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Show 18/9.] THE C O R E A N A N D JAPANESE SEAS. 53 ALPHEUS BIS-INCISUS. Alpheus bis-incisus, De Haan, Faun. Japon., Crust, pi. xiv. fig. 3 on plate, Alpheus avarus in text, I.e. p. 17; Stimpson, Proc. Ac. Nat. Sci. Phil. p. 30 (1860), nee Alpheus avarus, Fabricius, fide Stimpson. Two specimens are in the collection, one female, in fine condition, obtained at Katsura, on the east coast of Japan, and a smaller individual, without definite locality. Dr. Stimpson, in his report, quoted above, retains the name of bis-incisus for a species which he regards as distinct from the Alpheus avarus of Fabricius, with which, on the other hand, he considers the Alpheus strenuus of Dana (Expl. Exp., Crust, p. 543, pi. xxxiv. fig. 4), from Tongatabu, identical. Both species were collected in the American expedition to the North Pacific; and as I do not know the grounds on which he separated them, I follow for the present his nomenclature-although it would appear from comparison of the figures and descriptions that the Alpheus bis-incisus and A. strenuus are identical, while the A. avarus of Fabricius is described in such general terms that it would apply to several very different species ; indeed by Milne-Edwards it is thought to be probably identical with Alpheus brevirostris of Olivier, which belongs to a different section of the genus from A. bis-incisus and A. strenuus. ALPHEUS JAPONICUS, sp. n. Carapace smooth. Rostrum narrow-triangular and acute, projecting rather beyond the orbits, which themselves project beyond the lateral margins of the carapace. Orbits without spines. Between the eyes and rostrum the carapace is very slightly concave. Second joint of the antennules not twice as long as the first. Anterior legs very unequal, the larger with the arm short, trigonous, enlarging distally, with a small spine at the distal end of its upper and lower margin; wrist very small, transverse; hand (with fingers) laterally compressed, very slightly contorted, nearly three times as long as broad; palm smooth, not cristate above, with the upper and lower margins straight and terminating in an acute lobe a short distance behind the articulation of the fingers; on the inner and outer sides of the palm, near the upper margin, is a longitudinal depression gradually obliterated towards the proximal extremity, that on the inner surface is narrow and triangulate, that on the outer broader and oblong in shape ; the upper finger is broadest and rounded at its distal extremity, with a large tooth on its inner margin, fitting into a corresponding cavity on the inner margin of the lower finger; both are slightly hairy: the other anterior leg is slightly longer but very much more slender than the first described, which it resembles in the shape of the arm and wrist; the hand is very slender, smooth, and straight, no thicker than the wrist, the fingers hairy, and very sliehtlv longer than the palm ; the first joint of the wrist is longest, th third subequal and shortest, the fifth but little longer than the |