a 
1915] HUTCHINSON—PELLIA EPIPHYLLA 137 
usual divisions.”’ This character serves to emphasize the similarity 
which exists between the archegonium as shown (figs. 31-33), and 
the antheridium (figs. 16-21). Except for the position and pres- 
ence or absence of the involucre, these organs would be difficult to 
differentiate until the spermatogenous group or the archegonial 
axial row, as the case may be, begins to develop. The cap cell 
gives rise to a group consisting of more than the usual number 
of cells. The first division of the cap is often simultaneous with 
the division which gives rise to the primary neck canal cell and the 
primary ventral cell (figs. 32, 35), and four cap cells may appear in 
cross-section when there are but three neck canal cells and a ventral 
cell (fig. 36). Fig. 38 shows a group of cap cells, 6 in cross-section, 
which may be compared with those which form the neck of the 
archegonium of Filicineae. JANCZEWSKI reports that the number 
of neck canal cells may be as high as 16 or even 18; 9 is the greatest 
number seen by the writer (fig. 38). The venter becomes massive 
before fertilization; it may be 2 or 3 cells in thickness; a many- 
celled stalk is also formed (fig. 37). In the young archegonium the 
neck has usually only 5 vertical rows of cells. The cells originating 
from the third wall cell do not divide until the archegonium ap- 
proaches maturity (fig. 39). 
Methods of growth 
A certain form of apical cell may usually be given as character- 
istic of a genus or even of a larger group. In Pellia, however, there 
is no such conformity; the apical cell of P. calycina has four cutting 
faces, two lateral, a dorsal, and a ventral—the cuneate apical cell. 
The dolabrate apical cell of P. endivaefolia has but two cylindro- 
convex cutting faces; while that reported as characteristic of P. 
epiphylla, the lenticular cylindric apical cell, has a posterior convex 
and two lateral cutting faces. In the last named species, however, 
there are several methods of growth; these cannot be sharply 
delimited, but for clearness five rather distinct forms may | be taken 
as characteristic of successive periods of growth. 
During the time of intra-capsular gametophytic division a 
massive body is formed. There is no regional growth, but all cells 
have an equal power of division. This period of growth is of short 
