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Nautilus shells were popular items in the Renaissance and Baroque cabinet of curiosities and were often mounted by goldsmiths on a thin stem to make extravagant nautilus shell cups. The low fecundity , late maturity, long gestation period and long life-span of nautiluses suggest that these species are vulnerable to overexploitation and demand ...
The chambered nautilus (Nautilus pompilius), also called the pearly nautilus, is the best-known species of nautilus. The shell, when cut away, reveals a lining of lustrous nacre and displays a nearly perfect equiangular spiral, although it is not a golden spiral. The shell exhibits countershading, being light on the bottom and dark on top. This ...
Empty nautilus shells may drift a considerable distance and have been reported from Japan, India and Africa. Undoubtedly the same applies to the shells of fossil nautiloids, the gas inside the shell keeping it buoyant for some time after the animal's death, allowing the empty shell to be carried some distance from where the animal lived before ...
Nautilus is the type genus of the family Nautilidae, originally defined as any coiled-shell species with simple sutures, or walls, between shell compartments. [7] Any shells with complex sutures were assigned to the genus Ammonites .
This "shell" has a double keel fringed by two rows of alternating tubercles. The sides are ribbed with the centre either flat or having winged protrusions. The eggcase curiously resembles the shells of extinct ammonites. It is secreted by the tips of the female's two greatly expanded dorsal tentacles (third left arms) before egg laying.
Nautilus macromphalus, the bellybutton nautilus, is a species of nautilus native to the waters off New Caledonia and northeastern Australia. The shell of this species lacks a callus, leaving the umbilicus exposed, in which the inner coils of the shell are visible. This opening constitutes about 15% of the shell diameter at its widest point.
Allonautilus perforatus, also known as the Bali chambered nautilus, is a species of nautilus native to the waters around Bali, Indonesia. It is known only from drifted shells and, as such, is the least studied of the six recognized nautilus species. Thus, not much is known about it outside of the shell.
A shell of Nautilus pompilius in cross section. Septal necks are preserved, but the thin connecting rings have been degraded and lost. The siphuncle of fossilised cephalopods is assumed to have worked in the same general way as in living nautiluses.