GENERAL ZOOLOGY 



Fig. 8.21. Paramecium: locomotion, feeding, and the avoiding reaction. A, the spiral, rotat- 

 ing path described in swimming freely; the stippled cones represent the areas from which food 

 particles are drawn into the oral groove. B, behavior of an individual encountering an obstacle; 

 six successive positions. (Adapted from H. S. Jennings, The Behavior of the Lower Organisms, 

 copyright 1906 by Columbia University Press, printed by permission.) 



its long axis; an aboral swerving motion of the anterior end, in combination 

 with progression and rotation, causes the animal to describe a spiral course 

 instead of simply spinning like a rifle bullet (Fig. 8.21). 



Paramecium generally reacts to stimuli by movement; therefore, variations 

 of the locomotor patterns constitute its characteristic behavior. For example, 

 its reaction to strong chemical stimulation involves swimming backward in a 



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