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PROCEEDINGS OF THE AMERICAN ACADEMY. 



circus movements by stimulating only one eye. In order to obtain 

 such unilateral stimulation, a flap was fastened in the leather suit used 



TABLE VII. 



Photic Reactions of Toads Stimulated through the 

 Eyes alone. 



in previous experiments so that it could be made to cover either eye. 

 The individuals were placed so that they faced the light with only the 

 area about the uncovered eye illuminated. Under these circumstances 

 seventy per cent of the movements (Table VIII.) were not toward the 

 light but toward the side bearing the uncovered eye. These reac- 



TABLE VIII. 



Photic Reactions of Two Toads Facing toward the Light 

 and Stimulated through only one Eye. 



tions are what might be expected from a positively phototropic species 

 like the toad, as similar responses have been observed in many other 

 animals. For example, circus movements have been noted in several 

 arthropods after one eye had been blackened over or excised, by 

 Holmes (:01, :05), Parker (:03 a ), and Radl ( ; 03). No observations 



