. Cytology, with special reference to the metazoan nucleus. Cells. r x K The chromosomes of Lygaeus turcicus. (After Wilson, , 1905 and 1912.) A, spermatogonial telophase ; B, later telophase ; C, emergence of the massive chromatic bodies in the primary spermatocyte; D, leptotene stage ; E, " confused stage " ; F, evolution of the bivalents ; G, metaphase I.; H, I, daughter chromosome groups of anaphase I.; J, metaphase II., X and Y, now paired to form a bivalent; K, L, daughter chromosome groups from anaphase II. of spermatozoa in Lygaeus—one, the 6+X form, will on fertilizing
. Cytology, with special reference to the metazoan nucleus. Cells. r x K The chromosomes of Lygaeus turcicus. (After Wilson, , 1905 and 1912.) A, spermatogonial telophase ; B, later telophase ; C, emergence of the massive chromatic bodies in the primary spermatocyte; D, leptotene stage ; E, " confused stage " ; F, evolution of the bivalents ; G, metaphase I.; H, I, daughter chromosome groups of anaphase I.; J, metaphase II., X and Y, now paired to form a bivalent; K, L, daughter chromosome groups from anaphase II. of spermatozoa in Lygaeus—one, the 6+X form, will on fertilizing an egg produce a female, the other (6+Y form) will produce a male. The process of meiosis in the male Lygaeus is illustrated in Fig. 46. This figure demonstrates the important fact that the sex chromosomes of the male often (though not in all cases; see below) remain compact throughout the whole meiotic prophase, including the leptotene and zygotene stages. •It will be noted in Fig. 46, G, that X and Y are not paired to form. 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, W. E. (Wilfred Eade), 1882-1951. London, Macmillan and Co. , limited
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectcells, bookyear1920
