The Plathander " (Xenopus laevis). 
351 
vesicular (from bladder), and rectal (Rec) branches. The sciatic (also 
called iliac), which is the vein from the dorsal part of the femur, receives 
a cutaneous branch and is connected to the renal portal vein on the one 
hand and on the other to the abdominal by means of a long vein which 
I shall call "pubic"; the pubic vein receives blood from a "pubic" 
plexus (PP). 
In the frog the blood from the iliac (or sciatic) veins must pass 
through the kidneys ; in Xenopus the blood from the whole of the 
posterior part of the animal may take two courses, either through the 
kidneys or through the abdominal vein to the liver. 
There are three lumbar veins (L 1, 2, and 3) opening into each renal 
portal, and the latter also receives the blood from the oviduct or vas 
deferens. The anterior pair of lumbars (L 1) are long and drain the 
diaphragm muscles which attach the oesophagus and lungs to the anterior 
ends of the ilia. The ovaries and testes are drained by veins from the 
post-caval. 
The abdominal vein receives minute branches along its course under 
the skin and also a large branch (Per) from the body-wall over the heart. 
Anteriorly the abdominal, as usual, opens into the hepatic portal system. 
The hepatic portal system (HP) consists of (1) a vessel from the 
pancreas with a branch from the spleen, and (2) a vein from the 
duodenum ; it opens into the liver by means of three branches. From 
the liver the blood is taken to the heart through the hepatic veins (H). 
The venous system of the Plathander is thus only different from that 
of the frog (as described in Parker and Parker) in that the iliac veins are 
joined to the abdominal vein by the long " pubic " veins and that the 
pelvic veins are very short, being situated transversely across the end of 
the rectum. The "pubic" plexus is situated on the ventral face of the 
thigh ; the " pubic " veins join the abdominal at the ventral point of the 
pubic symphysis and the pelvic veins join the abdominal at the dorsal 
point of the symphysis. 
The Nervous System. 
The brain and cranial nerves are similar to those of the frog, and 
so need no special mention. The spinal nerves differ in that the seventh 
spinal nerve is not joined to the eighth in order to form the sciatic plexus ; 
also the tenth spinal nerve is absent. The sympathetic system (Fig. 6) 
is slightly different to that of the frog. There are, on each side, six 
ganglionic swellings and the chord is joined to all the spinal nerves and 
to the vagus. The seventh spinal has a double connection with the 
sympathetic chord and the chord, ends on the ninth spinal nerve as a 
broad flat swelling. There are three sympathetic nerves : one (CP) 
runs along the mandibular artery and no doubt goes to the cardiac 
