THE HIGHER CRYPTOGAMIA. 149 



divided cells) divides in the same manner immediately 

 after its formation, such division being, in most instances 

 exactly contemporaneous with the next division of the 

 apical cell, very seldom somewhat later, often earlier (PL 

 XX, figs. 2, 3). 



The archegonium now consists of a central string of 

 cells, which is surrounded by from four to six longitudinal 

 rows of cells. There are far more frequently six rows, in 

 consequence of the division of two of the original four, by 

 radial longitudinal septa (PI. XX, fig. 7). The arche- 

 gonium resembles, therefore, in its development, as well 

 as in its structure, the like organ in the liverworts. One 

 of the cells of the central string swells to a remarkable 

 extent, especially in width, whilst the upper end of the 

 archegonium continues to grow. This cell, however, is 

 never so near to the base of the archegonium, as in the 

 liverworts ; amongst the mosses which I have examined 

 it lies lowest in Phascum and Archidium, where it is the 

 third, fourth, or fifth, reckoned from below (PL XX, fig. 

 2 ; PL XXIII, fig. 13). Soon after it begins to swell the 

 cells underneath it divide by transverse, and partly by 

 longitudinal septa, whereby they expand only in length, 

 not in breadth. This cell-multiplication is more active 

 close under the swollen cell, than at the base of the arche- 

 gonium. In Phascum those cells which surround the sides 

 of the swollen cell divide, in the first instance, only by 

 transverse septa and by longitudinal septa perpendicular 

 to the outer surfaces (PI. XX, fig. 4) ; the division of the 

 above cells, by longitudinal septa, parallel to the axis of 

 the organ, commences at a somewhat later period (PL XX, 

 fig. 5). In other genera, as for instance, Funaria, Fissi- 

 dens, Dicranum, and Polytrichum, the cells which cover 

 the central cell of the ventral portion of the archegonium, 

 are already divided by longitudinal septa parallel to the 

 outer surface, long before the bursting of the apex of the 

 archegonium ; and this occurs particularly early in Sphag- 

 num (PL XV 111, fig. 14), where, even before the opening 

 of the top of the archegonium, this division is repeated in 

 the inner as well as in the outer cells (PL XVIII, fig. 15). 

 In this genus, consequently, the ventral portion of the 

 archegonium is larger than in any other moss. 



