Genus Synallactes Ludwig, 1894

Diagnosis.

Body cylindrical or subcylindrical. Tentacles 18–20. Ventral surface flattened, without any marginal border. Ventral tube feet and dorsal papillae in longitudinal series, confined to ambulacra. Three zones of tube feet on ventral surface. Body wall with tri- or quadri-radiate tables, the distal ends of the arms with a larger or smaller number of perforations, often lateral processes forming a complex lattice-like network with similar processes of other arms. Spire consisting of a single pillar, terminally divided or perforated, or both [adapted from Solís-Marín 2005: 570–571].

Type species.

Synallactes alexandri Ludwig, 1894 .

Type locality.

North Pacific Ocean, Azuero Peninsula, Gulf of Panama, depth 588 m (Solís-Marín 2003).