Thr Behavior of Loxophvlhiiu 407 



lated, and this would naturally produce a backward movement. 

 The second response is like that of the normal animal when irri- 

 tated at the posterior end. When the piece was swimming through 

 the water stimulation of the posterior end frequently resulted in a 

 marked acceleration of its speed. 



The righting movements of the anterior piece were much like 

 those of the entire animal. Generally the oral margin would be 

 raised up and waved rapidly back and forth, a movement which 

 probably causes the oral side to be elevated until the piece topples 

 over upon its right side. Considerable variation occurs in the 

 method of turning over in the pieces as in the whole organism. 



In another experiment in which attention was paid mainly to 

 the movements of the posterior piece a Loxophyllum was cut in 

 two near the middle. The posterior piece swam backward quite 

 rapidly for about three minutes. After this its movements became 

 slower and it would swim forward occasionally. In a few min- 

 utes the forward movements began to increase, and after a while 

 the infusorian settled down to moving forward and backward to 

 about its own length. Sometimes it would raise itself from the 

 bottom and tumble over on the other side only to quickly turn 

 again into its normal position. At one time it left the bottom and 

 swam in a spiral course for a considerable distance. 



When moving backward the piece would widen out, especially 

 at the anterior end. When moving forward, on the other hand, 

 the piece would become elongated and strongly drawn together 

 at the anterior end. These changes of shape were invariably 

 associated with the different directions of movement. 



Stimulation of the posterior end of the piece causes it to pinch 

 together in front, elongate, and swim forward. When the anterior 

 cut end is stimulated the piece spreads out and swims backward. 

 Comparatively strong stimuli are required, however, in this case 

 as the cut end is considerably less sensitive than other regions of the 

 body. By stimulating either end of the piece it may be caused 

 to swim continually forward or backward as the case may be. 



In about thirty minutes after the cut was made the regeneration 

 of the anterior end of the piece was well under way. The slight 

 waving motions of the anterior border were visible, but not so 



