Johann Carl described 390 species or subspecies of millipedes during his long career at the Muséum d'histoire naturelle de Genève, studying specimens collected on his own expeditions and on those of other, mainly Swiss, naturalists. The type specimens deposited in Geneva are enumerated, and the type specimens that could be located in other collections in other museums are reported. Lectotypes are designated for 17 species: Brachyspirobolus aequatorialis (Carl, 1909), Carlopeltis alatus (Carl, 1914), Mastigorhacus alatus (Carl, 1912), Salpidobolus annulipes (Carl, 1912), Erythrhacus arietis (Carl, 1912), Argentocricus bernardinensis (Carl, 1918), Trigoniulus bitaeniatus Carl, 1912, Desmocricus conjunctusCarl, 1918, Polylepis elberti Carl, 1912, Trigoniulus incommodus Carl, 1912, Stenobolus insularisCarl, 1918, Salpidobolus lateralis (Carl, 1912), Dinematocricus lombokensis (Carl, 1912), Prepodesmus longipes (Carl, 1913), Arostrophus mertoni (Carl, 1912), Salpidobolus moenensis (Carl, 1912) and Eucarlia velox (Carl, 1912). Polydesmus carli nom. nov. is introduced as a replacement name for Polydesmus japonicusCarl, 1902, a junior homonym of Polydesmus japonicusPeters, 1864. Odontopyge johanncarli nom. nov. is introduced as a replacement name for Odontopyge fasciataCarl, 1905, a junior homonym of Odontopyge fasciataAttems, 1896.