Echinoderms

http://www.flickr.com/photos/laszlo-photo/112258325/

http://www.flickr.com/photos/pacificklaus/4027510849/http://www.flickr.com/photos/kqedquest/3115941447/

http://www.flickr.com/photos/torvaanser/1072597692/

Sea Stars

http://www.flickr.com/photos/pfly/2474516448/

http://www.flickr.com/photos/zeveroni/109377143/

http://www.flickr.com/photos/gregthebusker/4320800213/

Brittle Star

Basket Star

http://www.flickr.com/photos/dkeats/3082886902/

http://www.flickr.com/photos/rling/2110342314/

Sea cucumbers

http://www.flickr.com/photos/boogieswithfish/4205285298/

http://www.flickr.com/photos/eclectic-echoes/5004309575/

http://www.flickr.com/photos/thebeest/1356812104/

Sea Urchins

http://www.flickr.com/photos/kqedquest/3115941447/

http://www.flickr.com/photos/rling/2110342242/

Sand Dollars

http://www.flickr.com/photos/fiveinchpixie/61176590/

What they have in common:

Spiny skin!http://www.flickr.com/photos/joe_r/246427851/

What they have in common:

Symmetryhttp://www.flickr.com/photos/zen/177383867/

What they have in common:

Tube Feet

http://www.flickr.com/photos/44603071@N00/4139096209/

http://www.flickr.com/photos/stevecorey/3185972974/

Sea Stars

http://www.flickr.com/photos/canopic/5895143960/

Pin-Cushion

http://www.flickr.com/photos/maynard/404485875/

Red-nobbed

http://www.flickr.com/photos/cybersam/234933965/

http://www.flickr.com/photos/28656738@N02/5309178024/

http://www.flickr.com/photos/saspotato/5283483698/

http://www.flickr.com/photos/ken-ichi/701239605/

Sand Star

http://www.flickr.com/photos/rling/2085141072/

Crown-of-thorns

http://www.flickr.com/photos/freelancer_markcariaga/5828235007/

http://www.flickr.com/photos/joe_r/246427851/

http://www.flickr.com/photos/zen/177383867/

http://www.flickr.com/photos/44603071@N00/4139096209/