18 
Obs. 
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WITTROCK, SPORES OF THE MESOCARPEZ. 
Explanation of the figures. 
All the figures are magnified 400 times, with the exception of the one 
copied after Hassall, fig. 14, which is probably magnified 300 times. 
1—13. Gonatonema ventricosum n. sp. 
; 
An 
HH DO 
13. 
18: 
195 
Piece of a vegetative filament with almost full-grown cells. » indi- 
cates the nucleus of the cell. 
A vegetative cell in such a position that the chlorophyllaceous 
band is seen from its edge. 
Piece of a vegetative filament with very young cells. The chloro- 
phyllaceous bands, which are seen from their edge, are in a cur- 
ling motion. 
Piece of a filament ready for spore-formation; the upper one of 
the two cells is at the first stage of spore-formation. 
A cell on a more advanced stage of spore-formation. One of the 
two septa is complete; the other is just being formed. 
Cell in which preparations to the formation of spores have taken 
place, but which has afterwards changed its plan and been divided 
in a vegetative manner. 
Part of a filament with ripe spores; the spores are here somewhat 
more slender than the common form. 
Part of a filament with ripe spores of the common form. 
and 10. Spores in side view. The cell-contents not drawn. 
Part of a filament with ripe spores of an uncommon form. 
Part of a spore-forming filament, where every other pair of mother- 
cells of the spores have bent in different directions. Contents of 
the eells not drawn. 
A ripe spore with the cell-contents removed through pressure. The 
three layers of the membrane of the spore, the exo-, meso- and 
endosporium, are visible. The spore has been treated with chlor- 
zinkjod. ; 
Gonatonema notabile (Hass.) nob. Part of a filament carrying spores. 
—-18. Mougeotia calcarea (Clev.) Wittr. 
A series of sporocarpia formed by conjugation followed by cell- 
partition. The two upper sporocarpia have pericarpia of 4 cells 
(Staurospermum-type) and the two lower pericarpia of 2 cells 
(Mesocarpus-type). 
A sporocarpium with a pericarpium of 3 cells (Plaqgiospermum-type).- 
Part of a filament whose cells have brought forth parthenospores 
by bipartition (Mesocarpus-type). 
Part of a filament whose eells have formed parthenospores through 
tripartition (Staurospermum-type). 
Mougeotia gemwflexa (Dillw.) Ag. Twin parthenospores formed in 
conjugation-outgrowths designed for longitudinal conjugation. 
