Ortmann, 1893
The carapace broadly pentagonal in outline, the posterior border almost straight but in the juvenile stage it is concave. The central gastric region and also the surface inside the antero-lateral margin are deeply hollowed, the former is triangular in outline, being bounded on either side by a raised carina leading from the raised mesogastric region toward the centre of the branchial region, where a conical spine is developed. The cardiac region is also convex, bearing a conical spine. The posterior and lateral slopes of the clypeiform expansions are marked with beaded tubercles.
The rostrum is broad and triangular, obtusely angular at tip and depressed on the upper surface. Behind the orbits, the hepatic margins are entire, while the antero-lateral border behind the hepatic margin is cut into about nine triangular teeth. The postero-lateral and posterior borders are indistinctly crenulated. The basal segment of antenna is short and broad, filling the base of the inner orbital hiatus; the epistome is smooth, a characteristic of this genus.
Arm of chelipeds depressed and its anterior and posterior borders denticulate, two or three teeth being larger; the wrist very small; palm distally thickened, its outer border has only one or two teeth, while the inner upper border has about eight erect triangular teeth; the fingers gaping at base and markedly incurved at tip. Ambulatory legs are pronouncedly depressed and cristate on both borders; the posterior border of merus of all pairs and also that of carpus and propodus of last pair are sharply denticulated. (Sakai, 1938: 346)
Type locality: Sagami Bay, Japan.
Range: India; Japan - Sagami Bay (Ortmann, 1893, Sakai, 1965b), Shimoda (Sakai, 1935), Misaki, Shimoda, Gobo and Nagasaki (Sakai, 1938a), Genkai-nada (Takeda, 1973c), Sagami Bay, Izu Peninsula, Mikawa Bay, Kii Peninsula, Tosa Bay and Nagasaki (Sakai, 1976a); Taiwan; China - Beibu Gulf (Shen et al., 1982), South China Sea (Dai & Yang, 1991); Philippines - south of Manila Bay (Serène & Vadon, 1981); 30-180 m.