42 THE AMERICAN MONTHLY [Feb 



Polyzoan was alive in my tank and apparently doing well. 

 The large Protista on the stone was also doing well and 

 spread out finely on the upper side of the stone. ' 



On the 24th of September, I made further notes. This 

 morning on examining one of the very fine portions of 

 the Protista, I found it to have playing around it, con- 

 fined mostly to the broad expansions and outer margin, 

 numerous oval active apparently ciliated animalcules. 

 They are colorless and have numerous stomachs which are 

 spherical. They are very active and seem to be feeding 

 upon the Protista. I can find nothing to correspond with 

 the active little fellows in the books. I found one in- 

 closed in a mass of the Protista, so, if they were some of 

 them feeding upon the Protista, he was punishing one of 

 them for so doing. The oval creatures seemed to be en- 

 cysted for there was a clear oval space around him which 

 was always maintained distinct during the circulation of 

 the Protista's granules. Inside of this endochrome the 

 oval creature was very active, turning over and over,tirst 

 this way and then that but seemingly not attempting to 

 escape and not being digested. I thought this the mode 

 in which perhaps the Protista took its food if it were 

 omniverous. Such would seem to be the case, as it cer- 

 tainly fed on diatomacege. This, I have several times seen 

 and it is shown by the diatoms passing up and down with 

 its current of granules. The excreted empty silicioug 

 pustules it leaves behind on its journey show this also. 

 It fed thus encysting it and constructing a temporary 

 stomach for each new morsel. I continued to watch this 

 particular case for nearly an hour. The vacuoles in the 

 oval creature appeared greenish but this may have been 

 due to refraction. After a while the Protista receded 

 from the position it held. This retrograde movement was 

 not accomplished after the same manner as the forward 

 one. Tills is by a constant bulging out in all directions 

 and the formation of lobulated expansions. Thereafter 



