120 
it follows that Nageli probably had united hetero¬ 
geneous species in his genus, and that consequently 
the diagnosis in Kützing’s Spec. Alg. had become 
so wrong, that later botanists could not with any 
certainty identify Herx:)Osteiron with Aphanochcete. 
On the value of original specimens cfr La Nuova 
Notarisia 1891 p. 449—454! Cfr also the figures 
of Gongrosira Sclerococcus in Kützing's Phycol. ge¬ 
neral. t. 17. 
3. Tribonema or Conferva? 
Both Thuret and Derbes et Solier participated 
in the same prize competition of the Acad, de Scienc. 
and Thuret published an abstract of his paper in Ann. 
d. scienc. nat. 1850—51. The diagnose of his new 
genus Microspora runs so 1. c. p. 12: ”Je crois devoir 
former ce genre pour quelques Conferves d’eau douce, 
à filaments simples, dans les l’émission des zoospores 
s’effectue au moyen d’une dislocation particulière du 
tube. Les cellules semblent pour ainsi dire se déboiter, 
et le tube se sépare en autant de fragments qu’il 
y avait d’articles”. About the species he says: ”Le 
type de ce genre est le Conferva floccosa^ A g. {Micro¬ 
spora floccosa^ Nob.), Algue remarquable par la dispo¬ 
sition carrée qu’affecte l’endochrome”. — — — ”une 
troisième espèce, dans laquelle la chromule est dispo¬ 
sée en petites masses sphériques, ce que donne aux 
filaments l’apparence de chapelets. Le Conferva hom- 
hycina^ Ag. doit vraisemblalement rentrer dans ce 
genre”. — — Consequently the form of the Chroma¬ 
tophor es was not a generic character for Thuret. 
Notwithstanding this, Hazen insists upon the 
contrary 1. c. p. 168: ”Thuret separated this genus 
from Conferva on account of the squared appearance 
of the chromatophore” — —. 
