AN AMICRONUCLEATE OXYTRICHA 



489 



smaller mean size than usual, there is an increase in both the 

 length and the width of the cannibals depending on the number 

 of organisms ingested. The size of cannibals after the digestion 

 of from two to six bodies is slightly greater than that of the 

 average size of typical animals from cultures. 



In the case of the cannibals which underwent fission before 

 digestion of the swallowed animals, the relatively great width 

 was maintained. While the table given above shows a small 

 increase in length and a greater increase in breadth in propor- 

 tion to the number of bodies contained, great variation has, 



Normal Oxytricha 



Oxytricha from culture in which cannibals were 



forming 



Cannibals with 1 body 



Cannibals with 2 bodies 



Cannibals with 3 bodies 



Cannibals with 4 bodies 



Cannibals with 5 bodies 



Cannibals with 6 bodies 



Cannibals with 12 bodies 



Cannibals with 15 bodies 



Cannibals before fission and after digestion of from 



two to six bodies 



AVERAGE 



LENGTH 



IN IX 



84.0 

 60.0 



84.0 

 86.4 

 86.5 

 88.5 

 96.4 

 94.0 

 114.0 

 135.0 



87.3 



AVERAGE 



WIDTH 



IN IX 



38.0 



24.0 

 43.5 

 45.4 

 54.0 

 55.5 

 55.5 

 63.0 

 66.0 

 72.0 



39.0 



nevertheless, been found, e.g., of two cannibals which had 

 swallowed one animal each, one measured 54 x 30 m, the other- 

 120 X 51 M. 



One interesting feature in the occurrence of cannibals was the 

 fact that usually when such a form was first seen it had already 

 eaten as many of its fellows as it could hold, while the greatest 

 patience was necessary to witness the process of swallowing the 

 first animal. The rapidity with which cannibals eat consider- 

 able numbers of their own species after the initial act of swal- 

 lowing seems to indicate that the ' swallowing reaction' persists 

 until it is a physical impossibility to ingest any more. Further, 



