. The elements of Embryology,. v.] THE MUSCLE-PLATES. 135. Section through the Dorsal Eegion of an Embryo at the end of the Third Day. Am. amnion, m. p. muscle-plate. C. V. cardinal vein. Ao. dorsal aorta. The section passes through the point which the dorsal aorta is just commencing to divide into two branches. Ch. notochord. W. d. Wolffian duct. W. b. commencing differentiation of the mesoblast cells to form the Wolffian body. ep. epiblast. SO. somatopleure. Sp. splanchnopleure. hy. hypoblast. The section passes through the point where the digestive canal communicates vnth the yolk-sac, and
. The elements of Embryology,. v.] THE MUSCLE-PLATES. 135. Section through the Dorsal Eegion of an Embryo at the end of the Third Day. Am. amnion, m. p. muscle-plate. C. V. cardinal vein. Ao. dorsal aorta. The section passes through the point which the dorsal aorta is just commencing to divide into two branches. Ch. notochord. W. d. Wolffian duct. W. b. commencing differentiation of the mesoblast cells to form the Wolffian body. ep. epiblast. SO. somatopleure. Sp. splanchnopleure. hy. hypoblast. The section passes through the point where the digestive canal communicates vnth the yolk-sac, and is consequently still open below. This section should be compared with the section through the dorsal region of an embryo at the commencement of the third day (Fig. 41). The chief differences between them arise from the great increase in the space (now filled with meso- blast-celis) between the notochord and the hypoblast. In addition to this we have in the later section the completely formed amnion, the separation of the muscle-plate from the protovertebrae, the formation of the Wolffian body, etc. The mesoblast including the Wolffian body and the muscle-plate () is represented in a purely diagrammatic manner. The amnion, of which only the inner limb or true amnion is represented in the figure, is seen to be composed of epiblast and a layer of mesoblast; though in contact with the body above the top of the medullary canal, it does not in any way coalesce with it, as might be con- cluded from the 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, Michael. London : Macmillan
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Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondo, bookyear1874
