xni SOUND-PRODUCING ORGANS 361 



undoubtedly constitute a vocal organ, there are many others 

 in which the bladder can only be inferred to be sound-producing 

 from its general agreement in anatomical structure with the 

 same organ in Fishes where its vocal function has been clearly 

 proved. 



By one or other of these various methods the air-bladder is 

 either know^n to be sound-producing, or is believed with good 

 reason to be such, in the following Teleosts, 1 and many others : 

 Certain species of the South-American genera of Siluridae, 

 Pimelodus, Sorubim, Platystoma, Piratinga, Centromochlus, and 

 Traclielyopterus ; species of the South-American family Chara- 

 cinidae ; Amblyojjsis spelaea, the blind Fish from the Mammoth 

 Cave of Kentucky (Amblyopsidae) ; among the Syngnathidae, 

 the short-snouted Sea -Horse (Hippocampus brevirostris) of the 

 British Coasts; certain Sclerodermi, such as the Trigger-Fishes, 

 Batistes vetula, Triacanthus brevirostris, T. biaculeatus, and 

 Monacanthus pardalis, and also some " Coffer Fishes " (e.g. 

 species of Ostracion) ; some Gymnodontes (species of Diodon and 

 Tetrodon) ; a few Serranidae (e.g. species of Therapon and 

 Pristipoma) ; species of Holacanthus (Chaetodontidae) and in 

 Holocentrum sogho (Berycidae) ; such Sciaenidae as the " Drum " 

 (Pogonias chromis}, the " Maigre " (Sciaena aquila), which has 

 sometimes been taken in British waters, Umbrina cirrhosa, 

 Otolitlius regalis, and Micropogon undulatus, and, with more or 

 less probability, many other species of the same family ; one 

 species of Zeidae, the John Dory (Zeus faber) ; Batraclius tan 

 among the Batrachidae ; several species of Gurnards (Triglidae) 

 belonging to the genera Prionotus and Trigla ; the so-called 

 Flying Gurnard, Dactylopterus volitans (Dactylopteridae) ; the 

 Indian species Ophiocephalus marulius and 0. gachua (Ophio- 

 cephalidae) ; amongst the Gadidae, the Cod (Gadus morrhua) 

 and the Haddock (G. aeglefinus) ; in such Zoarcidae as the blind 

 Fish (Lucifuga subterranea) from the subterranean waters of 

 the caves of Cuba, and also in some Ophidiidae (e.g. species of 

 OpMdium). 



In Fishes other than Teleosts, instances of normal sound- 

 production by special vocal structures are rare. No recorded 

 instances are known in the Cyclostomes or the Elasmobranchs, 2 



1 Sorensen, Lydorganer, p. 82, et. feq. 

 2 Cf. Mettenheimer, Arch. /. Anat. u. Physiol. 1858, p. 302. 



