Ser. CHLOROSPERMES. Fam. Oscillatoriee. 
Puate CCLI. 2. 
OSCILLATORIA NIGRO-VIRIDIS, Zw. x. s. 
Gen. Cuar. Filaments ae in a mucous matrix, rigid, simple, vividly 
oscillating. Zube continuous.  Lndochrome annulated with more or 
less close, parallel, transverse stiize. Osci//atoria (Vaucher),—from the 
motion observed in the filaments. 
OscILLATORIA xigro-viridis ; stratum of a very dark olive-green colour ; 
Jilaments delicate, pale green, rigid, with obtuse, curved apices ; striae 
inconspicuous, distant about half a diameter of the filament; exdo- 
chrome very slightly granulose. 
Has. In a brackish ditch at Slirehampton near Bristol. Aug. 1847, 
G. H. K. Thwaites. 
Descr. Stratum thin, of a dark olive green, almost black colour, growing upon 
the mud and subsequently floating in large masses. Filaments of a pale 
dull green colour, with obtuse, distinctly curved, scarcely attenuated apices. 
Stri@ not conspicuous, distant from each other about half a diameter of the 
filament. Hndochrome scarcely granulose. 
eee nnn 
This species, which I have met with only once, bears some re- 
semblance, as has been remarked to me by the Rev. M. J. Berkeley, 
to Oscillaria uncinata, of Kiatzing, but the latter is a smaller species 
than ours, and has the striz of its filaments more distinctly 
marked. Zhw 
Puate CCLI. B. 
OscitiatorIa subuliformis ; stratum of an intense eruginous green 
colour; filaments bright green, subuliform; série inconspicuous, 
distant from one half to three quarters of a diameter of the filament ; 
endochrome not evidently granulose. 
Has. In brackish ditches, at Shirehampton near Bristol, during the 
Summer and Autumn, not uncommon. G. H. K. Thwaites. 
Descr. Stratum thin, growing upon the mud, subsequently floating, appearing 
black in the water, but when taken out, of a beautiful deep blue-green colour. 
Filaments very delicate, bright green, gradually attenuated towards the apices, 
which are subacute and much curved. Série inconspicuous, distant from 
each other about three-fourths of a diameter of the filament. Lndochrome 
uniform, not visibly granulose. 
RAARAARAAAARAAAAAAAA AA An anne 
VOL. III. BE 
