. Cytology, with special reference to the metazoan nucleus. Cells. Ill GERM-TRACK 83 and gradually disappear, and a new set of granules makes its appearance in the next prophase. As the granules of the preceding mitosis have not quite disappeared by the time the new set develops, the cell is never altogether without them, and this fact makes its continuous identification possible. The new granules appearing at prophase are again concen-. FiG. 39. Differentiation of the germ-track in Cyclops fuscus (A-H), Zind Diaptomiis coerukits (\). (After Amma, , iQii.) A, prophase of first cleavage mit
. Cytology, with special reference to the metazoan nucleus. Cells. Ill GERM-TRACK 83 and gradually disappear, and a new set of granules makes its appearance in the next prophase. As the granules of the preceding mitosis have not quite disappeared by the time the new set develops, the cell is never altogether without them, and this fact makes its continuous identification possible. The new granules appearing at prophase are again concen-. FiG. 39. Differentiation of the germ-track in Cyclops fuscus (A-H), Zind Diaptomiis coerukits (\). (After Amma, , iQii.) A, prophase of first cleavage mitosis, granules congregated round one attraction sphere; a, same niitosis, metaphase; C, 2-cell stage, resting nuclei (note gonomery) ; D, prophase of second cleavage division: E, i6-cell stage. All the nuclei have completed their division, and entered uito the resting stage, except that of the granule ceU which is still in anaphase. F, division of the granule cell into the two primitive germ-cells; G, H, I, later stages. g, primitive germ-cells. trated round one attraction sphere only, and thus again pass into only one of the daughter cells. A differential cell division of this sort takes place four times, so that the cleaving egg up to the end of tlic 16-0011 stage contains one, and only one, cell with granules, or oranide cell. The nucleus of this cell does not as yet differ markedly from those of the other cells, except that it constantly lags a Uttle behind the others in 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 Agar, Wilfred Eade, 1882-. London, Macmillan
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectcells, bookyear1920
