The International Commission on Zoological Nomenclature has used its plenary power to emend the spelling of the family-group name Cepheidae Berlese, 1896 (Acariformes) to remove homonymy with Cepheidae Agassiz, 1862 (Cnidaria). The stem of the acariform generic name Cepheus Koch, 1835 has been emended to Cepheus- to give Cepheusidae Berlese, 1896, while the stem of the cnidarian generic name Cephea Péron & Lesueur, 1810 remains unaltered.