Ormoceras is an actinocerid nautiloid genus and type for the family , found in North America from the late Chazyan through the early Cincinnatian of the Middle and Upper Ordovician, but which continued through the Devonian worldwide. Ormoceras contains twelve named species: * O.boreale * O.centrale * O.dobrovljanensis * O.ferecentricum * O.koraiense * O.langskawiense * O.manchuriense * O.nanumforme * O.pollacki * O.schohariae * O.tenuifilum * O.yokoyamai