†FAMILY PYRGOMATIDAE GRAY, 1825

Diagnosis: Wall of four or six plates or wholly concrescent; parietes solid or tubiferous; when tubiferous, tubes occur between outer lamina and sheath or between external ribs of wall; interlaminate figures complex, radii solid; basis calcareous, rarely tubiferous, membranous in Pyrgospongia .

Comment: All species of this family are highly s p e c i a l i z e d t o s y m b i o s i s i n c o r a l s o r s p o n g e s (Anderson, 1992). This has affected many extreme morphological specializations in some clades. The existing subdivisions within the family may not always be based on monophyletic groups, but we have decided to retain them anyway. A future revised division is much needed.