. The cell in development and inheritance. Cells. Fig. 136. — Modification of cleavage by pressure in Nereis. A. B. Normal 4- and 8-cell stages. C. Normal trochophore larva resulting, with four entoderm- cells. D. Eight-cell stage arising from an egg flattened by pressure ; such eggs give rise to trocho- phores with eight instead of four entoderm-cells. Numerals designate the successive cleavages. If unsegmented eggs be subjected to pressure, as in Driesch's echino- derm experiments, they segment in a flat plate, all of the cleavages being vertical. In this way are formed eight-celled plates i
. The cell in development and inheritance. Cells. Fig. 136. — Modification of cleavage by pressure in Nereis. A. B. Normal 4- and 8-cell stages. C. Normal trochophore larva resulting, with four entoderm- cells. D. Eight-cell stage arising from an egg flattened by pressure ; such eggs give rise to trocho- phores with eight instead of four entoderm-cells. Numerals designate the successive cleavages. If unsegmented eggs be subjected to pressure, as in Driesch's echino- derm experiments, they segment in a flat plate, all of the cleavages being vertical. In this way are formed eight-celled plates in which all of the cells contain oil-drops (Fig. 136, D). If they are now released from the pressure, each of the cells divides in a plane approximately horizontal, a smaller granular micromere being formed above, leaving. 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 Wilson, Edmund B. (Edmund Beecher), 1856-1939. New York : The Macmillan company
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectcells, bookyear1896
