102 
153: ”Zur Gattung Ar ihr odesmus könnte Grevilles 
Desmidium cylindricum gehören.” 
Cylindrocystis Menegh. 1838 was regarded by 
Ralfs as a section of Fenium^ but its generic rank 
is now evident. Cfr Penium! 
The species of Cor da’s genera Mesotrema and 
Strephocystis 1839 are now placed in Cosmarium, 
Strephocystis pro max. p. = Cosm. sect. Eucosmarium 
De Bary. 
Eutomia Harvey, 1841, embraces one species 
of Micrasterias and one of Euastrum. 
The description of Gymnozyga moniliformis 
Ehrenb. 1841 was so short, that Kützing 1845 in 
a note to Bambusina Brehissonii certainly suspected 
both to be identical, but he had not seen copulation 
on his specimens. Tre visan in 1848 enumerates 
both Gymnozyga and a new genus Gymnodesmus (— 
Bambusina). The copulation does not prevent Gym¬ 
nozyga moniliformis from being a Des mid, but it can 
belong also to the genus Hyalotheca. There exist se¬ 
veral species of Hyalotheca, agreeing in size and in 
shape very much with Bambusina Brebissonii, e. g. 
H. elegans and H. neglecta, which latter species occurs 
in Europe. Therefore I cannot see the necessity of 
the resurrection of the genus Gymnozyga for Bam¬ 
busina. 
Ehrenberg brought together in 1841 into his 
new genus Hyalotheca both Desmidium cylindricum 
Grev. and D. mucosum Bréb., 1835, and Actino- 
cyclus variabilis Corda, not giving any description. 
The first diagnosis was published by Kützing in 
1845 in Phyc. germ. Desm. cylindricum Grev. be¬ 
longs not really to Hyalotheca sensu auct. recent., but 
to Desm. {ov Didymopriuni) and Desm. mucosum. Brèh. 
1835 was by Brébisson himself 1856 identified 
with Hyalotheca dissiliens. 
