Scientific Intelligence — Zoology. 401 



Among birds, the same periodical change takes place. The Mo- 

 tacilla alba was, thirty years ago, very numerous in Sweden, has 

 since vanished, and again reappeared. The Pyrrhula vulgaris has, 

 as far back as Nilsson remembers, been very common in Scania every 

 winter ; but during the last three winters, not a single example of 

 this little friendly guest has been seen near Lund. — (The Report of 

 the British Association for the Advancement of Science, for 1847, 

 p. 79.) 



12. On the Sounds emitted hy Molluscs. — Mr Level Reeve con- 

 tributed a " Notice of an observation made by Mr Taylor at Bath- 

 caloa, Ceylon, on the Sounds emitted by Mollusca." There is a cu- 

 rious thing here, which I do not know whether you ever heard of. 

 Going at night on the lake in the neighbourhood of the fort, one is 

 struck by a loud, musical noise proceeding from the bottom of the 

 water. It is caused by multitudes of some animals inhabiting shells, 

 I believe, — at least the natives call them " singing shells,"- — and I 

 have been shewn what they said were those which made the noise. 

 Some people doubt, however, whether it is these shells that sing, or 

 some others, or fish of some kind. Whatever it be, I can answer for 

 having heard the sounds repeatedly, — so distinctly, too, that you 

 cannot help hearing them, even when the oars and paddles are 

 splashing, and the boat going fast through the water. The sounds 

 are like those of an accordion or ^olian harp, guitar, or such like, 

 vibrating notes, and pitched in different keys. 



Lieut.-Colonel Portlock made the following communication on the 

 same subject. — I think it right to draw attention to the Helix aper- 

 tus, which is very remarkable for its property of emitting, when 

 irritated, a strong and well-marked sound. When I first noticed the 

 sound thus emitted, on accidentally touching the animal, I was pe- 

 culiarly struck by it, and immediately referred to Rossmaesler, who, 

 I found, describes the quality of the animal in a very graphic man- 

 ner, stating that the sounds were such as indicated irritation. The 

 Helix apertus is very abundant in Corfu, appearing sticking on the 

 squill leaves in the spring, when, about the beginning of March, the 

 annual increment of growth of the shell is perfectly soft. If the 

 animal be irritated by a touch with a piece of straw or other light 

 material, it emits a distinctly audible sound, possessing a singular 

 grumbling or querulous tone. This it frequently repeats, if freshly 

 touched, and continues to do so for, apparently, an unlimited space 

 of time, as I kept one for a considerable time in my house, and 

 heard this sound whenever I touched it. As Rossmaesler has so 

 fully described this fact, I shall only add that I have, on more 

 occasions than one, heard what I considered a similar, though very 

 feeble, sound from the Helix aspersa ; and I need not say that the 

 explanation seems very easy, from the structure of the animal. — 

 (Athena-um, No. 1089, p. 915.) 



13. On the Borimj of Molluscs into Rocks, and on the Removal 

 of portions of (heir Shells. By Mr A. Hancock. — The author stated 



