92 Part second. 



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 5 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 wave-like motion of the body, the dark side 

 being uppermost. A few strokes of the loose flaps of skin which 

 encircle the body suffice to throw up sand enough to conceal the animal 

 again, and then it will remain for hours awaiting its next prey. 



Economically the Flat Fishes are very important, as their flesh is 

 very delicate and keeps well, so that it can be transported to considerable 

 distances. Some of them attain a large size. England, Germany, France, 

 Holland and Denmark consume enormous numbers of Fiat-Fish. London 

 imports from Holland alone about ^ 100,000 worth of Turbot annually, 

 but this is only a quarter of the amount actually consumed in the metro- 

 polis; in the Italian markets, too, they are greatly prized. They are 

 caught with the trawl-net, and also with the line. The chief forms of 

 Flat Fishes are the Flounder, the Turbot and Halibut, the Sole and 

 Plaice. Only the smaller species can be kept in the Aquarium, generally 

 the Turbot. Rhombus maximus (Fig. 152), and the Sole, Solea vulgaris 

 (Fig. 153).' 



Allied in habits to the fishes just described are those which have 

 adopted the crevices of the rocks as their home and there lie in ambush 

 for their prey. Foremost amongst these is the Sea-scorpion or Sea-devil, 

 Scorpaena (Fig. 43), a heavily shaped fish with a broad head and mouth, 

 large spiny fins, and curious appendages on its skin in form of lappets, 

 horns or ribands. They hide themselves in the crevices of the rocks, 

 and can mimic the colouring so wonderfully that visitors will at first 

 not be able to distinguish them (tank Nr. 25). Some, in the semi-" 

 darkness of the water, bear a most striking resemblance to a rock covered 

 with sea-weeds ; so that they easily escape the notice of their enemies 

 and also of their prey. The same is the case with the crabs in this 

 same tank (see above p. 73); and in fact this protective colouring 

 is found in many animals. Thus the inhabitants of the deserts are 

 usually of a sandy colour. The Polar regions and the alpine heights are 

 inhabited by white animals, some of which, like the ptarmigan, can even 

 change their colouring according to the season of the year. The jelly-fish 

 and the other pelagic forms protect themselves from their enemies by 

 perfect transparency. Some insects and their larvae mimic the plants, or 

 portions of the plant, on which they live and feed. Others, again, mimic 

 animals which are themselves well protected , as for example by the 

 possession of defensive weapons or poisons. Thus some flies have adopted 

 the appearance of bees or wasps, and many butterflies perfectly in- 

 nocuous themselves, resemble very closely other butterflies which are 

 very distasteful to insect-eating animals. This interesting phenomenon 

 termed "Mimicry" has been observed in marine animals of almost every 



