The carapace is sub-rhomboidal in outline; the entire surface is thickly covered with round flattened tubercles of various sizes. The front is markedly produced forward and upward, forming a thick neck, and its anterior border is faintly bilobate.
The gastric region is very narrow, rather depressed, and studded with medium-sized pearly tubercles. The cardiac region is also small and very narrow, but slightly convex and thickly beset with rather large pearly tubercles. The intestinal region is markedly convex, semicircular in outline, bordered laterally and posteriorly by elongate tubercles and its posterior edge is markedly upturned.
The upper surface of the hepatic region is depressed, is bordered by a series of elongate tubercles and is studded with a few round tubercles; below and in front of this facet, a small obtuse hepatic lobe is visible. On the antero-lateral margin, behind the hepatic facet, is another semicircular facet projecting obliquely downward. The wing-like lateral lobe, bounded by a series of elongate tubercles, is upturned at the apex, whence a transverse crest of tubercles crosses the branchial region and ends in a small triangular or somewhat irregular facet, also elegantly bordered by a series of tubercles. The branchial area in front of the crest is flat or depressed and thickly covered with tubercles of various sizes.
On the postero-lateral margin there is an indistinct protuberance, which is obsolescent or absent in some specimens. The posterior margin is just as wide as the front and has three low, indistinct protuberances.
The chelipeds are robust and symmetrical, the merus has two obtuse processes on the posterior border, one being median and low, the other subterminal and prominent. The carpus bears two rows of tubercles on the upper outer border. The propodus has a prominent process near the distal end of the outer border. All parts of the ambulatory legs are thickly covered with granules, the merus bears a prominent process in the middle of the anterior border; the carpus and propodus have a series of elongate tubercles along the anterior or upper border.
The external maxilliped has the merus a little shorter than the ischium and is obtusely pointed at the tip; the exognath is not so broad as that of genus Merocryptus; its tip is rounded, not much exceeding the middle point of the merus.
The male abdomen is broadly triangular in outline; it is apparently broader than in the genus Merocryptus, and its terminal segment is rather short and peculiar in having a trilobate outline; the third to fourth abdominal segments of the male are fused together, but there remains a suture line on either side between each segment. The first male pleopod is markedly curved inward near the apex, and furnished with several long setae; in Merocryptus the tip of same is straight and flat, the outer border being very thickly furnished with soft hairs. (Sakai, 1963)
Type locality: between Hayama and Misaki, Miura Peninsula, Sagami Bay, Japan.
Range: Japan - Sagami Bay and Kii Nagashima (Sakai, 1963, 1965, 1976), Kurosaki, Miura City, and Tosa Bay (Muraoka, 1998); between high and low tidal zones.