(Sakai, 1935)
The new species dedicated to Dr. H. Balss seems to come near the genotype, Ralumia dahli Balss (1933) in the general appearance, but it can be easily distinguished by the following particulars, while, on the other hand, it seems to show transition to the genus Calmania, as described further on.
The carapace more vaulted than in Calmania prima, the antero-lateral borders are shorter and also more arcuated, armed with three obtuse tubercles behind the orbital angle.
The front is as wide as in C. prima, but more strongly inclined downward, and it is obscurely bilobed, the medial notch being very small and shallow. A transverse ridge which is furnished with long setae, traverses the frontal region, and in consequence of it, the free edge of the inclined front is hardly visible from above.
Carapace is everywhere eroded with shallow pits, which are furnished with some brown setae of various length.
On the eye-peduncle a dull tubercle is present near the middle of its upper, anterior border, and the distal end of the peduncle is ornamented with several brown setae above the cornea. Antenna is as in Ralumia dahli but the basal segment is longer, though it does not touch the front. Buccal cavity anteriorly widened. External maxillipeds close the buccal cavity but not so completely as in Calmania prima; the antero-external angle of the merus is produced. The ridge which defines the efferent branchial channel is obscure.
Female abdomen consists of seven, relatively narrower segments, of which the terminal segment is wider at the base and the penultimate segment is narrower. Male abdomen left unknown as in the genotype. Chelipeds very rough with tubercles and granules. Carpus with a stout tooth on the inner angle, and a smaller indistinct one below it; the upper surface pitted. Palm compressed, the upper ridge indistinctly granulated, and with several hairs; the outer surface coarsely tuberculated, the tubercles being arranged in longitudinal rows, and are larger in size than in Ralumia dahli. Fingers also compressed and longitudinally ridged, a wide hiatus is left at the base; distal half of the fingers form a cutting edge, which is armed with four sharp teeth, the distal ends are pigmented and slightly crossing each other in normal condition.
Ambulatory legs similar in shape, each segment is uneven and minutely denticulated on anterior and posterior borders. (Sakai, 1935)
Type locality: between Ito and Hatsushima, west of Sagami Bay, Japan.
Range: Japan - between Ito and Hatsushima (Sakai, 1935, 1939, 1976), south off Tsushima (Takeda, 1973), Sagami Bay (Sakai, 1965b, 1976), Shiono-misaki (Takeda, 1979a), Suruga Bay (Takeda, 1997); East China Sea (Takeda & Miyake, 1968c, 1972); South China Sea (Serène & Lohavanijaya, 1973); 35-320 m.