OCR Text |
Show 448 MR. f. E. BEDDARD ON THE [Mar. 10, worthy also that the entry of the veins into the liver is not coincident; the right epigastric enters that organ a considerable distance behind the entry of the left vein. Furthermore, each is associated with its own liver-lobe, right or left, though the point of entry into the same is only just right or left, as the case may be, of the median sulcus. In the larger specimen of Varanus the arrangement of these veins is slightly different in that the right epigastric enters the liver anteriorly to the left. Both veins, the right and the left, are continued forwards as well as backwards. On the left side I have ascertained that the anterior prolongation of the epigastric joins the mammary branch of the left jugular at a considerable distance from the heart. This branch seems to me to be quite comparable with the similar vein in Tiliqua (see p. 445), which arises, as I thought, from the jugulars and independently enters the liver; the main difference being that in Varanus the vein is double throughout, that it does not immediately underlie the skin for the greater part of its course, and that it fuses with the epigastric instead of entering the liver separately. Or this vessel in Tiliqua may be homologous with the single hepato-parietal ventral of Varanus, which I describe below. The epigastric of the left side, at any rate, gives off a branch to the fat-body of that side before joining the femoral vein. Lateral Abdominal veins.-Occupying the same position as the corresponding vein of Tiliqua, the lateral abdominal veins of Varanus have somewhat different relations. There were furthermore differences in the two individuals which I dissected*. In the first place, the vein is more complete anteriorly than posteriorly, while in Tiliqua and Iguana the reverse is the case. In the latter the vein arises from the leg vein and runs forward for a varying distance. In Varanus the vein does not appear to be connected with the veins of the hind limb, but it is connected with veins in the anterior region of the body. It arises anteriorly from the jugular in common with the mammary vein and branch of epigastric. In one specimen there is a second branch from the jugular rather nearer to the heart. In this specimen, however, there is not a plain superficial connection between the lateral vessel arising from the two branches of the jugular. However, the vessel passes backwards, and after its second origin receives a branch from the lung. It ends posteriorly in the suprarenal vessels, as has been described in considering these veins. I thus confirm Hochstetter in denying the existence of an anastomosis between this vein and the anterior abdominals posteriorly. Dorsal Hepato-parietal veins.-As in Tiliqua, there is but one vein, that of the right side. It either emerges from the parietes just below the point where it enters the liver or has a short superficial course, emerging rather further forwards; it gives off no branches to the left side such as are found in Tiliqua. * Both specimens were entered on the books of the Society as belonmne to the |