Motile cells typically biciliate, typically with heterokont ciliation; anterior cilium with tripartite mastigonemes in two opposite rows and a posterior usually smooth cilium.
1. Actinophryidae Dujardin 1841
Ciliated cells absent. Axonemal pseudopodia with stiff microtubular core (axopodia). Axopodia originate from an amorphous centrosome near nuclei. Single large central nucleus or several peripheral nuclei.
Mainly osmotrophic cells capable of producing an ectoplasmic network of branched, anastomosing, wall-less filaments via a specialized organelle known as the bothrosome; Golgi-derived scales; biciliate zoospores with lateral insertion in many species.