ZYGNEMACES, 109 
_ “The first sign of a beginning spore-formation is that the cell widens 
at its middle, so that this part resemblesacask. This widening is not, 
however, equally powerful on all sides, but is stronger on one side than 
on the other sides, At the same time the cell bends at its middle like a 
knee, so that its two halves form a more or less obtuse angle with each 
other. The point of the angle is placed where the before-mentioned 
more powerful widening of the cellhas taken place. Almost always the 
formation of spores takes place at the same time in all the cells of a 
filament. Then it regularly occurs that the cells bend alternately in 
opposite directions, so that if cell No.1 bends to the right, cell No. 2 
bends to the left, No. 3 to the right, and No. 4 to the left again, and so 
on. Consequently the cells in a filament-producing spores will form a 
zig-zag line. Exceptions from this rule do, however, now and then 
occur ; thus, that two cells abutting on each other bend in the same 
direction, after which the two next bend in an opposite direction and so 
on. When this occurs, the filament is gently curved like an §, alter- 
nately in two directions. When the spore-forming cell widens and 
bends, the chlorophyllaceous band of the cell is often interrupted at its 
middle part, by which the cell gets two chlorophyllaceous bodies instead 
of one. The chlorophyll-coloured protoplasm now begins anew to give 
proofs of its power of free motion. The chlorophyllaceous body (or 
bodies if there are two) moves freely and rather quickly, from the other 
parts of the cell to the widened middle part. When all of it has entered 
this part of the cell, which has thus become almost quite filled with 
chlorophyll-coloured protoplasm, the cell is divided into three cells by 
two septa, appearing one on each side of the chlorophyll filled central 
part. The cells formed by this partition are of two essentially different 
kinds. The two lateral cells have very little living contents. All the 
chlorophyll-coloured protoplasm is gone, and only the thin parietal layer 
of protoplasm and some drops of oil are left. The rest of the contents 
are only colourless cell-liquid. These cells have in fact filled their pur- 
pose. They soon die, and remain, as mere skeletons of cells, attached 
for some time (two or three weeks) to the central cell. The central cell is, 
in contrast to the lateral cells, very rich in living contents, having re- 
ceived all of the chlorophyll-coloured protoplasm of the mother-cell, It 
is also designed to become the hypnospore, through which the propaga- 
tion of the species is to be affected. But before it becomes a complete 
hypnospore it is to pass through several stages of development. The 
first, of these is that the cell-contents surround themselves witha new 
layer of cellulose (mesosporium) within the original one (exosporium). 
The mesosporium increases by-and-bye in thickness till it is considerably 
thicker than both the exosporium and the endosporium (which appears 
later), The mesosporium gets no sculpture (as is the case with so many 
Mesocarpe@) it remains always smooth. But having been at the begin- 
ning hyaline, it soon assumes a faint yellow colour. Within the mego- 
Sporium a new layer of cellulose forms during the first week; this is 
called endosporium. It remains always hyaline and very thin. During 
this time the contents of the cell have also suffered a change, The 
chlorophyll-coloured protoplasm, at least the greater part of it, has 
changed into a fat oil, which is coloured in the same manner ag the 
mesosporium, %¢, a faint yellow. The hypnospore which is now 
ready, shows a somewhat different shape, if regarded from different 
sides. If regarded inthe position it has when the curvatures of the 
spore-forming filament are directed to the right and left of the ob- 
server, the spore is, as a rule, non-symmetrically elliptic, with abrupt 
ends, very seldom it is almost circular. The want of symmetry con- 
sists in the spore being more convex on the side towards which the knee 
of the mother-cell has bent. If we imagine the spore being turned a 
quarter of a turn round its longitudinal axis, it appears somewhat 
