BIHANG TILL K. SV. VET. AKAD, HANDL. BAND 56 N:O 5. 13 
round themselves with a new layer of cellulose, mesosporium, 
within the original one, exosporium, see figs. 7, 8, 11, 13. 
The mesosporium increases by and by in thickness, till it is 
considerably thicker than both the exosporium and the endo- 
sporium (which appears later). The mesosporium gets no 
sculpture (as is the case with so many other Mesocarpew); it 
remains always smooth. But, having been at the beginning 
hyaline, it soon assumes a faint yellow colour. Within the 
mesosporium a new layer of cellulose forms during the first 
week; this is called endosporium (see fig. 13). 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 as the 
mesosporium, i. e. a faint yellow. — The hypnospore, which is 
now ready, shows a somewhat different shape if regarded from 
different sides. If regarded in the position it has when the 
curvatures of the spore-forming filament are directed to the 
right and left of the observer, the spore is as a rule non- 
symmetrically elliptic with abrupt ends (see figs. 7 and 8); 
very seldom it is almost circular; see fig. 11. The want of 
symmetry consists in the spore being more convex on the side 
towards which the knee of the mother-cell has bent. If we 
imagine the spore having turned + of a turn round its longi- 
tudinal axis, it appears somewhat narrower and perfectly ellip- 
tic with abrupt ends; see figs. 9 and 10. 
How the spores behave when germinating I have not yet 
had any opportunity of observing. And I think I have only 
very little hope of being able to observe the germination at 
some future period with the assistance of the material which 
I am cultivating, because the Gonatonema is almost quite over- 
grown by a species of Anabena, which occurs in a considerable 
quantity. ? 
It appears from the course of the spore-formation which 
I have described above, that the spores (of which I have had 
opportunity to see a very great number) in this species are 
always formed — unlike what is the case in other Mesocarpece 
— without a preceding act of conjugation. When attempting 
to explain this so very extraordinary phenomenon, we have 
two ways to choose between. We may, when choosing the 
flrst, simply and without any presuppositions regard the act 
