THE ELASMOBRANCH FISHES 



213 



(s.v., fig. 195c) by the liopatic veins (h.v.), which were previously the anterior 

 ends of the vitelline veins. In figure 195c and d the cardinal and renal systems 

 are also well developed. 



LATERAL ABDOMINAL SYSTEM OF VEINS 



The lateral abdominal veins {l.a.v., fig. 194) extend from the pelvic to the 

 pectoral segments of the body just under the peritoneimi in the sides of the 

 body wall. Posteriorly each vein may arise from a net of fine veinlets on the 

 side of the rectal and cloacal walls 

 {Raja,&g. 194b) ; or right and left 

 veins may be continuous across 

 the pelvic cartilage {Mustelus 

 antarcticus, fig. 194a ; Scyllium 

 canicula). Posteriorly a rectal 

 branch joins the lateral abdomi- 

 nal of Scyllium near the midven- 

 tral line. The first important trib- 

 utary (or tributaries) to the lat- 

 eral abdominal system of veins is 

 the iliac, resulting from a fusion 

 of the cloacal and femoral veins 

 from the cloacal and pelvic areas, 

 respectively {Mustelus, fig. 194a) . 

 In certain forms the cloacal and 

 femoral veins join the lateral 

 abdominal independently, as in 

 Heptanchus. In Raja an acces- 

 sory femoral vein also empties 

 into the lateral abdominal (fig. 

 194b). The femoral veins (f.v.) 

 are formed in the pelvic fin from 

 numerous veinlets, while the cloa- 

 cal veins (cl.v.) drain the sides of 

 the cloacal region. 



Blood collected from the deeper 

 structures in the posterior region, 

 then, whether from the cloaca or the pelvic fin, is carried forward by the 

 lateral abdominal vessel. As this vessel passes anteriorly many veins from 

 the body wall enter it. 



At the pectoral girdle the lateral abdominal vein receives important tribu- 

 taries. The first of these is the brachial vein. In the sharks the brachial arises 

 from the union of a dorsal, a median pterygial {m.p.v., fig. 196), and a lateral 

 pterygial vein {l.p.v.) of the fin. In rays where the pectoral fin is large in 

 extent, a much larger median pterygial branch is present and is joined by 

 the smaller lateral, ventral vein. In addition a large anterior branch from the 



Fig. 196. Veins of pectoral fin, Acanthias. (From 

 Erik Miiller.) 



l.p.v., lateral pterygial vein; m.p.v., medial 

 pterygial vein. 



