INSTINCTS AND EMOTIONS IN FISH. 49 



side of a boat, they at once took refuge in the coral, remaining in 

 it even after it was removed from the sea. In Burmese rivers, 

 where weirs are not permitted to entirely span rivers (as such 

 would impede navigation), the open side as far as the bank is 

 studded with reeds ; these, as the water passes over them, vibrate, 

 thus occasioning an unusual sound, alarming the fish and fright- 

 ening them over to the weired side of the stream. Every angler 

 knows the natural timidity of fish ; and keepers are aware how 

 easily poachers deter Salmon from ascending fish-passes. 



At the Andaman Islands fish are captured by the convicts by 

 means of weirs fixed across the openings of creeks. A fter exist- 

 ing a week or so, it is observed that captures invariably cease ; 

 and it is believed that such is due to barnacles &c. clustering on 

 to the wood of which they are composed. It does not seem impro- 

 bable that the fish have learned to avoid a locality out of terror 

 at those which enter but do not again return. 



Many fishes when captured emit sounds which appear to be 

 due to terror, as a Scad or Horse-Mackerel (Caranx hippos), a 

 Globe-fish (Tetrodon), and others grunt like a Pig. A Siluroid 

 found in the Rio Parana, and called the Armado, is remarkable 

 for a harsh grating noise which it emits when caught by hook 

 and line : this can be distinctly heard while it is still beneath the 

 water*. The Cuckoo- Gurnard (Triga pini) and the Maigre 

 (Scicena aquild) utter sounds, not only while being removed from 

 the water, but the latter likewise, when swimming in shoals, emits 

 grunting or purring noises that may be heard from a depth of 20 

 fathoms f- Herrings (Clupea harengus), when the net has been 

 drawn over them, have been observed to do the same. The fresh- 

 water Bullhead (Cottus gobio) emits similar sounds. 



Speaking of the river on which Brunei is situated in the king- 

 dom of Borneo proper, St. John remarks : — " I have described in a 

 previous chapter the appearance of the river ; but I have not men- 

 tioned that here I have most often heard the Singing or Hum- 

 ming-fish, which sticks to the bottom of the boat, and produces a 

 sound somewhat like that of a Jew's harp struck slowly, though 

 sometimes it increases in loudness, so as to resemble the full 

 sound or tones of an organ. My men have pointed me out a fish 

 about 4 inches long as the author of the music. It is marked 



* Darwin, ' Nat. Journal,' vol. vii. 



t Yarrcll, ' Brit. Fish.' 2nd edit, i. pp. 41, 106. 



