Classis Ophiuroidea

Gray, 1840

Brittle-stars and Basket-stars

Free-living Echinoderms with a round, flat disc-shaped body with 5 thin, articulate arms, which are well marked off from the disc.

The tube-feet are located in small pores in two series along the underside of the arms.

Mouth and alimentary canal
The mouth faces downwards towards the substratum. The intestine and the genital organs do not pas into the arms. There is no open furrow along the ventral side of the arms. The intestinal organs conist only of a simple sac-shaped stomach, without caeca or anal opening.

Treated taxon:
- Order Ophiurae