(Miers, 1879)
Carapace behind the orbits almost triangular in outline, regions deeply defined and covered with numerous tubercles. There are some hairs on protogastric, interorbital and lateral branchial surfaces, otherwise the carapace is naked. The gastric region has two median tubercles, of which the anterior one is acuminate and erect; on either side of this median row are three tubercles. Cardiac region markedly convex, armed with two median flat tubercles and three small ones on the anterior slope. The intestinal region little produced posteriorly and its summit armed with a tubercle. Hepatic region has five or six tubercles, of which one at the posterior angle is very large and dilated laterally into an obtuse lobe. The epibranchial region convex, armed with three large tubercles and seven or eight indistinct tubercles; meso- and metabranchial regions are continuous and low, with five or six small tubercles and with a large forwardly curved epibranchial spine at the lateral angle. On either side of the cardiac region are also four or five tubercles which are continuous and form an elongate elevation.
The pseudorostral spines are slender, horizontal, divergent at an angle of about 30°; they are covered with long hairs especially along the inner and outer borders. The preocular spine very prominent, the upper orbital sinus narrow; postocular cup very broad, its lower anterior edge is somewhat produced. Basal antennal segment has a usual terminal spine and an obtuse tubercle on the outer border near the base; the following two peduncular segments are long and flattened. Infraorbital lobe vestigial. The ridge of the pterygostomial region armed with six or seven tubercles; there are also nine or ten tubercles on the lateral surface of the carapace above the epimeral ridge.
Chelipeds are very stout; arm prismatic, with two prominent processes on the upper border near the base, its inner border cristate and the lower border with four or five tubercles; wrist short and irregular in shape, its inner border cristate and its upper and outer surfaces with 4 or 5 short cristate wrinkles; palm compressed and its upper border sharply cristate but the lower edge scarcely so; movable finger is armed proximally with a large tooth, distal half of both fingers being uniformly denticulated. Ambulatory legs are compressed and covered with pubescence, the dactylus is curved inwards and its tip naked.
Abdomen of both sexes consists of seven distinct segments. (Sakai, 1938: 285)
Type locality: near Shiriya-zaki, Aomori Prefecture, Japan.
Range: Japan - Shioya-zaki, Todo-saki, between Shiriya-zaki and Todo-saki, Shiriya-zaki, and Kinkazan (Yokoya, 1933), Shimoda (Sakai, 1935a), Misaki and Onagawa (Sakai, 1938a), Sagami Bay (Sakai, 1965b), Shiriya-zaki, off Kinkazan, Shioya-zaki, Inubo-zaki, Boso Peninsula and Sagami Bay (Sakai, 1976a), Sakata, Yamagata Prefecture (Suzuki S., 1979), Kamaishi (Miyake, 1983), Tsugaru Strait and Funka Bay (Komai et al., 1992), Suruga Bay (Takeda, 1997); 85-595 m.