40 



S. O. MAST AND F. M. ROOT 



During the following hour this same phenomenon was seen to 

 occur in three other amebae; two of the infusoria captured were 

 paramecia and the other was a stylonychia. All of these were 

 observed in the same watch-glass. At this time I hurriedly ex- 

 amined the entire bottom with a binocular and found over 

 twenty half paramecia. Since there were no other organisms 

 present that feed on paramecia, it seems evident that all of those 

 referred to above had been cut in two by amebae. The following 



Fig. 5 Free-hand sketches made by the iunior author, showing an ameba 

 capturing and cutting a Paramecium in two; p, Paramecium; a, b, c, ameba. 



daj^ this phenomenon was seen in two more cases, the prey being 

 paramecia in both. 



A year after these observations were made, one of our students, 

 Mr. H. S. Willis, in connection with a member of the course in 

 biology, made similar observations, but only in a single case. 

 The ciliate captured in this case was not identified, but judging 

 from the sketches and the description made at the time of obser- 

 vation, it probably was one of the hypotricha. The specimen 

 w^as killed for preservation before the process was complete, the 

 victim being not quite cut in two. In this condition it was seen 



