ostracean / ostracion [ɔs'trei∫ǝn]
ostracean – adj. & n. – adj. related to oysters; n. an oyster of the sub order – Ostraeacea of the order Eulamellibranchia – common oysters and similar molluscs
ostracion – n. – boxfish or trunkfish – a tropical fish with body and head having a hard carapace – family Ostraciontidae