owever, splendidly adapted to its water
life, and the rapidity of its motions places it near the head of the
higher active creatures,--with the woodchuck near the opposite extreme.

THE VOICE OF THE 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 disturbance 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 vocal
chords, but certain species, such as the drumfish, 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 prominent 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 and body which are susceptible to the watery
vibrations. These points are minute cavities, surrounded with tiny _cilia_
or hairs, which connect with the ends of the nerves.

The ears of the frogs and all higher animals are, like the tongue-bone and
the lower jaw, derived originally from portions of gills, which the
aquatic ancestors of living animals used to draw the oxygen from the
water. This is one of the most wonderful and interesting changes which the
study of evolution has unfolded to our knowledge.

The disproportionate voices are produced by means of an extra amount of
skin on the throat, which is distensible and acts as a drum to increase
the volume of sound. In certain bullfrogs which grow to be as large as the
head of a man, the bellowing power is deafening and is audible for miles.
In Chile a small species of frog, measuring only about an inch in length,
has two internal vocal sacs which are put to a unique use. Where these
frogs live, water is very scarce and t