periostracum

[ per-ee-os-truh-kuhm ]

Phonetic (Standard)IPA

noun

, plural per·i·os·tra·ca [per-ee-, os, -tr, uh, -k, uh].

the external, chitinlike covering of the shell of certain mollusks that protects the limy portion from acids.

1830–40; < New Latin, equivalent to peri- peri- + ostracum a shell < Greek óstrakon. See oyster

Gray calls it the Periostracum, from the membranous skin covering the bones of quadrupeds.

The periostracum, or epidermis, is heavy and often velvety or even hairy.

April 25, 2024firkin

[fur-kin ]

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