XII VASCULAR SYSTEM a7 
their extent they are embedded in the kidneys (Fig. 186); and in 
this region the two veins are in close relation in the median line, 
and here and there freely communicate with each other. More 
anteriorly, they enlarge so much 
that they present the appearance 
of cavernous sinuses. In addition 
to the anterior segmental and ovi- 
ducal veins, the posterior cardinals 
receive the spermatic or the ovarian 
vein from the male or female 
gonad. 
The precaudal section of the 
primitive subintestinal vein, now 
termed the internal intestinal vein 
(Figs. 186 and 187), traverses the 
spiral valve as it passes forwards 
to the liver, but from a_physio- 
logical point of view is now merely 
one of the factors of the great 
hepatic portal vein, the principal 
tributaries of which are the veins 
from the stomach and _ intestine, 
including the rectal gland, and the 
pancreas and spleen. On entering 
\ 
\\----4\-pw 
Fic. 186.—Venous system of Mustelus ant- 
arcticus. a, Auricle ; a.c, anterior cardinal ; 
6.a, conus arteriosus; 67.v, brachial vein ; 
ed, Cuvierian duct or precaval vein; ¢.v, 
caudal vein ; cl.v, cloacal vein ; 7.v, femoral 
vein ; 4.s, hyoidean sinus; #.v, hepatic vein ; 
i.1.v, internal intestinal vein ; 7.7, inferior 
jugular; &, kidney; J, liver; d.v, lateral, 
vein ; md.v, mandibular vein ; 2./.v, nutrient 
hyoidean veins ; 0.s, orbital sinus ; p.c, pos- 
terior cardinal ; p.v, hepatic portal vein ; 
rp.v, renal portal vein ; sc.v, subscapular 
VEL STATS PELMatICa mVelNes Sn (SINUS 9 Neeecemcenenmene C.U 
venosus ; v, ventricle; v.a, ventral aorta. 
(After T, J. Parker.) | 
the liver the hepatic portal vein divides into two_ principal 
branches for the right and left halves of the gland. From the 
liver the blood is conveyed by two hepatic veins to the sinus 
venosus. 
The lateral veins (Fig. 186) are situated in the lateral walls 
