Body cylindro-conical, head not retractable. Fins semicircular or kidney-like in larvae and juveniles, extending somewhat beyond mantle end, longitudinal-oval in adults, usually shorter than half of ML. Arms short. Suckers on 1st-3rd arms transformed into hooks in adults. Tentacles short (shorter than arms in larvae and juveniles), thin, club slightly widened. Carpal part with very many small suckers, central part with 2 rows (3-4 pairs) of very large ones and 2 marginal rows of smaller, on dactylus small suckers in 3 rows. Fixing apparatus: 2 close rows of alternating suckers and knobs along entire (in juveniles) or distal part of stem. Kidney-shaped fins, short thin tentacles, and large central club suckers are characteristic for juveniles. ML up to 27 cm.