74 
Tanks No. 10 and 24. 
is provided with rows of murderous-looking teeth. The mud-coloured 
monster lies half-buried at the bottom of the tank and gazes upwards 
with its large expressionless eyes, while the small lappets and outgrowths 
of its lower jaw are moved about at each breath it takes. From time to 
time it raises the fin-rays of its head as a bait and lets their lappets 
move about. Thus it is a "Compleat Angler” with rods and bait and 
always ready to engulf with its gigantic mouth the small fry which the 
bait attracts. It lives 
in the mud in medium 
depths and often attains 
an enormous size. Un¬ 
fortunately it does not 
last long in the Aqua¬ 
rium, as it cannot be 
made to take any food ; 
visitors will therefore 
only rarely find it (tank 
10). Young specimens 
and also another much 
smaller species are pla¬ 
ced in tank 24. 
In the same tank 
(No. 24) will be found 
the Soles. The Flat 
Fishes or Pleuronecti- 
dae to which these 
belong, form a quite 
distinct group of fishes. 
Their body is laterally 
compressed i.e. from 
right to left, and the 
head is turned in such 
a way that both eyes 
come to lie on the same 
side (either right or left). The two sides are quite distinct in colouring. 
The side which in swimming or resting is the undermost, is white, like 
the ventral surface of many other animals. The other side, which bears 
the eyes, has a dark colouring and possesses the power of matching 
itself to the colour of the bottom in a most remarkable manner. This 
protective colouring makes it very difficult at times to distinguish the 
specimens. The eyes will be the first objects to reveal themselves to 
the spectator; they can be moved about independently of each other in 
all directions, raised up or retracted, so that the fish commands a com¬ 
plete view of its surroundings. It catches its prey, consisting of small 
fish, by darting upwards and forwards with lightning-like rapidity. It 
swims with great skill, by a wave-like motion of the body, the dark side 
being uppermost. A few strokes of the lateral fins suffice to throw up 
sand enough to conceal the animal again, and then it will remain for 
hours awaiting its next prey. 
