Category:Sea Urchins

Please copy and paste ' [[Category:Sea Urchins]] ' into the end of your article to include it in this category.

Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from 3-10cm (1.2-3.9") across. Common colors include black and dull shades of green, olive, brown, purple, and red. They move slowly, feeding mostly on algae.