=Snails as Barometers.=--An American writer of more than thirty years ago[116] 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. pennsylvanica_, 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 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,[117] “came up from the water like the gentle thrills of a musical chord, or the faint vibrations of a wineglass 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 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 Mexico. _Dendronotus arborescens_, when confined in a glass jar of sea water, has been noticed[118] to emit a sound like the clink of a steel wire. According to Lieut.-Col. Portlock,[119] F.R.S., _Helix aperta_, a very common species in South Europe, has the property of emitting sounds when irritated. When at Corfu, he noticed that if the animal is irritated by a touch with a piece of straw or other light material, it emits a noise, as if grumbling at being disturbed. He kept a specimen in his house for a considerable time, which would make this noise whenever it was touched.