Schizaster incertus Aradas, 1850 – synonym of Brissopsis lyrifera
Solaster affinis Danielssen and Koren, 1887 – synonym of Crossaster papposus
Solaster endeca decemradiata Sladen, 1889 – synonym of Solaster endeca
Solaster galaxides Verrill, 1909 – synonym of Solaster endeca
Solaster intermedius Sluiter, 1895 – synonym of Solaster endeca
Spatagus pusillus O.F. Müller, 1776 – synonym of Echinocyamus pusillus
Spatangus arcuarius de Lamarck, 1816 – synonym of Echinocardium cordatum
Spatangus flavescens O.F. Müller, 1776 – synonym of Echinocardium flavescens
Spatangus meridionalis Risso, 1825 – synonym of Spatangus purpureus
Spatangus ovatus Leske, 1778 – synonym of Echinocardium flavescens
Spatangus reginae Gray, 1855 – synonym of Spatangus purpureus
Spatangus spinosissimus Desor, 1847 – synonym of Spatangus purpureus
Stellonia webbiana d'Orbigny, 1839 – synonym of Marthasterias glacialis
Stichaster arcticus Danielssen and Koren, 1887 – synonym of Stichastrella rosea
Stichaster roseus O.F. Müller, 1776 – synonym of Stichastrella rosea
Strongylocentrotus chlorocentrotus Brandt, 1835 – synonym of Strongylocentrotus droebachiensis
Strongylocentrotus droebachiensis
Synapta bergensis Ostergren, 1905 – synonym of Leptosynapta bergensis
Synapta buskii M'Intosh, 1866 – synonym of Labidoplax buskii
Synapta decaria Ostergren, 1905 – synonym of Leptosynapta decaria
Synapta digitata Montagu, 1815 – synonym of Labidoplax digitata
Synapta duvernaea de Quatrefages, 18?? – synonym of Leptosynapta inhaerens
Synapta minuta Becher, 1906 – synonym of Leptosynapta minuta
Synapta tenera Norman, 1865 – synonym of Labidoplax buskii