The Order Pleuronectiformes is in the infraclass Teleostei. But it is best to look upon it as a group of fish which are adapted to the same habitat. They share those features which suit their life-style. They have both eyes on one side of the head: the upper side. This is their main adaptation to living on the seabed (benthos). Other distinguishing features are the protrusible eyes: they can stick the eyes up a bit to see round.