In this article we report on a time-lapse microcinematographic and phase contrast study of the cell reformation of yolk granules which were isolated from mature oocytes in the genital sac of the middle female intersex of Chirocephalus nankinensis. The observations on yolk granules were made in fixed positions and the morphological changes of cell reformation were continuously recorded in vitro.The transformation of yolk granules into cellular structures may be tentatively described as follows: At the early stages in culture, it can be seen that the granular or bubbly structures gradually appear within the hyaloid and homogeneous yolk granules; the appearance of yolk granules gradually changes from elliptical into round shape. With further transformation, their appearances in general take the shape of oblate spheroids, their size is smaller than before and inside the yolk granules their granular and bubbly structures become more and more obvious. Finally, the nuclear and cellular structures can be seen i In this article we report on a time-lapse microcinematographic and phase contrast study of the cell reformation of yolk granules which were isolated from mature oocytes in the genital sac of the middle female intersex of Chirocephalus nankinensis. The observations on yolk granules were made in fixed in the morphological changes of cell reformation were continuously recorded in vitro. The transformation of yolk granules into cellular structures may be tentatively described as follows: At the early stages in culture, it can be seen that the granular or bubbly structures hyaloid and homogeneous yolk granules; the appearance of yolk granules gradually changes from elliptical into round shape. With further transformation, their appearances in general take the shape of oblate spheroids, their size is smaller than before and inside the yolk granules their granular and bubbly structures become more and more obvious. Finally, the nuclear and cellular struct ures can be seen i