SENSES HEAKING. 201 



quiring mutual impregnation, the sounds may jiossibly be a 

 means of counnunication between them ; or, if they be of an 

 electric nature, they may be a means of defending from 

 foreign enemies one of the most delicate, defenceless, and 

 beautiful Gasteropods that inhabit the deep." * 



You must not confound these sounds of the Tritonia and 

 Eolis with what has been absurdly called the *' music of 

 snails," a noise created by the crawling of them on a moist 

 window-pane of glass. j- This is mechanical, and has no 

 connection with the animal. As the source of the noise is 

 often unsuspected, and as it is heard only in the evening- 

 after the dew has fallen, or at the witching hour of night, it 

 has caused on some occasions a superstitious dread, and has 

 afforded the ingenious Mrs. Bowdich a fomidation for an 

 interesting tale. 



* Edinb. Phil. Journ. xiv. 186. f Mag. Nat. Hist. n. s. i. 107. 



