Wikipedia
Liroceras
Liroceras is the type genus of the clydonautiliacean family, Liroceratidae, and is characterized by a rapidly expanding, subglobular, nautiliconic shell with a reniform whorl section, small umbilicus, essentially straight sutures, and a siphuncle with a variable but not marginal position.
Liroceras has a range from the Mississippian to the Permian, longest of the Liroceratidae. It has been found the North America, Europe, China and the East Indies. Condraoceras differs in having a circular cross section and shallow ventral and lateral lobes. Bistrialites also has a reniform whorl section but differs in having a large funnel-shaped umbilicus.