Heliozoia

(invertebrate zoology) A subclass of the protozoan class Actinopodea; individuals lack a central capsule and have either axopodia or filopodia.

A subclass of the Actinopodea. Unlike Radio-laria, these protozoans have no central capsule. Most species live in fresh water. Pseudopodia may be either slender with an axial filament surrounded by cytoplasm (axopodia) or filamentous (filopodia). Certain floating species can roll along on the tips of their axopodia and also swim by moving their axopodia. Some species are naked; others have skeletal elements ranging from siliceous scales or spicules embedded in a gelatinous capsule to a reticulate chitinous skeleton often impregnated with silica. A centroplast may or may not be present. The subclass has three orders: Actinophryida (see illustration), Centrohelida, and Desmothoracida. See also Actinopodea.

Actinophryida type of Heliozoia. (After R. P. Hall, Protozoology, Prentice-Hall, 1953)