FRESHWATER PLANKTON ALGA3 FROM CEYLON 
167 
Crucigenia Morren. 
C. rectangularis (A. Br.) Gray. In groups of four cells or 
occasionally in twos, or more or less displaced and irregular loose 
syncoenobia. Cells 3-5 g x 4 5-5 g. Loc. 13, 37. Distr. Eur., 
N. & S. Amer. 
C. quad rata Morren. Probably Crucigenia triangularis Cliod. 
should be included in this ; certainly some of the younger colonies 
approached the description of this species (cf. Pascher’s Siisswasserfh). 
Log. 49. Distr. Europe. 
C. triangularis Ohod. A few specimens showing triangular 
cells are conveniently recorded under this name. Loc. IS. Distr. 
Europe. 
Tetrastrum Chod. 
T. multisetum (Sclmiidle) Chod. In the older colonies the cells 
reached a diameter of 5-6 g. Log. 12. Distr. Eur., N. Amer. 
Kirciineriella Schmidle. 
K. lunaris (Kirchn.) Moeb. Distinguished from the very similar 
Selenastrum Dibraianum Iteinscli by its mucous coat, and from other 
species by the form of its cells. K. obesa W. West is reported from 
tropical Africa but not K. lunaris. Loc. 8 , 11, 27, 56. Distr. 
Mostly Europe, Ceylon. 
Ankistrodesmus Corda. 
A. falcatus (Corda) Ralfs. Loc. 2, 8, 9, 12, 18, 26, 29, 49,56. 
Distr. General (inch Ceylon). 
A. setigerus (Schroder) G. S. West. Loc. 12, 25, 60. Distr. 
General. 
Golenkinia Chod. 
G. radiata Chod. Loc. 4, 12. Distr. Temperate. 
Ccelastrum Naeg. 
The two species recorded by W. & G. S. West were not found. 
C. microporum Naeg. Loc. 8, 18, 41, 50, 56. Distr. Eur., 
N. Amer., Ceylon (f. irrcgulare Fritsch from S. Orkneys). 
C. retioulatum (Dang.) Senn. Loc. 2, 4, 6, 9, 14, 27, 56. 
Distr. Chiefly tropical. 
C. proboscideum Boldin. Loc. 6, 9. Distr. N. Temperate. 
B. AKONTiE. 
Zygnemales. 
Zygnemaceae. 
Species of Spirogyra and Mougeotia occurred in a very large 
number of the samples. In these cases we were dealing with detached 
filaments which were in a sterile condition and hence could not be 
identified. 
