Crinoidea

Class of echinoderms containing about 600 living species and more than 2,000 fossil forms; the extinct crinoids are commonly called stone lilies, and the existing species sea lilies and feather stars.

Crinoids retain many primitive features, notably in the use of the hydraulic water-vascular system for powering the capture and transportation of food rather than for locomotion. Uniquely amongst living echinoderms, the mouth is on the upper surface. Food particles are collected by the waving arms, and directed to the mouth along food grooves lined with cilia. Most of the living species are non-sessile (free-living), although a stalked stage may occur in development.

Classification Crinoidea is in phylum Echinodermata.