Definition: A class of protozoans (subphylum Sarcodina) distinguished by stiff radiating axopodia on all sides, usually naked, though some have a skeleton of siliceous scales and spines, but without a central capsule. They are mostly fresh water dwellers, and colonial forms are common.
[helio- + G. zōon, animal]
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Examples: glitazone, GI cocktail, etc.