430 PROCEED [NGS OF THE CANADIAN INSTITUTE. 



mens curving upwards and backwards crosses and joins the portal at 

 this nucleus ; in others, however, it continues straight forward on 

 the right of the stomach and joins the portal vein near its termina- 

 tion in the liver. 



The venae intercostales opposite to the kidney enter that gland near 

 its ventral margin, but those more anterior consist of a dorsal and 

 ventral branch which unite in a horizontal stem on a level with the 

 ventral surface of the air-bladder. This stem consists of an anterior 

 and a posterior branch, which unite into a transverse stem across 

 the mesentery covering the ventral surface of the air-bladder, the 

 right to the right mesenteric vein, and the left to enter the portal 

 vein immediately in front of the spleen. The most anterior pair of 

 intercostal veins enter the head-kidney at its dorso-lateral angle. 



The portal vein continues forward to the median side of the left 

 posterior lobe of the liver, to which it gives a branch and continues 

 to give off branches as it passes around the posterior margin of the 

 gland below the oesophagus to terminate in two branches to the right 

 lobe. The gastric veins from the stomach enter the portal vein at 

 various points as it curves around between the stomach and the liver. 

 Sometimes they miss the portal vein and enter the liver direct. 



The hepatic, veins arise by small branches opening directly into 

 large sinus-like vessels which run downwards and forwards to meet 

 in the median line and pierce the aponeurotic membrane just above 

 the coracoids, where it is in contact with the sinus v&uosus. The 

 latter has but a single opening for the hepatic veins, but the division 

 between them extends quite up to the aponeurotic membrane. 



The neuial and lateral segmental veins above the body cavity unite 

 in a vein in the neural canal, which discharges itself into the pos- 

 terior cardinals by a pair of vessels between the transverse processes 

 of the fourth and fifth vertebrae. The highly modified region be- 

 tween the dorsal fin and the skull has special venous connections 

 which will be described below. 



The veins from the fin-rays enter a venous sinus or large vessel in 

 the canal at the base, from which the blood is chained by several of 

 the ordinary veins. 



The anterior cardinals arise by branches from the mandible, max- 

 illa, M. adductor mandibular, the operculum, and dorso-lateral surface 

 of the skull generally. These branches enter at the orbit, and uniting, 

 run along the ventral surface of the It. mandibularis trigemini. It 



