324 



FISHES 



the corresponding vein from the caudal myotomes ; 

 common trunk numerous branches enter the kidney. 



In the derivation 



from the 



Fig. 191. 



Venous system of Neoceratodus. 

 a.aft, Anterior abdominal ; af.r.v, afferent 

 renal veins ; b.v^ brachial ; c.d, Cuvierian 

 duct ; c.v^ caudal ; h.p.v, hepatic portal ; 

 h.v, hepatic ; i.c.v, intercostal veins ; i.j. 



of renal 

 portal veins from each of the 

 two veins into which the caudal 

 vein divides, Neoceratodus ap- 

 proaches the Elasmobranchs. 

 On the other hand, the utilisa- 

 tion of ordinary segmental veins 

 from the caudal and pre-caudal 

 myotomes, some of which 

 directly enter the kidney, is a 

 feature which has already been 

 remarked in some Teleosts ; 

 while the formation of a renal 

 portal affluent by a branch of 

 the femoral vein is an even 

 more striking Amphibian char- 

 acteristic. 



The efferent renal veins '^ 

 join the root of the left pos- 

 terior cardinal and the adjacent 

 portion of the caudal vein. 



Of the two great venous 

 trunks into which the caudal 

 vein divides, the right is much 

 the larger and behaves some- 

 what differently to the left. 

 The former {i.v.c) passes for- 

 wards in relation with the right 



inferior Jugular ; iZ.^:, iliac ; i.v.c, inferior kidney, receiving in its COUrSe 

 vena cava or postcaval ; k, kidney ; I, 



the spermatic or ovarian veins 

 from the gonad of its side, and 

 then traverses the liver, finally 

 opening into the median portion 

 of the sinus venosus, between 

 the orifices of the two hepatic 

 veins. The left branch of the 

 caudal vein {l.p.c) also passes forwards in relation with the left 

 ^ Baldwin Spencer, op. cit. pp. 24, 30-31. Not represented in Fig. 191. 



liver ; l.a, left auricle ; /.2-).c, left posterior 

 cardinal ; l.v, lateral cutaneous vein ; 

 pt.v, vein from postcloacal myotomes ; 

 p.v, pulmonary vein ; pv.v, pelvic ; r.a, 

 right auricle; rp.v, renal portal; s.c.v, 

 subscapular ; s.j, superior jugular or 

 anterior cardinal ; t, testis ; v, ventricle ; 

 v.i>, right vertebral vein. (After Baldwin 

 Spencer.) 



