Ridleia Dendy, 1888

Diagnosis: Pedunculate egg-shaped sponge with an oscular papilla. Skeleton mainly confined to the ectosome. From outside to inside there is a palisade of ectosomal tylostyles, a layer of intermediary tylostyles and longitudinal tracts of principal tylostyles which lie on a collagenous layer. In the outermost region of the choanosome there is a tangential layer of ectosomal tylostyles. The spicules are tylostyles in three size categories. Choanocyte chambers are diplodal (Boury-Esnault 2002).