1442 THE VOYAGE OF H.M.S. CHALLENGER. 



throuo-hout, with six little spine-teeth spaced along the inner margin, perhaps as many 

 close-set on the distal border, and five slender spines along the outer margin. 



Second Maxilla}. — The outer plate narrow and tapering, beset with hairs, and having 

 a sjjinule or two at the apex ; the inner plate much shorter, triangular, its outer margin 

 standing out nearly at right angles to the outer plate, the apex tipped with a spinule, 

 the inner margin carrying some hairs. 



Maxillipeds. — The inner plate inconspicuous, almost obsolete, with rounded apex ; 

 the outer plates narrow, tapering, hairy on the outer, slightly convex surface, carrying 

 two minute spinules on the nearly acute apex, and two or three at irregular intervals 

 alono' each mamin. 



First Gnatho2)ods small, without any distinct side-plates. The first joint about as 

 long as the next four joints together, with sinuous margins, the joint being narrower in 

 the middle than above and below ; the muscles do not reach to the middle of the joint, 

 the upper space being required for gland-cells ; the second joint longer than broad, bent, 

 so that the remainder of the limb is directed forwards and a little upwards to the mouth ; 

 third joint about as long as the second, the apical point lying upon the wrist ; wrist 

 cylindrical, as long as the preceding two joints together ; hand also cylindrical, narrowing 

 distally, longer than the wrist, having some minute spines and hairs on the margin ; 

 finger when outstretched about a third the length of the hand, the margin fringed with 

 short stiff hairs ; the nail short, pointed. 



Second Gnathopods larger than the first, which they tend to overlap. The side- 

 plates triangular, sharply pointed forwards, of a shape more commonly found attached to 

 the first than to the second gnathopods. Branchial vesicles longer than the first joint, 

 not broader, narrow at the neck. Marsupial plates very thin and transparent, smooth- 

 edged, rather longer than the first joint, shorter than the branchial vesicles. The first 

 joint oval, much wider than that of the first gnathopods, the muscles occupying only a 

 small space low down at the back, the remainder being nearly filled with the gland-cells ; 

 the remaining joints closely resemble those of the preceding pair, but are larger, the wrist 

 both broader and longer, and a little dilated at the proximal end ; the hand longer than 

 the wrist, tapering, with a slight curve, without hairs but with a few minute spinules; 

 the finger not a fifth the length of the hand, without any nail. 



First Perasopods. — The side-plates produced in front, broader than deep, deej^er 

 behind than in front. Branchial vesicles rather longer than the first joint. The 

 marsupial plates rather longer and broader than the branchial vesicles. The first joint 

 narrow, widening slightly from the narrow base ; the second joint longer than broad, 

 with one spinule at the middle of the hind margin ; the third longer than the second, 

 with two spinules wide apart on the hind margin ; the fourth joint almost as long as 

 the second and third together, with four spinules on the hind margin, two of them 

 at strong indents, a fifth spinule within the little produced apex ; the fifth joint 



