Spongodiscidae

Spumellarid polycystines, discoidal or cylindrical forms with or without a visible central chamber surrounded by concentric or spiral, continuous or interrupted finely chambered bands, or partially or totally spongy with no visible structure. The surface of some forms may be partly or totally covered with a very thin, porous sieve-plate, which in lenticular forms may extend beyond the central spongy mass forming a delicate equatorial girdle around the periphery of the shell. Major part of the shell can be represented by 2-4 thickenings of the spongy mesh or separate arms radiating from the central disc in the equatorial plane.

Spongodiscidae is a family of radiolarians in the order Spumellaria. According to the original description by Ernst Haeckel, members of the family have a flat discoidal shell, in which a simple spherical central chamber is surrounded by an irregular spongy framework.