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Show 474 MR. F. E. BEDDARD OX THE [Nov. 28, the posterior end of the stomach this portal affluent joins the main portal trunk in the immediate neighbourhood of the junction of the latter with the anterior abdominal vein. On the left side is a corresponding vein which takes up blood from the spleen as it passes that viscus. The liver anteriorly is supplied (see text-fig. 64, p. 475) with a series of some five gastro-hepatic veins, which run across from the stomach to the liver, where they are collected into a longitudinal vein before opening directly into the liver. This forwardly directed vessel is not, however, a direct prolongation of the conjoined portal and anterior abdominal as in Hatteria*. This vein also receives the dorsal parieto-hepatic affluents of the hepatic portal system, which will be dealt with immediately. Accompanying each gastro-hepatic vein is an artery, which arteries I have already described above. The close association of gastro-hepatic veins and supplementary hepatic arteries is very reminiscent of what is to be found among Snakes, and very unlike the prevailing arrangement among Lacertilia. It is doubtless to be correlated with the great length of the liver in Ophisaurus and Snakes. The dorsal parieto-hepatic veins are particularly well developed in this Lizard as compared with many other genera. And, furthermore, they differ from those of many other Lacertilia in being mainly developed upon the left instead of upon the right side. There is, in fact, only one of these veins upon the right side. On the left, on the contrary, three or four veins arise from a varied number of intercostal spaces. The most posterior of these runs along the vertebral column for a distance of seven vertebrae, receiving a branch corresponding to each intercostal space. The vertebral affluents of the hepatic portal system which arise in front of this have not so long a course along the vertebral column by far. They emerge from the parietes and at once pass downwards to the portal system. These dorsal parieto-hepatic veins join the longitudinal vein already described, which runs along the dorsal edge of the liver anteriorly and which also receives the gastro-hepatic vessels. The fact that this system is almost entirely developed on the left side is to be compared with the parallel fact that the only one of two azygos veins to be retained in Ophisaurus is also the left-hand vein. Epigastric System of Feins.-The smaller veins which run in the umbilical (falciform) ligament and pour their contents into the liver have a somewhat different arrangement from that found in certain other Lizards. The system, instead of consisting of one continuous vein running in the falciform ligament in close apposition to the ventral body-wall in the median line with branches to the liver-substance, consists of two separate veins of considerable size. The anterior of these enters the liver far forwards. ^ It is formed of two veins which unite just before their conjoined entry into the liver, of which the anteriorly * Above, p. 464, I offer some remarks upon this extension forwards of the portal vein, also on p. 484 of the present coitimunioation. |
