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POPULAR SCIENCE REVIEW. 
M. Moreau, in some slight degree, but more especially to the 
oft-repeated and most laborious observations and experiments of 
M. Dufosse, carried out upon several hunureds of fishes, mostly 
inhabitants of the Mediterranean, that we owe all our present 
information — which, it must be admitted, is wonderfully full 
and exact — on this hitherto obscure and totally neglected subject. 
It has long been known that many members of the Gurnard 
family possess and exercise the faculty of emitting sounds 
when still under water, from which circumstance they have been 
collectively termed “ Organo ” in Italy, and in France u Gron- 
din.” * M. Moreau describes the air-bladder of the “ Tub-fish ” 
or Sapphirine Gurnard (Trigla hirundo) as possessing thick and 
strong muscles, the fibres of which are of the striped variety, 
and are thus presumably voluntary. These are supplied by 
two large nerves which take origin from the upper part of the 
spinal cord, below the pneumogastric nerve, and close to the first 
pair of dorsal nerves. The mucous membrane lining the air- 
bladder is thrown into a fold or diaphragm (comp, d , fig. 2), 
which subdivides the main cavity into two secondary chambers, 
which communicate by an aperture (/, fig. 2) in this partition, 
having some functional analogy to the pupil of the eye ; for under 
the microscope this structure is seen to be provided with sphinc- 
ter-like muscular fibres, disposed concentrically to the opening, 
while other fibres, radially arranged, run at a tangent to these. 
Both sets of fibres are of the smooth , presumably involuntary, 
variety. In August 1863 M. Moreau sacrificed,” as he terms 
it, a grondin by section of its spinal cord above the dorsal 
region, and, after opening the abdomen of the fish, he applied a 
feeble galvanic current to the nerves proceeding to the air- 
bladder. Immediately there were produced sounds, audible to 
persons at some distance, having the same character as those 
emitted by the fish during life. A current was next applied 
directly to the muscle of the air-bladder, but without result. M. 
Moreau then cut a window in the lower portion of the bladder, 
so as to expose the diaphragm to view, and upon galvanisation 
being again repeated, this membrane was seen to be thrown into 
a state of vibration, but no sounds were produced. M. Moreau, 
who does not seem to have been satisfied with these results, then 
proposes to continue his experiments at some future time.f The 
absence of sound in the last experiment seems to me to be 
easily accounted for, seeing that the membranous cavity, more 
* The \vpa of Aristotle probably embraced fishes of this family. Yarrell 
thinks that the most probable derivation of the word gurnard is from the 
"Dutch guurheid , roughness, in allusion to the peculiarity of the head of this 
fish. (“ Hist. Brit. Fishes/’ 3rd edition, vol. ii. p. 106.) 
t Sur la voix des Poissons. (l Comptes Rendus,” tome lix. p. 436. 1864. 
