Thalassophysa (thal-ass-owe-fie-sa), a spumellarian radiolarian in which the cytoplasm is very clearly differentiated into the condensed inner region contained within the capsule, and the outer frothy later. Numerous symbiotic dinoflagellates (Scrippsiella - which also occurs in the cnidarian Velella) can be seen as orange spots in the cell. This is an example of one of the four types of large amoebae which is common in the marine water column. Dark ground image by N. R. Swanberg.