The Nautilus and Other Wonders of the Monaco Oceanographic Museum Nautilus The nautilus (from the Latin form of the original Ancient Greek : ναυτίλος , 'sailor') is a pelagic marine mollusc of the cephalopod family Nautilidae, the sole extant family of the superfamily Nautilaceae and of its smaller but near equal suborder, Nautilina . It comprises six living species in two genera, the type of which is the genus Nautilus . Though it more specifically refers to species Nautilus pompilius , the name chambered nautilus is also used for any of the Nautilidae. All are protected under CITES Appendix II . Nautilidae, both extant and extinct, are characterized by involute or more or less convolute shells that are generally smooth, with compressed or depressed whorl sections, straight to sinuous sutures, and a tubular, generally...