Opheodesoma

Fisher, 1907

10 species

Numerous madreporic canals, distributed around the ring canal. The cartilaginous ring sometimes present, when present, perforations are along anterior border, not along the posterior border as in Synaptula. The two large lateral holes in handle of anchor plate absent, the central hole larger than in Euapta and rounded, not acute on the outer edge; plates otherwise as in Euapta. Calcareous ring with conspicuous anterior projections. Tentacles and anchors as in Euapta. Retractors present. (Fisher, 1907)

Tentacles pinnate, 14-16. Digits numerous 10-35 on each side. Polian vesicles numerous. Stone canals numerous. Anchors as in Euapta. Anchor plates with large central hole surrounded by 6 (rarely 7) large holes, all more of less dentate; posterior end of plate abruptly narrowed so that there are only a few small, smooth holes there; a bow across plate is present. (Clark, 1907)

Presence of a web between the tentacles, shape of calcareous ring and the shape of the anchor plates are important. Rods from the oral disc and the tentacles are of great value, together with the numerous madreporic canals. (Heding, 1928)