Sakai, 1961
The colour in the fresh specimen is dainty, the carapace having fourteen purplish blue spots or circles fringed with brownish red on a uniformly brownish ground, the chelipeds and ambulatory legs have also such markings on the merus, carpus and propodus. No mention has been made of such a colour pattern in Edmondson's species.
The carapace closely resembles that of X. glabrous, but the breadth in the new species is somewhat smaller, the proportion of length to breadth being 1 : 1.54, instead of 1 : 1.6 as in the Hawaiian species. The areolation of the dorsal surface of the carapace is much like that of the Hawaiian species, the gastric, hepatic and branchial regions being delimited by shallow grooves, but these regions are not so markedly sculptured as in that species. The front is bilobed, each lobe is slightly arched with a rather faint notch at a short distance from the orbit.
The antero-lateral borders consist of five teeth, of which the first, or the outer orbital one, is very small, the second is of moderate size but obtuse, the third and fourth are equally large but obtuse, the last one is very small and indistinct.
In the fresh condition there are fourteen large round circular spots of purplish blue, fringed with brownish red; they are transversely arranged in four rows, i.e., two near the frontal region, five on the level of the third antero-lateral teeth, and again five on the level of the last antero-lateral teeth, and finally one on each side of the intestinal region.
The chelipeds are also marked with similarly coloured spots, of which three are on the carpus and one on the propodus near the articulation with the movable finger. The carpus has a shallow subcircular groove on the upper surface; the propodus has three longitudinal ridges on the outer surface and also a shallow groove near to and parallel with the upper border. The black colour of the immovable finger intrudes deeply on to the inner surface of the propodus. The ambulatory legs are very slender and naked; the merus has two coloured spots, the one proximal and the other distal; the carpus and propodus are also marked with the same colour pattern near the distal portion.
The anterior pleopod of the male is strongly arched. There is a collar-like projection beyond the tip and about twenty-one long setae arranged in three rows along the groove near the distal portion. In the Hawaiian species, according to Edmondson, the male pleopod has the apex divided into two pointed extremities. (Sakai, 1961)
Type locality: Okinoyama, off the coast of Jogashima, Sagami Bay, Japan, 80 m.
Range: Japan - Sagami Bay and Tosa Bay (Sakai, 1961), Sagami Bay, Tosa Bay and Kii Nagashima (Sakai, 1965b), Sagami Bay, Kii Nagashima, Tosa Bay, and Ishigaki-jima (Sakai, 1976a), Shiono-misaki (Takeda, 1979a), Nanki Koza (Miyake, 1983); 15-85 m.