12i 
The memoire of Derbès et S o li er (in suppL 
compt. r. d. séanc. d. l’acad. d. sc.) was published 
1856, as it seems, quite unaltered, without any refe¬ 
rence to Thuret’s paper. They had also established 
a new genus Trihonema on the same character as 
T huret had done with Microspora. They say: ”Le 
plus saillant de ces caractères est la rupture totale 
de l’article, immédiatement avant l’émission des zoo¬ 
spores”. 
They also had given a modified diagnose of the 
genus ^"‘Hormiscia Fries?” with the species '^floccosd!'' 
(Lyngb.). Honniscia D. et S. was then identical with 
Microspora Thur., although the diagnosis was different 
(e. g., ”Zoosporae apice filorum seriatim exeuntes”), 
but in the description of the species it was modified 
thus: ”Quelquefois l’article se brise circulaire ment, 
comme nous allons le voir dans le genre suivant” 
[Trihonema], 
Hazen 1. c. p. 183 points out that in the dia¬ 
gnose of Trihonema homhycina ”explicit mention was 
made of the most essential character, namely the form 
of the chromatophores. But the form of the chroma- 
tophores varies in the different species of Microspora 
(cfr Hazen 1.’ c. t. 24 f. 1 and 13), and, if the 
single chlorophyllplates of Trihonema be chained toge¬ 
ther (cfr Hazen 1. c.’ t. 25 f. 5), there will not be 
a very great difference from some forms at Micro¬ 
spora (cfr Hazen 1. c. t. 21 f. 1). A comparison 
of . the figures of Hormiscia and Trihonema D. et^S. 
and of Microspora Thur et could not give any good 
reason for separation of the species in two different 
genera. Therefore later authors had kept them to¬ 
gether until Lagerheim separated them in two genera 
upon other characters. He kept the names Microspora 
and Conferva. 
Lager heim, probably, did not abandon the name 
('onferva^ because he had followed its historical evo- 
