SOUND AS A DIRECTING INFLUENCE IN MOVEMENTS OF FISHES. 



Id 



In this table are recorded the reactions of 25 fishes in lots of 5 each. Each lot 

 was subjected to 50 individual stimuli from the concussion of the iron ball against 

 the end of the tank, and after each blow the number of indi\aduals in the half of the 

 tank next the sound center was recorded. The addition of these 50 records in the first 

 lot of fishes (1-5) when the blows were delivered at what may be called the west end 

 of the tank was 83; when the blows were delivered at the east end it was 80. Had 

 all the fishes remained all the time in the half of the tank next the sound center, these 

 records would have been 250 each. It is, therefore, quite clear that in both instances 

 the fishes avoided to a considerable degree the half of the tank next the sound center, 

 and this same feature, of course, appears when these records are added together. The 

 same is true for the other four lots of fishes (6-10, 11-15, 16-20, and 21-25), and the 

 grand total shows that out of a possible 2,500 records only 842, or rather less than 34 

 per cent, were from the half of the tank next the sound center. Had the fishes been 

 indifferent to the direction of the sound, we should have expected 50 per cent of the 

 records to have been from the half of the tank next the sound center and the same 

 proportion from the other half; had they been attracted by the sound, the record 

 would have been something over 50 per cent for the region next the sound center; as 

 it was, they have shown themselves as distinctly repelled by the sound, in that in only 

 about 34 per cent of the total number of possible records were they in the half of the 

 tank nearer the sound center. It is quite clear from these records, then, that Tautoga 

 onitis tends to swim away from a sound center. 



The same condition as that seen in Tautoga, though a little less pronounced, is to 

 be observed in the scup (Sienoiomus chrysops), as table 11 shows. 



Table; II.— Directive Responses op Stenotomus chrysops to Sound. 



The grand total of occurrences in a possible 2,500 in the half of the tank nearer 

 the sound was 890, or 36 per cent. In Stenotomus, though the individuals avoided 

 the sound center in a well-marked way, they were found somewhat more frequently (36 

 per cent) near the center than were the tautogs (34 per cent). 



Young kingfishes (Menticirrhns saxatilis), as table iii shows, also avoided the 

 region of the sound center, though they were found there somewhat more frequently 

 (39 per cent) than Stenotomus (36 per cent). 



