THE SENSE OF HEARING IN FISHES. 89 



source of sound, and that Fiinduliis, though much disturbed by the 

 sound, tended to go neither toward the source nor away from it. 

 These positive results show that many fishes respond to noises or 

 even tones, but they do not throw Hght on the question of the par- 

 ticular sense organ concerned and consequently it cannot be stated 

 whether they are due to stimulation of the ears or of the integu- 

 mentary sense organs or of both. 



As opposed to this line of evidence several investigators have re- 

 ported lists of fishes that are said not to respond to sounds in any 

 way. As already noted in an earlier part of this paper, Korner 

 (1905) recorded twenty-five kinds of fishes none of which re- 

 sponded to the sounds from a " cri-cri." This is certainly a for- 

 midable list. When Korner learned through the work of Maier 

 (1909, p. 394) and of Haempel (1911, p. 325) that Aminrus reacted 

 to a whistle blown in the air as well as to sounds from a submerged 

 electric bell, he undertook to test this fish with a variety of whistles, 

 the human voice, and other sound-producing devices including the 

 "cri-cri." His results were completely negative (Korner, 1916, pp. 

 263, 267), and he confessed his inability to explain the conflict be- 

 tween this outcome and the results of Maier and of Haempel. 

 Parker and Van Heusen (1917) have shown not only that Amiurus 

 is receptive to sounds but that, in respect to this stimulus, it is an 

 exceedingly sensitive fish. Their method of work throws some 

 light on Korner's results. When Amiurus was to be tested by them 

 for response to sound, blindfolded individuals were put into a large 

 aquarium. Here they appeared to settle themselves quickly near 

 the bottom and to assume in a short time a condition in which it 

 was reasonable to carry out tests. But in this state they seldom 

 responded to sounds and it was only after they had been some hours, 

 or better a day or so, in the aquarium that they really arrived at a 

 condition of responsiveness. After this period they began to desert 

 the bottom and to swim in the upper water, and in this state they 

 were most responsive to sound. When thus swimming near the 

 top, a blindfolded Amiurus would immediately descend to the deeper 

 water in response to a very slight finger-tap on the slate wall of the 

 aquarium. It was only under these conditions that Parker and 

 Van Heusen obtained responses to a whistle or to sounds from the 



