Fifteen species of the genus Symplectoscyphus Marktanner-Turneretscher have been studied, four of which are new to science (Symplectoscyphus anae sp. nov., S. frigidus sp. nov., S. sofiae sp. nov. and S. weddelli sp. nov.). The material studied originates from the Weddell Sea and was collected by several French and German Antarctic expeditions with R. V. Polarstern. Each species is described and figured, the systematic position amongst allied species discussed and available data concerning autecology and geographical distribution given. The type material of five poorly known species of Symplectoscyphus, S. aggregatus (Jaderholm), S. cumberlandicus (Jaderholm), S. glacialis (Jaderholm), S. hero Blanco and S. plectilis (Hickson and Gravely), has been re-examined, re-described and figured. Finally, a general survey of the bathymetrical and biogeographical distribution of the known Antarctic species is given.Descriptors: Symplectoscyphus anae, Symplectoscyphus frigidus, Symplectoscyphus sofiae, Symplectoscyphus weddelli
