Deimatidae

Théel, 1886

3 genera, 1 monotypic; 9 species

Body oval or elongate. Skin usually thin, parchment-like or brittle. Mouth terminal or ventral tentacles (14) 15-20. Papillae both along the dorsal radii and along the sides of the body; they are more or less stiff, their calcareous bodies being longitudinally directed. Tube feet usually only in ventro lateral ambulacra in single or double series. Calcareous deposits mainly cruciform bodies or large fenestrated plates; no wheels. Calcareous ring formed by fragile, imperfect network, not separated into distinct radial and interradial pieces. Gonads simple tubes. Mesentery a continuous membrane, but lacking on the second intestinal loop. (Mortensen, 1927)

Deposits varying from perforated plates and spatulated primary crosses to spatulated, or reduced, and deformed rods. Wheels absent. Gonads consisting of few sac shaped tubules. (Hansen, 1975)