1894. ] A Blue-Green Motile Cell. 97 
with considerable interest that the writer undertook the study 
of the form which he had found whose non-motile state so 
closely resembled Polycystis pallida. 
Motile stage. 
The motile cells were to be found at all times in small 
numbers. There was no time of day when they appeared in 
‘quantities, as is the habit of zoospores of members of the 
Chlorophycee, although they exhibited the same phenomena 
of collecting on the sides of the vessel nearest the light. When 
confined in a Van Tieghem cell they swarm about for a day 
or two, finally coming to rest at the edge of the drop of wa- 
ter 
The cells (plate x1, fig. 1) are broadly elliptical in outline, 
from 8-10 long and 5-6 wide. One end is slighly truncate 
in shape and contains a slight depression into which the pair 
of cilia are inserted. The cilia are not the same length, the 
longer being about as long as the cell is wide and the other 
somewhat shorter. They are so placed, and the figure illus- 
trates this point, that the longest cilium is nearest to the 
longest axis of the cell. 
Inside the cell are from six to ten disc-shaped bodies ar- 
ranged around the periphery of the cell. These bodies are 
seen chromatophores, although the blue-green tint is not al- 
bk confined to them. Sometimes the blue-green color 
the S to fill almost the entire cell, only the end which bears 
Cilia being hyaline. 
olen the middle of the cell on the periphery are one or 
Ways ‘ie bright red pigment spots: when two they are al- 
eacare near together, sometimes almost touching. The 
seem ae two Pigment spots in one individual did not 
‘aches, ‘cate that conjugation had taken place, for such 
Was S were not necessarily larger in size and no specimen 
t ver observed with four cilia. 
ually i ele end of the cell from the cilia there is us- 
the slate, ound a light colored area that probably marks 
Present ; we of the nucleus, which was demonstrated to be 
in the non-motile cells. 
