10 Brittox and Taylor : Life History of Schizaea pusilla 



the sixth cell there was another archegonium formed, and a cell 

 above this another one, and branches also gave rise to archegonia. 

 There is no filament that is specially reserved for the formation of 

 archegonia as is sometimes the case with the antheridia. Each 

 archegonium is derived from a single superficial cell. 



The archegonia are formed by the division of the initial cell 

 into three cells ; the basal cell forms the venter which may or may 

 not be imbedded in the cell of the filament. Some of the division 

 cells of the original cell of the filament grow up around it in 

 such a way as to make it appear as if imbedded (Fig. 65). From 

 the neck cell arises the neck of the archegonium, consisting of four 

 rows of cells, of four cells each (Figs. 60, 62, 63) ; a uniformity 

 which produces a straight neck to the archegonium. 



Occasionally the cells of the two rows on the posterior side, 

 though they do not increase in number, become larger than those 

 on the anterior side (Fig. 62) thus slightly bending the neck 

 toward the anterior side. From the middle cell of the superficial 

 mother cell arises the central cell and the canal cell ; the middle 

 cell becomes sharply pointed on the upper end and forces itself 

 between the neck cells ; this point is cut off, forming the canal cell ; 

 the larger cell divides again into two cells of unequal size : the 

 smaller and upper one forms the ventral canal cell, the lower and 

 larger one forms the egg cell (Fig. 59). When this is mature the 

 canal cells dissolve into mucilage. When the archegonium opens, 

 the four stigmatic cells, which in this species are very large, are not 

 thrown off but fold back (Fig. 63). It is at this stage that the 

 curve in the neck oqcurs in some archegonia due possibly to the 

 fact that as the filaments grow erect or nearly so, the archegonia 

 occupy the portion of the filaments below the antheridia, and by 

 bending the neck they bring the canal to the oosphere in a more 

 direct line for the capture of the antherozoids, an adaptation tend- 

 ing to secure fertilization. Generally several archegonia are pres- 

 ent, but only one seems to give rise to a sporophyte. 



The cushion of cells on which the archegonia are borne can 

 hardly be called an archegoniophore as some of these cells give 

 rise to vegetative branches (Fig. 65). Three cases were found 

 where an archegonium arose directly from a cell of the filament 

 without any partition other than that of the formation of the ar- 



