The purpose of this application, under Articles 23.9.3 and 81.1 of the Code, is to conserve the usage of the name Sycon Risso, 1827 (Porifera) for a genus of sponges by reversal of precedence with respect to its senior subjective synonym Scypha Gray, 1821 (Porifera). This is justified by the refusal of the wider community of sponge researchers to accept the adoption of Scypha as the valid name for this large and ubiquitous genus of calcareous sponges and by the current prevailing usage of the junior synonym. With reversal of precedence, stability of the nomenclature will be maintained, and confusion avoided.