A new species of sponge, belonging to the genusDelectona, has been observed in the corallites ofLeptopsammia pruvotiandMadracis pharensisliving in semidark caves on the Portofino Promontory (Ligurian Sea). The species, here described asDelectona madreporica, has a spicular complement composed of rhabds, which are very irregular in shape and size and derived from fusiform amphiasters, by oxyasters derived from slender amphiasters and by toxiform, sometimes centrotylote, microxeas. The taxonomic position of this species is discussed.