XII VASCULAR SYSTEM 337 
right and left suprabranchial arteries behind, the characteristic 
“circulus cephalicus” of Teleosts is completed! From the 
anterior part of the cephalic circle are derived two internal 
carotid arteries” for the brain, and also a pair of orbito-nasal 
arteries for the eye-muscles and the nasal sacs, while more 
posteriorly an external carotid has its origin from each supra- 
branchial artery. 
oph a. 
i ae ; 
af 6.0. Hy Bie. 
Fic. 199.—Branchial arterial system of the Cod (Gadus morrhua). Lateral view. 
af.b.a, First afferent branchial artery ; cl.a, coeliac artery ; d.a, median dorsal 
aorta ; ef.b.a, first efferent branchial artery ; ex.c, external carotid; H, heart ; 
hy.a, hyoidean artery; Hy.b.a, hypobranchial artery for the heart and pelvic 
fins ; hy.ps, spiracular pseudobranch ; in.c, internal carotid ;? d.d.a, left supra- 
branchial artery ; m.a, mesenteric artery; on, orbito-nasal artery ; oph.a, 
ophthalmic artery ; 7.d.a, right suprabranchial artery ; sb.a, subclavian artery ; 
v.a, ventral aorta ; 1-5, hyobranchial and succeeding gill-clefts. (Altered from T. 
Jeffery Parker.) ; 
(3) In most Teleostomi the air-bladder is supplied with blood 
by branches of the coeliac artery, with the addition of small 
branches arising directly from the dorsal aorta. Polypterus and 
Amia* are, however, exceptional, inasmuch as the arteries for the 
air-bladder are derived from the last or fourth pair of efferent 
branchial vessels, and in this respect, but not in the destination 
1 For the relations of the efferent branchial vessels to the cephalic circle and 
the median dorsal aorta in different Teleosts, see Ridewood, P.Z.S, 1899, p. 939. 
2 Only one of the two internal carotid arteries is shown in Fig. 199. 
3 J. Miiller, U. d. Baw u. d. Grenzen d. Ganoiden, Berlin, 1846, p. 43; Ramsay 
Wright, Standard Nat. Hist. ili. pp. 48, 49. 
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