The Behavior of Loxophyllutii 403 



water, but when in a state of unusual excitement it may do so 

 quite readily. It swims in a spiral course like most infusoria, 

 circling about in a clockwise manner and at the same time rotat- 

 ing on its long axis in the same direction. The spiral course is 

 maintained not so much through the natural asymmetry of the 

 body, as by the fact that the body is curved toward the inner side 

 of the spiral and held at a slight twist. By means of its spiral 

 movement Loxophyllum is able to travel in a nearly straight gen- 

 eral course for a considerable distance. 



REACTIONS TO STIMULI 



Mechanical. In experimenting on the reactions of Loxophyl- 

 lum to mechanical stimuli a glass rod was used which was drawn 

 out into an exceedingly fine thread at the tip. By using a Braus- 

 Driiner binocular microscope it was possible to apply stimuli of 

 various degrees of intensity to any part of the body and readily 

 observe the result. When the anterior part of the body is stimu- 

 lated the animal contracts longitudmally, swims backward and 

 to the oral side, and bends its body orally at the same time. After 

 this it extends the body again and swims forward. Stimuli applied 

 to the tip of the body most readily produce this reaction. It may 

 be produced even without contact by moving the rod about a short 

 distance in front of the anterior end. 



Stimulating either side of the body back to a considerable dis- 

 tance produces the same reaction. It is obvious, therefore, that 

 when the animal is stimulated on the oral side it turns directly 

 toward the stimulus instead of away from it. Repeated appli- 

 cations of the stimulus to the oral side will cause the animal to 

 keep turning toward the stimulus, notwithstanding the unadaptive, 

 or even mjurious, nature of the response. 



The facility with which a stimulus evokes a response diminishes 

 toward the posterior end of the body. Stimuli applied between 

 the middle of the body and the posterior third, especially after 

 the second or third trial, frequently produce no response, even 

 when quite strong. The animal may often be poked about in 

 this way, almost to the point of producing mutilation, without 

 suffering any interruption of its usual activities. 



