(Balss, 1924)
Carapace longitudinally ovate, constricted behind the orbits and also behind the hepatic regions. The regions are separated by smooth broad grooves, their elevated surface being covered with numerous tubercles of various sizes; viz., a group of 13 or 14 tubercles in the middle of the gastric region and 5 to 7 on either side of this group; about 20 small tubercles on the interorbital surface; about 9 to 10 and a large central one on cardiac region; one large and 4 to 5 smaller on the intestinal area, and 2 high tubercles, one behind the other, on either side of this region, the posterior one of which being largest of all the tubercles of the carapace; 2 to 5 dorsal and 2 marginal ones on the hepatic region; a group of about 30 smaller and 5 larger ones on each branchial region.
The true rostrum is very low and indistinctly bilobate, the pseudorostral spines are very short and widely separated by a median U-shaped sinus; they are broad at base and sharply pointed at tip, their outer margins being subparallel. Supraocular eaves are thick, no preocular spine, but the posterior angle forms an indistinct tooth; the intercalated, postocular and infraorbital lobes are very prominent and broad as aforementioned; the basal segment of antenna is also very broad and forms the ventral floor of the somewhat tubular orbit.
The ischium of the external maxillipeds is longitudinally sulcated, the merus produced at the antero-external angle; both segments are entirely fused with each other in the outer half of their width, in the inner half, however, they are separate.
Both chelipeds and ambulatory legs are very slender and thickly covered with tomentum, a small tubercle on the outer border of wrist, otherwise each segment is unarmed.
Abdomen of both sexes consists of seven distinct segments. (Sakai, 1938: 273)
Type locality: Misaki, Sagami Bay, Japan.
Range: Japan - Mikuni (Yokoya, 1933), between Ito and Hatsushima and Manazuru (Sakai, 1935), Sagami Bay and near Shimoda (Sakai, 1938a), Sagami Bay (Sakai, 1965b), Sagami Bay, Izu Peninsula, Tosa Bay and Oki Island (Sakai, 1976a), Okinose (Griffin & Tranter, 1986a); East China Sea (Takeda & Miyake, 1969e); 50-540 m.