xiil SOUND-PRODUCING ORGANS 363 



ear of the observer two metres above the water ; and it has been 

 recorded that by listening for these sounds, shoals of Maigres have 

 been successfully netted. They rarely emit sounds when isolated ; 

 but in shoals, during the breeding season, they do not cease to 

 make sounds with a vigour and a persistency which apparently 

 must soon wear out their strength. One of the Indian Horse- 

 Mackerels (Caranx hippos) grunts like a young Pig when captured, 

 and the sound is repeated whenever it is moved, as long as vitality 

 remains. A West Indian species of the same family (Argyriosus 

 vonier] has been observed to produce a like sound, while an. 

 Egyptian Caranx (0. rhonchus) is known to the Arabs as the 

 " Chakoura " or " Snorter." x The sounds produced by the 

 different British Gurnards, such as the Grey Gurnard (Trigla 

 gurnardus), the Piper (T. lyra], the Elleck or Cuckoo Gurnard 

 (T. cuculus), and the Tub-Fish (T. hirundo), have been compared 

 to snoring, a sonorous and prolonged grunting, crooning (whence, 

 perhaps, the term "crooner," by which the Grey Gurnard is known 

 in Ireland), and croaking. The John Dory (Zeus faber) 2 also 

 utters sounds analogous to those of the Gurnards. Among the 

 Dipnoi Lepidosiren is said to make a growling sound, and Neo- 

 ceratodus a grunting noise which may be heard at night for 

 some distance. 



Whatever the nature of the vocal mechanism, it is highly 

 probable that the sounds produced by Fishes travel to considerable 

 distances in the water, inasmuch as the latter medium is a far 

 better conductor of sound than air, and, moreover, the transmission 

 of sound-vibrations from the air-bladder to the water is facilitated 

 in many Fishes by the fact that, for a portion of its extent on 

 each side the bladder is in direct contact with the superficial skin 

 behind the pectoral girdle. 



From the by no means exhaustive list of examples given above, 

 it is obvious that in some form or other vocal organs are present 

 in a considerable number of Fishes, both freshwater and marine, 

 belonging to widely different groups ; and further, that even in the 

 same species (e.g. Doras maculatus and other Siluridae), both 

 stridulation and the action of extrinsic muscles on the air-bladder 

 may be utilised as a means of sound-production. Certain 

 Teleostean families like the Siluridae, the Sciaenidae, and the 

 Triglidae, seem to be distinguished above all others by the pre- 



1 Sorensen, op. cit. ' 2 Moreau, op. cit. 



