!52 



DIPNOI 



Dipneumones pass directly, without breaking up into capillaries, to 

 the aorta, as in terrestrial vertebrates. In Ceratodus, but not in the 



-sc 



CV. 



Fig. 



Diagram of the venous system of C< ratodus Fonteri, dorsal view. (After Spencer.) a, allium ; 

 c?/. anterior abdominal vein ; br, branchial vein ; c, conus; a /■. caudal vein ; ft.p, hepatic portal 

 vein ; i.j, inferior jugular vein ; <7, iliac vein ; fc, kidney ; I, liver; Lc, lateral cutaneous vein ; 

 l.p.c, left posterior cardinal ; p, pulmonary vein ; pt.v, posterior vein from body-wall ; /'■''■ peh ic 

 vein; r.p, renal portal vein; r.p.e, right posterior cardinal; sc, subclavian vein sj, jugular 

 vein; t, testis; v ventricle; v.c, vena cava. 



Dipneumones, the hyoidean hemibranch is a pseudobraneh, receiving 

 blood only from the efferent system (Spencer, Parker, Figs 220-21). 

 Three chief points of interest are found in the venous system 

 (Figs. 222-4). Firstly, the pulmonary blood is returned directly to 

 the heart by a vein passing to the left side of the sinus venosus, as 



