. An atlas of the fertilization and karyokinesis of the ovum. Ovum; Fertilization (Biology); Meiosis; Embryology -- Echinodermata. THE ANAPHASES. DIVERGENCE AND SEPARATION OF THE DAUGHTER-CHROMOSOMES. 27 Plate VIII. Phototype 31. Later Anapliasc\ showing especially the Chromosomes. The section passes slightly to one side of the spindle-axis, and hence does not show the achromatic figure as well as the last or the following. The chromosomes are, however, very clearly shown, and they may be seen to correspond accurately on the two sides, each daughter-chromosome having its fellow on the opposite
. An atlas of the fertilization and karyokinesis of the ovum. Ovum; Fertilization (Biology); Meiosis; Embryology -- Echinodermata. THE ANAPHASES. DIVERGENCE AND SEPARATION OF THE DAUGHTER-CHROMOSOMES. 27 Plate VIII. Phototype 31. Later Anapliasc\ showing especially the Chromosomes. The section passes slightly to one side of the spindle-axis, and hence does not show the achromatic figure as well as the last or the following. The chromosomes are, however, very clearly shown, and they may be seen to correspond accurately on the two sides, each daughter-chromosome having its fellow on the opposite side (cf. Text-fif. XVI. B). Observe the very considerable variation in size, and also the varying intervals between the halves of each pair. The latter fact shows that the chromosomes move to some extent independently of one another. Stretching between the two groups of daughter-chromosomes, in the equatorial region of the spindle, may be seen spindle-fibres, known as the " interzonal fibres" (" filaments reunissants," " Verbindungsfasern"), regarding which much discussion has arisen ( in Text-fig. V. C). According to Hermann they are non-contractile and form a "central spindle" alon â ; which the chromosomes are dragged, the contractile fibres forming the peripheral portion of the spindle ("Spindle-mantle"). As will appear beyond, there is no ground in Toxopneustes iox vi\-^^ Ti^ny distinction between these fibres and the \ .\vj,;,/ ('.â¢/ / ' / â â ].:â :/,â â ', , ^^ '"^^-x y. No^-. ,,, , ^ â-"-^ ,'".-â ' ' ^ 'â 0 -'â â^ 'â â 'â ''-. Mzr, -^; â -''â¢â '"!< m- â xyl:M / : â¢â â â â : â -\'^-n'^ -' / â¢; ) f ^v^V Fig. XVII. #/. -0 ^-:'i:l: -'^;v. \ B ' I \-\- X ^ Fig. XVII. â The closing stages of Uaryokinesis (looo iliameters). A. anaphase. The riaughter-chromosomes have passed to the spindle-poles and lie in contact with the reticular centrosphe
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Keywords: ., bookauthorwilsoned, bookcentury1800, bookdecade1890, bookyear1895
