FISHES 



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. 1 



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 



cL.C.V: 



d.a. 



l.v. 



FIG. 187. -Diagrammatic trans- 

 verse section of an Elasmo- 

 branch, showing the position 

 of the principal longitudinal 

 blood-vessels, c, Coelom ; 

 d.a, dorsal aorta ; d.c.v, 

 dorsal cutaneous vein ; d.i.v, 

 dorsal intestinal vein ; i, 

 intestine ; i.i.v, internal in- 

 testinal vein ; l.c.v, lateral 

 cutaneous vein ; l.v, lateral 

 vein ; m.v.a, myelonic vein 

 and artery ; p.c.v, posterior 

 cardinal vein ; sp.c, spinal 

 cord ; sp.v, spiral valve; v, 

 vertebral centrum ; v.c.v, 

 ventral cutaneous vein ; 

 v.i.v, ventral intestinal vein. 

 (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 



1 In the common Dog-Fish (Scyllium 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. 



