II 



MUSCINE.^—HEPA TIC-E—MARCHANTIA CE^ 



31 



Janczevvski gives ten in R. Bischoffii. The basal cell finally 

 divides into a single lower cell which remains undivided, com- 

 pletely sunk in the thallus, and an upper cell which divides 

 into a single layer of cells forming part of the venter, and 

 continuous with the other peripheral cells. The mature 

 archegonium (Fig. 4) has the form of a long-necked flask with 

 a much enlarged base. The canal cells are completely indis- 

 tinguishable, their walls having become absorbed and the 



Fig. 4. — A, Archegonium o{ Riccia hirta (Aust.), showing the ventral canal cell [v), X 525 ; 

 B, ripe archegonium of K. glaiica, longitudinal section, X260. 



contents run together into a granular mass. The nuclei of 

 the neck-canal cells are small and not readily recognisable after 

 the breaking down of the cell walls, but from analogy with the 

 higher forms it is not likely that they completely disappear in 

 the ripe archegonium. The cytoplasm of the central cell 

 contracts to form the naked globular &^%. The cytoplasm is 

 filled with granules, and the nucleus, which is of moderate size, 

 shows a distinct nucleolus, but very little chromatin. A 

 special receptive spot was not certainly to be seen. 



