Fish are generally covered in scales and have fins and a propulsive tail. There are several classes, Agnatha without jaws, the extinct Placodermi, modern Osteichthyes with a bone skeleton and Chondrichthyes with a cartilage skeleton.

Rays are Chondrichthyes like sharks. The specimen of Myliobatis cf. toliapicus, shown in the picture comes from the Eocene of Sheppey and is unusual in being an almost complete palate.