| OCR Text |
Show 354 MR. P. E. BEDDARD ON T U E [Feb. 16, here a distinct break. Immediately after its origin, this artery gives off a branch to the liver. After crossing the portal vein, the artery divides into two branches, one of which runs to the (esophagus and the other pursues its course towards the stomach, and when it reaches that organ again divides into t w o - a n anterior and a posterior branch. The latter is continuous with a trunk running in a sinuous course along the left side of the stomach from end to end, and which is connected (as will be mentioned presently) with other gastric arteries arising from the aorta. From where it crosses the portal vein this artery is accompanied in all its branches by a portal trunk. The second gastric artery is purely gastric. It runs straight to the stomach, and there divides into an anterior and a posterior branch. These together form a longitudinal gastric artery running along the right side of that organ. This artery is also accompanied by a portal vein ; and as it arrives at the portal vein a branch from the body-wall enters at a point nearly opposite. This trunk from the dorsal parietes arises from two roots which unite after passing the dorsal aorta. The third gastric artery is much farther away. The interspace is occupied by a parietal branch of the "portal, which arises by a single root only, and by a gastric branch of the same. This suggests a missing gastric artery, as the correspondence between the gastrics and portals is so great in this species; but it is to be admitted that there is no further evidence respecting it. The third gastric artery is the most important of the series. Unlike the preceding arteries, it supplies both of the longitudinal gastric arteries. It is accompanied by branches of the portal system. The fourth artery is more slender ; it does not seem to be connected with the longitudinal systems arising from the preceding arteries. The fifth artery is not exclusively gastric. It is, in fact, a branch of the superior mesenteric. This branch immediately divides into two trunks, one for each side of the stomach. The first branch, that given off nearest to the aorta, joins the third gastric artery; the main branch contributes to the longitudinal trunk of the stomach, which is connected with the first and with the third gastric artery. In the second specimen the arterial system of the stomach only appeared to differ in the absence of the fourth gastric artery, which is slender and unimportant in the first specimen. As in that specimen, the third gastric is by far the most important artery, and it supplies in the same way both sides of the stomach. Intestinal Arteries.-Of these, the first and most important is the superior mesenteric. The artery arises from the aorta just opposite to the end of the stomach, as is usual. The next artery, which I call the inferior mesenteric, is very much further back, and arises from the aorta opposite to about the end of the first third of the anterior kidney. It arises dorsal of the 2nd testicular artery. After this I counted four rectal arteries in one specimen (the female). |
