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this. That they are flagellates can only be made out with an oil immersion 
lens. In many of the specimens the intestine was gorged with the flagel- 
lates and in no case have I ever found them absent. In living material the 
typical flagellate movement can be discerned. _ 
The possibility has been suggested that the observed phenomena was only 
a Brownian movement, but upon staining enough organization can be made 
out to show clearly that the animal is a flagellate. Some individuals can 
be seen dividing. The unformity of the shape of the individuals also shows 
them to be living organisms, as it is not likely that powdered particles in 
suspension would be of a uniform pear shape. As a further evidence that 
the bodies were alive I ran some Flemming’s fixing solution under the cover 
glass and as soon as it reached the animal they immediately ceased all 
movement. 
It was also suggested that these might only be parasitic in the intestine of 
the daphnid, but it was observed that they were found almost exclusively in 
the anterior end of the intestine. However, the material from the anal 
end of the intestine showed a few, but it seems that even these might have 
been forced to their position by the movement of the water around the body 
of the daphnid at the time it was crushed. 
I also strained a large quantity of lake water through a silk net and then 
filtered it through filter paper. Upon examination this filtrae was found to 
coutain the same flagellates. This demonstrated that they were living in the 
same water with the daphnids. 
Since no other organized material was found in the intestine of the three 
species of cladocera and since their occurrence is constant, it seems reason- 
able to conclude that they form the food of the animal. While the number 
of individuals is not large, I believe that the times and conditions of col- 
lection of material are diverse enough to mean more than a much larger 
number of individuals collected at the same place during a single season. 
aMr. Homer Glenn Fisher died in Oct., 1917. Ile had hoped to be able to extend 
these studies before publishing. He had submitted this preliminary summary which 
is published with no substantial change.—-Will Scott. 
