158 ANNALS NEW YORK ACADEMY OF SCIENCES 



one-third of the distance from the posterior end (fig. 5 A) while in others it 

 is less than one-sixth of the distance (fig. 5B). Indeed, in the large number 

 of specimens examined, no two were found to be alike. Whether the vari- 

 ation is accompanied by any change in function, I was unable to determine. 



Sound Production in the Dnimfishes. 

 Recorded Observations and Theories. 



It has been noticed by many fishermen that the common squeteague 

 at times makes a very plain and unmistakable drumming noise. As to 

 how this noise is produced they can give no explanation nor is there any 

 account of it in scientific literature, with the possible exception of Dufoss6's 

 memoirs, which seem to be too little known at the present time. Their 

 observations do not tell us whether it is the male^, female, or both that 

 produce this characteristic noise. In the anatomical discussion, it was 

 found that only the male was supplied with the red drumming muscle 

 which, from its relation to the air-bladder, was considered to be connected 

 functionally with the latter organ. Further observations demonstrated 

 that the drumming occurred only in those animals in which this red muscle 

 was present — that is, in the male squeteague. In some other species, 

 as Micropogon undulatus, drumming occurs in both male and female, aid 

 likewise the m. sonifici are present in both sexes. 



In the rather limited amount of study that has been given to the noises 

 produced by these fishes, some of the conclusions are mere deductions 

 from anatomical data, without any experimental or physiological proof. 

 In other instances, the authors confuse the sounds produced by fishes of 

 entirely different orders, and which have swim-bladders both anatomic- 

 ally and pliysiologically different. For this reason it is very difficult to de- 

 duce correct conclusions from their writings. 



As noted in a previous paper, Aristotle spoke of fishes that produce 

 sound by some mechanism involving their air-bladder. The fact was thus 

 known to fishermen and scientists very early; but no scientific explanations 

 were offered nor were any experiments made which would account for 

 these noises. Cuvier (1834) writes that "these fishes [scisenoids] swim in 

 a troop and send forth a bellowing louder than that of the gurnards, and 



' Since the above was written Dr. H. M. Smith has published the results of some obser\-a- 

 tions, which show that both male and female of Micropogon make the drumming sound and 

 that the male only in Pogonias, Sciwnops, Cynoscion, Leiostomiis and Bairdiella produce the 

 drumming sound. (Science, vol. 22, 1905, p. 376.) 



