"New features of the Scottish middle Silurian phyllocarid crustacean Ceratiocaris papilio Salter in Murchison, 1859, are described and a reconstruction of the form is given. . . . Other recently collected specimens exhibit tagmosis and differentiated thoracic and abdominal limbs, which show that Ceratiocaris is the oldest known malacostracan. It belongs in the order Archaeostraca which is united with the order Leptostraca in the superorder Phyllocarida."