• Leiosoma Cotteau in Cotteau & Triger, 1869 † accepted as Trochalosoma Lambert, 1897 †
• Leiosoma Silvestri, 1897 accepted as Catharosoma Silvestri, 1897
• Leiosoma Victor (Motschoulsky), 1839 accepted as Hirudisoma Fanzago, 1881
• Liosoma Brandt, 1835 accepted as Chiridota Eschscholtz, 1829
• Liosoma Conrad, 1874 † accepted as Wesselinghia Kadolsky, 2021 †
• Lirosoma Conrad, 1862 †
• Litosoma Beneden, 1872 accepted as Litomosa Yorke & Maplestone, 1926
• Lomasoma Manter, 1935
• Longosoma Hartman, 1944 accepted as Heterospio Ehlers, 1874
• Longosoma Wesselingh & Kadolsky, 2006 † accepted as Wesselinghia Kadolsky, 2021 †
• Loxonema J. Phillips, 1841 †
• Loxosoma Keferstein, 1862
• Loxostoma Bivona e Bernardi, 1838 accepted as Rissoa Desmarest, 1814
• Loxostoma Howe, 1930 † accepted as Loxostomum Ehrenberg, 1854 †
• Loxotoma P. Fischer, 1885 † accepted as Palaeoloxotoma Hansen, 2019 †
• Loxsoma R.Br.
• Lygosoma Hardwicke & Gray, 1827
• Lyosoma C. A. White, 1876 † (uncertain > taxon inquirendum)
• Toxosoma Conrad, 1874 †