THE VOICE OF ANIMALS 



THROUGHOUT the depths of the sea, silence, 

 as well as absolute darkness, prevails. The 

 sun penetrates only a short distance below the 

 surface, at most a few hundred feet, and all dis- 

 turbance from storms ceases far above that depth, 

 Where the pressure is a ton or more to the square 

 inch, it is very evident that no sound vibration 

 can exist. Near the surface it is otherwise. The 

 majority of fishes have no lungs and of course no 

 Yocal chords, but certain species, such as the drum- 

 fish, are able to distend special sacs with gas or 

 air, or in other ways to produce sounds. One 

 variety succeeds in producing a number of sounds 

 by gritting the teeth, and when the male fish is 

 attempting to charm the female by dashing round 

 her, spreading his fins to display his brilliant 

 colours, this gritting of the teeth holds a promi- 

 nent place in the performance, although whether 

 the fair finny one makes her choice because she 

 prefers a high-toned grit instead of a lower one 

 can only be imagined! But vibrations, whether 

 of sound or of water pressure, are easily carried 

 near the surface, and fishes are provided with 

 organs to receive and record them. One class of 

 such organs has little in common with ears, as we 

 speak of them; they are merely points on the head 



245 



