578 



ON THE CARDINAL VEIN IN THE RABBIT. [JuDe 17, 



instead of, as in the ordinary Rabbit, ending or (more correctly) 

 beginning in its branches, the intercostal veins, the azygos vein pierced 

 the diaphragm by an aperture to the right of that of the aorta, and 

 continued its course posteriorly with a very slight diminution in size 

 and in the same relative position as in the thorax with regard to the 

 aorta and the vertebral column. 



At the point where the posterior vena cava reached the dorsal wall 

 of the abdominal cavity, the aorta curved slightly upwards and ran 

 dorsally to the cava ; the azygos continuing its course in a straight 

 line, ran parallel with and to the right of that vein, finally opening 

 into it by a large aperture on the right side about half an inch above 

 where it received the right renal vein. Since this aperture was as 

 large as the vein it opened into, the anterior part of the latter might 

 be regarded as a branch of the azygos, the posterior part becoming 



-V.C.I 



R.Kl 



Diagram showing abnormal relations of the Azygos Vein in a Eabbit. 



Az., azygos vein. V.C.I, vena cava posterior. R. V., right renal vein. 

 R.A., right auricle. B.K., right kidney. 



the prolongation of that vein, and not the posterior vena cava. The 

 total length of the vein from its junction with the anterior to where 

 it joined (or received) the posterior vena cava was six inches. Its 

 relatively large size would naturally lead one to the supposition that 

 the greater part of the blood brought by the iliacs, femoral, and other 

 branches of the posterior vena cava from the posterior ends of the 

 body was returned direct to the right auricle by means of this extra- 



