BLOOD-VASCULAR SYSTEM OF THE LORICATI 97 



cephalad, below the right gastric artery and the right gastric 

 ramus of the vafrus. Throufjhout its course it receives numerous 

 branches from the muscular coats of the stomach. Leaving 

 the anterior part of the stomach it crosses above the corre- 

 sponding artery and nerve, and the coeliac artery, and when 

 about midway between the stomach and the caudal tip of the 

 right lobe of the liver, directly behind a gland-like body marked 

 G. it unites with intestinal vein ^y^. This vein (PL I, figs, i and 

 6 : Int.V.(,)) usually arises in the region of the rectum by anas- 

 tomosing with branch Y of the posterior mesenteric vein (see 

 fig. i). In its cephalic course in the adipose tissue surrounding 

 the intestine, lying below the corresponding artery, it ordinarily 

 sends off from one to 3 branches, w^hich empty into the right 

 C£eca vein or its posterior gastric branch. In the specimen 

 from which fig. i was drawn 3 such vessels were given off. 

 The 2 posterior ones emptied into the right posterior gastric 

 vein and the anterior one into the right casca vein. Through- 

 out its entire course intestinal vein^i-, receives numerous branches 

 from the intestine and when the spleen is reached, which is in 

 the neighborhood of the anterior or duodenum portion of the 

 intestine, it receives a large vein from that organ. The splenic 

 vein (PL I, figs, i and 6; Spl.V.) arises in the center of the 

 spleen from a fan-like system of vessels, which unite in a com- 

 mon stem, that leaves the anterior part of the spleen with the 

 splenic artery and soon empties into intestinal vein^j). Im- 

 mediately after receiving the splenic vein, intestinal vein^i), 

 usually, sends off or receives a connecting vein (PL I, figs, i 

 and 6; C'.V'.), which unites with the anterior intestinal or 

 duodenum vein, a branch of the left portal. In another speci- 

 men this vein was seen to arise from the splenic instead of the 

 intestinal vein. Intestinal vein(i) terminates by uniting with the 

 right gastric vein, in the neighborhood of the right lobe of the 

 liver, to form the main right portal trunk. As has already 

 been stated this vessel (PL I, figs, i and 11 ; R.Por.V.) is 

 in itself a very short trunk, which penetrates the apex of the 

 right lobe of the liver, and exhausts itself in that gland by 

 breaking up into numerous interlobular veins (fig. 11, I. Lob. 

 v.), which finally terminate in numerous venous capillaries. 



Proc. Wash. Acad. Sci., June, 1905. 



