. An atlas of the fertilization and karyokinesis of the ovum. Ovum; Fertilization (Biology); Meiosis; Embryology -- Echinodermata. Fig. IX. sperm-aster about the middle-piece. From sections. Enlarged 2000 diameters. A. The sperm-head before entrance into the egg, as it appears after double-staining with hcematoxy- lin and Congo red. N, nucleus (deep blue- black); M, middle-piece (pale red). B. Immediately after entrance, showing the entrance- cone. C. Beginning of the rotation. D. Sperm-nucleus rotated 90°; aster developing about a central mass lying at the base of the nucleus and derived from
. An atlas of the fertilization and karyokinesis of the ovum. Ovum; Fertilization (Biology); Meiosis; Embryology -- Echinodermata. Fig. IX. sperm-aster about the middle-piece. From sections. Enlarged 2000 diameters. A. The sperm-head before entrance into the egg, as it appears after double-staining with hcematoxy- lin and Congo red. N, nucleus (deep blue- black); M, middle-piece (pale red). B. Immediately after entrance, showing the entrance- cone. C. Beginning of the rotation. D. Sperm-nucleus rotated 90°; aster developing about a central mass lying at the base of the nucleus and derived from the middle-piece. E. F. Completion of the rotation; growth of the astral rays. The last figure is 3| minutes after the rirst entrance. Plate II. Phototype 5. The First Entrance of the Spermatozoon. In this figure the sperm-head may be seen immediately after its entrance as a black, lance-shaped body at the lower pole of the egg opposite to the egg-nucleus. Another sperm-head, which has not entered, is seen at one side, lymg at the periphery of the egg. The sperm-head, as thus seen, represents only the nucleus of the spermatozoon. The middle-piece, which lies at the base of the nucleus, is not distinctly visible, since it is stained of the same [n many cases, however, — e. g., in the , the earthworm, the butterfly,— the tail also enters the egg. 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 Wilson, Edmund B. (Edmund Beecher), 1856-1939; Leaming, Edward, 1861-1916. New York, London, Pub. for the Columbia university press by Macmillan and co.
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Keywords: ., bookauthorwilsoned, bookcentury1800, bookdecade1890, bookyear1895
