Foraminifera are unicellular eukaryotes characterized by the presence of granuloreticulopodia and the possession of a membranous, agglutinated, or calcareous test, which is either monothalamous (single-chambered) or polythalamous (multi-chambered). Within monothalamids, some species like Reticulomyxa ﬁlosa are naked. Until 1859, foraminifera were only known from marine habitats, but that year Claparède and Lachmann described a monothalamid foraminifer, Lieberkuehnia wageneri, from an unknown water body in Berlin. It had a smooth, flexible test with a hyaline sheath that enveloped the peduncle. In 1886, Henri Blanc, a Swiss scientist, described another freshwater foraminifer, Gromia brunneri, which he had collected from the bottom of Lake Geneva. This monothalamous species had an agglutinated test, an organic layer embedded with foreign, mainly non-organic, particles. In subsequent years, Eugène Penard, another Swiss protozoologist, described four similar species Gromia gemma and G. squamosa (1899), G. linearis (1902) and G. saxicola (1905) from the same lake. He also described G. nigricans (1902), which he found not far from Lake Geneva in Mategnin and a marsh near Rouelbeau.