rhodopidæ

from The Century Dictionary.

• A family of simple marine invertebrates of uncertain relationship, typified by the genus Rhodope.
• They are of an elongate flattened form, somewhat convex dorsally, and destitute of mantle, dorsal appendages, tentacles, branchiæ, and odontophore. The digestive tube is very simple, and there is no pharynx, kidney, or heart. The family has been referred to the nudibranchiate gastropods and to the turbellarians. See cut under Rhodope.