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Show 1904.] ANATOMY OF THE LACERTILIA. 449 Ventral Parieto-hepatic veins.-These veins as independent veins are poorly developed in Varanus as compared with the other types. There are at most three of them. The anterior corresponds to a vein which seems to be a characteristic vessel and always found in Lacertilia. But its distribution in Varanus is rather different. In one specimen the vein is formed by two affluents, one from the ventral parietes and the other from the stomach. Concerning the second specimen I a m rather uncertain, but inclined to believe that there is also a connection with the m a m m a ry and epigastric branch of the jugular (see p. 448). In the second specimen, moreover, this vein enters the liver in company with the left epigastric. The second vein of this series is a medianly situated vessel which does not enter the liver independently, but is an affluent of the left epigastric. A third vessel enters the anterior abdominal vein near to its entry into the liver. Hochstetter observes*:-" Dass die Y e n e n der vorderen Brustwand in der Sternalgegend nicht in dei Zweige miinden, die als V . portae secundariae aufzufassen sind wie bei Lctcerta, sondern in die vorderen Hohlvenen, findet in der Lage des Herzens unci seiner grossen Gefiisse bei diesem Reptil seine Erklarung." I am disposed myself to look upon the fact rather as indicative of a resemblance to Tiliqua and Iguanet, which lizards, as has been mentioned, also have communications between the anterior veins and the portal system of the liver. Summary. Some of the more important new facts described in the foregoing pages m a y n o w be briefly recapitulated. (1) While there is generally (? always) an inequality in size between the two venae renales revehentes, Tiliqua is remarkable on account of the very reduced size of the left vein. (2) While Iguana possesses three epigastric veins, two lateral and a median, the last only is developed in Tiliyua. Varanus has the lateral epigastrics which, as in Iguanet, are connected anteriorly with the jugulars, but (? in correlation with the absence of a bladder) the median epigastric is at most rudimentary. (3) The intestinal portal systems of Iguana and Tiliqua differ. In the former there are only two branches from the small intestine, one of which joins the gastro-splenic trunk; in the latter there are three veins, all of which open separately into the portal trunk. (4) In both Iguanet and Tiliqua there is a superficial vein lying beneath the skin but above the musculature and along the middle line of the sternum, which enters the liver posteriorly and appears to be connected with the jugulars anteriorly. . (5) Varanus has but one vein running from the stomach and oesophagus directly to the liver (?'. e. not by way of the intestinal * Loc. cit. p. 467. |
