VASCULAR SYSTEM OF DOGFISH 615 



The ventral aorta (see Fig. 349) gives off three pairs of 

 innominate arteries, of which the anterior pair soon fork, 

 while the posterior pair divide into two immediately on 

 leaving the aorta, making five afferent branchial arteries to 

 the gills. Four efferent branchial or epibranchial arteries 

 rise from the gills to the dorsal aorta. The first of these 

 gives off the vertebral artery. Headwards from the level 

 of the second epibranchial the dorsal aorta is paired. The 

 (single) dorsal aorta gives off the following chief branches : — 



(a) Paired subclavian arteries, rising between the junction of epi* 

 branchials three and four with the dorsal aorta. 



(6) Coeliac artery breaking into hepatic, gastric, and intestino-pyloric 

 branches, rising about the level of the anterior dorsal spine. 



(c) Anterior mesenteric, to intestine, rising about the level of the 



hinder end of the anterior dorsal fin. 



[d) Just behind (c) lieno-gastric artery, going forward to the spleen 



and part of the pancreas and stomach. 

 {e) Renal arteries. 



(/) Posterior mesenteric, to the rectal gland, 

 (g) Iliac arteries — 



and continues as the caudal artery. 



(2) Venous blood, which reaches the kidneys by the 

 renal portal system, drains from them into the paired 

 posterior cardinal sinus. These great vessels, which are 

 fused and narrow posteriorly, broaden out greatly behind 

 the head and meet the outer ends of the duct of Cuvier^ 

 a very short wide tube extending laterally from the corners 

 of the sinus venosus. Into the duct of Cuvier, midway 

 along its short length, open — 



{a) In front. — Paired inferior jugular veins. 



(b) Behind. — Paired subclavian veins, each formed by 

 the union of a brachial vein from the pectoral fin, a 

 cutaneous lateral vein, and a lateral abdominal vein arising 

 by the junction of a femoral vein from the pelvic fin and 

 a cloacal vein. 



The anterior part of the body is drained by the paired 

 anterior cardinal sinus (with the small post-orbital sinus 



F., ventricle ; S.F., sinus venosus ; Z?., brachial arter>' ; //./I., hepatic artery ; 

 G.A., gastric artery; I. P., intestino-pyloric artery; LI., lienogastric ; 

 M. ant., M. post., anterior and posterior mesenteric arteries ; R., rectal ; 

 CD/4 ., caudal ; ^F., hyoidean afferent branchial artery ; Z).w4"., paired dorsal 

 aorta; EP.{x), EP.(^), first and fourth epibranchials ; VER., vertebral 

 artery; AF.(^), fourth afferent branchial; COE., coeliac; D., dorsal aorta; 

 7L., iliac. 



