. Cytology, with special reference to the metazoan nucleus. Cells. V CHROMOMERES 135 64, A, D) and between the conjugating chromosomes in the meiotic prophase (Figs. 64, C, and 66) is very striking. The latter phenomenon is specially significant, suggesting that syndesis does not concern the chromosomes as wholes, but that it takes place between the separate elements of which they are composed. The thesis formulated at the beginning of this chapter requires that the chromosomes should not merely be composed of smaller units, but that these should be differentiated among themselves. It further
. Cytology, with special reference to the metazoan nucleus. Cells. V CHROMOMERES 135 64, A, D) and between the conjugating chromosomes in the meiotic prophase (Figs. 64, C, and 66) is very striking. The latter phenomenon is specially significant, suggesting that syndesis does not concern the chromosomes as wholes, but that it takes place between the separate elements of which they are composed. The thesis formulated at the beginning of this chapter requires that the chromosomes should not merely be composed of smaller units, but that these should be differentiated among themselves. It further follows. Fig. 64. Chromomeres. A, epithelial cell of the salamander (Flemming, 1882); B, prophase of nucleus in root tip of Najas marina (after Miiller, , 8, 1912); C, zygo-pachytene nucleus of oocyte I. of EnUroxenos (after Bonnevie, , 1906); D, prophase chromosomes from alimentary canal of CuU-x (after Holt, , 1917)- that if in syndesis corresponding elements of the homologous chromosomes pair together, these elements must always be arranged in the same order along the length of the chromosome. Evidence that the longitudinal differentiation of the chromosomes is of a definite and relatively constant nature has been presented in the case of Lepidosiren (Agar, 1913). In this animal the 38 somatic chromo- somes are usually V-shaped, but in the shorter ones the hmbs of the V's tend to diverge, till at length the chromosome, by straightening out, becomes rod-shaped. The point of bending of the V can however be. 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
