267 
Angiopteris evecta , Hoffm. 
the lowest of the three first cells would thus be the equivalent 
of the basal cell of Janczewski. My material was however 
unfortunately not sufficient in quantity to enable this question 
to be conclusively settled. 
I had not the opportunity of observing the process of 
fertilisation and unfortunately none of my material showed 
the earliest divisions of the oospore, though in preparations of 
the youngest embryos, their succession could be determined 
without much difficulty. The basal wall is formed as in 
Isoetes and Equisetum , at right angles to the long axis of the 
archegonium, that is, in the plane of the prothallium. The 
next wall in order of succession I believe to be the median 
one ; it is at right angles to the basal wall, and parallel to the 
axis of growth of the prothallium. This wall can easily be 
distinguished, even in advanced embryos, as a well-defined 
vertical line. The transversal wall is much more indefinite, 
and soon becomes quite unrecognisable as the embryo grows 
in size. New cell-walls succeed each other very rapidly, and 
without much regularity (cf. Figs. 3 and 4 which represent 
almost identical stages), and they are far less easily followed 
than in the common types of leptosporangiate ferns. I was 
unable to determine the presence of segment-walls in most 
preparations of young embryos, though they are indicated in 
some cases. No doubt this comparative irregularity is to be 
connected with the absence of well-marked apical cells from 
the members into which the young embryo becomes differ- 
entiated. These members originate from the octants in a way 
recalling strongly the typical fern-embryo, as will be at once 
seen from what follows. 
The two anterior epibasal octants (i. e. the two anterior 
upper ones) give rise to the cotyledon. Of the two posterior 
epibasal octants one probably contributes the larger share in 
the formation of the stem, but, during the earlier stages at 
any rate, both are devoted to this purpose (Fig. 5 b). There 
is no single apical cell, and on each side of the median wall 
cells are seen clearly marked out by their contents and large 
nuclei, as merismatic cells. The foot originates from the 
