4 WITTROCK, SPORES OF THE MESOCARPEZEZ. 
mediately by the conjugation, DE BARY regards as the zygo- 
spore of the Mesocarpece, and gives it the character of being 
not contracted, in contrast with the zygospore of Zygnemee 
and Desmidiee. "This »zygosporey» exists, however, only for 
a very short time as such. The above-named moving of 
the chlorophyllaceous bodies (not of the whole protoplasmatic 
mass) into the connecting canal having been accomplished, 
the »zygospore» is divided, by two or four septa, into 3 or 
5 cells, of which one, the central one, is a hypnospore, rich 
in chlorophyllaceous protoplasm (and later in oil), whilst the 
2 or 4 lateral cells, containing no chlorophyllaceous proto- 
plasm, are sterile and soon going to die. 
Thus the Mesocarpew have, according to DE BARY, spores 
of two kinds?!?), namely zygospores, which are formed 
simply by the growing together of the two conjugating cells, 
without contraction ”), and which do not repose, and hypno- 
spores (»Ruhesporen»), which are formed by the partition of 
the zygospores and which repose (as the name indicates) for 
a time before germinating. The Zygnemee and Desmidiee 
have, on the contrary, according to DE BARY, spores of only 
one kind, namely typical zygospores”), in the formation of 
which a fusion and contraction of the whole protoplasmatic 
contents of the conjugated cells takes place”), and which be- 
come hypnospores without a preceding partition. 
DE BaARrRY'S interpretation of the nature of the spores of 
Zygnemee and Desmidiee has, on very good grounds, been 
accepted by all later investigators. But the interpretation of 
the spore-formation of the Mesocarpee has not been able to 
gain equal approbation. Almost all authors who have written 
on the Mesocarpee after DE BARY have, in the old manner, 
given their hypnospores the name of zygospores”), thus 
DI See DE BARY, La C:o Pp: (0. 
2) They have, consequently, exactly the same form as the two cells joined 
by the conjugation, when regarded together. 
3) With zygospores DE BARY, as well as almost all botanists after him, 
means membrane-coated spores formed immediately by an act of 
fecundation, in which two or more cells of the same kind (not sexually 
different) have participated. 
4) They have also quite another form than the conjugating cells. 
5) Thus L. RABENHORST in Flora Europ&ea Algarum, Sect. III. 1868. p. 
256—260;: M. CORNU in Bulletin de la Société botanique de France. 1869. 
Tome XVI, p. 240; J. SACHS in Lehrbuch der Botanik, 4:te Auflage. 
1874, p. 261. 
