14 proceediifgs of the 



Presidential Address. 



I propose on this occasion to say a few words on a subject of 

 considerable interest, namely, some of the many means by which 

 sound is produced by animals. It is clear that this is an ex- 

 ceedingly important question, for, in ourselves, we koow that it 

 is largely owing to the fact of that complex sound-production 

 which we call speech that we hold our present, more or less, 

 prominent position amongst our fellow creatures of this world. 

 We know, also, that the production of sound must be of con- 

 siderable importance amongst other and lower forms, for so many 

 have that power ; and it is without question that those who can 

 intentionally produce sound have also the apparatus by which 

 it can be heard. The simplest form, perhaps, in which sound is 

 produced is by mere percussion, the striking of a portion of the 

 body upon some other external material — either the ground, or 

 rock, or wood ; or a sudden striking of two portions of the body 

 together, as we do when we clap our hands as a sign of applause, 

 or when we snap our fingers, and so forth. The clapping of the 

 hands in this country is recognized mainly as a sign of applause, 

 whereas in most parts of the East we know that it is a customary 

 mode of summoning an attendant to minister to our wants. 

 Now there is an animal, a small Macrurous crustacean (Alpheus), 

 which is fairly common over the world. One species, A. mega- 

 cheles, may not unfrequently be taken in burrows in hte sand in 

 Gruernsey and Jersey, and in tropical countries this genus is 

 even still more abundant. It is about 2 inches in length, and 

 has the usual appearance of a Macrurous crustacean (e. g. 

 Lobster). The left nipper is peculiarly modified, having a 

 process of the propodite hollowed out into a sort of groove, and 

 the dactylopodite, which can be closed upon it, is provided with 

 a smooth prominence that fits accurately into the groove when 

 the nipper is closed. Now if this little crustacean be annoyed 

 by any intruder in its burrow, or be caught by some collector, 

 the first thing it does is to suddenly close this nipper, and pro- 

 duce a noise as sharp and as loud as that made by snapping the 

 finger and thumb, or made by the breaking of a piece of glass. 

 It is evident that it is rather as a warning to an enemy to 

 frighten it off than for any other purpose ; at all events, it is 

 under such circumstances of alarm that the animal produces 

 this sound. It has not been heard to do it under more peaceful 

 conditions ; but when frightened or disturbed it invariably makes 

 it. The first occasion on which I heard this done it was not 

 this particular genus, but a very closely allied species, Typton 

 spongicola. It is a smaller crustacean than the Alpheus, and 

 was found in the hollow cavity of a brown sponge. On turning 

 over the sponge to look for the crustacean, the first indication 1 

 had of my friend was this sharp noise deep down in the inter- 

 stices of the sponge. On tearing it open I found the animal was 

 coloured the same as the sponge, and was evidently endeavouring 



