THE BRYOPHYTA: HEPATICAE, THE LIVERWORTS 



393 



centrosomes, that is, they act as the poles of the spindles. During the 

 formation of the antherozoids these bodies attach themselves to one end of 

 the elongating nucleus and become blepharoplasts, which means that 

 they develop the two flagella. The body of the antherozoid is tapered and 



VENTRAL CANAL 

 CELL 



OOSPHERE 



NECK CANAL 



OOSPHERE 



p,G_ 3yg, — Pellia epiphxila. Development of the archegonium. 

 A, Initial cell. B, C and D. Successive divisions forming the 

 neck, neck canal cells, and ventral cell at the base of the neck 

 canal. E, Differentiation of the ventral cell. F, Division of 

 ventral cell into oosphere and ventral canal cell. G, Mature 

 archegonium. The neck is open and the oosphere ready for 

 fertilization. (After Hqfmeister.) 



spirally coiled, and the flagella are attached to the thinner end. The 

 antherozoids are liberated by dissolution of the mother cells and the opening 

 of the antheridial wall at the apex. 



The Archegonium 



The archegonium arises from a single superficial cell of the thallus which 

 enlarges and divides to cut off a basal cell (Fig. 375). From the upper cell 

 the archegonium is produced. This cell divides by three vertical walls 

 which form three peripheral cells, leaving a central cell in the middle. By 

 a transverse wall a cap cell is then cut off so that the central cell becomes 



