COMPARATIVE ANATOMY OF THE CIRCULATORY SYSTEM 261 



artery arises from its posterior surface. This vessel passes in the mesogaster 

 to the spleen, where it runs in the gastrosplenic ligament. In its course to the 

 spleen it provides the short gastric arteries to the left end of the stomach; along 

 the spleen it supplies splenic branches to the spleen; beyond the spleen it 

 branches into the omentum; at about the middle of the spleen a large branch, 

 the left gastro-epiploic artery, arises from the splenic and passes to the greater 

 curvature of the stomach. The coeliac artery beyond the splenic passes to the 

 lesser curvature of the stomach where it may best be followed by turning the 

 stomach forward. Here it gives off a group of vessels, the left gastric (or coronary) 

 arteries which radiate to the stomach wall on both sides of the lesser curvature 

 and also send small branches to the esophagus. Shortly beyond this point the 

 coeliac artery is known as the hepatic artery, which passes along the right end 

 of the lesser curvature, very shortly giving rise to the gaslroduodenal artery. This 

 runs to the pyloric region and there branches into the anterior pancreatico- 

 duodenal artery to the pancreas and first part of the duodenum and the right 

 gastro-epiploic artery which returns to the stomach wall by way of the great 

 omentum. The hepatic artery now passes to the dorsal side of the pylorus and 

 enters the hepatoduodenal ligament. After giving off the small right gastric 

 artery to the pylorus it proceeds to the liver, lying to the right of the bile duct. 

 The superior mesenteric artery is the chief artery of the intestine and has 

 many and complicated branches in the rabbit, these branches following for the 

 most part the branches of the hepatic portal vein. Clean the surface of the 

 vessel and follow it; it runs alongside the superior mesenteric vein. The first 

 branch is the small middle colic artery, arising from the ventral wall of the superior 

 mesenteric and passing to the transverse colon and beginning of the descending 

 colon. At the same level but from the dorsal side arises the posterior pancreatico- 

 duodenal artery which passes to the duodenal loop and pancreas. The superior 

 mesenteric artery then forks into the intestinal artery, which runs in the mesentery 

 of the small intestine and gives off numerous branches ventrally into the intestine, 

 and into the large ileocaecocolic artery. This last has many branches to the 

 ileum, the caecum, the appendix, and the ascending colon. Its branches are: 

 small arteries to the terminal part of the ascending colon; the anterior right 

 colic artery which forks several times, supplying the greater part of that portion 

 of the ascending colon which bears the haustra; the posterior right colic artery 

 arising near the preceding and supplying the remainder of the haustra-bearing 

 region of the ascending colon, its end joining one end of the preceding; the appen- 

 dicular artery arising with the preceding and running along the appendix and that 

 part of the ileum adjacent to the appendix; the large posterior ileocaecal artery 

 passing to the greater part of the caecum and to that portion of the ileum lying 

 between the caecum and the ascending colon ; the much smaller anterior ileocaecal 

 artery to the more distal part of the caecum and adjacent ileum, and running 

 toward the preceding with which it anastomoses ; and the caecal artery or arteries 

 to that portion of the caecum which adjoins the appendix. 



