Sclerothyone Thandar, 1989

Diagnosis (after Thandar, 1989, here amended)

Tube feet in double rows, restricted to ambulacra; interambulacra mostly naked or tube feet scattered over body. Calcareous ring compact, non-tubular, posterior processes of radial plates long, entire or subdivided. Body wall tables with regular, oval, four-holed discs, with or without handle or large, irregular multilocular discs with or without handle. Spire with pillars fused or not. Introvert with plates, rods, rosettes and tables. Tentacles with rods and plates. In the tube feet end plate, supporting tables and plates (table 1).