BIHANG TILL K. SV. VET.-AKAD. HANDL. BAND. 9. N:O 9. 5 
making them analogous to the spores (the real zygospores) of 
Zygnemee and Desmidiee. To me it seems, however, per- 
fectly clear that DE BaArRY is quite right in saying that the 
hypnpospores of the Mesocarpee are not analogous to the zy- 
gospores of the Zygnemec, or in other words, that they are 
no zygospores at all. The hypnospores of the Mesocarpece 
are formed by partition and not by an immediate fusion of 
the protoplasm of conjugating cells, as the case ought to be 
with zygospores. 
- 
Allowing DE BaAryY to be in the right as to the hypno- 
spores of the Mesocarpew not being zygospores, the question 
remains whether his interpretation of the cruciated or H- 
shaped, not quiescent »double cell», formed immediately by 
the conjugation, as being a zygospore, is adaptable. For 
my part, I have never found this interpretation quite satis- 
factory. This »double cell» differs too widely, as it seems to 
me, both as to its outer shape and its contents not only from 
typical zygospores, but from everything that has been called 
a spore. But I have not succeeded in finding a more satis- 
factory explanation of the nature of the result of the fecun- 
dation in these alge, nor has any body else given one. 
Not till N. PRInGsHEIm's ingenious work »Ueber die Spros- 
sung der Mossfrichte und den Generationswechsel der Thal- 
lophyten»') was published, the question seems to me to have 
gamed its solution. 
In accordance with the leading ideas which PRINGSHEIM 
develops in this work”), the course and result of the conju- 
gation seems to me to be naturally explained in something 
like the following manner. The act of conjugation may be 
divided into two different stages. The first, being properly 
speaking only introductory, consists in the two cells which 
participate in the conjugation growing together by conjuga- 
tion-outgrowths, and the septum between the cells thus grown 
together ' being resorbed. This part of the act of conjuga- 
tion is what PRINGSHEIM calls copulation. The second stage 
consists in an intimate fusion taking place of the proto- 
plasmatic contents of the conjugating cells. This fusion is 
1) In »Jahrbiicher fir wissenschaftliche Botanik». Band XI. 1877. 
2) Compare especially p. 14—22. 
