What is "pleuronectes platessa"

Plaice \Plaice\, n. [F. plaise, plais, prob. fr. L. platessa flatish, plaice. See Place.] (Zo["o]l.)

1. A European food fish ( Pleuronectes platessa), allied to the flounder, and growing to the weight of eight or ten pounds or more.

2. A large American flounder ( Paralichthys dentatus; called also brail, puckermouth, and summer flounder. The name is sometimes applied to other allied species. [Written also plaise.]

   Plaice mouth, a mouth like that of a plaice; a small or wry mouth. [R.]
   --B. Jonson.