. Senescence and rejuvenescence. Age; Reproduction. 342 f SENESCENCE AND REJUVENESCENCE which enter the cytoplasm of the egg and serve as food—are begin- ning to arise. The third figure (Fig. 189) shows a segment of the egg at a still later stage with follicle and test cells in the peripheral cytoplasm and yolk masses forming below them. Figs. 190, 191. Figs. 176, 177.—Embryo sacs of Helianthus (sunflower) and Rudbeckia (cone- flower) at time of fertilization, showing egg, o; two male nuclei, spz, spi\ embryo sac nucleus, en. From Nawaschin, 'oo. are two stages in the oogenesis of a fish egg,
. Senescence and rejuvenescence. Age; Reproduction. 342 f SENESCENCE AND REJUVENESCENCE which enter the cytoplasm of the egg and serve as food—are begin- ning to arise. The third figure (Fig. 189) shows a segment of the egg at a still later stage with follicle and test cells in the peripheral cytoplasm and yolk masses forming below them. Figs. 190, 191. Figs. 176, 177.—Embryo sacs of Helianthus (sunflower) and Rudbeckia (cone- flower) at time of fertilization, showing egg, o; two male nuclei, spz, spi\ embryo sac nucleus, en. From Nawaschin, 'oo. are two stages in the oogenesis of a fish egg, the first showing the young egg at the beginning of yolk formation, the second, a later stage in which the cytoplasm is loaded with numerous yolk spheres. In various invertebrate groups the same individuals produce at different times parthenogenic eggs, , eggs which develop without. 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 Child, Charles Manning, 1869-1954. Chicago, Ill. , The University of Chicago Press
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectreproduction, bookyea
