Pyrgulopsis archimedis, commonly known as the archimedes pyrg, is a species of minute freshwater snails with an operculum, aquatic gastropod molluscs or micromolluscs in the family Hydrobiidae. This species' natural habitat is rivers and lakes. It is endemic to the Upper Klamath Lake and the uppermost portion of the Link River near Algoma, Oregon, United States. Description Pyrgulopsis archimedis is a small snail that has a height of and a conical shell. Its differentiated from other Pyrgulopsis in that its penial filament has a medium lobe and medium filament with the penial ornament consisting of a short, transverse penial gland, short, transverse terminal gland, and stalked ventral gland. References Molluscs of the United States archimedis Gastropods described in 1947