1904.] CIRCULATORY SYSTEM IX THE OPHIDIA. 347 



the eighth intercostal and again on the right side. The common 

 trunk formed does not enter the liver directly, but joins the portal 

 vein. This is also the case with the last of this series of portals, 

 which arises, also to the right of the median line, just behind the 

 ninth intercostal. The following parietal portals are connected 

 with the suprarenal bodies. 



In the second and male individual there are some differences in 

 the arteries and veins in question. There are two intercostals in 

 front of the junction of the aorta and twelve between this point 

 and the origin of the superior mesenteric. All the arteries, how- 

 ever, are exactly median in position where they perforate the 

 body- wall. There are nine or ten portals arising from the left 

 side which extend down to a point about opposite to the end of 

 the liver. I cannot give an accui'ate description of how some of 

 them join each other before entering the liver. After these, six 

 trunks arise on the right side, each three forming a single trunk. 

 The last of these vessels joins the portal vein before it reaches the 

 liver. 



From the oiigin of the superior mesenteric arteiy to the cloacal 

 aperture there are 16 vertebral arteries, all of which, as before, 

 perforate the body- wall in the dorsal median line. The arrange- 

 ment of these is peculiar, in that they alternate in their points of 

 origin from the dorsal aorta. This obviously suggests an originally 

 paired series which have been pulled asunder in an antero-posterior 

 direction by the lengthening of the body. 



G'lsopliacjeal Branches. — The oesophageal branches are all very 

 slender and fairly numerous. The section of oesophagus which 

 lies in the fork formed by the right and left aorta is supplied from 

 three distinct sources. There is, first of all, a slender artery which 

 emerges from the body-wall in company with a vein to the right 

 of the middle line. Anteriorly there are one or two similar 

 arteries which may emerge from the middle line. The chief 

 blood-supply, however, of this part of the oesophagus is from two 

 vessels arising from the right aorta, between which arises a third 

 branch supplying part of the oesophagus behind the junction of 

 the aortse. The left aorta provides two branches, one arising near 

 its commencement, and another which is very inconspicuous and 

 given off not far from the junction with the right aorta. After 

 the junction of the aortee and before the beginning of the liver 

 I counted four oesophageal arteries. 



In the region of the liver the same arteries supply both liver 

 and oesophagus or stomach as the case may be. There are 8 of 

 these arteries, which inci'ease in length and sti'engiJi towards the 

 stomach. These 8 arteries are followed by one which serves the 

 stomach and the gall-bladder, spleen, and pancreas only. It is 

 the single gastric artery, and indeed it practically sujDplies the 

 stomach only, the twig to the other viscera being excessively 

 minute ; these viscera ai-e, in fact, cared for by the supeiior 

 mesenteric. This vessel, as i\sual, has two main branches — an 

 intestinal and a gastro-splenic. But before its division into these 



