. The cell in development and inheritance. Cells. Fig. 67. — Maturation and fertilization of tlie egg of the mouse. [SOKOTTA.] A. Tlie ovarian egg still surrounded by the follicle-cells and the membrane {:./., zona pel- lucida); the polar spindle formed. B. Egg immediately after entrance of the spermatozoon (sperm-nucleus at ,'^). C. The two germ-nuclei (j', ?) still unequal; polar bodies above. D. Germ-nuclei approaching, of equal size. E. The chromosomes forming. F. The minute cleavage-spindle in the centre; on either side the paternal and maternal groups of chromosomes. nomena in the sea-ur
. The cell in development and inheritance. Cells. Fig. 67. — Maturation and fertilization of tlie egg of the mouse. [SOKOTTA.] A. Tlie ovarian egg still surrounded by the follicle-cells and the membrane {:./., zona pel- lucida); the polar spindle formed. B. Egg immediately after entrance of the spermatozoon (sperm-nucleus at ,'^). C. The two germ-nuclei (j', ?) still unequal; polar bodies above. D. Germ-nuclei approaching, of equal size. E. The chromosomes forming. F. The minute cleavage-spindle in the centre; on either side the paternal and maternal groups of chromosomes. nomena in the sea-urchin Toxopnc/istcs (Fig. 69). As described at p. 146, the tail is in this case left outside, and only the head and middle-piece enter the Qgg. Within a few minutes after its entrance, and while still very near the periphery, the lance-shaped sperm-head, carrying the middlcrpiece at its base, rotates through nearly or quite 1 Cf. p. 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
