VASCULAR SYSTEM 



2U 



together of the epibranchial vessels to form the dorsal aorta, the 



■ rttcs 



of 3 



Fig. 2-20. 



Branchial circulation of Ceratochts (from Spencer's figures). I-V, live branchial slits; abr 

 anS efferent vessel'; a,-, anterior carotid : a/ M four afferent vessels (^rre = l,i,g to 

 the original arches 4-6) ; Cj conus ; ci, eoeliac artery ; d, ductus Cuvien ; *H second awT fourth 

 BDibranchial arteries; h.a, hyoid artery (from original 2nd arch); J,, air-bladder , La, lingual 

 "r p v , ' mesentric artery; p.a, pulmonary artery; pbr, posterior efferent vessel ; p. c, 

 rasterior can 1 ial j lv, putaonary vein ; i, position of closed spiracle ; * a, ventral artery ; 

 ■ c\ ena e£va nferioV. The gills are represented on the hyoid and next 4 branchial arches. 



branch alarel ?» . ' e'p branchial vessel' of hyoid arch ; U, heart ; L, lung ; m.a, median 

 ^tev^ulinoarV artery: p.v, pulmonary vein; v.ao, ventral aorta; v.c, vena cava 

 ESatar* The ^flve brlnchial slits are shaded ; tlie first two branchial arches are without gdls. 

 A dotted line indicates the position of the obliterated spiracle. 



structure of the conus, and the position of the auricles, are features 

 in which they distinctly approach the Amphibia. 



The aortic arches of the first two gill-less branchial bars of the 



