Rhopalodinidae

Perrier, 1902

3 Genera, 16 species

Pear-shaped to bottle-shaped holothurians with more than 10 (18-30) simple, unbranched tentacles. Mouth and anus lie thick on the ends of the bottleneck next to each other. The back of the animal, with the dorsal interradius, is on the narrow region of the upper poles between the mouth and the anus. The mouth and anus are shrunk together. The calcareous ring has bilateral symmetry with specially developed ventrolateral radialia and somewhat stunted medial (dorsal as well as ventral) parts. The radialia have irregularly developed small to rudimentary forked tails. Calcareous bodies are mostly in two layers in the body wall and the neck. The lower layer includes plates of the upper towers. (Heding and Panning, 1954)