1118 THE VOYAGE OF H.M.S. CHALLENGER. 



near the slightly produced apex ; the free part of the hind margin is curved and 

 forms an angle with the oblique portion which lies against the wrist and is apically acute ; 

 the distal margin is concave between the two apices ; the wrist is elongate, almost as 

 long as the hand, the hind margin serrate, bordered by a row of about fifteen spines ; it 

 has also some spines upon the surface and at the apex of the long frout margin ; the 

 band widens slightly towards the obliquely curved palm ; it has near the slightly convex 

 front margin four large groups of spines ; on the straight hind margin there are five 

 groups of slender spines, followed by a large palmar spine and then by another group of 

 slender spines ; the finely pectinate palm joins the hind margin by a smooth curve, and 

 is bordered by many submarginal spines of various lengths ; the finger is broad, slightly 

 curved, with a very small cilium near the base ; its inner margin is cut into fourteen 

 teeth, and there are one or two setules at the base of the nail, which projects considerably 

 beyond the palm. 



Second Gnathopods. — The side-plates deeper than in the preceding pair, but not so 

 broad, of nearly even width throughout, the front margin convex, the lower also convex, 

 fringed with setae. The first joint reaching beyond the side-plate, with some setae on 

 the upper part of the convex bind margin, the front margin concave till near the 

 distal part which forms a projecting round lobe carrying a spine and spinule ; 

 the second joint is short, with the front margin very convex, the hind margin only 

 slightly convex, carrying one or two spinules and at the apex a group of slender spines ; 

 the third joint is more regularly oblong than in the preceding pair, with many spines 

 about the distal margin, and a group a little way above the apex of the hind margin ; 

 the wrist is triangular, a good deal shorter than the hand, distally cup-like, with spines 

 at five points of the slightly convex front margin, and a bush of spines about the 

 rounded apical portion of the hind margin. The hand is broad, with six or seven groups 

 of spines along the slightly convex front margin and others near it ; the hind margin is 

 also slightly convex, with seven groups of slender spines ; it forms a rounded angle with 

 the oblique very sinuous palm, which is set with numerous slender spines of different 

 lengths, and over which the broad curved finger closes, so as to reach the angle with its 

 tip, the dentate inner margin leaving a small cavity between itself and the concave 

 commencement of the palm ; the palmar spine is set rather deeply on the surface and 

 projects beyond the palmar angle. 



First Per&opods. — Side-plates rather broader and deeper than the preceding pair. 

 Branchial vesicles as long as the side-plates, but much narrower. Marsupial plates long 

 and narrow, surrounded by very numerous setas, the surface appearing as if striped with 

 lines of tubercles, the appearance perhaps due to the internal vessels. The first joint 

 reaching a little beyond the side-plate, packed with gland-cells, carrying some setae or 

 setiform spines and spinules at various points of both margins, but especially on the 

 hinder ; the second joint rather longer than broad, with some slender spines at the apex 



