Part second. 



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 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 surrounding. It catches its prey, consisting of small fish 

 and shrimps, by darting upwards and forwards with lightning-like ra- 

 pidity. 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 L. 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 kinds 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 not be 

 able at first to distinguish them (tank Nr. 25). Some , in the semi- 

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

 vered with sea-weeds, so that they easily escape the notice of their ene- 

 mies 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 animals protect themselves from their enemies by 

 perfect transparency. Some insects and their larvse 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 



