Genus Grantia Fleming, 1828

Type species: Spongia compressa Fabricius, 1780 (by original designation).

Diagnosis: “ Grantiidae with a syconoid organization. The cortex is composed of tangential triactines and/ or tetractines, occasionally with small perpendicular diactines. Longitudinal diactines, if present, are not found exclusively in the cortex, but cross obliquely, at least a part of the choanosome and protrude from the external surface” (Borojević et al. 2000).