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MANUAL OF ELEMENTARY ZOOLOGY 



Figs. 274 and 275 show the ventral and dorsal arterial 

 systems of the whiting. They should be compared with 

 those of the dogfish (Figs. 257 and 258), and the differences 

 noted, particularly the absence of an afferent vessel to the 

 hyoid arch, which in the whiting carries no gill, but only a 

 vascular vestige or pseudobranch supplied from the hyoidean 



Fig. 274. — A semi-dia- 

 grammatic ventral view 

 of the heart and neigh- 

 bouring blood-vessels 

 of a cod. 



a. />.a., Afferent branchial 

 arteries; a.c.s., anterior 

 cardinal sinus ; an. .auricle ; 

 b.a., bulbus arteriosus; 

 d.C, ductus Cuvieri ; 

 p.c.s., posterior cardinal 

 sinus; v., ventricle ; v.ao., 

 ventral aorta. 



Fig. 275. — A diagrammatic ventral view 

 of the dorsal arterial system of a 

 cod. 



tunles., anterior mesenteric artery ; cc, common 

 carotid; c.c'., anastomosis between the in- 

 ternal carotids which completes the circulus 

 cephalicus; coe., cceliac ; d.ao., dorsal 

 aorta; e.b.a., efferent branchial; e.c, ex- 

 ternal carotid; hy.a., hyoidean; i.e., in- 

 ternal carotid; op., ophthalmic; p.c, 

 posterior carotid; psb., pseudobranchial ; 

 sir., suprabranchial ; scl., subclavian ar- 



artery, and the replacement of the dorsal aorta in the gill 

 region by two suprabranchial arteries, which recall those 

 of Amphioxus. The whiting also reveals a feature in which 

 the Teleostomi (with the exception of some ganoids) are 

 unique among Vertebrata — namely, that the oviducts are 

 continuous with the ovaries. The bony flat fishes (Soles, 

 Plaice, etc.) are related in general features to the whiting, 

 but are flattened — not, as is the skate, from above down- 



