(Sakai, 1933)
Carapace much wider than long, the proportion being 1:1.6; well calcified, smooth, and steeply rounding downward fore and aft. Antero-lateral margins are moderately rounded, and fringed with short pubescence from the posterior margin of the orbit to the lateral angle; similar pubescence border the carapace and rostrum on the interorbital line, and is dilated forwards mesially, the front being divided into two naked, concave portions.
Buccal cavern is small and triangular. Third maxillipeds are sparsely covered with feathered setae; exognath small, foliaceous in shape, not exceeding one third the length of the endognath. Ischio-merus joint broad, dilated on the antero-internal angle, palp is moderately stout, terminal segment jointed at the tip of the penultimate joint and furnished with several setae at the tip.
Abdomen has seven distinct segments in both sexes, with the third segment widest; terminal segment is oblong, especially in the male. Chelipeds stout, merus trigonal, with margins setose; carpus and propodus rounded moderately setose; fingers trigonal in shape, slightly incurved at the tip. First two pairs of ambulatory legs are long and stout, nearly twice as long as the carapace width, and are subequal in total length or the second pair is a little smaller; the third pair is distinctly more slender and does not exceed the propodus of the proceeding pair. These three pairs have dactyli of the same length and shape. The last pair is very small, not overreaching the merus joint of the third pair. (Sakai, 1933a: 143)
Type locality: Izu Shimoda, Japan.
Range: Japan - Izu Shimoda (Sakai, 1933a, 1939), Shimoda and Kii Nagashima (Sakai, 1976a).