Sealife guideCrinoids, feather stars and sea liliesEchinoderms

Last updated on 08/11/2026 at 10:23 PM

Classification

Phylum: Echinoderm
Class:

Common name: Crinoid
Scientific name: Crinoidea

Description

The crinoid class comprises more than 600 marine species.

Crinoids include organisms that are attached to a substrate, unlike all other classes, whose organisms are mobile.

Depending on how they attach themselves, crinoids are divided into 2 groups:

with a stalk: these are the sea lilies, named for their flower-like appearance
and without a stalk: these are the feather stars. The lower part of the body is attached to the substrate by means of cirri, which vary in number depending on the species.

The arms of the golden feather star have a main central ridge and secondary branches called pinnules

Crinoids have a disc-shaped body called the calyx, from which the arms extend. The arms bear paired branches called pinnules, arranged symmetrically.

Crinoids have an extensive water vascular system connected to the outside through countless openings, allowing food particles to be transported toward the mouth.

In crinoids, the mouth and anus are located on the same side of the body, whereas in other echinoderm classes they are located on two opposite sides.

Geographic range

Crinoids are found at all depths, from the surface to the deep sea.

Did you know ?

Crinoids first appeared around 350 million years ago and are therefore among the oldest echinoderms.

Nos fiches