. Carnegie Institution of Washington publication. . •iflji^pfe . • ' FIG. 28.—Parts of contents of young antheridia, showing nuclear history preparatory to formation of sperma- tozoids in 5. braunii.—(After Klebahn.) A, part of plasmic ring showing two nuclei in prophase of division. B, spindle stage of same mitosis. C, anaphase probably from second mitosis. D, Telophase of a later nuclear division. E, Condition of nuclei between successive mitoses, pyre- noids still present, F, nuclei shortly before formation of spermatozoids; the pyrenoids have disappeared. round up to form the egg-cells, of
. Carnegie Institution of Washington publication. . •iflji^pfe . • ' FIG. 28.—Parts of contents of young antheridia, showing nuclear history preparatory to formation of sperma- tozoids in 5. braunii.—(After Klebahn.) A, part of plasmic ring showing two nuclei in prophase of division. B, spindle stage of same mitosis. C, anaphase probably from second mitosis. D, Telophase of a later nuclear division. E, Condition of nuclei between successive mitoses, pyre- noids still present, F, nuclei shortly before formation of spermatozoids; the pyrenoids have disappeared. round up to form the egg-cells, of which two to four are seen in a cross- section of the cell. Neither shortly before nor during cleavage, according to Klebahn ('99), is there to be observed a division or fusion of the nuclei, so that (contrary to Rauwenhoff who claimed that during the formation of the eggs the number of nuclei was diminished) each egg1 may contain, in addition to 2 or more pyrenoids, several nuclei, the number varying from i to 5 (Fig. 29, A to E). The number of nuclei falling to any egg is largely a matter of chance, since the cleavage planes do not seem to be determined in any way by the number or position of the nuclei in the cytoplasm. 1 The so-called " giant eggs " are 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 Carnegie Institution of Washington. Washington, Carnegie Institution of Washington
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