. The cell; outlines of general anatomy and physiology. e,where they arrange themselves at•equal distances from one until this has occurred doesthe egg commence to segment, theperipheral layer splitting up many cells as there are nuclei init, whilst the central yolk remainsintact, or is only split up at amuch later period. This latteroccurs when in the eggs of insects,as in telolecithal eggs, the yolkcontains yolk nuclei, or merocytes(Fig. 122 C). The wall of the embryo-sac inPhanerogamia is coated with aprotoplasmic lining, which at acertain stage of development con-tains
. The cell; outlines of general anatomy and physiology. e,where they arrange themselves at•equal distances from one until this has occurred doesthe egg commence to segment, theperipheral layer splitting up many cells as there are nuclei init, whilst the central yolk remainsintact, or is only split up at amuch later period. This latteroccurs when in the eggs of insects,as in telolecithal eggs, the yolkcontains yolk nuclei, or merocytes(Fig. 122 C). The wall of the embryo-sac inPhanerogamia is coated with aprotoplasmic lining, which at acertain stage of development con-tains several hundred regularlyarranged nuclei; these were for-merly considered to develop likecrystals in a mother-liquor; butwe know now, that they are pro-duced by the repeated bipartitionof a mother nucleus, as in the ego-sof Arthropoda (Fig. 123). The divi-sions occur almost simultaneouslyin any one region of the embryo-sac. If the preparation is suc-cessful, nuclei in numerous stagesof division may be observed at onetime in a small space (Fig. 123)..
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Keywords: ., bookcentury1800, bookdecade1890, bookidcelloutlines, bookyear1895
