1904.] CIRCULATORY SYSTEM TN THE OPHIDIA. 345 



series supplies the right side and also sends back a large branch 

 to the liver. The alternation is kept up with perfect regularity 

 until the ninth and largest of the series, which, immediately 

 after its origin from the aorta, divides into two vessels, each of 

 which supplies one only of the longitudinal gastric trunks. The 

 same is the case with the tenth vessel, which is also concerned 

 with the blood-supply of the gall-bladder. The eleventh arises 

 opposite the gall-bladder and runs over it. Immediately after 

 the gall-bladder arises the very large mesenteric vein, which is 

 really almost as thick as the aorta. It runs down the intestine, 

 giving off branches to the same. The first branch is much the 

 largest and supplies the gall-bladder, spleen, and pancreas. 

 I could not find any gastric branch to this artery and feel 

 assured that if such a branch exists, which might I admit be 

 expected, it is not large. It looks to me very much, in fact, as 

 if the superior mesenteric artery in this snake had I'etained its 

 original derivation from two separate trunks, one gastric and 

 one intestinal, and that therefore the last gastric which crosses 

 the gall-bladder really belongs to it. 



Ovarian and Oviditcal Arteries. — As is usual in the Ophidia, the 

 arteries to the gonads come between the superior mesenteric and 

 the remaining arteries of the alimentary tract. The first of this 

 series of arteries is the anterior ovarian artery, which opens into 

 a longitudinal artery running down the gonad. Separated from 

 this by five intercostal arteries is a much larger vessel which 

 supplies the oviduct belonging to that ovary and the fat-bodies ; 

 its mode of distribution to these two organs is rather curious. 

 It divides almost immediately into trunks, roughly equisized, 

 which pursue a toi'tuous course at right angles to each other, the 

 one anteriorly and the other posteriorly. The former reaches the 

 oviduct and forms a longitudinal vessel running along the oviduct 

 and giving off numerous branches to the lobules of the fat-body. 



The posterior bi'anch seems to be entirely concerned with the 

 blood-supply of the fat-body ; it forms a longitvidinal trunk and 

 gives ofi' numerous branches right and left. 



Very close to this trunk and behind it arises the second ovarian 

 artery. The oviducal artery lies much further back and is separated 

 from the ovarian arteiy by two intestinal arteries and two renals 

 belonging to the anterior kidney. 



Intestinal Arteries. — I observed only two of these, but there 

 may be others posteiiorly, where the injection had failed. It is 

 noteworthy that in this species, unlike what is found in some 

 others*, the first intestinal artery, which we may term the 

 inferior mesenteric, immediately follows the gonad arteries and 

 precedes the renal. The rectal artery lies next to the second renal 

 artery of the anterior kidney. 



Renal Arteries. — Here, again, I am unable to give full details. 

 I can only say that two renal arteries of the anterioi' kidney arise 



* E. g.j Naia trijpudians. 



