A revision of Cryptosoma Brullé, 1837 and Cycloes de Haan, 1837 (Crustacea: Brachyura: Calappidae)

The nomenclature of the calappid genera Cryptosoma Brullé, 1837 and Cycloes de Haan, 1837 is reviewed. Cryptosoma Brullé, 1837 is recognized as an available genus name of decapod Crustacea and not a junior homonym of Cryptosoma Berthold, 1827 (Insecta, Coleoptera). The Eastern Pacific and Adantic species are assigned to Cryptosoma and Indo-Pacific species to Cycloes. The revision of these genera includes descriptions of two new species, one assigned to Cryptosoma and the other to Cycloes, descriptions of all species, distributional data, synonymies, figures of first and second pleopods, photographs and a key.