88 PARKER— A CRITICAL SURVEY OF 



of a special muscle on the abdominal organs and particularly on 

 the air-bladder. The females not only do not drum, but they do 

 not possess the drumming muscle. This condition of high special- 

 ization, which is doubtless connected with the breeding habits of 

 Cynoscion, is common to many of the sound-producing fishes and 

 makes it impossible to agree with Korner (1905, p. 103) in dismiss- 

 ing all such cases as of accidental nature. Though it is possible 

 that fishes produce sounds that are in some way serviceable to them 

 but that they themselves do not hear, it is very unlikely that such is 

 the case and the occurrence of instances of unisexual sound produc- 

 tion, as in Cynoscion, strongly suggests the presence of the sense of 

 hearing rather than the reverse. 



It is reasonable to suppose that if fishes hear, they will show 

 some form of response to sounds. If it could be demonstrated that 

 no fish responds to sounds of any kinds, it would be highly improb- 

 ably that fishes heard. Several investigators have thus tested fishes 

 and, without reference to skin or ear, they have attempted to ascer- 

 tain whether in fact fishes respond to sounds at all. Such inves- 

 tigations are fundamentally important for the problem at hand but, 

 as already explained, they do not allow of a discrimination between 

 touch and hearing. Bateson (1890, p. 251) noticed that to the 

 vibrations from blasting pouting scattered, sole, plaice, and turbots 

 buried themselves, and congers drew back a few inches. To a blow 

 on the aquarium wall pollack made an obvious response. Kreidl 

 (1896, p. 585) stated that Salmo iridcns was stimulated by the vibra- 

 tion from the human footfall. Zenneck (1903) found that Lcucis- 

 cus rutiliis, L. dohula, and Albiirntis liicidus swam away from an 

 electrically driven bell immersed in a stream. Parker (1903a, p. 

 62) showed that mackerel (Scomber scombnis) and menhaden 

 (Brcvoortia tyrannus) responded to the vibration of a cord applied 

 to an aquarium. Lafite-Dupont (1907) found that, except for two 

 elasmobranchs (la Roussette, la Torpille), the other fishes tested (le 

 Grondin papillon, la Vieille, le Mulct, la Sole) were responsive to 

 a stroke on the side of the containing vessel. Parker (1912) found 

 that certain fishes, Tautoga, Stenotomus, Menticirrhus and Sphc- 

 roides, avoided the end of an aquarium at which blows were deliv- 

 ered by a swinging pendulum, that Prionottis gathered near this 



