Asteroidea

Century Dictionary and Cyclopedia

1. An order of echinoderms, the starfishes: so called from their star-like form. They have a more or less lobed or pentagonal disk; lobes continuous with the disk, receiving prolongations of the viscera, and bearing tube-feet with suckers, as locomotory organs; and an aboral madreporic body. The group includes several families, as Brisingidæ, Pterasteridæ, Astropectinidæ, Asterinidæ, Goniasteridæ, Linckiidæ, and Asteriidæ, or the starfishes proper as distinguished from the sand-stars and other echinoderms of the class Stellerida (which see). They have a coriaceous skin, in which are implanted spines or tubercles. The body is expanded into arms, the under surface of which is marked with grooves, radiating from the center, and pierced with rows of holes, whence issue tentacular feet, by means of which the animals move. Most have 5 arms or rays, but some have more, varying from 8 to 30. They have the power of reproducing these arms if they are broken off; and if an entire arm, with a small portion of the body attached to it, is torn off, it forms a new and perfect animal. The mouth is in the inferior center of the rays, is not provided with teeth, and leads by a short gullet into a large stomach, from which a pair of lateral tubes are prolonged into each ray. A distinct intestine and anus may or may not be present. The animals feed chiefly on mollusks.
2. A class of echinoderms, containing the sand-stars or ophiurians together with the starfishes, and more or less exactly equivalent to Stellerida (which see).
3. Same as Alcyonaria.

Wiktionary

1. n. A taxonomic class within the superclass Asterozoa — the starfish.

WordNet 3.0

1. n. sea stars