mantle

mantle (noun; Latin mantellum, cloak): 1. Something that enfolds, envelopes or covers.

2. (Arthropoda: Crustacea) In thoracic Cirripedia, membranous covering of the body, often strengthened by calcareous plates.

3. (Brachiopoda) Prolongation of the body wall as fold of ectodermal epithelium.

4. (Bryozoa: Phylactolaemata) Ciliated fold of colony wall covering one to four small, sexually produced colony progenitor polypides.

5. (Mollusca) A membranous covering that secretes the shell; the marginal glands produce the periostracum

See also: pallium.