Seventeen species of the genus Staurotheca Allman have been studied, three of which are new to science ( Staurotheca abyssalis sp. nov., S. densa sp. nov. and S. profunda sp. nov.). The material studied was collected by several US Antarctic expeditions. Each species is described and figured, the systematic position amongst allied species discussed and available data concerning autecology and geographical distribution given. The remaining six known species of the genus are also considered, regarding synonymy, autecology and geographical distribution. The type material of two poorly known species of Staurotheca, S. juncea (Vanhoffen) and S. pachyclada (Jaderholm) has been re-examined, re-described and figured. Finally, a general survey of the bathymetrical and biogeographical distribution of the known species of Staurotheca is given.Descriptors: Staurotheca abyssalis, Staurotheca densa, Staurotheca profunda