A very large gelatinous spumellarian radiolarian (Physematium sp.) with a prominent yellowish central capsule and numerous fine cytoplasmic strands (axopodia) radiating out from the surface. There is no shell surrounding the central capsule, but the radiolarian secretes small crescent-shaped siliceous spicules on the surface of the central capsule. This picture was taken by O. Roger Anderson of material from oceanic samples. Image copyright: O. R. Anderson, image used under license to MBL (micro*scope).
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From the collection
Radiolaria by O. R. Anderson
|Description of Physematium: Very thin capsular membrane surrounding a spherical nucleus suspended within cytoplasmic strands delineating alveolar spaces radiating toward the peripheral capsular membrane. Spicules smooth and spindle-shaped. |