4i 6 Lang.- — On the Morphology of Cyath odium. 
antberidia forms behind these ends, which for a time behave as growing 
points, is supported by the much greater elongation of these ends in 
Schiffner’s specimens from Java. 
The mature antheridium (Fig. ti) is essentially similar to that of other 
Marchantiaceae. It consists of a short stalk composed of two cells, the wall 
composed of a single layer of large clear cells, and the mass of spermato- 
cytes. The antheridia throughout their development closely fill the cavities 
in which they stand, and at maturity have almost obliterated the septa 
between the chambers. Each of the latter opens by a pore raised above 
the general surface (Fig. 12). 
The antheridiophore in C. cavernarum is smaller, and is situated 
immediately below the margin of the thallus (Figs. 28, 29). Except that 
no distinct stalk is present, it is similarly constructed to that of C. foetidis - 
simum . The projecting rim of cells around the summit of the disk is 
clearly comparable, in the smaller species, to the clear rim of cells at the 
margin of the thallus. In the specimen figured in section in Fig. 29 
the openings of the chambers in which the antheridia stand can be seen, 
but the septa between the chambers are obliterated ; in younger stages 
(Fig. 30) the septa are distinct. 
The antheridia are similar to those of C. foetidissimum . In both 
species the stalk-cell immediately below the base of the antheridial wall 
differs in the characters of its cell-wall from the others. The development 
of the antheridium presents no special peculiarities. The young antheridium 
is first divided by a number of transverse walls into a row of about six cells. 
The three lowest form the stalk and the base of the wall ; the terminal cell 
forms the summit of the wall ; and the two or three middle cells give rise 
to the spermatocytes and the other cells of the wall. It is clear from the 
study of the antheridia in these two species that Leitgeb’s surmise that 
the antheridial wall was not formed of a layer of cells may be definitely put 
on one side. Even in material preserved in alcohol it is often difficult, in 
those which have opened, to detect the nature of the antheridial wall. 
Comparison with Targionia renders it almost certain that the structures, 
which have been termed antheridiopores above, correspond to the specialized 
antheridial branches, which in that genus spring from the under side of the 
midrib. The comparison is closest as regards position in the case of 
C. foetidissimum. The view that the antheridiophores of Cyathodium are 
highly modified adventitious branches is further strengthened by comparison 
with the sub-marginal vegetative branches of both species. It is, however, 
difficult to carry the comparison into the details- of development, and 
especially to place the succession of the antheridia in relation to the apical 
growth of a branch. 
The difficulties chiefly appear in the case of the more reduced 
antheridiophores of C. cavernarum , and it is only in this form that I have 
