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Show 1906.] VASCULAR SYSTEM OF THE HELODERM. 605 they are somewhat asymmetrical; a fact which does not disguise the resemblance which they bear in details to the corresponding veins of Var anus. On the right side, the two veins which issue from the leg are connected below the pelvic region by an anastomosis whose calibre is as great or nearly so as that of the two veins which it joins. The junction lies to the dorsal side of the femoral artery which crosses it below. The more anterior of the two veins, which I presume to be the sciatic, then bends upon itself, but passes directly into the anterior abdominal vein, of which it forms the right root. The other vein, the femoral, receives the usual lateral caudal vein and joins the right branch of the caudal, forming with it the renal afferent vein of the right kidney. This junction takes place behind the kidney. The ischiadic artery lies dorsal of this vein, and is crossed ventrally by the conjoined femoral and lateral caudal. It appears from Hoch-stetter's figure that the relative positions of these blood-vessels is exactly the reverse in Varanus, that the artery is ventral of the vein. On the left side of the body, the likeness to Varanus is exhibited in a more striking way, since the junction of the veins in the leg is more normal. The two veins of the leg unite with each other, and shortly thereafter divide into the left root of the anterior abdominal vein and a branch joining the left renal afferent vein behind its point of contact with the corresponding kidney. Just before this division the common trunk from the leg receives the lateral caudal. The arrangement of these various veins is therefore exactly as in Varanus, and thus differs equally from that prevalent among the Lacertilia. The anterior abdominal is chiefly concerned with the blood returned from the fat-body, from which it receives a considerable number of affluents. I noticed only one branch from the fat-body to join the right root of the anterior abdominal, the rest poured their contents into the common trunk. The hepatic portal system of this Lizard is more complex than that of many other Lizards. In addition to the usual veins, derived from the parietes and viscera, common to the Lacertilia as a whole, there are, as will be seen from the following account, certain veins which are not represented, or are rarely represented, in other genera of the Lacertilia. System o f Vertebral Veins and branches to Liver.-It is the rule among the Lacertilia for the azygos and the vertebral veins and their branches to the liver to be mainly developed upon the right side of the body, and for the separate gastro-hepatic affluents of the portal system to be independent not only of the main portal vein, but also of the dorsal parieto-hepatic veins running from the body-wall to the liver-substance. In these various particulars the venous system of Heloderma is rather different from that of other Lizards. The Azygos Vein in Heloderma is short and to be found only |