. Cytology, with special reference to the metazoan nucleus. Cells; Cytology. Fig. Q The chromosomes in the life-cycle of Aphis saliceti. (After von Baehr, , 1912.) A, spermatogonia! prophase; B, primary spermatocyte, beginning of the meiotic phase; C,D, E, F, G, evolution of the definitive chromosomes. Note the two bivalents and the single X chromosome. H, metaphase I.; I, ana- phase I.; J, K, telophase I. All the chromosomes now alike, all being univalent and split in preparation for the second division. L, resting stage between the two divisions; M, prophase II.; N, metaphase II.; O
. Cytology, with special reference to the metazoan nucleus. Cells; Cytology. Fig. Q The chromosomes in the life-cycle of Aphis saliceti. (After von Baehr, , 1912.) A, spermatogonia! prophase; B, primary spermatocyte, beginning of the meiotic phase; C,D, E, F, G, evolution of the definitive chromosomes. Note the two bivalents and the single X chromosome. H, metaphase I.; I, ana- phase I.; J, K, telophase I. All the chromosomes now alike, all being univalent and split in preparation for the second division. L, resting stage between the two divisions; M, prophase II.; N, metaphase II.; O, telophase II. (N and O illustrate the case of the spermatocyte II., which contains the X chromosome.) P, cell from a segmenting egg with five chromosomes ( a <S)', Q, cell from an embryo with six chromosomes { a 9). p, plasmosome; X, the sex chromosome. (2 + X) at one pole and only two chromosomes at the other, in the familiar manner. When cell division takes place, however, this is 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
