(Sakai, 1939)
Carapace entirely naked and smooth, rounded quadrangular in outline but the lateral borders are obscurely angular in the middle; the front not at all produced beyond the eyes and the posterior border almost straight. The external maxillipeds are covered with very short pubescence, the ischium-merus joint very broad and its outer border expanded; the dactylus of the palp is spoon-shaped and a good deal exceeding the tip of the propodus, which is moderately narrowed distally.
Chelipeds are entirely naked, but the palm is sparingly hairy along the inferior border near the distal half, the cutting edge of immovable finger bears 8 or 9 denticles near the proximal half, its distal half is entire and the tip incurved. The cutting edge of the movable finger bears a triangular tooth near the proximal end, and is followed by a number of fine irregular denticles, the distal half being entire.
Ambulatory legs are very thin, anterior three pairs are subequal in length and are equally thick, the last pair somewhat slender and short, the carpus and propodus of all pairs are fringed with a row of longish feathered hairs. (T. Sakai, 1939: 595)
Type locality: Asamushi, Mutsu Bay, Japan.
Range: Japan - Mutsu Bay (Sakai, 1939), Mutsu Bay and coast of Hidaka Province, Hokkaido (Sakai, 1976a), Otsuchi Bay, Iwate Prefecture (Takeda & Konishi, 1991), Kikonai, Usujiri, Muroran, Hidaka Province, Akkeshi, Abashiri, Nemuro, Ohmu, Okkobe, and Wakkanai (Komai et al., 1992), Soya Strait (Takeda & Miyauchi, 1992), Soya Strait off Cape Noshappu and Otsuchi Bay, Iwate (Takeda & Masahito, 2000).