Confusion in the literature over the definitive traits used to separate freshwater sponge taxa included currently in the genus Dosilia initiated this review of their taxonomic history and a re-examination of specimens to elucidate questions pertaining to determination of their identities at the species-level. A comparison was made between two North American specimens using light and scanning electron microscopy of the significant features of their gemmules and spicules. This comparison illustrated key taxonomic problems in the literature and the need for collection of additional specimens from voucher localities in order to successfully resolve questions remaining regarding inter-specific relationships in North American members of this genus.