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Show 618 MR. F. E. BEDDARD ON THE [May 29, is a particularly prominent vein in the "Varanidae as contrasted with other families of Lacertilia. In the connection of the lateral vein system with the hepatic circulation, Varanus shows a point of resemblance to the Crocodilia, where such a connection also occurs, and with which I deal in a subsequent page of the present communication*. I do not, however, lay so much stress upon this comparison as upon the difference which Varanus shows in this part of its circulatory system from other Lacertilia. Gastro-hepatic Vein.-It is important to note that Varanus differs from many other Lacertilia t in the limitation of the gastro-hepatic veins to a single vein. Hochstetter has already correctly noted that there is but one vein of this series which enters the extreme anterior tip of the left liver-lobe. I have found exactly the same state of affairs in an example of Varanus griseus recently dissected. I find also exactly the same vein occupying the same position in V. exanthematicus. In Varanus niloticus the same gastro-hepatic vein was present and appeared to be particularly large. It is a jDoint worthy of note that the position of this vein, that is of its place of entrance, is exactly the same in the left lobe as the anterior parieto-hepatic vein in the right lobe. It is possible that the great width of the liver in Varanus is responsible for the separation of two veins which in Heloderma + enter conjointly, the liver being in that Lizard narrow anteriorly. (3) On some Veins in the Crocodilia. Although the main features of the vascular system generally, including the veins, in the Crocodilia are fairly well known §, there are a few details which have not received attention ; and, moreover, there yet remains, as it seems, a good deal to be ascertained before the variations of the venous system from genus to genus is at all understood. I shall show in the following pages that the veins with which I deal are by no means uniformly disposed in all Crocodiles. The observations which I place before the Society were almost entirely conducted upon well-injected specimens, and are therefore, as I hope, trustworthy as records of positive fact. It is obviously less possible to insist upon the absolute reliability of negative facts. § Azygos Veins or Venae, Vertebrales. Rathke's description of the azygos veins would not give rise to the impression that they show differences among different * V. infra, p. 622. f Not, however, from PJielsuma viadagascariensis and Tarentola annularis, where there is also but one gastro-hepatic vein. X Above, p. 607. ^ § See especially : Rathke, " Untersuchungen uber die Entwickelung und den Korperbau der Ivrokodile," Braunschweig, 1866; Jacquart in Ann. Sci. Nat. (4) ix. 1858, p. 129 ; Hochstetter in Morph. Jalirb. xix. 1893, p. 476 ; Jourdain in Ann. Sci. Nat. (4) xii., 1859; Beddard in P. Z. S. 1905, vol. ii. p. 466. |