. The comparative anatomy of the domesticated animals. Horses; Veterinary anatomy. 1044 EMBRYOLOGY. Fig diagoam of the cir- culation at the commencement of the formation of the placenta (seen from the front). a, Venous sinus re- ceiving aH the sys- temic veins; 6, right auricle; 6', left auricle; c, right ventricle; c', left ventricle; d, bulbus aorticus,subilivi(iing into, e, e', e", bran- chial branches; /, /', arterial trunks formed by their con- fluence; g, g', vena azygos superior; h. h'y confluence of the superior and inferior azygos; j, vena cava inferior; k, k', vena azygos
. The comparative anatomy of the domesticated animals. Horses; Veterinary anatomy. 1044 EMBRYOLOGY. Fig diagoam of the cir- culation at the commencement of the formation of the placenta (seen from the front). a, Venous sinus re- ceiving aH the sys- temic veins; 6, right auricle; 6', left auricle; c, right ventricle; c', left ventricle; d, bulbus aorticus,subilivi(iing into, e, e', e", bran- chial branches; /, /', arterial trunks formed by their con- fluence; g, g', vena azygos superior; h. h'y confluence of the superior and inferior azygos; j, vena cava inferior; k, k', vena azygos inferior; m, descending aorta; n, n, umbilical arte- ries proceeding from it; 0. o', umbilicil veins; g, omphalo- mesenteric vein ; r, om I .halo-mesenteric artery distributed on the walls of the vitelline vesicle, t\ V, ductus venosus; (/, vitelline duct; z, chorion. branches, which are hollowed in the centre by a cavity in which the cells become free. In proportion as these new vessels are developed, the omphalo-mesenteric vessels dis- appear, until at last there only remain one or two ducts that pass to the umbilical vesicle. The umhilical veins are developed immediately after the formation of the omphalo-mesenteric veins ; they enter the common trunk of the latter, and when its ramifications diminish in volume, the umbilical veins increase rapidly ; when the liver is formed around them, they throw into it branches, which are the rudiments of the hepatic network. Between the hepatic and sublobular veins, the umbilical vein communicates with the vena cava by the ductus venosus of Aranzi, which, according to M. Colin, does not exist in the foetus of Solipeds in the last moiety of uterine life. The veins of the embryo form four principal trunks at first—two anterior, the anterior cardinal veins; and two posterior—the posterior cardinal veins. The veins of the same side unite in twos, from which result the Cuvierian ducts ; these open transversely into the omphalo-mesenteric
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Keywords: ., bookauthorcha, bookcentury1900, bookdecade1900, booksubjecthorses
