103 
Polysolenia Ehrenb. 1841 is a Closterium with 
parasitic fungi. 
Zygoxanthium Ehrenb. 1841 is identical with 
Xanthidimn armatum. 
Didymoprium Kütz. 1843 is retained as a 
proper genus or as a section of Desmidium^ but Did. 
Borreri^ added by Ralfs, does not belong here. 
Palmogloea Kütz. 1843 was established upon 
one species, protuberans^ which ’’geht in ein Sey tonerna 
über.” Even after the publishing, 1847, of a figure 
of it it has remained so doubtful, that nobody could 
afterwards elucidate its real nature. The adding of 
3 species 1845 did not mend the genus; 1 belongs to 
Limnodictyon^ 1 is a Mesotaeviium and Archer 1864 (in 
Dubl. Kat. Hist. Soc. Pr. 1864 p. 16) was inclined 
to the eventual uniting of the third species with the 
genus Spirotcenia. As Kützing himself in Spec. Alg. 
1849 brought Entospira closteridia into Palmogloeaj 
somebody perhaps could think of taking up Pahno- 
gloea for Mesotœnium or rather for Entospira or Spiro¬ 
tcenia. Kützing added in Tab. phyc. and Spec. alg. 
several species, which really belong to Cylindrocystis.^ 
Gloeothece^ Pleur ococcus and probably other genera. 
Brebisson (in Diet. univ. d’hist. nat. t. 4, 1844, 
p. 711) made mention of Spirotænia as a name 
for a genus of Desmids, but it was not until 1849, 
in tom. 11 that his description of it was published; 
and consequently the first description appeared in 
Ralfs Brit. Desm. 1848. In 1843 and 1839 Bre¬ 
bisson was, already acquainted with 2 other algæ, 
which nowadays are regarded as Spirotcenice. To the 
first, ^Cylindrocystis endospira Bréb. mscr.”, Kützing 
gave the name Palmogloea efidospira (Tab. phjm. 1, 
1847, p. 19 t. 24 f. 6), to the second^ that of Ento¬ 
spira closteridia Bréb. in litt. (1. c. p. 24 t. 36 f 2), 
Brebisson considered that neither'^of them belonged 
to Spirotcenia.^ nor to the Desmids at all, especially 
