. The cell; outlines of general anatomy and physiology. centrosomes of the first division figure. This con-cludes the process of fertilisation, since all further changes areconnected with the division of the nucleus. b. Eggs of Ascaris megalocephala. Further knowledge of theprocess of fertilisation may be gained from the study of the eggsof Ascaris megalocephala. Here the spermatozoon penetrates intothe egg before the development of the pole-cells (c/. Fig. 127, andthe text on p. 237), arriving finally at the centre (Fig. 142 I) ;meanwhile the germinal vesicle, after changing itself, in theman
. The cell; outlines of general anatomy and physiology. centrosomes of the first division figure. This con-cludes the process of fertilisation, since all further changes areconnected with the division of the nucleus. b. Eggs of Ascaris megalocephala. Further knowledge of theprocess of fertilisation may be gained from the study of the eggsof Ascaris megalocephala. Here the spermatozoon penetrates intothe egg before the development of the pole-cells (c/. Fig. 127, andthe text on p. 237), arriving finally at the centre (Fig. 142 I) ;meanwhile the germinal vesicle, after changing itself, in themanner already described, into the pole spindle, mounts up to thesurface of the yolk, and gives rise to several pole cells. Twovesicular nuclei develop, one derived from the nuclear substanceof the spermatozoon, which has entered, and the other from onehalf of the second polar spindle (Fig. L42 I). Egg-nucleus andsperm-nucleus (Fig. 142 II) then approach each other ; in thiscase, however, the male nucleus is in the centre, whilst the female 260 THE CELL.
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Keywords: ., bookcentury1800, bookdecade1890, bookidcelloutlines, bookyear1895
