ARTERIAL SYSTEM 



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a. The cardiac aorta is a direct continuation forwards 

 of the conus arteriosus. It is a median vessel, 

 lying beneath the floor of the mouth and pharynx, 

 and deeply placed in the muscles of the under 

 surface of the head. It is a little more than an 



DA 



F G. 39. Scyllium canicula. Dissection of the arterial system from 

 ' the ventral surface. The floor of the mouth has been cut through 

 close to the median plane, and the right half turned outwards. 

 (c. H .H.) 



A, nostril. ATI, auricle. B, right orbit. BA, cut end of hindmost 

 branchial artery of the right side. BA1, first branchial artery of the left 

 side. B A5, fifth branchial artery of the left side. BE, first efferent branchial 

 trunk, or epibranchial artery, of the right side. BIT, fourth efferent 

 branchial trunk, or epibranchial artery, of the right side. C, caiotid, 

 artery. CA, cardiac aorta. D, the fifth or trigeminal nerve. UA, dorsal 

 aorta. E, external carotid artery. F,, internal carotid, artery at the point 

 where it enters the cranial cavity. G-, the hindmost of the efferent branchial 

 vessels. H, spiracle. I, efferent branchial loop of the first branchial cleft. 

 K, subclavian artery. Ml, first branchial cleft of the right side. M-5, fifth 

 branchial cleft of the right side, ff, longitudinal hypo-branchial artery. 

 O, connecting-branch between the efferent branchial loops. SV, sinus 



veuosus. T, teeth. V, ventricle. 



Q2 



