98 ALLEN 



Shortly before entering the liver, however, the right portal re- 

 ceives a vein from a gland-like body, marked G in tig. i, and 

 the anterior gall-bladder vein. The latter vessel (fig. 11, A. 

 G.Bl.V.) arises from the anterior part of the bladder, and like 

 the corresponding artery, anastomoses with the posterior gall- 

 bladder vein. 



In some cases, as was also noted with the corresponding 

 artery, intestinal vein^_, does not always have its origin in the 

 rectum and anastomose with the posterior mesenteric vein and 

 the vessels emptying into the right cseca. vein ; but sometimes 

 arises much further cephalad, and the part of the intestine 

 usually drained by this vessel was poured into the posterior 

 mesenteric vein and the veins emptying into the right cseca 

 vein, 



(d) Left Portal Vein (PL I, figs, i, 6 and 11 ; L.Por.V.). — 

 This is somewhat the larger of the two portals. In Ofhiodon 

 it has its source, principally, from the right and left pyloric 

 casca veins and intestinal vein(2)- Of the 2 pyloric ccBca veins^ 

 the right (PL I, figs, i and 6; R.Cae.V.) is the larger. Beside 

 receiving 3 or 4 large branches coming from the c^eca it receives 

 a right, and a left -posterior gastric vein (PL I, figs, i and 6 ; 

 R, and L.P.Gas.V.). The right vessel comes from the right 

 and ventral side of the posterior or cardiac portion of the 

 stomach, where its branches anastomose with those of the right 

 gastric vein and branch Z of the posterior mesenteric vein. In 

 the specimen from which figures i and 6 were drawn the right 

 posterior gastric vein received 2 branches from intestinal vein^) 

 and the right pyloric caica vein received a third one. In those 

 specimens in which these vessels unite with both intestinal 

 vein^,^ and the right pyloric caeca vein or its posterior gastric 

 branch it would be possible for the blood to flow in either direc- 

 tion, but it is probable that the least resistance is toward the 

 pyloric Ciiica vein. Shortly before the right pyloric cteca vein 

 unites with the left in front of the pylorus, it receives a small 

 vein from the pylorus. Usually the left pyloric cceca vein (see 

 PL I, figs. I and 6), is much the smaller. It receives about 2 

 branches from the cseca and one or 2 small ones from the 

 pylorus. Both of the pyloric ca?ca veins run outside of their 



