DE. J. MUKIE ON THE ANATOMY OF THE SEA-LION. 543 



to the left being slightly the larger one. The right hepatic division, three quarters of an 

 inch from its origin, subdivides into two. One branch, directed outwards, supplies the 

 first and second lobules to the right of the liver ; the other strikes more upwards and 

 slightly to the left, being distributed to the third hepatic segment, viz. the right moiety 

 of the cystic lobe. The left hepatic division is longer and straighter than the right, 

 and furnishes several branchlets. About an inch and a half from its origin one or 

 two small twigs are sent to the Spigelian lobe and what represents the transverse 

 fissure. An inch beyond these a branchlet goes upwards, which gives offshoots to the 

 minute lobule(*fig.72) and to the IV. or left half of the cystic lobe. The main left hepatic 

 division proceeds onwards for above two inches, and splits into several terminal seg- 

 ments distributed to the V. and VI. lobes, or left half of the liver. 



The cystic artery is a very long and narrow branch. It accompanies the cystic duct 

 as far as the neck of the gall-bladder, where it penetrates the coats of that reservoir. In 

 its course it lies to the left of the duct, and is superficial to the pancreas and hepatic 

 artery. The arteries of the liver, excepting the cystic branch, have a position beneath 

 the gall-ducts and above the veins and hepatic plexus of nerves. I observed a peculiarity 

 in the first portion of the hepatic artery previous to its dividing into right and left 

 branches. This consisted in its possessing a median septum, apparently produced by a 

 splitting of the inner coat. I could not well satisfy myself, however, whether this 

 might not have been the result of injection rather than a natural condition. 



The gastro-duodenal branch of the hepatic is of good size. About one inch from its 

 commencement it gives short offshoots to the pancreas and first part of the small 

 intestine, the latter distant two inches from the pylorus. Thence continuing beneath 

 the duodenum it runs along the outer pyloric border of the stomach as the gastro- 

 epiploica dextra, inosculating in the ordinary manner with the sinistral epiploic extre- 

 mity of the splenic. 



The superior mesenteric artery springs from the abdominal aorta one and a quarter 

 inch below the cceliac axis, has a calibre equal to that vessel, and indeed is relatively 

 little inferior in size to the aorta itself, where they are divergent. In forming the 

 mesenteric arch it is enclosed and hidden within a double, long, narrow, continuous strip of 

 lymphatics, the mesenteric glands. The so-called vasa intestini tenuis are derived from 

 the trunk of the mesenteric by about twenty very short but wide branches, which 

 divide and subdivide into primary, secondary, and tertiary forks, ultimately ramifying 

 on the intestinal surface. Of the named branches of the superior mesenteric artery the 

 ileo-colic is well marked and of moderate size. 



The renal arteries, derived posteriorly, strike off opposite one another and at right 

 angles to the aorta. They are each 2 inches long. 



The spermatic vessels and the inferior mesenteric trunk spring separately and to the 

 rear of the preceding. Sigmoid and hsemorrhoidal branches of the latter obtain in well- 

 defined arches ; and lymphatic glands lie towards the main vessel. 



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