514 



ME. F. E. BEDDARD ON THE VASCULAR AND [May 1, 



thread lying on the ventral surface of the body-waU. It did not 

 extend for a great distance, but was visible for four inches or so 

 down the body. It did not join any of the veins putting the 

 epigastric into communication with the portal system v/ithin the 

 liver. It was quite clear from dissection that such of these veins 

 as occurred in its neighbourhood crossed it without forming a 

 junction with it. These various facts leave little doubt in my 

 mind that this vein is the persistent umbilical, which is longer 

 than in Python, and more like that of Eunectes for this reason. 



Text-fig. 91. 



umh. 



Umbilical veins of (a) Boa and (b) Tytlion regius. 

 ep. Epigastric veins ; L. Liver; umh. Umbilical vein; Vci. Post-caval vein. 



The umbilical vein in Boa co7istrictor offers some interesting 

 variations from the condition found in Boa diviniloqua, though I 

 do not assert for the present that they are actually specific varia- 

 tions. In the example which I dissected, the vein was longer than 

 in the last species, and also vascular for a greater extent, thus 

 resembling the Anaconda. Its relations to the postcaval vein 

 were, however, quite as in Boa diviniloqua. The vein is as usual 

 attached to the ventral surface of the liver, and it extended down 

 to about the middle of that organ. A careful examination of the 

 vein showed that it gave off, or rather received, a number of 

 subsidiary trunks of very small calibre. These branches run over 

 the liver, but they do not appear to form any part of the portal 

 system. They are, in fact, so far as I could make out, distributed 



