PLATE I. 



Figures and Diagrams of the circulatory centers of Vertebrata. Copied from 

 Gegenbaur and His, mostly enlarged. 



Fig. 1. Diagram of the arterial arches of a Fish (species not given). 



Fig. 2. Head of an embryonic Teleostean, with the rudiments of the vascular 

 system (diagrammatic). 



Fig. 3. Heart and arterial trunks of a larva of a Salamander. 



Fig. 4. Arterial system of the Frog. 



Fig. 5 Heart and arteries of an Ophidian (Boa). 



Fig. 6. Diagram of the arterial system of the adult Fowl. 



Fig. 7. Central circulatory system of Man ; foetus of the second month ; front 

 view. 



Fig. 8. Same as Fig. 7, left side. 



V, ventricle of heart. 



«, auricle of heart. 



s V, sinus venosus of heart. 



b a, bulbus arteriosus of heart. 



a 6, aorta branchialis. 



1, 2, 3, 4, 5, arteriae branchiales. 



V 1, 2, 3, venae branchiales. 



ao, aorta. 



ad, aorta dextra (right). 



a 5, aorta sinistra (left). 



p, arteria pulmonalis. 



db, ductus botalli. 



ca, arteria carotis. 



cca, common carotid. 



Jisc, Isc, right and left subclavian arteries. 

 i?m,^m, right and left innominatearteries. 

 cut, arteria cuticularis. 

 occ, arteria occipitalis. 



V c, vena cardinal! s. 



V c7, right vena cava. 



V s, left vena cava. 



vi, inferior (posterior) vena cava. 



ces, (esophageal artery. 



wi, mesenteric artery. 



s, spiracular or branchial fissure. 



«, nostril. 



dc, ductus cuvieri. 



I, lingual artery. 



