184 MUSCINEJ;. 



ti 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 spenuatozoid itself 

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

 antheridinm 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 (venter) having 



FIG. 189. Marchantia polyrnorpha. A A young, and B a ripe archegonium with open 

 neck. C An unripe sporangium enclosed by the arcaegonium a : st the stalk ; / 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, Z.-) : 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 



