112 



PISCES 



branchial arch (p. 258 and Figs. 72, 220). The dorsal portion of 

 the mandibular aortic arch (anterior carotid) having lost its 



Fig. 71. 



Diagram of the branchial circulation of an Elasmobranch lish (modified from T. J. Parker). 

 a.a, median anterior prolongation of aorta ; a.c, anterior carotid, efferent vessel of spiracular 

 gill (pseudobranch) ; a.ef, efferent vessel from last hemibranch ; a.f, anterior efferent vessel ;■ 

 af ''■*>, live afferent vessels from ventral aorta ; af.a, afferent artery of spiracular gill ; c, con us 

 leading to ventral aorta ; <■/, coeliac artery ; d, ductus Cuvieri ; d.a, dorsal aorta ; ef, epibranchial 

 artery; h.a, hyoid efferent vessel; ftp, hepatic veins; ht, heart; p.c, posterior carotid ;; p. ef, 

 posterior efferent vessel ; s, spiracle ; D.a, ventral artery ; 1-V, branchial slits. 



connection with the ventral aorta, acquires a new supply of blood 

 for the spiracular gill from the efferent vessel of the hyoid arch. 

 It passes thence across the floor of the orbit, through the lateral 



Diagram of the branchial circulation of a Teleostean fish (modified from T. J. Parker), a.b, 

 artery to air-bladder ; a/8-8, lour afferent vessels from ventral aorta ; aa, carotid artery, c.c, 

 Circulus cephalicus ; cl, coeliac artery ; d, ductus Cuvieri ; d.a, dorsal aorta ; t/3, efferent vessel 

 of first branchial arch : ep, epibranchial artery ; h.a, hyoidean artery (afferent vessel of pseudo- 

 branch) ; hp, hepatic vein ; ht, heart; mis, mesenteric artery; o.a, ophthalmic artery (efferent 

 vessel of pseudobranch); ps, pseudobranch (hyoidean gill, "possibly with spiracular gill);'*, 

 position of spiracle (closed) ; v.a, ventral artery ; I-V, five branchial slits.. 



carotid foramen, into the cranial cavity, where it joins its fellow 

 from the other side (front end of the original circulus cephalicus), 

 and gives oft' paired cerebral arteries and a median spinal artery. 



