The periostracum (/ˌpɛriˈɒstrəkəm/ PERR-ee-OS-trə-kəm) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled...

are features of the shell, including crease and an encrusting layer (periostracum) that covers most of the shell. Gills and reproductive structures also...

the land snail shown above) also have an outer shell layer called the periostracum which is composed of the protein conchiolin. Some land snails (especially...

resembles the quahog, but the shell of the ocean quahog is rounder, the periostracum is usually black, and on the interior of the shell, the pallial line...

the outermost layer, which in almost all cases is all conchiolin (see periostracum). Molluscs never use phosphate to construct their hard parts, with the...

prominent columellar plicae. It is usually pure white under a heavy brown periostracum, but it can also be a pale apricot color. It can sometimes be dotted...

carbonate in a protein matrix; and the periostracum, an outer pigmented layer resembling a skin. The periostracum is composed of a protein called conchin...

it can show irregular, concentric zigzags on a cream background. The periostracum is dark brown and forms a broad band around the shell margin; it is velvety...

Allonautilus Allonautilus scrobiculatus shell with periostracum removed Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Mollusca...

The outermost layer of the shell is the periostracum, a thin layer composed of horny conchiolin. The periostracum is secreted by the outer mantle and is...

family of bivalves: it is rounder than the hard clam, usually has a black periostracum, and there is no pallial sinus in the interior of the shell. The hard...

the shell of most species has a top shell layer that is thick brown periostracum affixed to the harder calcareous part of the shell. In some species such...

layers, an outer periostracum made of organic compounds and two biomineralized layers. Articulate brachiopods have an outermost periostracum made of proteins...

dense and homogeneous organic layer is loosely attached to the upper periostracum and the inner mineral layer. In the organic layer of the shell, there...

Malacostraca, ostracism, ostracize, ostracod, ostracoderm, ostracon, periostracum ostre- oyster Greek ὄστρεον ostreophagist, oyster ot- ear Greek οὖς,...

completely hidden under an opaque layer of periostracum. In other species, the topmost shell layer is a thin periostracum, a transparent yellowish or brownish...

(left), and an entire bivalve shell of a smaller individual with brownish periostracum, Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum:...

consists of iron sulphides, the middle layer is equivalent to the organic periostracum found in other gastropods, and the innermost layer is made of aragonite...

into an organic matrix known as conchiolin. The outermost layer is the periostracum which is resistant to abrasion and provides most shell coloration. The...

The name also recognizes the surface of Alviniconcha shells: the spiky periostracum resembles the fashion of punk rock bands." Amata gil Witt et al., 2007...

but instead it is a very thin protein layer known as the periostracum. Under the periostracum the shell is yellow. Overharvesting of the species for commercial...

also frequently bearing spines, tubercles, or blade-like processes. Periostracum is absent in this family. The aperture is variable in shape; it may be...

the extrapallial space, which is sealed from the environment by the periostracum, a leathery outer layer around the rim of the shell, where growth occurs...

greyish white to salmon-orange when adult, with a light tan or dark brown periostracum. This species dwells on sand, weed, and mud flats from the low intertidal...

Islands: Solomon Islands northern Australia China The periostracum is thick, and the color of the periostracum is dark brown or black. The shell has about 20...

apricot in color, however in life it is covered by thick brown or grey periostracum. The shell color can fade to a creamy yellow. The whole shell has a spindle-like...

with radial stripes. The outer surface of the shell is covered by the periostracum which as eroded, exposes the colored prismatic calcitic layer. Blue Mussels...

other bivalve molluscs. They are white, with a covering of pale brown periostracum, and have rough ridges. The mollusc uses them to grasp the wood and slowly...

Malacostraca, ostracism, ostracize, ostracod, ostracoderm, ostracon, periostracum ostre- oyster Greek ὄστρεον ostreophagist, oyster ot- ear Greek οὖς,...

External Aperture Apex Callus Lirae Periostracum Sculpture Spire Sutures Umbilicus Internal Body chamber Camerae Nacre Phragmocone Septa Siphuncle Whorls...