1384 THE VOYAGE OF H.M.S. CHALLENGER. 



Third Per&opods. — The first joint oval, with smooth edges ; the second joint short ; 

 the third rather longer than the fourth ; the fifth longer than the third ; each of these four 

 with one or two minute spinules on the front margin ; the finger slender, curved, acute, a 

 little more than half the length of the fifth joint. 



Fourth Perasopods. — The first joint narrower than in the preceding pair, with one 

 spine not far from the apex of the front margin. 



Fifth Perasopods like the two precediug pairs, but having the fourth and fifth joints 

 shorter ; the first joint is rather wider than in the preceding pair. 



Pleopods more slender than in Hypeina sibaginis, the rami with seven joints, in 

 other respects very similar. 



Uropods. — The peduncles of the first pair longer than the rami, reaching almost 

 equally far back with the peduncles of the third pair ; the outer ramus a little shorter 

 than the inner, pectinate on the inner margin, the inner ramus pectinate on the outer 

 margin, both rami narrowly lanceolate ; peduncles of the second pair shorter than the 

 inner ramus, scarcely longer than the outer ; peduncles of the third pair set wide apart, 

 a little longer than the rami ; the rami about equal, not reaching so far back as the 

 rami of the first pair, which they in general resemble. 



Telson forming an oval truncate at the base, about three-quarters of the length of 

 the peduncles of the third uropods. 



Length, three-twentieths of an inch, exclusive of the antennae. 



Localities. — January 9, 1875 ; Chiua Sea, off Luzon; lat. 16° 35' N., long. 117° 47' 

 E.; surface; surface temperature, 76° - 5. One specimen, young male. 



January 1875; Zebu Harbour, Philippines; surface. Two specimens from this 

 locality appear also to belong to this species. 



Hyperia luzoni, young (?). 



Head deeper than long ; first two segments of the perseon dorsally coalesced ; postero- 

 lateral angles of the first, second, and third segments of the pleon squared or a little 

 acute. 



Upper Antennae two-jointed, placed rather high up and reaching about down to the 

 lowest point of the deep head, the first joint a little longer than broad, the second 

 between two and three times as long as the first, tapering, with one or two long fila- 

 ments at about the middle of the inner margin, and a row of cilia near the outer margin 

 at its lower half. 



Lower Antennas much shorter than the upper, with a short basal joint, and a longer 

 slightly tapering one, on the blunt end of which there is a cilium. 



Mandibles without palp. 



Maxillipeds. — The shaft narrow, shaped like a dice-box, the inner plate small, 



