Clathrulinidae

Heliozoan-like protists, with body located in a perforated extracellular and usually stalked lorica, colloquially called the desmothoracids. Cells with single central nucleus. Long, sometimes forked axopodia extend through the pores of the capsule. Axonemes terminate on the nuclear envelope. Microtubular cristae are tubular. Extrusomes are complex and resemble those of some cercomonads. There is a complex life cycle with the trophic heliozoon stage dividing by binary fission. One product may become a free swimming forms with one (in one species) or two flagella, which settle to form amoebae, subsequently developing stiff pseudopodia and eventually secreting the capsule and stalk. Products of division may encyst within the capsule. Stalked capsules may join end-to end to form colonies.