npleuronectesA genus of flatfishes, giving name to the family Pleuronectidæ, formerly conterminous with the family, later variously restricted. By most recent writers the name has been limited to the group typified by the common plaice, P. platessa, sometimes to the few species much like this type, sometimes extended to a larger assemblage. By others it has been used for the turbots, otherwise called Bothus and Psetta. By others still it has been employed for the genus otherwise called Arnoglossus. In a common European acceptation it includes flounders of northern seas, having the eyes and the color on the right side, the colored side of each jaw usually toothless, the blind side with close-set teeth in one (rarely two) series, the body ovate or elliptical, the small scales ctenoid or cycloid, the lateral line nearly straight or more or less arched anteriorly, and the small gill-rakers widely set. About 12 species of Pleuronectes in this sense are found in North America, a majority of them on the Pacific coast, as P. (Platichthys) stellatus, the California flounder, one of the largest and most important. P. (Limanda) ferrugineus is the sand-dab of the Atlantic coast. P. (Pseudopleuronectes) americanus is the mud-dab or winter flounder, common on this coast from New York northward.
The flounder; but the name, which is of very old standing, is also applied to various other pleuronects or flat-fish.