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radiolarian

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noun ra·di·o·lar·i·an \ˌrā-dē-ō-ˈler-ē-ən\

Definition of radiolarian

  1. :  any of three classes (Acantharia, Polycystina, and Phaeodaria) of usually spherical chiefly planktonic marine protozoans having radiating threadlike pseudopodia and often a siliceous skeleton of spicules

radiolarian adjective


Illustration of radiolarian

1875

First Known Use of radiolarian

1875


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