248 REPR0DUCT10i\ OF RICCIOCARPUS 



soon begin to divide vertically and thus form an elliptical mass 

 of cells (Fig. 181, B, C). As this growth goes on the outer or 

 wall cells become larger than the others and generally develop 

 chlorophyll, while the inner cells divide repeatedly and become 

 very numerous with dense granular contents (Fig. 181, D). 

 Each of the latter cells produces a single male gamete that is 

 motile by means of two cilia (Fig. 181, E). This complex game- 

 tangium is suggestive of the structure we have seen in the Ecto- 

 carpus (Fig. 119, B). The male gametangium is commonly 

 called the antheridium, and the male gametes are often termed 

 sperms or antherozoids. The male gametes are discharged from 

 the antheridium owing to the absorption of water by the walls 

 of the central cells which become mucilaginous at maturity and 

 expanding, rupture the apical cells of the wall and force out the 

 contents of the antheridium. This mucilaginous mass rapidly 

 dissolves in the water and sets free the male gametes or sperms. 

 The female gametangium is also quite different from the single- 

 celled gametangia which we have noticed among the algae and 

 fungi. It originates as in the case of the antheridium, but devel- 

 ops into a flask-shaped body, consisting of a long neck of several 

 rows of cells surrounding a central row, called the canal cells, 

 and an enlarged basal region in which is developed the female 

 gamete (Fig. 182). The female gametangium is commonly 

 known as the archegonium and the female gamete is sometimes 

 called the oosphere or egg. The female gamete presents essen- 

 tially the same characteristics as seen in many of the algae, as 

 Vaucheria, Oedogonium, etc., but it is surrounded by a jacket of 

 cells which constitute the basal portion of the archegonium in- 

 stead of being contained in a single cell. Possibly the archego- 

 nium has come about from a multicellular gametangium, as seen 

 in the brown algae, owing to the sterilization of all but one of 

 the cells. Archegonia, with two or more gamete-like cells, are 

 sometimes found in the mosses and ferns. As soon as the female 

 gamete is formed, the walls of the canal cells become mucilaginous 

 and expanding through the absorption of water, force open the 

 apical or lip cells of the neck, thus leaving an open passageway 

 to the egg cell (Fig. 182, F). The male gametes, attracted, it is 



