Ichthyostraca (Branchiurans And Tongue Worms) is a class of oligostracan crustaceans. There are 266 species of Branchiurans And Tongue Worms, in 26 genera and 8 families.
Definition: overall repetitive or reflective pattern in the body of one individual of this taxon. eg: bilateral symmetry, rotational symmetry, radial symmetry