Shen, 1932
Diagnosis: Dactylus of third maxilliped small, attached to penultimate segment a little behind its middle and not reaching its extremity. Propodus bluntly rounded at its extremity. Third ambulatory leg longest (on right side). Carpus and propodus of third leg subequal in length, the former about twice as long as that of fourth, the latter subequal to that of fourth in length. Dactylus of first leg shorter than second, of third (on right side) about twice as long as second, of fourth longest, even longer than propodus of the same leg, nearly straight, tapering and hairy.
Description of female: Carapace rather broad. Proportion of length to breadth about 1: 1.4, broadest at bases of second pair of ambulatory legs. Surface glossy, slightly convex. Regions indistinct. Its antero-lateral and postero-lateral angles rounded, lateral margins convex, posterior margin slightly concave at middle.
Front narrow, strongly deflexed, margin truncate from its dorsal aspect, its median portion triangular from its frontal aspect.
Orbit rounded. Eye-peduncle very short, its distal end ball-shaped in orbita.
Antenna large, obliquely concealed under front. Antenna very small, situated below antero-lateral angle of front or between eye and antennula.
Endostome depressed and produced anteriorly to tip of front, forming a septum between antennulae. Buccal cavity broad but very short.
Third maxillipeds glossy. Ischium-merus large, very oblique, its outer margin arcuated and inner concave, bearing some plumose setae. Palpus reaching little beyond inner angle of merus. Propodus large, bearing a small dactylus on basal third of its inner margin. Dactylus not extended beyond tip of propodus. Exognath elongate oval, its flagellum two-segmented.
Cheliped smooth. Coxa and basi-ischium very short. Merus cylindrical. Carpus longer than broad. Palm distally broader than basally, longer than fingers. Fingers sharply pointed, with hairy margins. Movable finger bearing a tooth at its basal third. Immovable finger bearing two smaller ones near its base, of which the distal one is larger than basal. Tip of movable finger more curved than that of immovable.
Ambulatory legs smooth, third pair longest. Carpus and propodus of third leg subequal in length, the former usually longer than that of either of the first two legs and about twice as long as that of the fourth leg. Dactyli of first two pairs short, conical, of third pair long, of fourth still longer, even longer than propodus of the same leg, nearly straight, tapering and hairy, hairs usually on its inner margin and around its distal portion.
Abdomen large. First segment with its distal margin concave at middle, lateral portion partly covered by carapace. Second with its distal and basal margins more or less convex. Third with its distal margin straight. Fourth, fifth and sixth each with its basal margin smoothly convex and distal smoothly concave; the former always broader than the latter. Seventh with its distal margin slightly convex.
Description of male: Carapace roundish, harder than that of female. Front more produced anteriorly. Abdomen narrow and elongate. First segment converging distally. Second with its median length greater than lateral. Third with its distal and basal margins slightly concave, lateral convex. Fourth shorter than fifth, each with its basal margin broader than distal. Sixth broader than long, its lateral margins slightly convex. Seventh longer than sixth, its margin broadly rounded. Sixth and seventh each with a part of its lateral margin folded internally. First male abdominal appendage with its distal portion curved laterally and bearing a small pointed tip. (Shen, 1932: 131)
Type locality: Qingdao, Shadong Peninsula.
Range: Japan - Tokyo Bay (Ortmann, 1894a), Tokyo Bay, Misaki, Shimoda, Aichi, Ise Bay, Nanki Shirahama, Miyazaki Prefecture, Hakata Bay and Nagasaki (Sakai, 1939), Shimoda, Aichi Prefecture, Ise Bay and Hakata Bay (Sakai, 1939), Sagami Bay (Sakai, 1965b), Tokyo Bay, Sagami Bay, Izu Peninsula, Mikawa Bay, Ise Bay, Kii Peninsula, Seto-Naikai and Nagasaki (Sakai, 1976a), Amakusa (Yamaguchi et al., 1976), Yamagata Prefecture (Suzuki S., 1979), Tanabe Bay (Miyake, 1983), Otsuchi Bay, Iwate Prefecture (Takeda & Konishi, 1991), Yoichi, Oshoro, Tomari, Suttsu, and Usu (Komai et al., 1992); Korea - Inch'on (Sakai, 1939, 1976), Inch'on, Keijo and Toei (Kamita, 1941), Odong Island, Yuldo Island, and Yeong-jong Island (Kim, 1973); China - Qingdao and Tsangkou, Shandong Peninsula (Shen, 1932), Jiaozhou Bay (Shen, 1937), Liaodong Peninsula and Shandong Peninsula (Dai & Yang, 1991).