184 MUSCINEJ;. 



n spermatozoid. The spermatozoids are self-motile ; they are 

 slightly twisted, with two cilia placed anteriorly (Fig. 188), while 

 posteriorly they are generally a trifle club-shaped, and often bear 

 at that part the remains of the cytoplasm, the spermatozoid itself* 

 being formed from the nucleus. In the presence of water the ripe 

 antheridium bursts, and its contents are ejected ; the spermato- 

 zoids, being liberated from their mother-cells, swarm about in the 

 water in order to effect fertilisation. 



The female sexual organs are termed archegonia. They are flask- 

 shaped bodies (Fig. 189), the lower, swollen portion (renter) having 



FiQ. 189. MarcTiantto polymer pha. A A young, and B a ripe arclifgonium with open 

 neck. C An unripe sporangium enclosed by the archegoniutn a : st the s^talk ; / the wall 

 of the sporangium. Elaters are seen between the rows of spores. 



a wall, in most cases from 1-2 cells thick, enclosing the oosphere 

 (Fig. 189 B, k) : the long neck is formed of tiers of 4-6 cells, 

 enclosing a central row of cells the neck-canal-cells (Fig. 189 A). 

 When the archegonium is fully developed, the walls of the neck- 

 canal-cells become mucilaginous and force open the neck of the 

 archegonium. The mucilage thus escapes, and, remaining at the 

 mouth of the archegonium, acts in a somewhat similar manner to 

 the stigma and conducting tissue of a carpel, by catching and con- 

 ducting the spermatozoids to the oosphere (Fig. 189 B, m), with 



