528 FAUNA HAWAIIENSIS 



less conspicuously widened, nor can I guarantee that the armature of spines on the 

 uropods is precisely the same in both forms. 



In the second gnathopods of the male the large oval sixth joint has a smoothly convex 

 palmar margin, bordered with submarginal spinules. Round this the long finger curves, 

 closely fitting it, but laying its apical part within a long groove which succeeds the 

 palmar margin. Kroyer, it should be observed, neither figures nor describes this apical 

 part of the finger, which is membranaceous in appearance, slender, but not very acute 

 at the point. According to Kroyer the telson is at the apex flatly rounded off or nearly 

 truncate. In the specimens which 1 have examined in this respect it is minutely 

 emarginate. 



The peraeopods are without specially dilated joints. The second joint of the 

 fourth peraeopods is much more narrowly oval than that of the fifth pair; the second 

 joint of the latter has its hind margin rather strongly serrate. The first pair of uropods 

 have the outer ramus free from spines except at the apex, but this character is common 

 to various other species in the family. 



Length reaching 12 mm. 



Orchestia pickeringii Dana. 



Plate XXI. B. 



1S53. Orchestia pickeringii Dana, U. S. Exploring Exp., Crustacea, pt. 2, 

 p. 882, pi. 59, f. 9 a — f 



Dana, at p. 1595 of his great work, states that 'the locality of Orchestia 

 pickeringii, was Kauai or Oahu, Sandwich Islands.' He does not give any further 

 detail as to the habitat. Stimpson records it from California, without comment. The 

 specimens obtained by Mr Perkins are labelled " Honolulu. Oahu. 2000 ft." They 

 were taken on the same date and at the same height as specimens of Orchestia platensis. 

 and the question suggested itself whether by chance the two species might be identical. 

 There is considerable general resemblance, but that perhaps is only as much as to say 

 that both are species of Orchestia. The idea of uniting them is, 1 think, untenable. 



The second gnathopod of the male has a very large sixth joint, the sloping palmar 

 margin ot which is in these specimens diversified b\- two spinulose projections, in 

 correspondence with which the strongly curved finger has a very sinuous inner margin, 

 its apex entering a small pocket or groove of the somewhat flattened hind margin of the 

 sixth joint. Dana describes the palm as having two very low prominences near base of 

 finger, whereas these are very marked, and one of them is remote from the base of the 

 finger. But an Oahu specimen from the Copenhagen Museum and an Australian 

 specimen from the Australian Museum, show modifications approximating to Dana's 



