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Show 464 MR. F. E. BEDDARD ON THE [Nov. 28, as is also often tlie case with the Lacertilia, are separated by the dorsal mesentery. The afferent renals are, as is the case with Lizards, derived from two sources : the caudal vein divides into the two veins of Jacobson and there is also a system of vessels derived from the hind limbs and from the parieties in that neighbourhood. ] traced the veins of Jacobson for some way into the substance of the kidney. It appeared to me that they did not directly join the anterior abdominal vein ; and in any case it seems clear that instead of there being a branch superficial to the kidney which joins the ischiadic afferent renal system as in other Lizards (for instance, in Lacerta, as figured by Hochstetter *), there is at most a branch which effects such a union running within the substance of the kidney. I am inclined even to think that the union is indirect. But in either case there is obviously an approach to the condition observable in non-Boine Snakes, where the anterior abdominal vein is independent of the caudal vein. It will be noted, moreover, that the condition observable in the kidney-region of Hatteria is quite remote from that to be noted in the Varanidfe and in the Crocodilia, where the ischiadic, or both the ischiadic and caudal, veins are directly continuous with the anterior abdominal vein or veins, and merely send branches to the kidney. The afferent renal system of Hatteria is, as it were, an exaggeration of the typical Lacertilian type. It is more particularly the anterior abdominal vein which appears to me to show these Ophidian characters, partly matched, however, as I shall indicate later, in a legless Lizard, Pygopus lepidopus. In Lacertilia, at least as a rule, the conjoined anterior abdominal and portal veins enter the left lobe of the liver at or quite close to its posterior border. In Snakes, on the other hand, there is, at least in some cases, a different arrangement. In Eryx, for instance!, the portal runs along the side of the liver to its anterior end, giving off branches at intervals to the liver-substance. In Hatteria also (see text-fig. 60) this is precisely what happens. The anterior abdominal vein, reinforced by the portal, runs in the membrane which connects the stomach with the left lobe of the liver, giving off branches at intervals to the liver-substance and receiving at intervals branches from the stomach. Towards the anterior end of the liver the conjoined porto-abdominal trunk finally disappears in the liver. The details of the branching described here in general terms can be understood by a reference to the figure (text-fig. 60). Pygopus t shows an intermediate state of affairs. The main branch of the conjoined portal and anterior abdominal veins enters the liver near to its posterior extremity, as in Lacertilia * Morpli. Jahrb. vol. xix. pi. xvi. fig. 12. f " Notes upon the Anatomy of certain Snakes of the Family Boiche " P Z S 1904, vol. n. p. 113. ' ' ‘ ' I P. Z. S. 1904, vol. ii. p. 17. |
