What is "sclerodactylidae"

Sclerodactylidae is a family of sea cucumbers, marine invertebrates with elongated bodies, leathery skins and tentacles.

Members of the family are characterised by the complex ring of ossicles they have near the anterior end. These may or may not take the form of a short tube but are quite unlike the long tubes found in the phyllophorids. The tentacles number ten to twenty.