de Blainville, 1824, (sensu van der Spoel, 1976)
Diagnosis
Molluscs without shell or mantle; body usually cylindrical; in some families with gill-like appendages on lateral and/or posterior sides of the body; all species with radula and hooks; some families with acetabuliferous arms, others with buccal cones.
Families treated:
Family Clionidae Gray, 1840
Family Cliopsidae Dall, 1889
Family Notobranchaeidae Pelseneer, 1886
Family Pneumodermatidae Pelseneer, 1887