BLOOD-VASCULAR SYSTEM OF THE LORICATI IO5 



blood from the ileum ; passing beneath intestinal vesselS(,) and 

 the splenic vessels, it crosses under the anterior part of the 

 spleen, where it joins a common trunk formed by the union of 

 the right pyloric C£eca vein and a very large j[)ylorns vein (fig. 

 32, Pyl.V.). The common trunk thus formed is the left portal, 

 but instead of breaking up into numerous radicals it empties 

 with the left pyloric cceca vein (tig. 32, L.Cae.V.) and the 

 ventral gastric vein (fig. 32, V.Gas.V.) into the common fortal 

 vein (fig. 32, C.P.V.). By anastomosing with the common 

 portal, the right portal might also be said to empty into the com- 

 mon portal. 



Stmimary of the Portals. — As in the case with the corre- 

 sponding arteries, intestinal veins^ (,„,, ,) are arbitrary names given 

 to the two principal intestinal veins. Considerable variation 

 occurs in these two veins in the same species, but in O^hiodon 

 the vessel designated as intestinal vein(2) arises in the posterior 

 part of the intestine, and in its cephalic course along the ventral 

 side of the intestine receives the splenic vein, and joining the 

 right gastric vein forms the right portal. The corresponding 

 vein in Hexagr aminos pursues a similar course ; while in Scopce- 

 nichthys the two intestinal veins unite and empty into the left 

 portal ; and in Sebastodcs intestinal vein^i^ drains only the pos- 

 terior part of the intestine, and may unite with the splenic vein, 

 or each of these vessels may empty separately into the right 

 gastric vein to form the right portal. In every case the right 

 portal breaks up in the right lobe of the liver. The vessel 

 designated as intestinal vein(2) in Ophiodon arises from the 

 ventral posterior end of the intestine and terminates in the left 

 portal. In Hexagranmios this vessel might possibly correspond 

 to an elongated duodenum artery ; while in Scorpcenichthys if 

 this vessel is represented at all, it unites with intestinal vein^) 

 and the combined trunk empties into the left portal ; and in 

 Schastodes this is the principal intestinal trunk, arising from the 

 iliac loop it unites with the right pyloric casca vein to form the 

 left portal trunk. All the genera but Hexagrammos have a 

 posterior gastric vein ; in Ophiodon it terminates in the right 

 pyloric caeca vein ; while in ScorfcB7iichthys and Sebastodcs it 

 empties into the splenic vein, a branch of the right portal. 



