Wikipedia
Rhaphischismatidae
Rhaphischismatidae is an extinct family of fossil sea snails, marine gastropod mollusks in the superorder Vetigastropoda. They date from the Lower Carboniferous (Mississippian). The family contains a single genus, Raphischisma. In the Bouchet & Rocroi, 2005), this family is assigned to the Pleurotomariacea.