Haeckel, 1879
Diagnosis
Spherical to subspherical regular lattice shells, with circular to subcircular pores, numerous by-spines, and sometimes larger main-spines, and with mouth, usually circular, often surrounded by ring of teeth.
Genera treated:
Genus Castanarium
Genus Castanea
Genus Castanella
Genus Castanidium
Genus Castanissa
Genus Castanopsis