Nautiloid fossils for sale.
Members of the cephalopod family Nautilidae are commonly called "Nautilus."
Present day nautiluses are the only living members of the subclass Nautiloidea.
Nautiluses belong to an ancient cephalopod family that has survived several severe extinction events that destroyed much other sea life.  A possible reason for the longevity of the nautilus clan is an ability to enter a type of "hibernation" life mode that can bridge long periods of poor environmental conditions.
There is more information at: The Nautilus

The Cymatoceras nautilius specimens offered here are from Madagascar.  They date from the mid-Cretaceous Albian Age The specimens were prepared in Madagascar by local native artisans.

Cymatoceras species recognized from Madagascar:       Other Nautilaceae recognized from Madagascar:
 C. sakalavum                                                                      Eutrephoceras desertum - desertorum?
 C. Kayei - kayeanus?                                                           Eutrephoceras sublaevigatum
 C. crebricostatum                                                                Hercoglossa danica - danicus? var. indica
 C. andranofotsyense                                                            Hercoglossa madagascariense
 C. madagascariense                                                            Paracymatoceras rota
 C. formosus                                                                        Paracenoceras sp.
 C. huxleyanus