34 H0FME1STER, ON 



lower portion are of a deep-brown colour. Of these 

 abortive archegonia some have only just burst at the apex, 

 some are still closed, and others again are in the earliest 

 stages of development. 



I consider those archegonia whose apices have just 

 opened, and the cell-walls of whose necks have not yet 

 become brown, as in a state ready for impregnation ; and I 

 believe that, in order to effect such impregnation, it is 

 requisite that some, perhaps one only, of the motile threads 

 formed in the antheridia should reach the funnel-shaped 

 opening of the archegonium. I have not, indeed, seen the 

 spermatozoa of Pellia in that position, even if such be the 

 case with other liverworts, about which I shall speak here- 

 after. I have frequently found, however, that in those 

 flowers of Pellia to which I had applied a drop of water 

 containing ripe, opened antheridia, several (from three to 

 seven) archegonia have produced the rudiments of fruit 

 (PL V, fig. 9"). The circumstance, that the ripening of 

 the antheridia and the bursting of the archegonia begin and 

 end precisely at the same time, affords as good ground for 

 the above view as the more exact knowledge which we 

 possess with regard to mosses a view, moreover, 

 which in all essential points has been entertained for an 

 equal length of time with regard to both liverworts and 

 mosses. 



The outer cells of the expanded portion of the im- 

 pregnated archegonium divide rapidly several times one 

 after another, by radial septa, by longitudinal septa 

 parallel to the free outer walls, and by transverse septa ; 

 this cell-multiplication is most vigorous at the base of the 

 archegonium. All the newly formed cells become filled 

 with chlorophyll. Thus, very soon after the beginning of 

 the development of the rudiments of the fruit, the ex- 

 panded portion of the surrounding archegonium assumes 

 the form of a somewhat large, dark-green, cellular mass. 

 The neck of the archegonium remains unaltered. 



The fruit is developed from the free spherical cell which 

 is enclosed in the central cell of the expanded por- 

 tion of the archegonium. That cell first divides by a 

 transverse septum into a lower and an upper cell, of which 



