6o3 



Fig. 465. — Diagrams of heart and aortic arches. Ventral view with heart un- 

 twisted, to bring the chambers into one plane and the ventricle anterior. — 

 From Goodrich. 



A , Amphibian ; B, mammal ; C, most reptiles ; D, crocodile. In A and C, B and T are 

 sections of the proximal and distal parts of the truncus arteriosus respectively. 



asc, Anterior subclavian ; c, carotid arch ; d, ductus Botalli ; da, dorsal aorta ; ex, external carotid ; k, 

 internal carotid ; la, left auricle ; Isa, left systemic arch ; Iv, left ventricle ; p, pulmonar\- arter>- ; 

 pr., pulmonarv vein; r, ductus arteriosus; ra, right auricle; rsa, right systemic arch; n-, right 

 ventricle ; s, systemic arch; sc, subclavian ; spa, interauricular septum ; spi; interventricular septum ; 

 St', sinus venosus ; i', ventricle ; ir, superior caval vein ; I'ci, inferior caval vein ; 1-6, original embryonic 

 arterial arches. 



