m t f c m . ■ Ì
A .
B .
C .
P la t e CCLI. A.
OSCILLATORIA NIGRO-VIRIDIS, Tim.n.s.
Ge n . Ch a e . Filaments lying in a mucous matrix, rigid, simple, vividly
oscillating. Tale continuous. Fkdochrome annulated with more or
less close, parallel, transverse striæ. Oseillatona (Vauoher),—from the
motion observed in the filaments.
Osoillatoeia nigro-viridis ; stratum of a very dark olive-green colour ;
filaments delicate, pale green, rigid, with obtuse, curved apices ; striæ
inconspicuous, distant about half a diameter of the filament ; e?ido-
chrome very slightly granulose.
H ab. In a brackish ditch a t Shirehampton near Bristol. A u g . 1 8 4 7 ,
G. E . K . Thwaites.
D esce. Stratum thin, of a dark olive green, almost black colour, growing upon
the mud and subsequently floating in large masses. Mlaments of a pale
dull gi-een colour, with obtuse, distinctly curved, scarcely attenuated apices.
Striæ not conspicuous, distant from each other about half a diameter of the
filament. Endochrome scarcely granulose.
This species, which I have met with only once, bears some resemblance,
as has been remarked to me by the Rev. M. J. Berkeley,
to Oscillaria uncinata, of Kützing, but the latter is a smaller species
than ours, and has the striæ of its filaments more distinctly
marked. Thw.
P la t e CCLI. B.
OsciLLATORiA subuUformis ; stratum of a n in te n s e æ ru g in o u s g re en
colour ; filaments b rig h t gre en, su b u lifo rm ; s tr ia inconspicuous,
d is ta n t from one h a lf to tlire e q u a rte rs o f a d iam e ter of th e filament ;
endochrome n o t evidently g ranulose.
H ab. In brackish ditches, at Shirehampton near Bristol, during the
Summer and Autumn, not uncommon. G. E . K . Thwaites.
D esc e . Stratum thin, growing upon the mud, subsequently floating, appearing
black in the water, but when taken out, of a beautiful deep blue-green colour.
Eilammts very delicate, bright green, gradually attenuated towards the apices,
which are subacute and much curved. Striæ inconspicuous, distant from
each other about three-foui'ths of a diameter of the filament. Endochrome
uniform, not visibly granulose.
VOL. I I I .
W.H.K.deL.ct Jitlu . Ì i ,R