THE GAMETES IN PLANTS AND ANIMALS 



319 



cell and the egg. The fully developed archegonium, containing 

 the egg o, is shown in Fig. 139. The canal cells take no part in 

 reproduction, but degenerate before fertilization. 



133 



136 



132 



138 



139 



FIGS. 132-139. Stages of gamete formation in the liverwort Riccia: Fig. 132, 

 aatheridium in stage at which spermatogenous cells become segregated from cells 

 of wall; Figs. 133-139, formation of archegonium and egg, o, in Riccia. From Coulter, 

 etc., '10. 



