36 Guide fo tJic British Fresh-Water Fishes 



dilToiviil parts of its range; the form tliat inhabits the 15ritish 

 Islands and France is distinguislicd from that of Northern I'^urope 

 by its shorter spines. In habits this species differs from the 

 Three-spined Stickleback in that tlie nest is not Imilt on the 

 bottom, but is attached to weeds or grasses. 



PLEURONECTIDAE. 



Tlie Flat-fishes lie on one side ; both eyes are on the upper 

 side, which is coloured, whilst the lower side is white. Most of 

 the Flat-fishes are marine, but some enter fresh water. 



65. Flounder, Plcuronccics flesus. — The Flounder is closely 

 related to the Plaice ; it is common on all the coasts of Europe, 

 and ascends rivers as far as the first falls. It is 'remarkable for its 

 power of changing its coloration to resemble the ground on which 

 it lies. It feeds especially on small shellfish, but also eats worms, 

 little fishes, etc. It grows to a length of ai)out 18 inches. 



