THE HIGHER CRYPTOGAMIA. 151 



vesicle (i. c, the small free daughter-cell of the central cell 

 of the archegonium), grows with extraordinary rapidity, 

 and displaces the dissolving primary nucleus of the central 

 cell. In F/inaria hyyrovietrica the ripe germinal vesicle is 

 usually in close proximity to the transverse septum, which, 

 even after the canal of the neck is fully formed, and some- 

 times even after the apex has opened, still shuts on the 

 central cell of the archegonium (PI. XIX, fig. 8). It often 

 happens, however, in Funaria, in Phascum, and in Liver- 

 worts, that the germinal vesicle rests upon the bottom of 

 the central cell (PI. XIX, fig. 7 ; PL XX, fig. 9), or that 

 it lies against one of the side-walls of the latter (PI. XX, 

 figs. 5, 6, 8).* 



After the termination of the longitudinal growth, the 

 cells of the apex of the archegonium divide by radial septa 

 which are partly vertical and partly inclined sideways ; and 

 to some extent also by transverse septa. In many genera, 

 such as Polytrichum and Sphagnum (PI. XVIII, fig. 15), the 

 new cells thus formed expand in a radiate manner, in con- 

 sequence of which the apex of the archegonium appears 

 strongly clavate. In the mean time, the walls of the string 

 of cells which traverses the neck of the archegonium dis- 

 solve. The dissolution progresses from above downwards. 

 Thus there originates in the axis of the neck a canal, con- 

 taining only mucilaginous fluid, which leads to the large 

 cell in the upper end of the ventral portion. Suddenly the 

 cells of the apex separate from one another, and bend them- 

 selves backwards in the form of irregular flaps ; in this state 

 they form the so-called stigma (PL XX, figs. 6, 9, 13). 

 The archegonium is now in the condition in which I con- 

 sider it to be ready for impregnation. After the rupture of 

 the apex of the archegonium, the mucilage which fills the 

 canal of its neck not unfrequently oozes out of the opening, 

 protruding above the funnel-shaped mouth in a hemisphe- 



* The rapid disappearance of the primary nucleus of the central cell, and the 

 agreement with it in size and form of the nucleus of the germinal vesicle, led 

 me at first to the conclusion (' Vergl. Unters.,' p. 67) that the germinal vesicle 

 might originate by free cell-formation round the primary nucleus of the central 

 cell. The mode of its development, as given above, was first arrived at by me 

 in 1S54 ('Berichte Kon. Sachs. Ges. d. Wissensch. Math. Phys. CI.,' 1854, 

 p. 95). 



