REPORT ON THE AMPHIPODA. 1591 



gnathopods, may prove to be characters sufficiently constant to warrant the establish- 

 ment of a distinct species, but in the meantime, as the specimen is not adult, the 

 reparation of it from the older species may await further information. 



Oxycephalies longiceps, Claus (PI. CCI V., B). 



1879. Oxycephalic longiceps, Claus, Die Gattungen und Arten der Platysceliden, p. 48. 



1887. „ „ Bovallius, Systematical List of Amph. Hyper., Bihang till K. 



Svensk. Vetensk.-Akad. Handl., Bd. 11, No. 16, p. 37. 

 1887. „ „ Claus, Die Platysceliden, p. 72, Taf. xxiv. fig. 10. 



Head considerably longer than the perseon, not showing any constriction at the neck 

 while in position, the rostrum acute, not very much shorter than the ocular region, the 

 edges smooth ; the coalesced fifth and sixth segments of the pleon about as long as 

 the telson and scarcely broader, the postero-lateral angles of the first three pleon-segments 

 acute, not much produced. 



Upper Antenna? attached a little in advance of the eyes, straight in the specimen ; 

 the first joint of the peduncle more than twice as long as the second ; the first joint of 

 the flagellum a little longer than the first of the peduncle, narrowing distally, with a few 

 apical and subapical filaments, the second joint not half the length nor nearly half the 

 breadth of the first, the third as long but only half as broad as the second. 



Lower Antenna? (of the young male), the three free joints of the peduncle subequal, 

 short, smooth, comparatively thick, closely folded, indistinctly jointed ; the flagellum of 

 one joint, tapering, not acute, nearly as thick as the peduncle, but shorter than any of 

 its joints. 



Mandibles. — The palp not as yet distinctly jointed. 



First Gnathopods. — Side-plates with the lower front angle acute, not produced. The 

 first joint reaching a little below the side-plate ; the second joint broader than long, with 

 one subapical spinule on the convex hind margin ; the third joint little longer than the 

 second, distally widened, with three spinules on the convex hind margin ; the wrist 

 much longer and broader than the hand, with numerous spines on the inner surface and 

 along the minutely pectinate hind margin, which is apically only a little outdrawn but 

 into a very acute point ; the hand with numerous spines on the inner surface, the front 

 margin very convex, the hinder nearly straight and smooth, with a little apical tooth ; 

 the finger short, very acute. 



Second Gnathopods. — Side-plates with the lower front angle acute and a little 

 outdrawn. The branchial vesicles simple. The third joint considerably longer than the 

 second, with one spinule at the apex of the hind margin ; the wrist much more widened 

 than in the first pair, w T ith few spines on the inner surface and hind margin, the latter 

 apically outdrawn almost to the end of the hand, the process at first broadly triangular, 



