1400 THE VOYAGE OF H.M.S. CHALLENGES. 



extending with almost undiminished breadth to near the end of the sixth peraeon- 

 segment. 



The Eyes occupying the sides of the head almost completely. 



Upper Antennas. — Peduncle with the first joint as broad as long, the two following 

 joints short ; first joint of the flagellum stout, tapering, longer than the peduncle, with 

 a thick brush of not very long filaments, the second joint narrower than the apex of the 

 first, a little longer than broad, with a couple of filaments, the third, fourth, and fifth 

 joints successively longer and narrower ; there were six other linear joints remaining, 

 each of them rather longer than the fifth joint. 



Lower Antenna?. — Third (first free) joint of peduncle rather broader than long, the 

 fourth shorter and narrower than the third, the fifth nearly as long as the third and 

 fourth together ; the first joint of the flagellum nearly as long as the peduncle, abruptly 

 narrower, a bttle bulbous at the base, then linear ; part of the second joint remaining, 

 the rest of the flagellum missing. 



Upper Lip unecmally bilobed by a small triangular distal emargination. 



Mandibles. — The trunk long and narrow, with the palp fixed at the upper front 

 corner, and the small cutting plate projecting from the lower front angle ; the edge of 

 the cutting plate divided into ten or eleven little teeth ; the secondary plate of the left 

 mandible having its edge divided into ten teeth, which are smaller than those on the 

 larger principal plate ; between the cutting plate and the straight part of the lower 

 margin there is a convex piece thickly set with long bristles, and above this there is a 

 slightly projecting molar tubercle having its lower front angle armed with a tuft of 

 bristles ; the palp longer than the trunk, the first joint broader but shorter than the 

 second ; the second is in a fine with the first, narrowest at the middle ; the third is as 

 long as the two preceding together, tapers to a fine point, is set at an angle to the second, 

 and has its outer surface covered with adpressed cilia. It should be noticed that the 

 molar tubercle in these organs differs strikingly from that in Hyperia and Euthemisto. 



Lower Lip. — The distal and inner margin flattened, strongly ciliated ; the mandi- 

 bular processes short, with rounded apices. 



First Maxillw. — Inner plate wanting ; the outer plate broad, partially folded, the 

 distal part set all round with spines, of which many are bke fine bristles, while others 

 are proper spines ; the palp reaching much beyond the outer plate, the inner margin 

 fringed with closely set cilia, the rounded distal margin finely pectinate ; there are also 

 many groups of pectinate markings on the adjoining surface ; there is a longitudinal fold 

 of the inner surface starting from the base, and there are two or three scattered spinules 

 on the outer surface. 



Second Maxilla'. — The inner plate much shorter and apically more obtuse than the 

 outer, both of them having the distal part beset with numerous bristle-like spines. 



Maxillipeds. — The joint which carries the plates is at the base broader than the 



