The structure & development of the mosses and ferns (Archegoniatae) . oth in longitudinal and cross-sections (see Fig. 68,D). The full-grown antheridium is more flattened than ineither species of Anthoceros examined by me, and the stalkshorter and thicker, but otherwise closely resembles it, althoughthe extremely symmetrical arrangement of the cells, especiallyof the wall, is much less noticeable. The archegonia correspond very closely, both in position 1 Leitgeb (7), vol. v. p. 39. THE ANTHOCEROTEJE 141 and structure, with those of the other genera, the most markedpecuUarity being the more ne
The structure & development of the mosses and ferns (Archegoniatae) . oth in longitudinal and cross-sections (see Fig. 68,D). The full-grown antheridium is more flattened than ineither species of Anthoceros examined by me, and the stalkshorter and thicker, but otherwise closely resembles it, althoughthe extremely symmetrical arrangement of the cells, especiallyof the wall, is much less noticeable. The archegonia correspond very closely, both in position 1 Leitgeb (7), vol. v. p. 39. THE ANTHOCEROTEJE 141 and structure, with those of the other genera, the most markedpecuUarity being the more nearly equal diameter of the covercell and central cell, and a corresponding increase in the breadthof the neck canal cell. Subsequently the central cell becomesmuch enlarged and the appearance of the fully-developed arche-gonium is very much like that of Anthoceros (Fig. 69, A). Asin A. fusifonnis, the usual number of neck canal cells seems tobe four, and in no case did the number exceed five. The covercells were four in number in all the archegonia studied, and are. Fig. 68.—Notothylas orbicularis (Sull.). Development of the antheridium. D, cross-section, theothers longitudinal sections; E, nearly ripe antheridium, X300, the other figures x6oo; f,. A,the primary antheridial cells. larger than in Anthoceros. As in that genus, they are thrownoff when the archegonium opens. The youngest embryo found was composed of four cells,and presented quite a different appearance from the corre-sponding stage in Anthoceros. It is impossible from this stageto tell whether the first wall in the embryo is vertical or trans-verse. This embryo consisted of four nearly equal quadrants,instead of having the two upper cells larger than the lowerones. By comparison with the older stages there is littledoubt that here the first transverse wall separates the footfrom the capsule, as in SpJicerocarpus, and that the upper cell 142 MOSSES AND FERNS CHAP. develops directly into the capsule instead of the
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