1.
[syn: seed shrimp, mussel shrimp, ostracod]
The Collaborative International Dictionary of English v.0.48:
Ostracoda \Os*trac"o*da\, prop. n. pl. (Zool.)
An order of Entomostraca possessing shrimplike bodies
enclosed in hard bivalve shells; called also seed shrimp
and mussel shrimp. They were formerly referred to as
Ostracoidea. They are of small size, and swim freely about;
many are less than 1 mm in length. Microfossils of certain
extinct orders have been found extending back to the Cambrian
age.
[1913 Webster +PJC]
WordNet (r) 3.0 (2006):
mussel shrimp
n 1: tiny marine and freshwater crustaceans with a shrimp-like
body enclosed in a bivalve shell [syn: seed shrimp,
mussel shrimp, ostracod]