ostracod

Noun

os=tra=cod

WORDNET DICTIONARY

ostracod(n = noun.animal) mussel shrimp, seed shrimp - tiny marine and freshwater crustaceans with a shrimp-like body enclosed in a bivalve shell;

is a kind of crustacean

is a member of ostracoda, subclass ostracoda

ostracod, n.

A member of the Ostracoda, an order of tiny marine and freshwater crustaceans with a shrimplike body enclosed in a bivalve shell. [WordNet 1.5]