1904 | HOLFERTY: ARCHEGONIUM OF MNIUM r2r 
the preceding pages, would seem to support them. The modified 
organs just discussed (figs. 36, 37, 45, 46), and the archegonia 
taking on antheridial characters in their development reported 
by Lindberg (11) and de Bergevin (20), linterpret as indicating 
that the archegonium is the more specialized of the two organs, 
and that its atavistic tendency is toward the sporangium-like 
form and structure of its ancestor. Itis natural, since the anther- 
idium is less differentiated, that this atavistic tendency of the 
archegonium should express itself by first taking on antheridial 
characters. This it does by its reduced row breaking up again 
into gamete mother-cells (fig. go); by the neck enlarging (fg. 
40, also de Bergevin 20); by its wall tissue becoming chlorophyll- 
bearing; by the loss of egg and ventral canal cell (figs. 45, 46); 
and by its assuming a general antheridial aspect. A vestige of 
these processes is also seen in very many archegonia where the 
expanded apical regions inclose masses of indefinite cells. The 
explanation offered for the appearance of these expanded apical 
regions has been that they arose on account of the stretching in 
a tangential direction of the peripheral cells (Janczewski 9); but 
I interpret this as nothing more than an expression in every 
archegonium of this atavistic tendency. This view of the occa- 
sional partial atavism of archegonia expressing itself in anther- 
idial characters bases itself upon the common origin of the two 
organs from a primitive organ of a sporangial nature, and upon 
the demonstrated homology of archegonia and antheridia. 
SUMMARY. 
1. The receptacle is flat-topped with many papilliform cells 
on its surface, which give rise to archegonia, antheridia, and 
paraphyses. 
2. Archegonia arise from single super 
tinguishable at first from those which give rise to antheridia. 
3. The first two divisions of the archegonium initial are oblique 
and give rise to a two-sided apical cell. 
4. The succeeding divisions up to as many as six are from 
the faces of this two-sided apical cell, archegonia and antheridia 
agreeing in this regard. 
ficial cells not dis- 
