The
radiolaria comprise three groups of
amoeboids protists which form intricate mineral skeletons. They feed and move by means of axopods, and have a frothy ectoplasm often including symbiotic
zooxanthellae, which is separated by a central capsule. Among the
Polycystinea[?] and
Phaeodarea[?], the skeleton is made of silica and sometimes organic materials, but among the less common
Acantharea it is made of strontium sulfate.
