1906.] ANATOMY OF CENTROPHORUS CALCEUS. 877 



The visceral arteries arising from the dorsal aorta are three in 

 number — the cceliac, the lieno-mesenteric, and the posterior 

 mesenteric. Tlie cceliac, as indicated in Pi. LYII. fig. 3, supplies 

 the liver, stomach, and duodenum. The lieno-mesenteric, 

 about four inches from its origin, divides iiato the splenic and 

 anterior mesenteric ; the former runs to the middle of the larger 

 spleen where, after giving ofi" small branches to this oi'gan, it 

 divides into two vessels, one of Avliich runs to the cul-de-sac of 

 the pylorus and the other to the posterior extremity of the outer 

 lobe of the panci-eas ; the latter runs directly to the anterior 

 portion of the spii'al-valve intestine. The posterior mesenteric 

 supplies the rectal gland as usual. The oviducts are each supplied 

 in the region of the oviducal gland by three arteries arising from 

 the dorsal aorta at about the level of the eleventh or twelfth 

 vertebra, as shown in PI. LXII. fig. 19. 



The posterior cardinal sinuses are large in diameter and lie on 

 each side of the vertebral column ; they arise by the bifurcation 

 of the caudal vein about three inches in front of the anterior 

 extremities of the pelvic fins. Tliei^e is no " renal-portal system " 

 — the slender kidneys lying externally to the sinuses. The 

 posterior cardinals suddenly diverge anteriorly to open as usual 

 into the Cuvierian sinuses, the small lateral veins opening into 

 the posterior cardinals just before. The anterior cardinal sinuses, 

 subclavian arch, brachial veins, and internal jugulars exist as 

 usual. The hepatic-portal vein (which has several conspicuous 

 factors in connection with the spleens, pancreas, and spiral-valve 

 intestine) is large and runs, as before described, in the same 

 muscular band as the bile-duct and goes first to the right lobe of 

 the liver, as shown in fig. 3 (PI. LYII.). I neglected to ascertain its 

 further course anteiiorly, including its relation to the left lobe of 

 the liver. The hepatic veins enter the sinus venosus by two large 

 apertures situated some distance ajaart (PI. LYIII. fig. 4). Ac- 

 cording to Neuville ^° (who has dissected Centro'iyhorus granulosus 

 and C. squamosus), the genus Gentrophorus is characterised by the 

 absence of hepatic sinuses : " les veines sus-hepatiques forment des 

 troncs qui, au lieu de confluer pour former un sinus commim, 

 restent completement independants et debouchent directement 

 dans les canaux de Cuvier, apres avoii subi un renflement presque 

 insensible." Also, according to ISTeuville, Centrophorus, with 

 Selachians generally ""*, possesses an intra-intestinal artery and 

 vein which course along the margin of the spiral valve, the 

 lattei" of course forming a factor of the hepatic-portal vein. 

 The ap{)earance of the hepatic apertures in the sinus venosus of 

 G. ccdceus is confirmatory of Neuville's former statement. 



Each of the oviducts has a conspicuous vein running along its 

 outer edge, which I presume enters the posterior cardinal of the 

 corresponding side anteriorly. 



A small vessel, apparently a vein (PI. LXI. fig. 16, B.Y.), ran 



2-4 " Sur les Vaisseux intra-intestiiiaux des Selaciens." Bull. Mus. Paris, 1897 (7). 



