•J (.4 
lime crystals, as there is no mention of the green threads 
of the plant. Xo wonder that Kiitzing rejected this name 
for a genus of plants, as soon he became aware of hi-, 
mistake! 
6. Microcystis. 
From what year has Kützing’s genus * Microcystis » 
priority? 
It was set up by him in Linnaea v. 8, 1833, p. 372, 10 
species being described, all of which have been since trans- 
ferred to the genera: Euglaena, Haernatococcus, Trente- 
pohlici, Pleurococcus, Glneothece or Gloeocapsa. 
The 16 species of Microcystis in Meneghini's Mo- 
nographia Nostoch., 1842, belong to at least 4 genera of 
later time: Gloeocapsa, Gloeothece, Aphanothece, and Chro- 
ococciis. 
Not one of these species of Kiitzing and Meneghini 
belongs to Microcystis, as now understood. 
In Phycologia Generalis, 1843, Kiitzing had only 4 
species. The two, Noltii and olivacea, have been regarded 
as species of Euglaena. On M. parasitica he made the fol- 
lowing remark: Entwickelt sich zu Cylindrosperniuni con- 
fervicola (a name, which is not taken up in his Phycol. 
german, or in Spec. Alg.). M. ichthyoblabe here included 
Microhalea aeruginosa. I think therefore Kiitzings genus 
Microcystis should be dated from the year 1843. 
Rabenhorst iFlor. Europ. Algar. II. 1865) gives the 
name Polycystis (Kiitz. 1845) to a part of the older Micro- 
cystis, saying in a note p. 53: Kuetzingii nomen antiquius 
quam illud Léveillei pro fungi typo sumptum». But K tit- 
zing's genus Polycystis must be dated from 1849, Spec. 
Alg., and not from 1845, because in Tab. Phycol. 1 p. 7 he 
says: Die Gattung Microcystis muss eigentlich in drei Gat- 
tungen gespaltet werden, die ich vorläufig als Unterabthei- 
lungen hier anführe . 
In Ann. d. Scienc. Nat sér. 3 t. 5, 1846 p. 269 Poix- 
