. M. mesenteric veins. Cy.M. con- 

 necting vessel between the branches of the portal vein and 

 the system of the vena cava inferior. It is called the coccy- 

 geo-mesenteric vein, and unites the cross branch connecting 

 the two hypogastrics with the mesenteric vein. The ductus 

 venosus has become obliterated. The three venae oavse fall 

 independently into the right auricle and the pulmonary 

 veins into the left auricle. Cr. crural vein. k. kidney. 

 I. liver, pp. hypogastric veins. 0. V. caudal vein. 



have in the meantime been taking place in the arterial 

 system. The condition of things v^hich exists on the 

 fifth or sixth day is shewn in the diagram (Fig. 92). 



