Ossicle (echinoderm)

Ernst Haeckel's drawing of a brittle star showing spines and articulated arms
This article is about elements embedded in the body wall of echinoderms. For the bones in the human ear, see Ossicles.

Ossicles are small calcareous elements embedded in the dermis of the body wall of echinoderms. They form part of the endoskeleton and provide rigidity and protection. They are found in different forms and arrangements in sea urchins, starfish, brittle stars, sea cucumbers, and crinoids. The ossicles and spines (which are specialised sharp ossicles) are the only parts of the animal likely to be fossilized after an echinoderm dies.