Search results
Results from the WOW.Com Content Network
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 ...
Many biological structures including the shells of mollusks. [14] In these cases, the reason may be construction from expanding similar shapes, as is the case for polygonal figures. Logarithmic spiral beaches can form as the result of wave refraction and diffraction by the coast. Half Moon Bay (California) is an example of such a type of beach ...
Patterns in nature are visible regularities of form found in the natural world. These patterns recur in different contexts and can sometimes be modelled mathematically . Natural patterns include symmetries , trees , spirals , meanders , waves , foams , tessellations , cracks and stripes. [ 1 ]
The iridescent nacre inside a nautilus shell Nacreous shell worked into a decorative object. Nacre (/ ˈ n eɪ k ər / NAY-kər, also / ˈ n æ k r ə / NAK-rə), [1] also known as mother-of-pearl, is an organic–inorganic composite material produced by some molluscs as an inner shell layer. It is also the material of which pearls are composed.
Cutaway of a nautilus shell showing the chambers. Camerae (singular camera) are the spaces or chambers enclosed between two adjacent septa in the phragmocone of a nautiloid or ammonoid cephalopod molluscus. These can be seen in cross-sections of a nautilus shell and in the polished cross-sections of
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where the head-foot part of the body of the animal emerges for locomotion, feeding, etc. The term aperture is used for the main opening in gastropod shells, scaphopod shells, and also for Nautilus and ammonite shells.
Volborthella, some fossils of which predate , was long thought to be a cephalopod, but discoveries of more detailed fossils showed its shell was not secreted, but built from grains of the mineral silicon dioxide (silica), and it was not divided into a series of compartments by septa as those of fossil shelled cephalopods and the living Nautilus are.