. Outlines of zoology. iorlya large vascular network orrete mirabile, which receivesblood from the mesenteric arteryand returns blood to the portalvein. Circulatory system.—The heartlies within a pericardial chamber,separated by a partition fromthe abdominal cavity. The bloodfrom the body and liver enters theheart by the sinus venosus, passesinto the thin-walled auricle, andthence to the muscular the ventricle it is driven upthe ventral aorta, the base of whichforms a white non - contractilebulbus arteriosus. The ventral aorta gives off, oneach side, four afferent branchialvesse
. Outlines of zoology. iorlya large vascular network orrete mirabile, which receivesblood from the mesenteric arteryand returns blood to the portalvein. Circulatory system.—The heartlies within a pericardial chamber,separated by a partition fromthe abdominal cavity. The bloodfrom the body and liver enters theheart by the sinus venosus, passesinto the thin-walled auricle, andthence to the muscular the ventricle it is driven upthe ventral aorta, the base of whichforms a white non - contractilebulbus arteriosus. The ventral aorta gives off, oneach side, four afferent branchialvessels to the gills. Thence theblood is collected by four efferenttrunks, which unite on each sidein an epibranchial artery. Thetwo epibranchials are united pos-teriorly to form the dorsal aorta,while anteriorly they give off thecarotids, which are united by atransverse vessel closing the cephalic circle. Blood enters the sinus venosus by two vertical precavalveins, and by hepatics from the liver. Each, precaval vein Fig. 298. — Diagram ofTeleostean circulation.—After Nuhn. auricle; F., ventricle ; ,.bulbus arteriosus ; z;.a., ventralaorta; ^ afferent branch-ials-; , efferent branchials;c;c., cephalic circle; ?., caro-tids; anterior cardinalveins; , posterior car-dinal _ veins; , ductusCuvieri; , dorsal aorta;,, caudal vein ; ^ caudalartery; .ff*., kidney. ^58 PISCES FISHES. formed from an anterior cardinal from the head and aposterior cardinal from the body. The posterior cardinalsextend along the kidneys, and are continuous with the caudalvein, but the middle part of the left cardinal is circulation of the blood seems to be helped, in somefishes at least, by the respiratory movements and by themuscular contractions in swimming. Excretory system.—The kidneys are very long bodies,extending above the swim-bladder under the vertebralcolumn. The largest parts lie just in front of and justbehind the swim-blad
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Keywords: ., bookcentury1900, bookdecade1910, bookidcu3192, booksubjectzoology
