title: Paleozoic Mollusk: Hyolithes.
abstract: An unusually well-preserved Ordovician fossil from Czechoslovakia shows that the enigmatic paired structures once thought to be outgrowths of the operculum of Hyolithes are really independent structures lying between the operculum and the aperture of the shell. The find seems to provide conclusive proof of the morphologic uniqueness of hyolithids.
authors.forename: L
authors.initials: L
authors.lastname: Marek
authors.forename: E L
authors.initials: EL
authors.lastname: Yochelson