630 ON CRUSTACEA BROUGHT BY DR WILLEY FROM THE SOUTH SEAS. 



Eyes rounded, with thirty to forty ocelli. In one set of specimens dark brown, 

 in another set black. 



First antennae scarcely as long as peduncle of second, tliird joint a little longer 

 than first or second, the latter two faintly separated; flagellum equal in length to the 

 peduncle, ten-jointed, with hyaline filaments. In the specimen dissected the first joint 

 of the flagellum was extremely short on one antenna, on the other it was the longest 

 of all ; each flagellum was ten-jointed. 



Second antennae nearly reaching the end of the fourth peraeon segment, fourth 

 and fifth joints of the peduncle subequal, flagellum nearly twice as long as the 

 peduncle, twenty-seven-jointed, sparingly ciliated. 



Upper lip short but broad, rather strongly emarginate. 



Mandibles. The left mandible shows on the cutting edge four distinct teeth, 

 though the two in the centre have their broad edges almost in a continuous line ; 

 in both mandibles the plate between the cutting edge and the molar has two or three 

 of the spines rather conspicuous; the third joint of the palp is shorter than the first, 

 broad, except at the truncate apex. 



First maxillae. The inner plate has the usual three thick plumose setae, of 

 which the lowest is the longest; the outer plate has twelve spines, all slender, three 

 or four very slight, one or perhaps more a little dentate, and on the plate's inner margin 

 are four minute teeth or spinules. As usual, the muscles of these appendages are very 

 powerful. 



Second maxillae. The inner plate has the broad oblique distal margin fringed 

 with slender setiform spines and three plumose setae below, of which the lowest is 

 the longest ; the other two plates, which in Hansen's later view belong in common 

 to the third joint of the maxilla, are naiTOw, rather long, carrying several apical 

 setae, the inner having setae also on its inner margin. 



Maxillipeds. These have the fifth joint much wider than the fourth, with seven 

 setae on its outer margin, and its inner apex a little emarginate ; the sixth and 

 seventh joints each have five setae on the outer mai-gin. 



First gnathopods. The fourth joint on its inner margin has six short blunt- 

 headed spines attached to the inner surface, four ordinary spines attached to the 

 outer surface: the fifth joint is triangular, small, almost embedded in the inner 

 surface of the fourth, and somewhat under-riding the sixth, which has on its inner 

 margin three spines, the apical the largest. 



Second gnathopods. These are rather longer and more slender than the first; 

 the third joint has at the inner apex two spines, the upper of which is button-like, 

 scarcely at all projecting; the fourth joint has four blunt spines, and a little apart 

 from them a stout apical spine ; the fifth joint is short, not overlapped by the fourth, 

 and not under-riding the sixth. 



First peraeopods. These closely resemble the second gnathopods. 



Second to fifth peraeopods. These are nearly alike except in length, the fourth 

 being the longest; all having numerous apical spines on the thu-d, fourth, and fifth 

 joints; the second joint is smooth except in the fifth pair, which has a scanty supply 

 of setae on its outer margin. 



