WarBn, A. 1983. An anatomical description of Eulima bilineata Alder with remarks on and a revision of Pyramidelloides Nevill (Mollosca, Prosobranchia, Eulimidae).-Zool. Scr. 12: 2 7 5 294.The anatomy and biology of Eulima bilineata Alder is described and compared with Pyramidel-Ioides miranda (A. Adams) and P. angusta (Hedley). All the species are parasitic on ophiuroids, have a ptenoglossate radula, an acrembolic proboscis with a pair of salivary glands close to the buccal mass and a reduced stomach with two histologically different digestive glands. The males have a well developed penis, the female a partly open or closed pallial oviduct. The central nervous system is concentrated. The sub-and supraoesophageal ganglia are completely integrated in the nerve ring. In Eulima, the supraoesophageal ganglion is split into two parts. Few differences were found between the species investigated, and it is concluded that Pyramidelloides should be classified in Eilimidae, not in Rissoidae where it has been placed previously.