. The cell; outlines of general anatomy and physiology. w thesplitting up becomes either pretty well completed, or the fourspindles, before the furrows have penetrated far into the yolk,commence to divide, the nuclear segments travelling towards thepoles. The result of this is that the four first protuberancesbegin to become constricted a second time and to separate fromone another (cell-budding, bud formation). The most striking of the phenomena described above is thesudden appearance of the four pole radiations, for which, accord-ing to our present knowledge, an equal number of centrosomesmu
. The cell; outlines of general anatomy and physiology. w thesplitting up becomes either pretty well completed, or the fourspindles, before the furrows have penetrated far into the yolk,commence to divide, the nuclear segments travelling towards thepoles. The result of this is that the four first protuberancesbegin to become constricted a second time and to separate fromone another (cell-budding, bud formation). The most striking of the phenomena described above is thesudden appearance of the four pole radiations, for which, accord-ing to our present knowledge, an equal number of centrosomesmust have served as bases. An explanation of this is afforded usby the processes connected with the fertilisation of the Echinodermegg, which are discussed on p. 259. Modifications of the form of nuclear transformation, shown inFig. 129 0, occur not infrequently ; these are due to one of theradiations being somewhat separated from the three others (). In this case the three that are situated close to one another if, ^ ;iiiVVi^Si^g^ Ml////.
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Keywords: ., bookcentury1800, bookdecade1890, bookidcelloutlines, bookyear1895
