483 
the young plants in Oedogonium. 
menon has been observed and described by Hirn (1900, p. 14), 
although he experimented with a 13 per cent solution of 
cane-sugar in order to plasmolyse cells suddenly, in which 
zoospore formation was already going on. He considers this 
mucilage to be homologous with the membrane, which normally 
surrounds the zoospore during its liberation, but it seems to 
me probable that this membrane is entirely suppressed here, 
and that mucilage is always (even normally) present between 
the zoospore and the wall of the mother-cell, though probably 
not in such quantities as in this case. Sporangia of Oed. capillar e 
with the zoospores half out were stained with Chlor-zinc- 
iodide, and it was found that the empty half of the cell became 
stained with a deep violet colour (much darker than that due 
to the cellulose-walls), which is undoubtedly caused by an 
aggregation of mucilage behind the zoospore. The latter was 
surrounded by the typical thin membrane. Most probably 
this mucilage is of use in effecting the liberation of the 
zoospores ; at all events I do not think that it has anything 
to do with the membrane of the emerging zoospores. 
Not all the cells of Oed . Vaucherii formed abnormal zoo- 
spores in this manner when cultivated in a 2 per cent, solution 
of cane-sugar ; in some filaments the cell-contents merely 
contracted irregularly, whilst the walls presented curious and 
irregular thickenings (Fig. 27, b). With Iodine or Chlor-zinc- 
iodide these thickenings stain a deep reddish-brown, whereby 
they are clearly differentiated from the original cell-wall. 
I also observed such thickenings in Oed. capillare, where, how- 
ever, they took on no colour with the above-mentioned 
reagents. These masses seem to consist of different kinds of 
mucilage, which is formed under abnormal conditions 1 and 
differs from the mucilage above described as existing between 
the mother-cell and the zoospore. In Oed. Vaucherii the 
legte und dann mit Iod totete. Dann traten an den plasmolysierten Zellen, 
soweit sie in Zoosporen umgewandelt waren, die violetten Hiillen deutlich hervor.’ 
The ‘violette Hiille ’ is in my opinion not the same as the ‘ Hiillblase ’ of the 
zoospore. 
1 These thickenings also appeared in old cultures of Oed. capillare, in which, 
however, common tap- water had been employed. 
L 1 
