REPORT ON THE AMPHIPODA. 1015 



or five teeth, the lowest the most prominent; on the right mandible this plate has a bifid 

 termination, with two or three accessory teeth higher up ; spine-row of seven or eight 

 denticulate spines ; molar tubercle with prominent dentate crown ; the process between 

 the molar tubercle and the palp is broad-headed ; the palp set a little in advance of the 

 molar tubercle, contrasting by its slenderness with the breadth and bulk of the trunk 

 of the mandible, the first joint unusually long, more than twice as long as its greatest 

 breadth, the second joint longer than the first, bent, with seven or eight setse, or thin 

 setiform spines, along and near the convex inner margin ; the third joint straight, sub- 

 equal in length to the second, with three or four long thin setae on each margin and a 

 group of six at the apex. 



Lower Lip broad, not very deep ; the principal lobes widely dehiscent, much of the 

 gap being occupied by the large inner lobes ; the mandibular processes well developed, 

 with rounded ends. 



First Maxillae. — Inner plate small, oval, apparently with one apical seta; outer plate 

 with spines variously denticulate on the rather narrow truncate distal margin ; these 

 spines were worn and damaged, but the new ones (obscurely seen) in preparation within 

 the plate appeared to be ten in number ; the palp reaching beyond the outer plate, its 

 first joint more than half the length of the second, with two setules at the upper part of 

 the outer margin, the second joint broad, with two setules on the convex outer margin, 

 ten or eleven long feathered spines round the distal margin, and some submarginal seti- 

 form spines. 



Second Maxillae. — The inner plate narrower and a little shorter than the outer, with 

 spines round the distal border, and some plumose setse at the upper part of the inner 

 margin, also one or two setules lower down ; the outer plate apically fringed with spines, 

 the apex sloping towards the convex outer margin, which is fringed with setules. 



Maxillipeds compact. Inner plates reaching far beyond the first joint of the palp, with 

 plumose setse on the upper part of the inner margin, which is apically produced into a 

 tooth, the truncate distal margin being fringed with spine-teeth and curved spines ; the 

 outer plates reaching the distal end of the second joint of the palp, the inner margin fringed 

 with long serrate teeth, of which there are eight round the apical border, longer and 

 curved, none of them setiform ; on the outer surface near the inner margin are groups of 

 long spines, not dissimilar in character to the marginal teeth ; first joint of the palp very 

 short, a little longer than broad ; second joint very long, between two and three times as 

 long as the first, with numerous groups of spines along the inner margin ; the third joint 

 longer than the first, broadest at the centre, with spines on the inner margin and about 

 the apex ; the finger nearly as long as the third joint, with a spine-like nail, four or five 

 setules along the slightly serrate inner margin, the dorsal cilium long, at some distance 

 from the base. 



First Gnathopods. — Side-plates greatly produced below and in front, so that the 



