REPORT ON THE AMPHIPODA. 807 



Mandibles short and stroug ; cutting edge divided into four teeth ; secondary plate 

 on the left mandible with a strong upper tooth and three smaller below it, on the right 

 mandible bidentate, but with denticles on the larger teeth ; the plan of these plates is 

 best seen in the unworn condition as it appears through the transparent integument in 

 preparation for the next change of skin ; the spine-row exhibits three curved serrate 

 spines on the left mandible, on the right only two, but one of these two laminar ; the 

 molar tubercle very large and prominent, with strongly dentate crown ; the palp set 

 rather behind the very forward molar tubercle, its first joint very short, the second longer 

 than the first and third united, with spines on the surface near to both margins ; the 

 short third joint, widest about the centre, has spines on the inner side of the upper 

 half, the longest at the rounded apex. 



Lower Lip short and broad, inner lobes stout. 



First Maxillse. — Inner plate broadest at the base, with twelve plumose setse round 

 the inner margin and apex ; outer plate broadest at the base, carrying on the truncate 

 apical margin nine finely denticulate or pectinate spines ; the long second joint of the 

 palp overarching the outer plate, and on its apical margin carrying six slender spine- 

 teeth, and seven small setse below the apex. 



Second Maxillae. — Both plates broad, with long slender spines on the broad apical 

 margins ; the inner plate also with a row of sette passing from the inner margin across 

 towards the outer apex, and with two spines or setse on the inner margin just below 

 the apex. 



Maxillipeds. — Inner plates rather small, but extending considerably beyond the 

 very short first joint of the palp, the broad apical margin irregularly denticulate, 

 carrying several plumose setse ; there are some long plumose setaj on the inner margin 

 and a curved spine-tooth at its apex ; outer plates nearly reaching the apex of the long 

 second joint of the palp, inner edge almost smooth till near and at the apex, where it is 

 serrate and armed with setse successively increasing in length as they pass to the outer 

 part of the apical margin ; within the inner margin, at a little distance from the 

 base, begin rows of slender spines, not very acute ; the inner margin of the large 

 second joint of the palp has abundance of long seta3 ; the short third joint has also 

 several ; this widens distally, and is apically set about with strong spines, some of them 

 long, one of them finely pectinate ; the fourth joint or finger seems to be absent or 

 rudimentary. 



First Gnathopods. — Side-plates quite small and inconspicuous, front margin rounded. 

 First joint long, equal to the wrist and hand together, finely pectinate on the lower part 

 of the almost straight hind margin, there also carrying some long plumose setse, distally 

 lobed in front, the lobe fringed with plumose setse ; the second joint shorter than the 

 small oval third joint, both furred slightly on the hind margin, the third with numerous 

 spines round the lower part of the hind and the somewhat squared apical margins ; the 



