. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. MUSCINE^—HEPA TICJE—MARCH ANT I ALES SI seated as empty. The antheridium becomes sunk in the thallus precisely as in Riccia. The sperm cells are nearly cubical and the spermatozoid is formed in the usual way. The free spermatozoid (Fig. i6, D) shows about one and a half com- plete turns of a spiral. The cilia are very long, and the vesicle usually plainly evident. According to Ikeno (4), in Marchantia polymorpha the final division, resulting in the pair of spermatids, is unaccom- panied by a d
. The structure and development of mosses and ferns (Archegoniatae). Plant morphology; Mosses; Ferns. MUSCINE^—HEPA TICJE—MARCH ANT I ALES SI seated as empty. The antheridium becomes sunk in the thallus precisely as in Riccia. The sperm cells are nearly cubical and the spermatozoid is formed in the usual way. The free spermatozoid (Fig. i6, D) shows about one and a half com- plete turns of a spiral. The cilia are very long, and the vesicle usually plainly evident. According to Ikeno (4), in Marchantia polymorpha the final division, resulting in the pair of spermatids, is unaccom- panied by a division wall, and this seems also to be the case in. Fig. 16.—Fimbriaria Californica. A. Longitudinal section of a fully-developed male receptacle, X8; B, longitudinal section of a nearly ripe antheridium, Xioo; C, young sperm cells, X6oo; D, spermatozoids, X1200. Fimbriaria. In the earlier divisions of the sperm-cells, each cell shows two centrosomes (Fig. 17, i), and Ikeno does not recognise any difference between these and the so-called "blepharoplast" of Webber and other recent students of sperma- togenesis, who look upon the blepharoplast as a different organ from the centrosome. After the final division, each spermatid is provided with a single centrosome (blepharoplast), from which, later, the cilia 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 Campbell, Douglas Houghton, 1859-1953. New York, The Macmillan Company;
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