_ i i. 
430 PROCEEDINGS 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 vene 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 cesophagus 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 sinws venosus. The 
latter has but a single opening for the hepatic veins, but the division 
between them extends quite up to the aponeurotic membrane. 
The neural 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 vertebre. 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 drained by several of 
the ordinary veins. 
The anterior cardinals arise by branches from the mandible, max- 
illa, M. adductor mandibulz, 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 R. mandibularis trigemini. It 
