2 20 
F. E. Fritsch. 
whilst the empty case of the latter (with exospore and endospore 
intact) lies at the side and plainly exhibits the now wide aperture, 
through which the contents were protruded ; for in the large majority 
of cases the pressure of the mucilage in the spore is too considerable 
and the originally narrow terminal aperture gets more or less widened 
out, as shown in Figs. 15 and 26. The empty spore then has a cup¬ 
shaped form with the open edges often more or less turned back 
(cf. Fig. 26). Although the mucilage, which causes the liberation of 
the spore-contents is mostly readily visible as a surrounding envelope 
after their escape, it is very difficult to demonstrate it during the 
actual process of protrusion. Staining with Vesuvin for instance 
results in the first place in the external mucilage taking on a deep 
brown colour and this obscures everything else. In isolated spores, 
however, it seemed as though the mucilage inside the spores with 
half-liberated contents were coloured faint brown by the stain. 
Iodine, as is to expected, does not affect it. The giving way of the 
spore-membranes to the pressure of the mucilage may take place at 
an earlier or later stage in the liberation of the contents (cf. Fig. 20 
with Fig. 26). In some few cases the contents of the spore had 
been liberated laterally instead of terminally (Figs. 10 and 21); 
this is probably due to the spores lying closely together, instead of 
considerably separated, as is usual, so that the pressure of the 
mucilage inside the spore forces open a lateral aperture. The 
liberated contents are in most cases without a distinctly differentiated 
membrane at first. Abundant formation of mucilage inside the 
spore may lead to still another (rarely occurring) variation of this 
type of germination, in which a part of the spore-membrane is split 
off as a whole and thus forms the necessary opening for the libera¬ 
tion of the contents (cf. Figs. 3, 7 and 10). This lid is either 
pushed out in front of the exuding mucilage (Figs. 3 and 7), or may 
remain attached on one side to the rest of the spore-wall (Fig. 10). 
The detached portion may be either terminal (Fig. 10 at t) or lateral 
(Fig. 10 at l). 2 In this type of germination it frequently happens 
that the contents of the spore are not liberated at all, but germinate 
in situ, the filament formed by the division of the spore-contents 
gradually pushing its way out of the open spore-membrane (cf. Fig. 7)- 
But as a rule in all the cases as yet described, the spore-contents do 
1 Fig. 16 represents an interesting case in which the contents of 
two spores have been liberated towards one another and are 
enveloped in a common mucilaginous envelope, due to the 
confluence of the mucilage of each. 
2 In Figs. 3 and 7, the detached portion has been lost in the 
surrounding water. 
