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Show 1 9 0 5 .] VASCULAR SYSTEM OP CROCODILUS. 4 6 7 sponcling vessel in Tiliqua *, which arises on the left side of the vertebral column and joins the right parieto-hepatic. In the Lacertilia generally the dorsal parieto-hepatic veins are on the right side only; and if there are such vessels on the left they either join the right-hand vein before entering the liver, as in Tiliqua, or, as in Iguana t and Anguis J, supply the gastric and oesophageal networks and thus reach the liver indirectly. It may be said, therefore, so far as present knowledge allows the statement, that the Crocodilia differ from the Lacertilia in having a left as well as a right dorsal parieto-hepatic, entering the liver independently into both right and left lobes. On the right-hand side of the body the single dorsal hepato-parietal trunk is composed of three stout affluents, of which the two posterior are joined by a cross anastomosis. The anterior vessel is continued forwards superficially and joins, or nearly joins, the right azygos. I may remark that on the left side the gaps between the several superficially running sections of the azygos are more pronounced. Finally, the venous system of the liver in Crocodilus acutus receives another affluent, which is not, as I believe, represented in the Lacertilia. This is a vein which arises from the parietes on the right side, in a position intermediate between the dorsal and ventral parieto-hepatics. This single vein arises from a longitudinally running trunk in the parietes which corresponds, as I think, to the lateral abdominal vein; it passes straight to the liver, which it does not, however, enter independently, but in common with the dorsal parieto-hepatic. The above-given facts are, as has been already mentioned, not in entire accord with previous statements. Hochstetter observes § " Eine vena hepatica advehens vertebral is [ = my right dorsal parieto-hepatic] wie bie Lacerta und anderen nicht vorkommt." But his observation refers to Alligator lucius. Jacquart ||, who previously studied the venous system of the same species (" Caiman a museau de Brochet "), makes no particular mention of the vessels which I describe here in Crocodilus acutus. He refers to what is possibly the right dorsal parieto-hepatic (figured in fig. 1, pi. iii. 20 d, of his memoir) merely as " une petite veine qui contourne le bord tranchant du lobe droit du foie " ; and the vein in question may be really a branch of the ventral parieto-hepatic system. For the possibly corresponding vein of the left side (figured by Jacquart in fig. 1, pi. iii. 41, of his memoir) no special reference is made in the text. Rathke^l", however, under the name of " vena epigastrica * Beddard, " Contributions to tlie Anatomy of tlie Lacertilia : Pt. I.," P. Z. S. 1904, vol. i. p. 445. t Id. ibid. p. 440. X Morph. JB. vol. xix. p. 473. § Morph. JB. xix. p. 478. || Ann. Sci. Nat. (4) ix. 1858, p. 129 &c. ‘ Untersuchungen iiber die Entwickelung und der Korperbau der Krokodile ' (Braunschweig, 1866), p. 256. The same name is also applied to the abdominal veins; but, I presume, in error for " externae." |
