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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 e^-er 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 flltrae was found to 

 contain 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. 



iMr. Homer Glenn Fisher died in Oct., 1917. He 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. 



