Odhner, 1937
Shell and operculum absent in the adult phase; operculum absent in post-larval stages; calcareous spicules may be present in the skin; body usually of small size (less than 10 mm); cephalic shield fused with the dorsal mantle, bearing antero-lateral oral tentacles and antero-dorsal rhinophoral tentacles (rarely absent); mantle cavity and gill lacking; foot elongated, with a free, attenuated, metapodium; gizzard plates lacking; potash-resistant jaws may be present; radula narrow, with a median tooth in each row; abraded or broken teeth are discarded, not retained in a special sac; sexes separate or united; penis usually unarmed; impregnation never hypodermic; central nervous system euthyneurous, forming a ganglionic ring in front of the buccal mass.
Source: Thompson, 1988.
The following subtaxa of this order occur in the region:
Family Asperspinidae
Genus Asperspina
Asperspina brambelli
Family Microhedylidae
Genus Microhedyle
Microhedyle lactea
Family Philinoglossidae
Genus Philinoglossa
Philinoglossa helgolandica