. The elements of Embryology. Embryology. VII.] THE HEAET. 229 a single trunk, the allantoic vein, which, running along the splanchnopleure, falls into the vitelline vein (Fig. 74, U.). Meanwhile the heart is undergoing considerable changes. Though the whole organ still exhibits a marked curvature to the right, the ventricular portion I becomes directed more distinctly ventralwards, forming a blunted cone whose apex will eventually become the apex of the adult heart. The concave (or dorsal) walls of the ventricles be- come much thicker, as did the convex or ventral walls on the third day. Well
. The elements of Embryology. Embryology. VII.] THE HEAET. 229 a single trunk, the allantoic vein, which, running along the splanchnopleure, falls into the vitelline vein (Fig. 74, U.). Meanwhile the heart is undergoing considerable changes. Though the whole organ still exhibits a marked curvature to the right, the ventricular portion I becomes directed more distinctly ventralwards, forming a blunted cone whose apex will eventually become the apex of the adult heart. The concave (or dorsal) walls of the ventricles be- come much thicker, as did the convex or ventral walls on the third day. Well-marked constrictions now separate the ven- tricles from the bulbus arteriosus on the one hand, and from the auricles on the other. The latter constriction is very distinct, and receives the name of canalis auri- cularis (Fig. 75, ); the former, sometimes called the/return Halleri, is far less conspicuous. Fig. I Heart of a Chick on the Fourth Day of Incubation VIEWED FROM THE VeNTRAL SURFACE. La. left auricular appendage. canalis auricularis. v. ven- tricle, h. bulbus Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Foster, M. (Michael), Sir, 1836-1907. London, MacMillan
Size: 1816px × 1375px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookautho, bookcentury1800, bookdecade1880, booksubjectembryology
