^^^•^] Gee: Behavior of Leeches 269 



vigor of response, but this is obviously a character not easily 

 capable of quantitative determination. Following this stage of 

 activity, in which the stimulus immediately made the animal 

 vigorously active, and in which responsiveness continued for 

 much longer swimming periods, was one of a somewhat slow 

 decrease, resembling the increase in its successive gradations. 

 This decrease is more marked from the point of view of vigor 

 than of duration of response, since, as will be observed from 

 the accompanying record (see table VII), progressive movement 

 had practically ceased long before the stage at which wigwag 

 movements had become so diminished in character as not to push 

 the animal at least a slight distance forward in the water. When 

 the animal reached such a stage of depression as the results of 

 the movements evoked by the application of the stimulus, the 

 experiment was discontinued. In the individual whose curve of 



TABLE VII 



Duration in Seconds of Swimming Response in Fatigue Produced in 



Bina microstoma by Repeated Contact Stimulation 



