336 FISHES CHAP. 
branchial artery of the first branchial arch, the corresponding 
efferent trunk forming an ophthalmic artery, and passing to the 
choroid gland of the eye (Fig. 199). Both the proper afferent 
and efferent arteries of the hyoidean hemibranch either dis- 
appear or, as in the Cod (Gadus morrhua), the efferent artery 
may be represented on each side by an anastomosis between the 
hyoidean artery and the cephalic circle. Hence, the “ hyoidean ” 
artery of Teleosts corresponds to the one which has a similar 
origin in Lepidosteus. 
A brief description of the remaining efferent branchial arteries 
Sp- Ps. oes 
Wi 
His cod 
hy.a. ..S wr 
Fria. 198.—The -branchial circulation in Lepidosteus (diagrammatic). a, a, Afferent 
branchial arteries ; c, carotid ; d.a, dorsal aorta ; e, e, efferent branchial arteries ; 
ef.a, efferent vessel from the hyoidean gill which, after its union with the hyoidean 
artery, becomes the afferent vessel of the spiracular pseudobranch ; ef.a’, efferent 
vessel of the spiracular pseudobranch ; hy.a, hyoidean artery ; hy.g, hyoidean 
gill; sp.ps, spiracular pseudobranch ; v.a, ventral aorta; 1-5, the hyo-branchial 
and succeeding gill-clefts. (After F. W. Miiller and Ramsay Wright. ) 
and their derivatives in the Cod (Gadus morrhua) will illustrate 
the condition of these structures in a well-known Teleost. 
In this Fish the efferent branchial vessels open dorsally into 
right and left suprabranchial arteries,’ which unite behind to 
form a median dorsal aorta (Fig. 199). Anteriorly, the paired 
suprabranchial arteries extend towards the base of the skull as 
the so-called “carotid” arteries. The two carotids enter the 
cranial cavity, and there unite in the median line, as in the 
Cyclostomes. By the union of these arteries in front, and of the 
1 These vessels are not to be regarded as homologous with the primitive paired 
aortae of Amphioxus and the embryos of higher Vertebrates. The true dorsal 
aorta sometimes persists as a median vestigial vessel which traverses the circulus 
cephalicus. 
