332 IIO F M E I S T K R , ON 



had germinated. There can be no doubt that in the regular 

 course of nature, they are set free from the microsporangia 

 by gradual decay of the walls of the latter. 



In archegonia which die without being impregnated and 

 become brown, the remains of the germinal vesicle are still 

 visible, and of their original size. Those archegonia how- 

 ever which by the widening of the central cell and the 

 multiplication of the cells adjoining to the latter give 

 evidence of impregnation, exhibit a considerable increase in 

 size of the germinal vesicle, which now almost fills the 

 central cell (PI. XLV, fig, 9). # As soon as it quite fills 

 the central cell, the first division of the impregnated ger- 

 minal vesicle takes place, by means of a transverse septum 

 slightly inclined to the longitudinal axis of the archegonium. 

 Cross longitudinal septa are produced in each of the two 

 halves, and then again slightly inclined transverse septa 

 are formed. The succession of these divisions is not 

 subject to any definite rule (PI. XLV, figs. 11 — 14): 

 the final result however is always the same, viz. the forma- 

 tion of an oval cellular body having its longitudinal axis at 

 right angles to that of the archegonium, and having one of 

 its apices, the blunter one, composed of four cells placed 

 crosswise (PL XLV, fig. 14 c ), whilst the other apex only 

 exhibits a single top cell (PL XLV, figs. 13, U\ 15'). I 

 will call the latter the fore-end, and the former the hinder 

 end of the embryo. 



At the hinder end the number of the cells increases 

 almost uniformly in all directions (PL XLV, figs, 19, 21, 23). 

 At the fore-end on the other hand a particularly active cell- 

 multiplication occurs, which commences in the growing cell 

 adjoining the original apical cell of the pointed end of the 

 embryo. This cell-multiplication is produced by septa 

 inclined alternately forwards and backwards, and at right 

 angles to a plane passing through the longitudinal axis of 

 the archegonium and of the oval embryo. In this way an 

 excrescence originates which is directed upwards (PL XLV, 



* I did not succeed in observing spermatozoa in the interior of these arche- 

 gonia. A phenomenon which has been observed in different mosses and in 

 Pteris aquilina occurs, as an irregularity, also in Salvinia, viz , that the interior 

 of the archegonium enlarges more rapidly than the imperfectly developing 

 embryo, which is thus surrounded by a wider cavity (PI. XLY, fig. 12). 



