1) Mollusc shell
Found on
https://www.crosswordclues.com/clue/periostracum
The periostracum is a thin organic coating or `skin` which is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in gastropods and bivalves, but it is also found in cephalopods such as Allonautilus scrobiculatus. Periostracum is an integral p.....
Found on
http://en.wikipedia.org/wiki/Periostracum
• (n.) A chitinous membrane covering the exterior of many shells; -- called also epidermis.
Found on
http://thinkexist.com/dictionary/meaning/periostracum/
(from the article `bivalve`) The bivalve shell is made of calcium carbonate embedded in an organic matrix secreted by the mantle. The periostracum, the outermost organic layer, ... ...the outer lip of the aperture by the fleshy part of the animal called the mantle, first by outward additions to the shell lip and then by ... [2 relate...
Found on
http://www.britannica.com/eb/a-z/p/45
Per`i·os'tra·cum noun ;
plural Periostraca . [ New Latin , from Greek ... around + ... shell of a testacean.]
(Zoology) A chitinous membrane covering the exterior of many shells; -- called also
epidermis .
Found on
http://www.encyclo.co.uk/webster/P/56
No exact match found.
