Balss, 1921
Carapace hexagonal, regions not well defined, usually with two strong tubercles on protogastric regions, but sometimes absent; surface covered with thick pubescent. Antero-lateral margins separated into four lobes; the first and second generally truncate, separated by narrow fissures, usually appearing fused, margins usually straight or distinctly concave, lined with many tubercles, often callositised, edge of lobes highly spiniform; third and fourth lobes distinctly dentiform, almost equal, directed strongly forward, margin of third lobe might be covered with some tubercles thus appearing straight. Postero-lateral margin mildly tuberculated, sometimes absent. Frontal margin with small median fissure, slightly deflexed, appearing straight from dorsal view, shallow median cleft, covered with many tubercles. Strong infraorbital and subhepatic teeth which are often covered with callosities. Merus of third maxilliped tuberculated. Chelipeds cylindrical, carpus without large tubercle or spine on distal inner margin of carpus. Ambulatory legs short and stout, ratio of length to width of fourth ambulatory merus 2.6-3.4, anterior margin of the ambulatory merus lined with very strong spinules. Distal part of G1 bends approximately 90° or very slightly downwards. (Chia & Ng, 1998)
Type locality: Sagami Bay, Japan.
Range: Japan - Kagoshima (Urita, 1918), Ibusuki (Urita, 1926a), Sagami Bay (Balss, 1921b), Tateyama and Sagami Bay (Sakai, 1932), Nagasaki (Sakai, 1934a), Shimoda (Sakai, 1935), Misaki (Yokoya, 1936), Izu-shoto (Sakai, 1938b, Suzuki K. & Kurata, 1967), Tateyama Bay, Misaki, Shimoda, Nanki Shirahama, Gobo and Nagasaki (Sakai, 1938b), Amakusa (Miyake, 1961), Kii Peninsula (Ozaki, 1964), Sagami Bay (Sakai, 1965b), Tokyo Bay, Sagami Bay, Kii Nagashima, Kii Minabe, Tosa Shimizu, and Nagasaki (Sakai, 1976a), Amakusa (Yamaguchi et al., 1976, Miyake & Takeda, 1978, Kikuchi, 1985, Yamaguchi et al., 1987), Shiono-misaki (Takeda, 1979a), Kominato (Imanaka et al., 1984), Nanki Shirahama (Miyake, 1983), Sagami Bay, Wagu, Misaki, Tosa Bay, Amakusa, Izu-Oshima, Nanki Shirahama, Manazuru, Kushimoto, Omae-zaki, and Ibusuki (Chia & Ng, 1998); Korea - Cheju (Kim, 1977); China - Cape Christiansen (Chia & Ng, 1998).