50 PRODUCTION OF MUSICAL SOUNDS chap. 



Helix aspersa is said to excavate holes 10 to 12 cm. deep at 

 Constantine,^ and H. Mazzullii is recorded as perforating lime- 

 stone 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. lie/era^ H penn- 

 sylvaniea^ and H. elevata climb trees two days before rain, if it 

 is to be abundant and continuous. Succinea 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 mol- 

 luscs are said to be capable of producing musical sounds. Sir 

 J. E. Tennent describes his visit to a brackish-water lake at Bat- 

 ticaloa, 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 gen- 

 tle 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 alto- 

 gether." According to the fishermen, the shells Avere Pyrazus 

 palustris and Littorina laevis. It appears uncertain whether the 

 sounds are really due to Mollusca. 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 



1 Forel, An7i. Sci. Nat. (3) xx. p. 576 ; Bretonniere, Comptes Bendus, cvii. 

 p. 566. 



2 Brit. Mus. Collection. 



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

 ^ Nat. Hist, of Ceylon, p. 382. See also T. L. Taylor, Eep. Brit. Ass. for 

 1848, p. 82. 



