. Text-book of embryology. Embryology. -Foul' stagea iu the maturation aud fertilization of tlie egg of Grepidula plana. (After Conklin.) A, formation of first polar body; the spermatozoon has entered the egg and has begun to swell up into the male pronucleus. B, formation of second polar body ; the first polar body has divided into two. C, the male and female pronuclei have come together. D, formation of the first cleavage spindle ; the female pronucleus above and the male pronucleus below are still clearly distinguishable from one another, fp, Female pronucleus ; mp, male pronucleus; pi (in
. Text-book of embryology. Embryology. -Foul' stagea iu the maturation aud fertilization of tlie egg of Grepidula plana. (After Conklin.) A, formation of first polar body; the spermatozoon has entered the egg and has begun to swell up into the male pronucleus. B, formation of second polar body ; the first polar body has divided into two. C, the male and female pronuclei have come together. D, formation of the first cleavage spindle ; the female pronucleus above and the male pronucleus below are still clearly distinguishable from one another, fp, Female pronucleus ; mp, male pronucleus; pi (in A), first polar body, (in B and C), two cells resulting from division of lirst polar body ; p^, second polar body. divides. In some few cases it is possible to distinguish in this first equatorial plate the chromosomes derived from male and female pronuclei respectively, for they are of different sizes and arranged in two different groups. This is especially clear in the egg of Grepi-. 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 MacBride, E. W. (Ernest William), 1866-1940; Kerr, John Graham, 1869-; Heape, Walter, 1855-1929. London : Macmillan
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Keywords: ., bookcentury1900, bookdecade1910, bookpubli, booksubjectembryology
