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Show 342 MR. F. E. UEDDARD OX THE [Feb. 10, Visceral Branches of the Aorta.--There are a large number of branches to the oesophagus and to the liver, which I do not particularise. Between the posterior end of the liver and the mesenteric artery there are in both specimens 6 branches of the aorta, which I may term gastric arteries. Of these the last two are the most important. As illustrative of the small range of variation on the arterial system in individuals, I may mention that the number of intercostal arteries arising from the stretch of aorta which bears the six gastric arteries was 13 in one individual and 14 in the other. Immediately after the origin of the superior mesenteric, which branches similarly in both specimens, two intercostal portals arise from the parietes and join the main portal trunk. In both specimens these vessels lie at approximately the same distance from the origin of the superior mesenteric, and of the two the more posterior is the larger. The next artery which arises is the single artery of the anterior testis ; the posterior testis also has but a single artery. In both cases the testicular artery is continued along the vas deferens, where it receives a very slender branch from the aorta a little way behind each testis. The vas deferens of the anterior testis at any rate receives a second slender branch from the aorta, which springs from that trunk some little way behind the point whence is given off the anterior of the two arteries of the fat-body. Moreover, this latter artery gives off a branch to the vas deferens which joins the longitudinal artery running along that duct. A similar branch arises from the second fat-body artery. The fat-body is supplied by two special arteries already mentioned, and anteriorly by a strong branch of the superior mesenteric. They form a longitudinal trunk running along the fat-body. There are two well-developed intestinal arteries arising posteriorly, of which one, springing just in front of the posterior testicular artery and just below the second fat-body artery, m ay be called the inferior mesenteric. COLUBER CATEXIFER. In this species the left aorta is the larger of the two and considerably the longer; it has therefore to follow a sinuous course on its way to the junction with the right and smaller aorta. It gives off several slender branches to the oesophagus. The right aorta gives off two intercostals before its junction with the left. The common aorta from its origin up to the origin of the superior mesenteric gi\*es off 17 intercostal arteries. They are distributed as follows in relation to the principal alimentary viscera :-In front of the liver there is 1 intercostal, 8 arise along the course of the liver, and the remainder belong to the stomachal region. Corresponding in some degree to these intercostal arteries are a series of accessory portal veins which run from the parietes to the liver directly and of parietal affluents of the principal portal trunk. As to the arteries, they penetrate the |
