12 WITTROCK, SPORES OF THE MESOCARPEZA. 
at the same time in all the cells of a filament. Then it regu- 
larly occurs, that the cells bend alternately in opposite direc- 
tions, 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; see figs. 7, 8 and 11. 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 S, alternately in two directions; see fig. 12. — 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; see fig. 4a. 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 (compare fig. 5, where one of 
the septa is already complete, but the other one is just being 
formed, whilst the chlorophyllaceous body from one half of 
the cell is still moving into the widened middle 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 purpose. They 
soon die, and remain, as mere skeletons of cells, attached 
for some time (2 or 3 weeks) to the central cell. The 
central cell is, in contrast to the lateral cells, very rich 
in living contents, having received all of the chlorophyll- 
coloured protoplasm of the mother-cell. It is also designed 
to become the hypnospore, through which the propa- 
gation of the species is to be effected. But before it becomes a 
complete hypnospore, it is to pass through severai stages of 
development. The first of these is that the cell-contents sur- 
