REACTIONS OF CRAYFISHES. 



193 



n I I i 3U 



C. diogenes 

 Kxpt. 42 



' 



CHART II. Showing reaction of the crayfishes to gradients of carbon dioxide 

 and acetic and hydrochloric acids. The horizontal distance represents the length 

 of tank. The vertical distance represents time in minutes. Different tracings 

 represent individual animals. In all experiments except experiments and controls 

 27 and 47 each animal was tested separately, 20 minutes each. 



