Aspidochirotida

Grube, 1840

3 Families; 35 Genera, 13 monotypic; 339 species

Tube feet present. Tentacles shield-shaped. No pharyngeal retractor muscles. Respiratory trees present. Mesentery of posterior intestinal loop attached in the right ventral interradius. Calcareous deposits simple, pointed rods, tables, buttons, etc. Body cylindrical or flattened, bilaterally symmetrical. (Mortensen, 1927)