68 Campbell. — On the Prothallium and Embryo of 
wall divided the canal-cell into two complete cells. It is pos- 
sible that this may occur oftener than it seems to, and that in 
some cases the wall may be absorbed after its formation, but 
in most cases it seems more likely that no such division 
wall is formed. The occasional formation of such a wall 
however, regularly the case in the Marattiaceae \ indicates 
a probable reversion to the type always found in the Bryo- 
phytes. 
A longitudinal section of the nearly full-grown archegonium 
(Fig. 67) shows a straight neck consisting of about six tiers of 
cells, and having its central part occupied by a row of three 
(or four) cells, of which the lowest is the egg ( o ). The neck- 
cells have small nuclei, and in the living state appear almost 
transparent and with little chlorophyll, but sometimes nu- 
merous colourless, glistening granules that seem to be of 
albuminous nature, and which are very conspicuous in ma- 
terial fixed with chromic acid (Fig. 69), are present. The 
central row of cells contains finely granular protoplasm, but 
not as dense as is usually the case in these cells. Almost no 
starch is present in these cells in either O. cinnamomea or 
O. claytoniana , which is somewhat remarkable, as both Kny 2 
and Luerssen speak of the large amount of starch in the canal- 
cells and egg of O. regalis. 
As the egg-cell approaches maturity its nucleus becomes 
very large and distinct (Fig. 70). One and sometimes two 
nucleoli are present, but it is not very rich in chromatin, a 
condition that is not unusual in the egg-nucleus. 
In several instances, when the archegonium seemed about 
ready to open, an appearance was noticed that looked very 
much like the formation of a true polar body, and was not to 
be confounded with the ventral canal-cell. In these cases 
(Fig. 73), in the upper part of the egg was a not very clearly 
defined body that coloured strongly with alum-cochineal, and 
was apparently nuclear in its nature. Where this was ob- 
served, the nucleus of the egg seemed to have lost part of its 
chromatin, and in what seemed to be later stages (Fig. 71) the 
1 Jonkman, 1 . c. p. 216. 2 L. c. p. 11. 
