TIIE JOURNAL OF ROT ANY 
waters they seldom compete successfully with the Cganophycece. 
Dediastrum is ecologically by far the most important genus. Coelas- 
trum, Kirchneriella , and the Dictyospheeriecece seem also to be 
among the more important forms ; Scenedesmus is well represented ; 
Ooci/stis is apparently much less important than in the European and 
North American limnoplankton. 
Chlamydomonadales. 
Sphaerellaceae. 
SpiiiERE lla Somme rfeldt. 
S. lacustris (Girod.) Wittr. A few doubtful specimens. Loc. 9. 
Distr. Temperate. 
Yolyox L. 
Y. aureus Ehrenb. Loc. 15, 35, 44 (abundant), 56 (rare). 
Distr. Eur., Ceylon. 
Clilamydomonadaceae. 
Ciilamydomonas Ehrenb. 
This genus, which here as elsewhere does not form an important 
constituent in the plankton of the larger pieces of water, was found 
in small quantities from localities 42 and 50 and doubtfully from 
some other localities. Specific determinations were not possible with 
the material at hand. 
Pandorina Bory. 
P. morum Borv. Normal 10-celled colonies. Loc. IS. Distr. 
Eur., N. Amer., Afr. 
Eudorina Ehrenb. 
E. elegans Ehrenb. According to West it is likely that two 
distinct varieties (species?) are included under this name. The vast 
numbers of'colonies observed by West in Great Britain were per¬ 
fectly spherical without mammillate outgrowths; but Conrad (Kec. 
Inst. Bot. Brux. ix.) and Chodat (Algues vertes) record colonies of 
ellipsoidal form and possessing mammillate outgrowths towards the 
phialoporic pole : the Ceylon specimens are quite clearly of the latter 
type. It must be noted, however, that the characters in question 
are not altogether constant. A few of our specimens very closelv 
approach the spherical form, and whilst many show pronounced 
mammillae, the latter feature may in others be poorly developed and 
sometimes even absent. In view of these facts, we have hesitated to 
regard the mammillate form as a distinct species or even variety. 
Moreover, analogous variants have been recorded for Volvox , escaping 
from the oospores in spring. 
Conrad found that Eudorina elegans has a membrane structure 
and protoplasmic outgrowths as in Volvox aureus. Further investi¬ 
gations may show this and other supposed Clilamydomonadacece 
belong more strictly to the Splicerellacece {cf. Crow, “ The-Classifica¬ 
tion of some Colonial Chlamydomonads,’’ in New Phyt. xvii. p. 151). 
Loc. 9, 10, 35, 50, 58. Distr. Eur., Asia (inch Ceylon), N. Zealand, 
N. Amer. 
