The Origin of Land Plants 87 



ture in all mosses and ferns, which are hence called 

 the " Archegoniates." The male organ, or anthe- 

 ridium, is also multicellular and contains many 

 sperm cells, each of which gives rise to a ciliate 



FIG. 9 



A Section of the antheridium or male organ of a liver- 

 wort, Riccia. 



B The motile male gamete, or sperm. 



C The female organ, or archegonium, containing the fe- 

 male gamete, or egg, o. 



D The embryo-sporophyte enclosed in the enlarged basal 

 part of the archegonium. 



sperm much like that of certain algae (Fig. 9, A, B). 

 Neither archegonium nor antheridium will open 

 unless wet; but if the ripe organs are covered 

 with water they will promptly open, and the lib- 

 erated sperms then swim to the open archegonium, 



