MUSCI AND HEPATICAE 



361 



is a club-shaped body, seated on a short massive stalk, and it is 

 frequently large enough to be seen by the naked eye. It consists of a 

 peripheral wall of tabular cells, covering a mass of cubical spermato- 

 cytes (vi.). It bursts when ripe at the distal end (viii.). There is often a 

 special cap of mucilaginous cells which produce and control the pore 

 of exit. The spermatozoids can then escape in a thin stream, 

 embedded in mucilage from which they soon escape.% In cases where 



FIG. 304. 



i.-v. Stages in development of the archegonium of Funaria, after Campbell ( x 400) . 

 vi. Mature archegonium of Andreaea, after Kiihn ( x 250). i. shows cover-cell 

 separated from central-cell (shaded.) ii. iii. cover-cell (x) undergoing segmentation 

 as an initial cell, giving rise to three rows of lateral and one of basal segments : the 

 former constitute the " neck," the latter are the canal cells, iv. shows the ovum (ov), 

 ventral canal cell (v.c.c.), and canal-cells (c.c). V. shows the apex of the neck before 

 rupture, with canal-cells (c.c.) within. 



the perichaetial leaves face upwards, a shower of rain would bring 

 the rupture about, and the mucilaginous contents may be seen and 

 collected on a slide in a drop of water. The biciliate spermatozoids 

 may then be observed in active movement (Fig. 303, vii.). 



The archegonium is a flask-shaped body with a long neck (Fig. 304). 

 It is seated on a massive stalk, and it also arises from a single superficial 

 cell. When mature it consists of a peripheral wall, which in the lower 

 ventral portion is double, but the neck consists of a single layer built 

 up of six rows of cells, as against four in the Pteridophyta. The wall 



