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



to cross the hollow centre of the crown ; there is a short seta accompanied by some cilia ; 

 the palp is of great size, the first joint short, the second long and broad, with about a 

 dozen spines of various lengths on and near the inner margin ; the third joint longer 

 than the second, with the concave inner margin fringed for most of its length densely 

 with spines, those about the narrow apex being more obviously pectinate than the rest ; 

 the convex outer margin shows no spines. 



Lower Lip. The principal lobes distally rounded and ciliated, rather widely 



dehiscent, the inner margins also ciliated ; the mandibular processes very short. 



First Maxillse. — The inner plate comparatively long, with a short setule and a 

 plumose seta on the inner side of the rounded apex ; of the nine spines on the truncate 

 distal margin of the outer plate five are long, and all except the outermost have five or 

 six lateral denticles ; the other four are shorter, and have a single lateral tooth, unless 

 this be wanting on the outermost ; the second joint of the palp is very long, much over- 

 topping the outer plate, it is strongly ciliated, and has several long setae near the apex 

 and some long spines upon it. 



Second Maxillw.— The inner plate with the inner margin slightly concave, the outer 

 very convex, spines round the narrowed apex, and a very little way down the inner 

 maro-in : the outer plate of more even breadth, not so broad as the greatest breadth of 

 the inner plate ; the spines on the narrowed apex and a little way down the inner margin 

 much larger than those of the inner plate. 



Maxillipeds.—The inner plates not reaching far along the first joint of the palp ; 

 the broad distal margin has three spine-teeth set close together on the inner part, and three 

 curved spines on the serrate outer part ; the outer plates are narrow, not reaching the 

 middle of the second joint of the palp ; about twenty long spines arm the inner margin, 

 and five still longer ones pass round the narrow apex down the upper part of the convex 

 outer margin ; the first joint of the palp is short, with a couple of spines on the outer 

 margin just below the apex, and a small one lower down ; the second joint is elongate, 

 not broad, with several spines on the inner surface and along the inner margin ; the third 

 joint is long, shorter than the second, longer than the first, with many spines of various 

 sizes, some pectinate, along both margins and on the surface ; the finger is long and 

 slender, much curved, and sharply pointed. About the mouth-organs and other parts of 

 this creature there are many conspicuous oval parasites. 



First Gnathopods.—Side--p\ates narrow and tongue-like, directed towards the base of 

 the lower antennae. The first joint reaching much below the side-plate, proximally very 

 narrow, then widening, concave, and channelled in front, with spines near the apex, the 

 hind margin convex, with some small submarginal and one or two apical spines ; the 

 second joint short, with an apical spine ; the third joint longer than broad, with two 

 groups of spines on the hind margin, and a larger group on the squared apical border ; 

 the wrist short, cup-like, with a small calx, having the hind margin serrate, the apex 



