. The cell in development and inheritance. Cells; Cells. I lO THE GERM-CELLS two primordial germ-cells lying at the apex of the archenteron. In some of the insects they appear still earlier as the products of a large " pole-cell" lying at one end of the segmenting ovum, which divides. ^ig- 55- — Origin of the primordial germ-cells and casting out of chromatin in the somatic c&W^oi Ascaris. [ A. Two-cell stage dividing ; s. stem-cell, from which arise the germ-cells. B. The same from the side, later in the second cleavage, showing the two types of mitosis and the casting o
. The cell in development and inheritance. Cells; Cells. I lO THE GERM-CELLS two primordial germ-cells lying at the apex of the archenteron. In some of the insects they appear still earlier as the products of a large " pole-cell" lying at one end of the segmenting ovum, which divides. ^ig- 55- — Origin of the primordial germ-cells and casting out of chromatin in the somatic c&W^oi Ascaris. [ A. Two-cell stage dividing ; s. stem-cell, from which arise the germ-cells. B. The same from the side, later in the second cleavage, showing the two types of mitosis and the casting out of chromatin (c) in the somatic cell. C. Resulting 4-cell stage; the eliminated chromatin at c. D. The third cleavage, repeating the foregoing process in the two upper cells. into two and finally gives rise to two symmetrical groups of germ- cells. Haecker has recently traced very carefully the origin of the primordial germ-cells in Cyclops from a "stem-cell" (Fig. 56) clearly distinguishable from surrounding cells in the early blastula stage, not. 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
