BLOOD-VASCULAR SYSTEM OF THE LORICATI 7 1 



trating the liver with the right portal vein, anastomoses with the 

 most anterior branch of the left hepatic arter3^ By this anasto- 

 mosis the conditions are somewhat analogous to Ophiodon; 

 where the posterior gall-bladder artery, which arises from the 

 most anterior branch of the left hepatic artery, anastomoses on 

 the surface of the gall-bladder with the anterior gall-bladder 

 artery, which is a branch from the right hepatic artery. The in- 

 testinal artery(jj then crosses above the anterior or duodenum 

 portion of the intestine and intestinal vein,,), gives off several 

 branches to the intestine and then continuing caudad with the 

 intestinal vein^), between the arms of the iliac loop, extends past 

 the loop to supply the rectum. When near the end of the loop 

 the splenic artery (PI. IV, fig. 27 ; Spl.A.) is given off to the 

 spleen, which, strange to say, is located on the posterior end of 

 the intestine close to the rectum. However, before entering 

 the spleen, the splenic artery sends off a branch to the posterior 

 end of the intestine. 



Mesenteric Artery in Sebastodes (PI. IV, fig. 31 ; Mes. A.). 

 — In this genus, which is supposed to be less specialized than 

 the above genera, several new features are introduced, among 

 them, a vessel for the air-bladder and 2 for the reproductive 

 organs. After giving off the left gastric artery (PI. IV, fig. 

 31 ; L.Gas.A.), which is the principal artery for the stomach, 

 the mesenteric artery bifurcates into its 2 characteristic divisions, 

 namely, the right gastric, and intestinal artery(j). The right 

 gastric artery (fig. 31 ; R.Gas.A.) in Sebastodes is much shorter 

 than in the other 3 genera and gives off several important 

 trunks. The first important branch is the right anterior sper- 

 matic artery (PI. IV, fig. 31 ; R.Sper.A.). Together with the 

 corresponding vein this vessel passes caudad under the air-blad- 

 der vessels to supply the right ovary or testis with a large part 

 of its arterial blood, and anastomoses above with the spermatic 

 artery proper (fig. 31 ; Sper.A.). The second vessel to be 

 given off from the right gastric is the small right hepatic ar- 

 tery (PL IV, fig. 31 ; R.Hep.x\.). This vessel penetrates the 

 right lobe of the liver with the right portal vein, and often sends 

 off a branch to a gland-like body situated near the right portal 

 vein. Usually the right hepatic artery gives off the anterior 



