406 FISHES 



species of gurnards are said to produce sounds, but although 

 the bladder generally has powerful external muscles the dia- 

 phragm does not seem to be always present. The John dory 

 utters similar sounds. The maigre (Sciczna aquild) has at- 

 tracted attention in all ages, especially in the Mediterranean, 

 for the loud and varied sounds it makes. The voice in this 

 case is sexual in function, and is chiefly produced in the breed- 

 ing season, when the fish are in shoals. It has been suggested 

 that the ancient Greek myth of the song of the sirens arose 

 from the sounds uttered by the maigre, but it may be doubted 

 whether human imagination required any such aid in the evolu- 

 tion of fairy tales. Another species of the same family as the 

 maigre, the "drum" (Pogonias chrontis) has a more muscular 

 air-bladder and produces louder sounds. Like the latter it is 

 an inhabitant of the tropical and subtropical parts of the Atlan- 

 tic, and its drumming is heard chiefly in the spawning season. 

 The exact mode in which sound is produced in the two 

 families to which these fishes belong (Sciaenidae and Triglidae) 

 has quite recently been successfully explained by the researches 

 of Tower in America. In the former family there is a specific 

 sound-producing muscle, the musculus sonificus, which is not 

 directly attached to the bladder but arising from the wall of the 

 abdomen on each side, passes upwards to a central tendon which 

 lies above the air-bladder ; the muscle is red in colour. The 

 muscle is thrown into a series of contractions at the rate of 

 twenty-four per second, and these throw the abdominal walls 

 and organs, but especially the air-bladder, into vibration. When 

 the bladder was removed or deflated the sound ceased but it 

 was produced again when an artificial bladder of india-rubber 

 was introduced, which proves conclusively that though the 

 sound proceeds from the bladder it is caused by the muscle and 

 that the bladder does not itself set up the vibrations. In Micro- 

 pogon the sound is produced by both sexes, in Pogonias, the 

 drum, Cynoscion, the squeteague, Leiostomus, and Bairdiclla it 

 is produced only by the males : Tower found that the musculus 

 sonificus was present only in the males of these latter genera 

 but in both sexes of Micvopogon. The sound uttered by these 

 Sciaenidae is described as a drumming noise, that is to say it is 

 a continued booming sound such as that produced by beating 

 rapidly on a drum. In the gurnards, on the other hand, the 



