205 
Lang. — On the Sporogonium of Notothylas. 
not observed, but most of the capsules were not quite mature. The occur- 
rence in the underlying soil of intact capsules isolated by decay suggests, 
however, that in many cases they may not open. It is indeed difficult to see 
how the small part of the capsule projecting from the calyptra can suffice for 
effective dehiscence. The cavity of the capsule was occupied for the 
greater part of its extent by a uniform mass of spores and elaters, a sterile 
columella being completely absent or only present at the base. The spores 
measured 40-45 /oc in diameter: the wall was dark and the convex outer 
face was studded with short, blunt, almost black projections. The indi- 
vidual sterile cells or elaters, which at first were united into flat transverse 
plates, measured about 40 /jl x 30 ju, and had thin walls with yellowish-brown 
thickenings in the form of more or less complete rings. 
The general appearance of an almost mature sporogonium in median 
longitudinal section is shown in Fig. 4, and Fig. 5 represents a similar 
section of a smaller and slightly less advanced sporogonium under a some- 
what higher power. These figures, together with Figs. 6 and 7, which 
represent median longitudinal and transverse sections from mature capsules 
under a high power, demonstrate the absence of a sterile columella from 
the greater part of the capsule. The cavity of the latter is seen to be filled 
with a reticulum of sterile cells, in the meshes of which the spores lie. 
The structure is in fact that described and figured by Leitgeb as occurring 
in some cases in Notothylas , although, as will be shown below, its origin in 
development is different from what he supposed. When a columella was 
present it only extended a short distance from the base, and its diameter 
varied in different capsules. 
From this general survey of the structure of the mature sporogonium 
we may return to trace its development. A sufficient number of young 
embryos were found to indicate clearly the course of the early segmenta- 
tions of the fertilized ovum. In Fig. 8 a young embryo is shown in median 
section as it lies in the venter of the archegonium, and the commencing 
growth of the surrounding tissue to form the calyptra is evident. The 
first division is in the line of the axis of the archegonium (Fig. 9 a). In the 
next stage found the embryo consisted of three tiers of four cells each 
(Fig. 9 b ) ; this stage has been found in the embryogeny of all Anthocero- 
taceae that have been investigated. Comparison with succeeding stages 
shows that here, as in Anthoceros , the two lower tiers go to form the foot, 
while the capsule and stalk originate from the uppermost tier. The peri- 
clinal divisions in the four cells of the latter separate the endothecium 
from the amphithecium, as in Anthoceros (Figs. 8, 9 c). After some anti- 
clinal divisions have occurred, and the young capsule has increased in size, 
the archesporium is cut off from the amphithecium. This begins at the 
summit of the embryo and extends to the cells below, but, as Fig. 10 shows, 
not to the base of the region derived from the uppermost tier of cells. The 
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