(de Haan, 1839)
The carapace behind the orbital region is subcircular and pronouncedly convex, the regions are fairly well defined; the dorsal surface is closely covered with tubercles of unequal sizes, interspersed with fine tomentum. The gastric region is mounted with two conical spines placed in the median line; the cardiac region with two conical tubercles side by side, which are surrounded by small tubercles; the intestinal region with one or three large dorsal tubercles and also two spines side by side on the posterior margin. The hepatic region has a large lateral spine followed by a smaller one on its posterior slope; the branchial region has three large marginal spines and a dorsal mesobranchial one, which is usually worn out in full-grown specimens.
The true rostral spine is rather small and conical; the pseudorostral spines are horizontal, nearly one sixth the length of the carapace and are not much divergent. The supraocular eaves are very thick, its posterior angle ends in a large tooth, while it has no preocular tooth.
Intercalated spine sharp and elongate triangular in shape. Postocular tooth triangular and its inner surface hollowed, the two upper orbital fissures are very narrow.
The basal segment of antenna is very broad and armed with two terminal spines, one ventral and the other lateral; the flagellum is very slender and slightly exceeding the length of pseudorostral spines. Infraorbital tooth is rudimentary. Ischium of the external maxillipeds has a deepish channel, extending from the base towards the antero-internal angle; the channel has a shallow outer branch near the middle. The merus is broad and its anterior border very thin.
The arm of chelipeds is dorsally covered with sharp tubercles and distally armed with a sharp spine; the wrist is also dorsally covered with sharp tubercles; the palm is entirely smooth and moderately swollen on the inner surface; the fingers not gaping and their cutting edges are entire. Ambulatory legs are cylindrical and unarmed, dactylus being strongly incurved.
Abdomen in both sexes consists of seven distinct segments. (Sakai, 1937: 302)
Type locality: Japan.
Range: Japan - (de Haan), Tokyo Bay (Ortmann, 1893), Omae-zaki, Owase, west of Kagoshima Prefecture, Goto-retto, Tsushima Strait and north-west of Nagato (Yokoya, 1933), Shimoda (Sakai, 1935), Tateyama Bay, Sagami Bay, Shimoda, Ise Bay, Nanki Shirahama, Gobo and Nagasaki (Sakai, 1938a), Sagami Bay (Sakai, 1965b), Tsushima Strait and Genkai-nada (Takeda, 1973c), Tokyo Bay, Sagami Bay, Shimoda, Wagu, Kii Nagashima, Kii Minabe, Tosa Bay, and Nagasaki (Sakai, 1976a), Yamagata Prefecture (Suzuki S., 1979), Kii Minabe (Miyake, 1983), Nagasaki (Griffin & Tranter, 1986a); Korea - Cheju-do (Kim, 1973, Kim & Chang, 1985); East China Sea (Takeda & Miyake, 1969e, 1972); 50-200 m.