4 T 9 
Lang . — ( 9 ;/ the Morphology of Cyatliodium . 
Development and Structure of the Sporogonium. 
The structure of the mature sporogonium has been described in 
C. cavern arum by Leitgeb and later by Andreas 2 , but from the nature of 
the material used its development was not described. The development 
of the sporogonium was therefore followed in detail in C. cavernarum , and 
enough of it was seen in C. foetidissimum to make comparison possible. 
C. foetidissimum. The first division in the fertilized ovum is trans- 
verse, and this is followed, as in the other Marchantiaceae, by longitudinal 
divisions in both upper and lower halves (Fig. 17). Only a few examples 
of stages intermediate between this and the almost mature sporogonium 
were seen, but these (Figs. 18, 19) resembled other Marchantiaceae, and 
made it almost certain that the sporogenous tissue and the greater part of 
the wall of the capsule were derived from the upper cell of the embryo, 
while the foot and the base of the capsule-wall were developed from the 
lower segment. By the stage represented in Fig. 19 the sporogenous tissue 
was clearly defined from the wall, and was conspicuous by reason of the 
dense and deeply-staining contents of its cells. With the first divisions of 
the embryo the venter of the archegonium becomes two-layered, and by 
this stage it is three or four cells thick. While closely investing the basal 
region of the sporogonium the young calyptra is separated from the upper 
portion of the capsule by a space which persists until the spores have been 
formed (Fig. 20). In the stage represented in this figure the spore-mother- 
cells had become rounded off and distinct from the young elaters. They 
are spherical and contain abundant protoplasm and a single nucleus : the 
elaters were somewhat elongated, but had no thickenings on their walls. 
The wall of the capsule is composed of a single layer of cells, except at 
the apex, where a disk of cells similar to that described by Leitgeb for 
C. cavernarum is present. The foot consists, as seen in longitudinal section, 
of two rows of vacuolated cells. At its base are larger cells densely filled 
with protoplasm. The calyptra is four to five cells deep around the foot, 
but thins off above to two layers. 
The spore-mother-cells increase in size and the tetrad division takes 
place without the cell becoming lobed. This stage was indifferently pre- 
served, so that no observations were made on the division. About the same 
time, however, a remarkable change occurs in the four cells at the base 
of the foot. These grow out into a number of relatively long tubular 
processes, each of which may branch once or oftener ; these greatly increase 
the absorbent surface of the foot. Their general appearance will be evident 
from Figs. 21 and 23, which represent longitudinal and transverse sections 
of the foot of a sporogonium of this age. A transverse section of the 
stalk-like portion of the foot is seen in Fig. 22, which shows that this also 
consists of four rows of cells. 
1 Loc. cit. 
2 Loc. cit. 
