(Ortmann, 1893)
The carapace very broadly triangular, the dorsal surface marked with three obtuse carinae, one in the median line and the other on the branchial region parallel to the antero-lateral border. There are three gastric tubercles, two being placed side by side in front of the posterior median one; the cardiac region with a high median tubercle, in front and in rear of which is a smaller tubercle. The branchial region has a tubercle on the said oblique carina near the postero-lateral border. The rostrum is medially produced into an obtuse tooth; the upper orbital sinus distinct. The hepatic region is fused with the postocular tooth and is produced into a lobe near the branchial margin; the latter is armed with 11 or 12 laciniated teeth, the last one being predominant in size, forming the lateral angle of the carapace. The postero-lateral border armed with a tooth in a line with the branchial carina; a tooth on either side of the posterior border. The basal segment of antenna is broad and large, filling, though somewhat loosely, the inner orbital hiatus. The pterygostomial region is markedly carinated.
The chelipeds are slightly unequal, the merus not much compressed, the upper surface being armed with two or three spines, its anterior border finely denticulated and the posterior border with four or five sharp spines. The inner border of wrist and palm is finely and irregularly denticulated, while the outer border of the latter segment bears five or six large obtuse teeth. Ambulatory legs are markedly depressed and crested on both borders. The dorsal surface of carapace is usually smooth but in some specimens covered with minute pits. (Sakai, 1938: 339)
Type locality: Sagami Bay, Japan.
Range: Japan - Sagami Bay (Ortmann, 1893, Sakai, 1965b), Inubo-zaki, Tanabe, Bungo Strait, Ashizuri-misaki, Goto-retto, Mikuni, Noto, Toyama Bay, off mouth of Mogami-gawa and Jusan-gata (Yokoya, 1933), between Ito and Hatsushima (Sakai, 1935, 1938), Sagami Bay, Mikawa Bay, Kii Nagashima and Tosa Bay (Sakai, 1976a), Yamagata Prefecture (Suzuki S., 1979), Kii Susami (Miyake, 1983), Tosa Bay (Baba, 1986); East China Sea (Takeda & Miyake, 1969e); South China Sea (Dai Yang, 1991); Philippines - north of Lubang Island (Serène & Vadon, 1981); 50-200 m.