Ehrenberg, 1875
Solitary or colonial radiolarians with a well-developed shell of radial symmetry or one derived from the above. Variations in the type of symmetry include spiral shells (e.g., Lithelius minor group?; Lithelius minor group? 2; Lithelius minor group? 3), asymmetric, discoidal or lenticular (biconvex) (lentelliptical shell; lentelliptical shell 2; Stylodictya multispina ov; Stylodictya aculeata ov; Spongotrochus glacialis ov), triaxonic (spongy shell 4; spongy shell 5), quadrangular (Spongaster tetras tetras; Spongaster tetras irregularis), etc. In many cases two axes of symmetry can be clearly differentiated (D. tetrathalamus intro) but, as opposed to the Order Nassellaria, the larger axis is homoaxonic. The central capsule (organic) of these cells has many small pores.
All spumellarid families are treated in the present volume:
Family Collosphaeridae
Family Actinommidae
Family Coccodiscidae
Family Phacodiscidae
Family Spongodiscidae
Family Litheliidae
Family Pyloniidae
Family Tholoniidae