Classis Asteroidea

de Blainville, 1830

True Starfish and Cushion-stars

Description
Free-living Echinoderms with a flat, star-shaped or pentagonal body.

Tube-feet and arms
The tube-feet are situated in an open furrow along the underside of the arms. The arms are not sharply marked off from the disc. The arms contain the genital organs and the pyloric caeca (liver).

Mouth and alimentary canal
The stomach is large , sac-shaped; the intestine is rudimentary; the anal opening is small or wanting. The mouth is faced towards the substrate.

Treated taxa:
- Order Forcipulata
- Order Phanerozonia
- Order Spinulosa

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