. Carnegie Institution of Washington publication. •; «k" - •' - v>;^i^yp;-. 'v- t>^:~> TTf^^^ &£&%m £*„•: J' .','•; \. :w>^;:~:r^ *m&&£j?\ *m$&x<\ D /HOT V FIG. 30.—Fecundation in Fucus. A-D, Fucus vesiculosus. E, .F. serratus.—(After Strasburger.) A, Egg-cell ten minutes after mixing of sexual elements ; male nucleus applied to that of egg. B, same two nuclei more highly magnified. C, similar to B; sperm nucleus lies between the observer and egg-nucleus. D, fusion of nuclei has progressed further ; 10 minutes after mixing of sexual
. Carnegie Institution of Washington publication. •; «k" - •' - v>;^i^yp;-. 'v- t>^:~> TTf^^^ &£&%m £*„•: J' .','•; \. :w>^;:~:r^ *m&&£j?\ *m$&x<\ D /HOT V FIG. 30.—Fecundation in Fucus. A-D, Fucus vesiculosus. E, .F. serratus.—(After Strasburger.) A, Egg-cell ten minutes after mixing of sexual elements ; male nucleus applied to that of egg. B, same two nuclei more highly magnified. C, similar to B; sperm nucleus lies between the observer and egg-nucleus. D, fusion of nuclei has progressed further ; 10 minutes after mixing of sexual elements. E, i% days after fecundation; fusion nucleus preparing for division; poles of future spindle present, but limits of the two nuclei still recognizable ; the part derived from male nucleus (on the left) has also a nucleolus. chromatin thread becomes more prominent, and the boundary between sperm and egg-nucleus gradually disappears (Fig. 30, D, E). In the meantime a nucleolus is found in that portion of the fusion-nucleus coming fi-om the sperm. This is in all probability not brought in as such, but is developed during the process of fusion much in the same-way as in the reconstruction of daughter-nuclei following karyo- kinesis. In no case observed by the authors mentioned was the sperm-nucleus accompanied by a centrosphere or a system of radiations, either during its passage through the cytoplasm or during fusion. Strasburger ('97, p. 365) states, however, that in some cases he was able to trace the apparent connection between the two centrospheres and the limits of the two sexual nuclei in the oospore (Fig. 30, E), and he infers that the centrosomes may have been brought into the egg by the sperm in. 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 Washing
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