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MANUAL OF ELEMENTARY ZOOLOGY 



arteriosus leads into a long ventral aorta, from the end of 

 which arise four vessels to the branchial arches. 1 From 

 the gill capillaries there arises in each arch an efferent 

 vessel which discharges into a longitudinal suprabranchial 



Fig. 380. — Diagrams of the heart and chief arteries of a tadpole. — 

 From Bourne. 



A , The vessels of a tadpole at the stage when three external gills are present ; B, 

 the arrangement when secondary gills are in use ; C, the adult arrangement. 



a.c, Anterior commissural vessel ; a.cb., anterior cerebral artery ; a/. t afferent 

 branchial arteries ; ao., dorsal aorta ; car., carotid artery ; eg-., carotid gland ; 

 cu., cutaneous artery ; d.b., ductus Botalli ; e/., efferent branchial arteries ; /*/., 

 heart ; hy., efferent hyoidean artery ; *'., connecting vessel ; I., lingual artery ; 

 md., efferent mandibular artery ;p.c, posterior commissural vessel \pLc-, pulmo- 

 cutaneous arch; put., pulmonary artery; sys. y systemic arch ; rr., truncus 

 arteriosus ; v., ventricle ; l.-IV., branchial aortic arches. 



artery. The two suprabranchial arteries join behind to 

 form the dorsal aorta. In front they are continued as the 

 common carotids. In the presence of a single efferent 



1 There are traces of similar vessels in the hyoid and mandibular 

 arches. 



