Class of Crustacea - Ostracoda
Generally called mussel or seed-shrimps, Ostracoda include both fresh water and marine forms. The small crustaceans, computing a few mm have their body covered in a carapace formed by two elliptical valves. The head is the dominant part of the body, along with well developed appendages. The trunk is much more reduced and unsegmented. Only two pairs of appendages are found. Single median eye is common in between all Ostracoda and a few have sessile compound eyes. Some of the fresh water forms are parthenogenetic. For example Cypricercus, Cyprus, Ponti Cyprus, Gigantocypris, Candona.
Figure: Example of Ostracoda