Cannibalism in Amoeba vespertilio 



(Penard). 



By 



Geoffrey Lapage, M.Se., M.B., 



Lecturer in Zoology, Tlie Victoria University of Manchester. 



With Plates 28, 29, and 3 Text-figures. 



1. Material and Methods. 



Towards the end of July 1920 an old hay infusion, which 

 had been made some ten years previously and had been 

 left untouched in the laboratory since then, was examined to 

 find out what organisms it still contained. Among a fairly 

 abundant fauna, which included Ciliata and some Flagellata, 

 a good supply of small amoebae was obtained from the bottom 

 deposit. 



By transferring portions of this bottom deposit to Petri dishes 

 and adding tap-water, these amoebae were cultivated. Although 

 some of the cultures failed, others throve well, especially those 

 in which the amoebae were feeding on the layer of small diatoms 

 which quickly spread over the bottom of the dish and were 

 present also in the clumps of vegetable debris. 



From time to time aquarium water and boiled hay infusion 

 were added to replace the loss of fluid by evaporation. 



The amoebae were examined on slides with and without 

 cover-glasses ; but this method was soon abandoned in favour 

 of hanging drops, made in the following way : 



A glass ring, vaselined on both surfaces, was placed upon 

 an ordinary shde. A cover-glass, upon which a drop of the 

 culture fluid from the bottom of the culture had been placed, 

 was inverted, lowered upon the glass ring and then pressed 



NO. 264 z Z 



