134 ARCHEGONIUM. [CH. X 



Sexual reproductive organs. 



These are of two kinds : the archegonia, which contains 

 the egg-cell, and antheridia, in which the male elements 

 are developed. The archegonia (fig. 60) are found near 

 the notched end of the prothallus and on its under surface. 

 Each archegonium consists of a rounded cavity sunk in the 

 tissue of the prothallus and contains the egg-cell: the 

 cavity of the archegonium communicates with the outer 

 world by a canal, a curved chimney-like tube projecting 



A. YOUNG ARCHEGONIUM OF THE FERN (Polypodium vulgare). 



B. THE SAME MATURE AND OPEN. 



C. THE EXPULSION or THE SLIME AT THE MOUTH OF THE ARCHEGONIUM 

 (in Pteris serrulata). 



p, p, cells of the prothallus ; o, egg-cell ; v.c.c., ventral-canal-cell 

 m, neck-canal-cell. (After Strasburger.) 



beyond the surface of the prothallus. This canal is seen 

 in section to be made up of four rows of cells, as though a 

 chimney were built of tiers of four bricks each. In the 

 immature archegonium the free end of the canal is shut, 

 and its cavity is filled up by a long cell or cells called 

 neck-canal-cells. Between this and the egg-cell at the 

 bottom is another cell called the ventral-canal-cell, which 

 fills up the rest of the cavity of the archegonium. 



