208 
G. dermochroa, Näg. Hinz. Alg., 51. On wet stones amongst 
other blue-green Algae, Victoria regia house, September, 1902. 
New for the British Isles 
G. violacea, Rabenh. Aly. Eur., ii., 41. Forming a greyish-violet 
incrustation on rocks in palm house, September, 1902. New for 
the British Isles. 
Aphanocapsa, Näg., 1849. 
A. virescens (Hass.), Rabh. Alg. Eur., ii., 48. On walls, &c., in 
pits, February-September, 1902 sete diteémingisd with other 
blue-green forms 
A. rivularis (Carm.), Rabh. loc. cit., 49. Amongst other blue- 
green Algae on wet stones in the Victori ia regia house, September, 
1902. 
Microcystis, Kitz., 1833. 
M. protogenita (Bias.), Rabh. Alg., ii., 51. oe with 
other blue-green Algae on walls of palm and Aroid (No. 1) houses, 
March, 1902; plankton of pond, September, 1902; plankton of 
Thames, August, 1902. 
M. marginata (Meneg.), Kirch. Alg. Schl., 255. Laboratory 
vank and lake, amongst filamentous Algae, 1902; amongst other 
blue-gree en Algae on n wet stones in Victoria oe house, September, 
1902 ; plankton of Thames, August, 
Clathrocystis, Henfrey, 1856. 
C. aeruginosa, Henf. Micr. Journ., 1856, 53, t. 4, f. 28-36. 
Plankion of pond, dead, April, 1902 (Chodat 4), September, 1902 
(mihi !) ; plankton of Thames, August, 1902. In this season never 
observed in any considerable quantity. 
oan apii: Näg., 1849. 
tzingianum, Nig. Hinz. Alg., 94, t. le. Plankton of lake, 
Apri il, 1902 (Chodat aa common throughout the sammer in 
plankton of lake, pond, & 
Merismopedia, Meyen, 1839. 
` M. violacea, Kütz. Spec., 472. Amongst other Algae in Victoria 
regia tank, June, 1902. 
M. glauca, Näg. Hinz. Alg., 55, t. 1, D., f. 1. Lake, pond, water- 
lily pond, May-September, 1902 ; not uncommon 
Tetrapedia, Reinsch, 1867. 
T. setigera, Archer in Grevillea, i., 46, t. 2, f. 14-17. Isolated 
amongst Cladophora i in lake, September, 1902. 
Dactylococcopsis, Hansg. 
D. raphidioides, Hansg. Prod. Alg. Böhm., ii., 139. Forma 
furcatum, nov. form. One of the pointed ends of the S-shaped 
cells often ends in two short points; chief tank of water-lily 
house, September, 1902. Species not yet described for England, 
