BLOOD-VASCULAR SYSTEM OF THE LORICATI 99 



corresponding arteries and unite in forming the left portal trunk 

 directly in front of the point of bifurcation of the coeliac artery. 

 Near its origin from the union of the two pyloric caica veins 

 the left portal, or occasionally it is the right pyloric casca vein, 

 receives intestinal vein^^^y This vein (PI. I, figs, i, 6 and ii ; 

 Int.V.(„)) usually has its source from the ventral side of the 

 intestine close to the rectum. Its course is cephalad in the 

 adipose tissue below the intestine. Before going very far, how- 

 ever, it crosses to the upper side of the intestine, changing 

 places with intestinal vein(j). Then proceeding cephalad above 

 the artery until the duodenum is reached, it crosses over the 

 intestine, intestinal artery^j^ intestinal vein^^ the anterior part 

 of the duodenum, the coeliac artery, and empties into the left 

 portal close to its origin from the two pyloric caeca veins. Con- 

 tinuing cephalad for a short distance between the stomach and 

 liver and to the left of the coeliac artery, the left portal receives 

 the anterior intestinal or chtodenuni vein (PI. I, figs, i and 

 II ; A. Int. v.), which returns the blood from the anterior loop. 

 The course of this vessel is at first directly behind the corre- 

 sponding artery ; then after passing under intestinal artery(j) and 

 intestinal vein^j^ it ordinarily gives off or receives the connecting 

 vein (figs, i and 6; C.'V.'), a small vein which usuall}'- anas- 

 tomoses with intestinal vein^j^ a branch of the right portal. 

 Then after passing over the anterior arm of the duodenum from 

 which it receives a branch, it crosses the coeliac artery, and after 

 following along behind the hepatic artery for a short distance 

 terminates in the left portal. The left portal enters the dorsal 

 surface of the liver through 5 large radicals or terminal branches 

 designated by the letters a to e (figs. 6 and 11). These vessels 

 immediately penetrate the large left lobe of the liver and break 

 up into the interlobular veins (fig. 11 ; I.Lob.V.), which, in 

 turn, break up into venous capillaries. Usually several veins 

 from the ventral surface of the stomach, designated as ventral 

 gastric veins (fig. 6 ; V.Gas.V.), empty into some of these radi- 

 cals, and some of the ventral gastric veins often penetrate the 

 dorsal surface of the liver and break up into venous capillaries 

 without emptying directly into the portal system. The -posterior 

 gall-bladder vein (fig. 11; P.G.Bl.V.), which arises on the 



