Echinoderms (Phylum Echinodermata, from the Greek for spiny skin) are a phylum of marine animals found at all depths. This phylum appeared in the early Cambrian Period and contains about 7,000 living species and 13,000 extinct ones. Five or six classes (six counting Concentricycloidea) are alive today:

• Asteroidea (asteroids, starfish, or sea stars): about 1,500 species that capture prey for their own food.
• Concentricycloidea (sea daisies), notable for their unique water vascular system; two species; recently merged into Asteroidea.
• Crinoidea (crinoids, feather stars or sea lilies): about 600 species that are suspension feeders.
• Echinoidea (echinoids, sea urchins and sand dollars): notable for their movable spines; about 1,000 species.
• Holothuroidea (sea cucumbers): elongated animals resembling slugs; about 1,000 species.
• Ophiuroidea (brittle stars and basket stars), the physically largest of echinoderms; about 1,500 species.

Extinct forms known from fossils include blastoids, edrioasteroids, and several early Cambrian animals such as Helicoplacus, carpoids, Homalozoa, and possibly machaerids.

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@echinodermata @charlesingram totally worth it for the amazing use of a wind machine!
GSnumber23 (Claire Wihnyk) Thu, 05 Nov 2009 22:21:07 -0000
@echinodermata @charlesingram totally worth it for the amazing use of a wind machine!
@echinodermata I feel greeeaaaat. U guys are getting some drug induced tweets
pavlestojkovic (Pavle Stojkovic) Thu, 05 Nov 2009 16:37:02 -0000
@echinodermata I feel greeeaaaat. U guys are getting some drug induced tweets
blm tan, lg ngerjain yg echinodermata. bedeh subuh kali selesainya. lu tan? RT @tanyaoO: @nunuuuuu bio udh slse lom? TT
nunuuuuu (Nufus Dwianita) Thu, 05 Nov 2009 14:36:22 -0000
blm tan, lg ngerjain yg echinodermata. bedeh subuh kali selesainya. lu tan? RT @tanyaoO: @nunuuuuu bio udh slse lom? TT
@itsmeSharee i'm sorry my head just full of echinodermata Ophiuroidea Mollusca Oligochaeta and everything like that.
nindyoa (Nindya Ariyanti) Wed, 04 Nov 2009 11:10:11 -0000
@itsmeSharee i'm sorry my head just full of echinodermata Ophiuroidea Mollusca Oligochaeta and everything like that.
@echinodermata You should provide a proof for anything with a unit number over "1". #KINKOSFAIL
thoughtmecca (Matthew Hartwell) Wed, 04 Nov 2009 03:54:53 -0000
@echinodermata You should provide a proof for anything with a unit number over "1". #KINKOSFAIL
@echinodermata It is bitch work, but so long as I'm getting paid I'm ok with it. :D
joespain (Joe Spain) Wed, 04 Nov 2009 02:48:30 -0000
@echinodermata It is bitch work, but so long as I'm getting paid I'm ok with it. :D

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