. Carnegie Institution of Washington publication. . FIG. 18.—Cell-cleavage in Hydrodictyon utriculatum.—(After Klebs.) A, cell showing cleavage furrows at early stage in the process; «, place in protoplasm free from chlorophyll. B, sausage-shaped protoplasts formed in early stage of cleavage. C, two protoplasts similar to those in B, showing manner of further cleavage. D, final result of the cleavage. contains a single nucleus. In this manner the entire protoplast is divided into uninucleated spores or gam- etes, as the case may be. Judging from Strasburger's account of the process in Ulothrix
. Carnegie Institution of Washington publication. . FIG. 18.—Cell-cleavage in Hydrodictyon utriculatum.—(After Klebs.) A, cell showing cleavage furrows at early stage in the process; «, place in protoplasm free from chlorophyll. B, sausage-shaped protoplasts formed in early stage of cleavage. C, two protoplasts similar to those in B, showing manner of further cleavage. D, final result of the cleavage. contains a single nucleus. In this manner the entire protoplast is divided into uninucleated spores or gam- etes, as the case may be. Judging from Strasburger's account of the process in Ulothrix, it seems probable that cell-formation leading to the development of gametes or swarm-spores is also a cleavage similar to that in Hydrodictyon. In Ulothrix, however, the cells are uninucleate, and a nuclear division must either accompany or precede cell-division. Until the behavior of the nucleus is known, and the process carefully worked out with the aid of more improved methods, the exact nature of the cell-formation in question must remain largely a matter of conjecture. In the light of more recent investigations concerning cell-formation among the lower thallophytes, it is evident that our present knowledge of this process in connection with the development of gametes or asexual zoospores among the algae is very meager and 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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