244 VICTOR E. SHELFORD AND W. C. ALLEE 



avoidance did not begin until the fishes Jiad tried the boiled 

 water about twenty-five times during the first twenty-five min- 

 utes. In the Hybopsis experiments the fishes began to turn 

 back after about fifteen trials of the boiled water during the 

 first ten minutes. The testing or backing-starting reaction was 

 given when the boiled water was encountered and while the 

 fishes were turning back. The experimental fishes began rising 

 to the surface and taking the surface film for respiration at about 

 the time the turnings at the center became frequent. In spite 

 of the marked difference in reflexes, et cetera Ameiurus reacts 

 similarly, as shown in experiment 4, table 11. The control fishes 

 went back and forth quite symmetrically, turning at the center 

 when going in either direction and showing no marked preference 

 for either end. The experimental fishes reacted to boiled. water 

 by showing a time preference for the tap water, by vigorous 

 opercular movements, and by gaping and rising to the surface. 

 There were no turnings back from the boiled water and the two 

 from the tap water are due to the fact that the fishes thus turn- 

 ing were swimming at the surface of the water and encountered 

 the center drain. 



The behavior of Abramis (experiments 1 and 1 B, table 11) 

 was in some respects similar to that of Notropis. The control 

 behavior was very similar, being simple symmetrical back-and- 

 forth movements in both cases. The behavior of Abramis in the 

 experiment was however different, in that the fishes rarely 

 turned back more often from one-half than the other but estab- 

 lished an apparent preference for one end and did not move 

 out of it. 



Ambloplites is the most pecuUar of the swimming fishes which 

 we have studied. In experiment 2 (table 11) the control graph 

 would make a good experimental graph for most of the fishes. 

 In this case the fishes acquired an apparent preference for the 

 end of the control corresponding to the tap water of the experi- 

 ment and turned back eight times from the half corresponding 

 to the boiled water. In the case of the experimental fishes, on 

 the other hand, two of the three moved into the boiled water 

 when they were put into the center at the beginning of the experi- 



