1904] HOLFERTY: ARCHEGONIUM OF MNIUM 10g 
zZ,12). This ends the work of the two-sided apical cell and 
introduces that of the three-sided one, so characteristic of grow- 
ing organs in the archegoniates. Leitgeb (4, p.6) sought some 
instances of divergence by which this shift from a one-half to a 
one-third divergence could be explained, but without success. 
The transition is abrupt and not by gradual stages. The next 
division of the apical cell is longitudinal and cuts off a tangential 
segment from a middle cell. It is evident that the introduction 
of the last three walls constitutes the beginning of the arche- 
gonium proper, and the middle cell the beginning of the canal. 
All that lies below this constitutes the pedicel, which in mosses 
comes to be very massive (figs. 4, 19, 25, 28) and often very . 
long (jigs. 16, 20, 45, 47). 
While the divisions of the apical cell have been in progress, 
transverse and longitudinal divisions have been taking place in 
the segments below ( fig. 72), only two or three of the lowest 
segments not being thus divided (jig. 72), and the transverse 
divisions generally appearing first (fig. 7). Longitudinal divi- 
sions occur in the three peripheral cells, producing a neck of 
seven cells, a middle cell surrounded by six peripheral cells 
(fig. 48, c,d). The middle cell next divides transversely, pro- 
ducing a terminal cell (¢) and an inner cell (2) (figs. 73, 14, 18). 
There is no dissent from the view that this inner cell in both 
mosses and liverworts is the first of the axial row and a progeni- 
tor of the egg. It divides transversely, giving rise to the central 
cell (c) (figs. 15, 76, 79, 22) and the primary canal initial (f) 
(figs. 19, 22). The central cell does not divide again until the 
division which gives rise to the egg and ventral canal cell, gradu- 
ally increasing in size until its volume is six or eight times that 
of the neck cell lying next to it (figs. 24, 33). The primary 
canal initial, on the other hand, soon divides, and with the sub- 
sequent divisions of its daughter cells helps to form the canal 
series. It will be seen that the development thus far is practi- 
cally that of the archegonium in liverworts.’ 
* Compare Leitgeb (10), Kny (3), comeelrl (9, p- 402), Strasburger (6 and 7), 
and other observers who deal with liverwo 
