142 
THE JOURNAL OF BOTANY 
convenient to retain it for filaments 1—1*5 /.i in width with septa 
scarcely visible and no obvious sheath. Moreover, in those recorded 
here a more or less yellowish colour was retained, and in the speci¬ 
mens from Mancadawewa distinctly blue-green concave cells were 
seen. They are mostly from the heleoplankton. Loc. 1 , 26, 30 (water- 
bloom), 36 (water-bloom), 41, 47. Distr. Cosmopolitan. 
Oscillatorian filaments of bacterial size were also met with in 
loc. 13, 42, 43. These were either thread bacteria or bleached fila¬ 
ments of species of Oscillatoria. 
Beggiatoa Trev. 
B. alba (Vaucher) Trev. Loc. 24. Distr. Cosmopolitan. 
PlIORMIDIUM Kuetz. 
The following were met with as detached trichomes; in the 
absence of the colony the determinations cannot be regarded as 
certain :— 
P. Retzii (Ag.) Gomont. Tycholimnetic. Loc. 32. Distr. 
General (except Africa). 
P. luridum (Kuetz) Gomont. Tycholimnetic. Loc. 50. Distr. 
Eur., N. Amer., W. Indies, Ceylon. 
Lyngbya C. Ag. 
L. Kutzingii Schmidle. Attached to portions of filamentous 
Algae etc. Loc. 51, 52. Distr. Eur., N. Amer., Africa. 
Yar. distinct a (Nordst) Lemm. A variable form. The sheath of 
Ceylon specimens did not stain with Chlor-zinc-iodide. Slightly 
capitate. Loc. 9. Distr. Europe. 
L. contorta Lemm. A typical plankton species. In spider¬ 
like masses. Loc. 5. Distr. Eur., Afr., Ceylon. 
L. futealis Montague. The typical form. Sheath stains with 
Chlor-zinc-iodide. Loc. 53. Distr. Eur., Centr. Amer. 
L. major Menegh. Tycholimnetic. This forms an important 
constituent of bluish-black scum in littoral and other regions. Sheath 
does not stain with Chlor-zinc-iodide. Loc. 9, 16. Distr. Eur., 
N. and S. Amer., S. Afr., Ceylon. 
L. lutea (Ag.) Gomont. Tycholimnetic. In floating masses. 
The t} T pical form, sheaths staining with Chlor-zinc-iodide. Loc. 9. 
Distr. Eur., N. Amer., W. Indies. 
L. majuscula (Dillwyn) Harvey? A marine form. Trichomes 
30 fi diam.; segments 3 fi in length. There was a rich glycogen 
content in some of the filaments. Loc. 7. Distr. Mostly Europe. 
Nostocaceae. 
Anabjena Borv. 
t 
The Nostocacese are chiefly represented by this genus, which was 
abundant or at least frequent, although never sufficient to form 
appreciable water-bloom. At the time of collection the vast majority 
of the specimens possessed no trace of spores, and some were even 
without heterocysts, so that in the majority of cases identification 
