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Show 1904.1 ANATOMY OF THE LACERTILIA. 447 sternum. The vein reappears just below the skin and just superficial to the musculature, passing forwards along the ventral middle line to the neck. Before terminating on the neck the vein gives off a branch on each side, which runs clown the neck among the muscles a little anteriorly to the origin of the fore limb. I traced the vein on one side to a point close to the auricles, and I think that it communicates with the jugular vein. Since the vessel showed no diminution of calibre up to the point where I lost it (owing to the failure of the injection), I do not think that it can arise from a capillary network on-for example-the heart. As to the course of the blood in this vessel I have of course no positive facts to offer; I believe, however, that the blood must flow towards the liver-that the vessel is, in fact, part of the portal system, chiefly for the reasons that if the vein be regarded as an hepatic vein its course would seem to be unnecessarily erratic. A connection between the head-end of the body and the hepatic or other portal systems is not common in reptiles ; but I shall presently have to refer to analogous cases in the Monitor (see below, p. 449). Gastro-hepatic veins.-This lizard has a well-developed system of gastro-hepatic vessels, by which I understand those veins which communicate directly between the stomach and the liver and do not reach the latter indirectly via the common portal vein. I find either three or four of these trunks, which are all of them situated anteriorly, and are supported by one or other of the two (right and left) gastro-hepatic ligaments. Anteriorly the two membranes in question become joined, and this unpaired region bears two of the veins; the next vein runs in the right and the last in the left sheet of the mesentery. Varanus griseus. Of this lizard I have dissected two examples, both of them males. The circulatory system has been described by Corti* ; and Hochstetter T has added some details of value, which I have confirmed. The original of the anterior abdominal vein is correctly described by Hochstetter, who figures the vessels %. I may remark that each anterior abdominal receives before its union with its' fellow only two branches from the fat-body, which contrasts with the larger number characteristic of Iguana. Epigastric veins.-The right and left epigastric veins arise from the outer, sciatic, veins of the legs immediately behind the last of the branches which come from the fat-bodies. Each is closely accompanied by an epigastric artery, the course of which is not dealt with here. During their course along the ventral parietes the veins receive many branches from the parietes, and they finally end in the liver independently of each other. It is note- * 'De Systemate vasorum Paammosauri grisei,' 1853. I am not acquainted with this work. \ Morph. Jahrb. xix p. 404. X Loc. cit. pi. xvi. fig. 17. |
