324 



FISHES 



the corresponding vein from the caudal myotomes ; from the 

 common trunk numerous branches enter the kidney. 



In the derivation 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 1 

 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- 

 i relation with the right 



FIG. 191. Venous system of Neoceratodus. 

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

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



inferior jugular ; il.v, iliac ; i.v.c, inferior kidney, receiving in its COUrse 



vena cava or postcaval ; k, kidney ; I, ,-, , 



liver ;l.a, left auricle ; I.p.c, left posterior the Spermatic Or Ovarian Veins 



cardinal ; l.v, lateral cutaneous vein ; from the gonad of its side, and 



pt.v. vein from postcloacal myotomes ; , , , , , . 



P.V, pulmonary vein ; pv.v, pelvic ; r.a, then traverses the liver, finally 

 right auricle ; rp.v, renal portal ; s.c.v, opening into the median portion 



subscapular ; s.j, superior jugular or *, . 



anterior cardinal ; t, testis ; v, ventricle ; Ot the SinUS VenOSUS, between 



vv, right vertebral vein. (After Baldwin fche or ifi ces O f t he two hepatic 



Spencer. ) * 



veins. The left branch of the 



caudal vein (I.p.c) also passes forwards in relation with the left 

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



