18/9.] THE COREAN AND JAPANESE SEAS. 53 



Alpheus BIS-INCISUS. 



Alpheus bis-incisus, De Haan, Faun. Japon., Crust, pi. xlv. fi<r. 3 

 on ^Isiie, 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 indi- 

 vidual, 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 compari- 

 son of the figures and descriptions that the Alpheus bis-incisus and 

 A. strenuus are identical, while the A. avarus oi Fabricius is de- 

 scribed in such general terms that it would apply to several very 

 different species ; indeed by JNlilne-Edwards it is thought to be pro- 

 bably 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, pro- 

 jecting 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 autennules 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 gra- 

 dually obliterated towards the proximal extremity, that on the inner 

 surface is narrow and triangulate, that on the outer broader and ob- 

 long in shape ; the upper finger is broadest and rounded at its distal 

 extremity, with a large tooth on its inner margin, fitting into a cor- 

 responding 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 

 slightly longer than the palm ; the first joint ot the wrist is longest, 

 the third subequal and shortest, the fifth but little longer than the 



