The purpose of this application, under Articles 23.2 and 23.9.3 of the Code, is to conserve the usage of the genus-group name Cognettia Nielsen & Christensen, 1959 (enchytraeidae, Oligochaeta, Annelida) for a genus of annelid worms (type species Pachydrilus sphagnetorum Vejdovský, 1878 (‘1877’)). Cognettia, a name for a Holarctic genus of terrestrial and semi-aquatic annelid worms, is threatened by two subjective senior synonyms, Euenchytraeus Bretscher, 1906 and Chamaedrilus Friend, 1913. If these two names are considered synonyms, Euenchytraeus will replace Cognettia; if they are considered to represent two different genera, Chamaedrilus will replace Cognettia. In 2015 Martinsson et al. adopted the latter course, replacing Cognettia by Chamaedrilus, and allocated its species between both Euenchytraeus and Chamaedrilus. Cognettia is a widely used name and is well-known in the fields of soil biology, ecology, and ecotoxicology, and we propose it be given precedence over Chamaedrilus and Euenchytraeus, which had not been used as valid for almost a century.