body cavity they possess, in a non-taxonomic, utilitarian way, as the Acoelomata, Pseudocoelomata, and Coelomata. These groups were never intended to represent...

Branch Radiata Phylum Cnidaria Phylum Ctenophora Branch Bilateria Grade Acoelomata Phylum Platyhelminthes Phylum Nemertea or Rhynchocoela Grade Pseudocoelomata...

body cavities. There were three types, or grades of organization: the Acoelomata (no coelom), the Pseudocoelomata (partial coelom), and the Eucoelomata...