50 PRODUCTION OF MUSICAL SOUNDS chap. 



Helix asjjersa is said to excavate holes 10 to 12 cm. deep 

 at Constantine/ and I£. Mazzullii is recorded as perforating 

 limestone at Palermo.- 



Snails as Barometers. — An American writer of more than 

 thirty years ago ^ gave his experience of Helices as weather- 

 prophets. According to him, H. alternata is never seen abroad 

 except shortly before rain ; it then climbs on the bark of trees, 

 and stations itself on leaves. Helix clausa, H ligera, H i^enn- 

 sylvanica, and H elevata climb trees two days before rain, if it 

 is to be abundant and continuous. Succinca does the same, and 

 its body is yellow before rain and bluish after it. Several of the 

 Helices assume a sombre colour after rain, when their bodies 

 are exceedingly humid ; after the humidity has passed off they 

 resume a clearer and lighter tint. 



Production of Musical and other Sounds. — Certain molluscs 

 are said to be capable of producing musical sounds. Sir J. E. 

 Tennent describes his visit to a brackish-water lake at Batticaloa, 

 in Ceylon, where the fishermen give the name of the ' crying 

 shell ' to the animal supposed to produce the sounds. " The 

 sounds," he says,* " came up from the water like the gentle 

 thrills of a musical chord, or the faint vibrations of a wine-glass 

 when its rim is rubbed by a moistened finger. It was not one 

 sustained note, but a multitude of tiny sounds, each clear and 

 distinct in itself; the sweetest treble mingling with the lowest 

 bass. On applying the ear to the woodwork of the boat, the 

 vibration was greatly increased in volume. The sounds varied 

 considerably at different points as we moved across the lake, 

 and occasionally we rowed out of hearing of them altogether." 

 According to the fishermen, the shells were Pyrazus palustris 

 and Littorina laevis. It appears uncertain whether the sounds 

 are really due to MoUusca. Fishermen in other parts of India 

 assert that the sounds are made by fish, and, like those in 

 Ceylon, produce the fish which they say ' sings.' The same, or a 

 similar sound, has also been noticed to issue from the water in 

 certain parts of Chili, and on the northern shores of the Gulf of 



^ Forel, Aim. Set. Nat. (3) xx. p. 576 ; Bretonniere, Comptes Eendus, cvii. 

 p. 566. 



- Brit. Mus. Collection. 



^ Thomas, quoted by Recliiz in Journ. de Conch, vii. 1858, p. 178. 



* Nat. Hist, of Ceylon, p. 382. See also T. L. Taylor, Ecp. Brit. Ass. for 1848, 

 p. 82. 



