and the obsolete Maxillopoda. The Ostracoda have the body enclosed in a bivalve shell-covering, and are normally unsegmented. The Branchiopoda have a very variable number of body-segments, with or without a shield, simple or bivalved, and some of the post-oral appendages normally branchial. The Copepoda normally have a segmented body, not enclosed in a bi-valved shell-covering, fewer than twelve segments, the limbs not branchial.

References