Stimpson, 1858
Carapace deep, subquadrilateral, broader than long, strongly convex fore and aft, declivous anteriorly. Regions indistinct, incompletely indicated. Antero-lateral angles rounded off. Antero-lateral margins curved, entire, sharp. Fronto-orbital border about two-thirds the greatest breadth of carapace. Front about a third the greatest breadth of the carapace. Eyestalks immovably fixed in the orbits and completely filling them. Eyes fairly well formed, but deficient in pigment. Antennules fold transversely in proper fossae. Basal antennal article short, the flagellum standing in the orbital hiatus. Buccal cavern quadrilateral, almost completely closed by the third maxillipeds. Third maxillipeds with the merus much produced at the antero-external angle; palp articulating with the antero-internal angle of the merus. Chelipeds subequal, more massive but decidedly shorter than the legs; palm short and compressed. Ambulatory legs slender, unarmed; dactyli styliform. (Guinot 1998)
Type species: Ceratoplax ciliata Stimpson, 1858.
Species treated:
Ceratoplax ciliata Stimpson, 1858
Ceratoplax sagamiensis Sakai, 1935
Ceratoplax truncatifrons Rathbun, 1914