Genus Megadenus Rosen, 1910

Type species.

Megadenus holothuricola Rosén, 1910:18 by monotypy.

Diagnosis.

Shell conical to globular, translucent, colorless, sculpture of fine axial striae. Pseudopallium covers the shell or not; proboscis large or short forming a thick contracted disc; large pedal gland ( Rosén 1910; Humphreys and Lützen 1972).

Remarks.

Megadenus species are found in shallow waters in tropical or subtropical regions, especially as endoparasites of Aspidochirotida ( Echinodermata, Holothuroidea); usually they live in the cloacal chamber or attached to the respiratory tree. Megadenus oneirophantae Bouchet & Lützen, 1980 is the only abyssal species (4796 m). Warén (1984) defined Megadenus as "shell fragile, globular, and at least lower part is covered by a big pseudopallium, has separate sexes, with smaller males and the animals live in the cloaca of holothurians." He also indicated there was no type material.