| 释义 |
peri·os·tra·cum
\ˌperēˈästrəkəm\ noun
(plural periostra·ca \-kə\)
Etymology: New Latin, from peri- + Greek ostrakon shell — more at oyster
: a chitinous layer covering the exterior of the shell in many mollusks, being usually well developed in freshwater forms, and serving to protect the shell from corrosion |