Branchiopoda

1 :  a subclass of crustacea comprising primitive aquatic forms typically having an elongated body, a carapace, and many pairs of foliaceous appendages and including the orders Anostraca, Notostraca, Conchostraca, and Cladocera

2 in some especially former classifications a :  an order of Entomostraca including the Cladocera b :  an order of Phyllopoda excluding the Cladocera c :  phyllopoda b