(subphylum Echinozoa, class Holothuroidea)
A subclass of sea cucumbers that have 10–30 shield-shaped tentacles which spoon organic debris from the sea floor into the mouth. There are no pharyngeal retractor muscles. The test is vestigial, consisting of scattered spicules in the dermis. The subclass first appeared in the Carboniferous.
Subjects: Zoology and Animal Sciences.