366 CHORDATA. 
jugulars anastomose together below the tongue. The post- 
caval can be traced backwards through the liver where it 
receives paired epatics. A little way behind the liver it 
diverges into two lac veins. The portal vein may be seen 
passing to the liver from the stomach and intestine. Its 
most posterior branch, the posterior mesenteric, anastomoses 
with the systemic system (see below). The portal has the 
same relationships as in the skate and frog, but there is no 
anterior abdominal. 
The epigastric vein is said to represent this vein. It drains the 
omentum, a fatty fold of peritoneum, and runs forward to join the 
left hepatic vein. 
If the rectum be cut through and the intestine carefully 
removed, the veins and arteries in the abdominal region will 
be easily seen (see Plate IX.) They are in relation to the two 
large three-lobed kidneys, lying in a hollow of the pelvis. 
From the tail there emerges a small caudal vein which 
bifurcates into two renal portals diverging right and left 
towards the kidneys. Each receives an internal iliac and 
then passes through the kidney. Between the second and 
third lobe of the kidney, the renal portal receives the seéatic 
and between the first and second it receives a large femoral. 
The femoral and sciatic then form the zac which receives 
a venal from the kidney, and then unites with its fellow to 
form the gostcaval. Hence the iliacs and renal portals 
form a complete “renal cycle” running left and right from 
caudal to postcaval. 
At the point of junction of caudals and renal portals 
there runs forward beside the rectum a large median vein, 
the posterior mesenteric. It joins the portal anteriorly. 
The arterial system consists, like the venous, of two 
parts. (1) The right ventricle gives off a trunk which 
immediately bifurcates into two pulmonary arteries going to 
the lungs. These correspond to the third 
arterial arches (pulmocutaneous) of the frog. 
(2) The systemic system—the left ventricle 
gives off a main trunk which divides into three. Two 
are paired and anterior; they are called the zanominate 
arteries and divide into carotid to the head and sué- 
clavian which itself divides into drachial and pectoral. 
The third bends over to the right and passes dorsal to the 
Respiratory 
System. 
