Ecdysozoa
Taxonomy: Protostomes are ecdysozoa; insects and crustaceans; their mouth is the first opening; they have a coelom.
Molluscae are unsegmented, the others are segmented
Orders
Insectae
Crustaceae
Molluscae: unsegmented
Arthropodae have an exoskeleton and jointed appendages.
Annelidae
Nematoda