Campbell. — Studies on some Javanese Anthocerotaceae . /. 477 
defined, and in cross section (Fig. 39 a) the archegonia usually show the 
same number, six, that is characteristic of the lower Hepaticae. 
The first division of the axial cell is transverse (Fig. 33) and usually 
there are no longitudinal walls formed ; but in some cases the outer cell 
divides by a longitudinal wall (Fig. 34) before any further transverse 
divisions appear. In such cases the neck canal-cells are consequently 
much narrower than usual, and the central cell relatively broader. In most 
cases the breadth of all the cells of the axial row is approximately equal. 
The next transverse division is in the outer cell, and divides it into the 
cap-cell, and the primary neck canal-cell. The former divides by a vertical 
wall into two nearly equal cells, which may remain undivided, or one 
or both of them may divide again, so that the final number of cap-cells 
is two to four. The canal-cell divides by a series of transverse walls into 
four or sometimes five cells. In no case was a larger number found. 
Janczewski states that as many as twelve neck canal-cells may be formed 
in Anthoceros laevis , but the writer has never found more than six in any 
species of Anthoceros , Notothylas^ or Dendroceros that he has studied. 
As in other cases that have been observed, the cover cells are thrown off 
when the archegonium opens, and the upper neck cells which project 
considerably above the thallus diverge more or less. As in the other 
Anthocerotaceae the central canal-cell is nearly or quite equal in size to 
its sister cell, the egg (Figs. 37, 40). No marked difference was observed 
between the archegonia of the two species studied. Of the three genera 
that have been examined hitherto, Notothylas has the axial cells relatively 
broadest, approaching in this respect the lower Pteridophytes. Dendroceros 
is intermediate between Notothylas and Anthoceros in the form of the 
archegonia, and Megaceros resembles it closely in this respect. 
The Embryo. 
The very small size of the spermatozoids makes the Anthocerotaceae 
unsuited to a study of the details of fertilization, and no attempt was made 
to investigate these in Megaceros . The egg-cell at the time of fertilization 
does not fill the central cavity, and its nucleus is small. After fertilization 
it grows until it fills the venter before the first division occurs. 
In the early divisions of the embryo Megaceros more nearly resembles 
Dendroceros than it does Anthoceros. As in both of these forms the first 
wall is longitudinal and the second transverse ; but whereas in Anthoceros 
the transverse walls are below the middle of the young embryo, this being 
very marked in A. fusiformis (Mosses and Ferns, 2nd Edition, Fig. 69), 
in Dendroceros they are nearly median, and the young embryo is divided 
into nearly equal quadrants. The same is true in Megaceros , although the 
two lower quadrants are slightly smaller (Figs. 41, 48). Of the two species, 
