| OCR Text |
Show 1904.] CIRCULATORY SYSTEM IX THE OPHIDIA. 367 practically in contact with the pericardium. At the opposite extremity it ends but a very short way in front of the gall-bladder. The blood-supply of the oesophagus, stomach, and liver is therefore rather different to that of some other snakes. There are, as is usual, series of hepato-cesophageal, hepato-gastric, and gastric vessels. No arteries, however, supply the liver only to the exclusion of other organs. Altogether the liver is supplied by nine vessels, of which the last two are the largest and run longitudinally and superficially for some distance. The last of these arteries is very nearly converted into an independent trunk, for the gastric branch is given off immediately after the origin of the combined trunk. Between this hepatic vessel and the next one A ' Text-fig. 78. no ° (Esophageal and hepatic arteries of Lachesis gvam.vn.eus. Ao., aorta; An.', left aortic arch; L., liver; as., oesophagus. in front three arteries arise from the aorta, which only supply the alimentary canal and send no branch to the liver. In front of this again are seven branches of the aorta which supply both liver and gut. The two anterior of these at any rate arise from the left aorta before its union with the right. Apart from these trunks already mentioned, which lie between the last two hepatic arteries, there is only a single gastric artery, which arises from the aorta some little way behind the last gastro-hepatic. The superior mesenteric artery presents no remarkable features. The arteries of the posterior part of the intestine arise in irregular alternation with the arteries to the oviducts, ovaries, and kidneys. A more exact description of some of these arteries is as followrs:- The first artery after the superior mesenteric is that to the anterior (and in m y specimen not fully developed) ovary. After this arises the posterior mesenteric and, after a gap, two other intestinal arteries; between the last of these and the third intestinal artery are two slender oviducal arteries. Then follows the artery of the posterior ovary (which was full of mature ova). Immediately after this are five oviducal arteries supplying its oviduct, and on the opposite side an oviducal artery belonging to the other oviduct, the first renal artery and the first of a rectal series. |
