214 



MR. F, E. BEDDARD ON THE 



[Feb. 19, 



the vein of its side which has just been described and opened 

 in common with it into the precava. 



In one at any rate of the Rodents this vein bent distinctly to 

 the right before effecting this connection, and in another there 

 was the same bend and (see text-fig. 73) a slender straight vessel 

 continued on the direction of the vein and apparently opened into 

 the paired vein rather nearer to the precava. It was generally 

 to be seen — possibly invariably present though hard to see owing 

 to deficiencies in the blood — that this vein was connected by cross 

 vessels with both of the paired vessels already described as running 



Text-fie-. 73. 



Lateral view of the thovacic region of newly-born Myopotamus coypu, dissected 

 to show azygos vein {Az.r.) and persistent postcardinal (post.c). 



alongside of the vertebral column on either side. I am inclined 

 to think that these cross trunks were segmentally arranged in 

 accordance with the vertebrae. This vessel was longer than either 

 of the paired trunks, and posteriorly the last cross anastomosis 

 that I observed 'on the right side was continuoxis with a longi- 

 tudinal vessel obviously continuing on the paired vessel of its 

 side, though a break occurred between the two. This trunk, 

 receiving affluents in the lumbar region, ended by opening into 

 the postcava near to the entry into the same of the right renal 

 vein. Anteriorly the unpaired vessel lay outside the area which 

 would be occupied by tlie intercostal arteries (though I did iiot 



