318 FISHES CHAP. 
of the abdomen, immediately external to the peritoneum (Fig. 
187). Each vein begins near the pelvic fin, where it is con- 
nected with its fellow across the dorsal face of the ischio-pubic 
cartilage, and thence runs forward towards the pectoral fin. At 
its origin the lateral vein receives a femoral vein from the pelvic 
fin and a cloacal vein, and also, near its anterior end, a brachial 
vein from the pectoral fin, finally joining the Cuvierian duct of 
its side.’ 
The anterior cardinal vein is situated directly above the gill- 
arches of its side of the head, and extends forwards from its 
junction behind with the Cuvierian duct to the outer side of the 
Fia. 187.—Diagrammatic trans- 
verse section of an Elasmo- 
branch, showing the position 
of the principal longitudinal 
blood-vessels. ¢c, Coelom ; 
d.a, dorsal aorta 3 -d-cia, 
dorsal cutaneous vein ; d77.v, 
dorsal intestinal vein; 7, 
intestine ; 7.7.7, internal in- 
testinal vein ; /.c.v, lateral 
cutaneous vein ; /.v, lateral 
vein; #.v.a, myelonic vein 
and artery ; p.c.v, posterior 
cardinal vein; sp.c, spinal 
cord ; sp.v, spiral valve; », 
vertebral centrum; 1.¢.2, 
ventral cutaneous vein ; 
: a v.1.v, Ventral intestinal vein. 
ete (From T. J. Parker.) 
auditory capsule, where it communicates by a valvular orifice with 
a large sinus surrounding the eye-muscles (orbital sinus), and 
ventrally, by means of a similar aperture, with another large 
sinus, the hyoidean sinus, which lies on the outer face of the 
corresponding hyoid arch,and is continuous ventrally with its fellow 
of the opposite side. Into the orbital sinus open the anterior 
facial vein from the anterior and external regions of the head, and 
the anterior cerebral vein from the lateral half of the brain, and, 
into the hyoidean sinus, the nutrient veins from the hyoidean 
hemibranch. 
The inferior jugular veins are situated beneath the branchial 
apparatus. Each vein begins anteriorly by communicating with 
' In the common Dog-Fish (Scylliwm canicula) each lateral vein joins the posterior 
cardinal near the junction of the latter with the Cuvierian duct, the subclavian 
vein from the pectoral fin opening directly into the corresponding Cuvierian 
duct. 
