. The elements of embryology . Embryology. III.] THE NEUKENTERIC PASSAGE. 73 into the notochord,-where the latter joins the primitive streak (B). A narrow diverticulum from this passage is continued for- wards for a short distance along the axis of the notochord (A, cK). After traversing the notochord, the passage is continued into a hypoblastic diverticulum, which opens ventrally into the future lumen of the ahmentary tract (0). Shortly behind the point where the neurenteric passage communicates with the neural tube the latter structure opens dorsally, and a groove on the surface of the primi
. The elements of embryology . Embryology. III.] THE NEUKENTERIC PASSAGE. 73 into the notochord,-where the latter joins the primitive streak (B). A narrow diverticulum from this passage is continued for- wards for a short distance along the axis of the notochord (A, cK). After traversing the notochord, the passage is continued into a hypoblastic diverticulum, which opens ventrally into the future lumen of the ahmentary tract (0). Shortly behind the point where the neurenteric passage communicates with the neural tube the latter structure opens dorsally, and a groove on the surface of the primitive streak is continued backwards from it for a short distance (0). The first part of this passage to appear is the hypoblastic diverticulum above mentioned. Fig. Diagrammatic Longitudinal Section through the Pos- terior End of an Embryo Bird at the time op the Formation of the Allantois. ep. epiblast; spinal canal; ch. notochord ; neurenteric canal; hy. hypoblast; post-anal gut; pr. remains of primitive streak folded in on the ventral side ; al. allantois; me. mesoblast; an. point where anus will be formed; perivisceral cavity; avi. amnion; so. somatopleure; sp. splanohnopleure. In the chick we have found in some cases an incomplete pas- sage prior to the formation of the first somite. At a later stage. 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; Balfour, Francis M. (Francis Maitland), 1851-1882; Sedgwick, Adam, 1854-1913; Heape, Walter, 1855-1929. London ; New York : Macmillan
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Keywords: ., bookcentury1800, bookdecade1880, bookpubli, booksubjectembryology
