780 THE VOYAGE OF H.M.S. CHALLENGEK. 



Eyes oval. 



Uiyper Antenna?. — The first joint about equal in length to the next two united, not 

 twice as long as broad ; the third joint much more than half the length of the second ; 

 the flagellum tapering, of five joints, together shorter than the first joint of the peduncle ; 

 the third joint of the peduncle and the first four of the flagellum carrying long cylinders ; 

 the secondary flagellum minute, not longer than broad. 



Lower Antennie. — First three joints short, the first dilated, the fourth as long as the 

 three preceding united, the fifth rather shorter ; the flagellum tapering, of four joints, 

 together equalling the length of the fifth joint of the peduncle. 



U2iper Lip comparatively broad, the narrow lol^e not produced much beyond the 

 other. 



Mandibles. — -The cutting edge divided into nine or ten denticles, on the left mandible 

 the two in the centre projecting beyond the rest; the secondary plate on the left 

 mandible nearly as large as the principal, with a straight row of eight denticles ; on 

 the right mandible the secondary plate is very small, its distal margin not clearly 

 observed ; the spine-row of about ten not very long spines ; the palp broad, the second 

 joint with three or four spines near the apex on the inner side ; the third joint much 

 narrower than the second, more than half its length, with two apical spines or set* 

 exceeding its own lensjth. 



First Maxillw. — So far as observed, the spines of the outer plate were slender, in 

 general structure like those of Leucothoe tridens, the second joint of the palp long and 

 broad, with three short spines on the apex, and some rather long cilia on the outer 

 margin. 



Second Maxillw. — The inner plate scarcely broader than the outer, with a few spines 

 on the apex ; the outer plate not reaching quite so far as the inner, the narrow apex 

 tipped with three spines, the convex outer' margin ciliated. 



Maxillipeds. — The inner plates seem to be slender, nearly as long as the second joint 

 of the maxillipeds ; this has a very small rudimentary plate, a spine on the outer apex, 

 but none on the margin below ; the first joint of the palp is broad, rather longer than 

 the second or third ; the first and second joints have three or four spines on the inner 

 margin, the third has a group of three or four near the inner apex, and one on the outer 

 apex; the finger is longer than the third joint, with a short sharp nail, and a ciliated 

 inner margin. 



In the triturating organs of the stomach the lower margin has six unequal spines. 



First Gnathopods. — Side-plates broader below than above, but with the front lower 

 corner little produced. The first joint as long as the hand, reaching much below the 

 side-plate, the hind margin gently convex, with an apical seta, the front margin sinuous, 

 fringed with ten long setae ; the second joint scarcely longer than broad ; the third rather 

 longer than the second, more squared than in the preceding species, carrying two setae at 



