. The elements of embryology. Embryology; Embryology. A. Yellow yolk-spLere filled with fine granules. The outline of the sphere has been rendered too bold. B. White yolk-spheres and spherules of various sizes and pre- senting different appearances. (It is very difl&cult in a woodcut to give a satisfactory representation of these pe- culiar structures.) The yellov^ yolk, thus forming the great mass of the entire yolk, is clothed externally by a thin layer of a dijBferent material, known as the white yolk, which at the edge of the blastoderm passes underneath the disc, and becoming thicker
. The elements of embryology. Embryology; Embryology. A. Yellow yolk-spLere filled with fine granules. The outline of the sphere has been rendered too bold. B. White yolk-spheres and spherules of various sizes and pre- senting different appearances. (It is very difl&cult in a woodcut to give a satisfactory representation of these pe- culiar structures.) The yellov^ yolk, thus forming the great mass of the entire yolk, is clothed externally by a thin layer of a dijBferent material, known as the white yolk, which at the edge of the blastoderm passes underneath the disc, and becoming thicker at this spot forms, as it were, a bed on which the blastoderm rests. Immediately under the middle of the blastoderm this bed of white yolk is connected, by a narrow neck, with a central mass of similar material, lying in the middle of the yolk (Fig. 1, w. y). When boiled, or otherwise hardened, the white yolk does not become so solid as the yellow yolk; hence the appearances to be seen in sections of the hardened yolk. The upper expanded extremity of this neck of. 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 : Macmillan and Co.
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Keywords: ., bookcentury1800, bookdecade1, booksubjectembryology, bookyear1883
