Ortmann, 1892
The carapace is rounded pentagonal, or perhaps can better be described as circular in outline. The marginal lamelliform expansions are somewhat narrower than in Cryptocnemus pentagonus. The front is bidentate, each denticle is separated by a U-shaped median sinus and is bent upward. The anterior angles of the hepatic laminae are as also the the junction of the antero-lateral and postero-lateral laminae, produced to form an obtuse tooth.
Chelipeds are much slenderer than in Cryptocnemus pentagonus, and the carinae of each segment are also narrower; the fingers are proportionally longer and slenderer. The ambulatory legs are also very slender. (Sakai, 1937)
Type locality: Sagami Bay, Japan, 180 m.
Range: Japan - Sagami Bay (Ortmann, 1892, Sakai, 1965b), Kagoshima and Bungo Strait (Yokoya, 1933), Misaki, Sagami Bay (Sakai, 1935), Sagami Bay and Kumano-nada (Sakai, 1937a), Tsushima Strait (Takeda, 1973c), Sagami Bay, Kii Peninsula, Bungo Strait, Kagoshima and coast of Fukuoka Prefecture (Sakai, 1976a), Suruga Bay (Takeda, 1997); East China Sea (Takeda & Miyake, 1970a); South China Sea (Dai & Yang, 1991); Sulu Archipelago (Ihle, 1918).