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



first joint sliort, the second slightly constricted below the centre, with eleven or twelve 

 spines near the upper end passing round to the outer apex ; the third joint with the first 

 about equalling the length of the second, widening from the base for the first third of 

 its length, from that point narrowing to the apex, and fringed on the inner margin with 

 nineteen or twenty spines ; one spine or seta on the back near the base. ■ 



Loiver Lip. — The front lobes strongly ciliated ; the mandibular processes rounded, a 

 little ciliated. 



First Maxillae. — Inner plate small and narrow, carrying on the apex two unequal 

 plumose setse of no great length ; outer plate large, apical margin very oblique, furred, 

 the two lowest spines broad, multidentate, standing rather apart from the rest, the other 

 nine all powerful, the outermost with three lateral teeth, none of the others with less than 

 four ; the palp with the inner margin straight, the outer curving as the second joint 

 expands from a narrow base almost to the apex, which in our specimen in one of the pair 

 had eleven serrate spine-teeth and a spine, in the other eight spine-teeth and a spine.^ 



Second Maxilla. — The plates strongly ciliated, rather long and narrow, the outer 

 overtopping the inner ; the inner plate on the very sloping apical portion carrying 

 a row of spinules and a row of pectinate spines, ending below in a spiniform 

 plumose seta ; the pectinate spines of the outer plate not confined to the apex, but 

 appearing some little way down the inner margin. 



Maxillipeds. — Inner plates short, rather rectangular, not reaching so far as the apex 

 of the first joint of the palp, the apical margin excavate, produced on the inner side, the 

 process carrying at its tip a minute tooth, two others equally minute being set at 

 intervals in the excavation ; the series of plumose setse of the inner margin is continued 

 round to the outer apex by cilia and spiniform setse ; the outer plates large, extending 

 beyond the second joint of the i^alp, the inner margin carrying fourteen little nodulous 

 teeth, while the apical border has two much larger teeth, the inner short and broad, the 

 outer somewhat longer and thinner ; the plates carry also a row of spinules on the outer 

 surface near the inner margins ; the first joint of the palp is large, distaUy rounded, very 

 little shorter than the second joint ; the fourth joint ends in a very minute sharp nail, 

 and has on its inner border near the nail a row of five cilia. 



First Gnathopods. — Side-plates nearly as broad as deep, lower part of the plate 

 produced forwards, hind and lower margins nearly straight ; first joint short and massive, 

 subequal in length to the wrist and hand combined ; second, third and fourth joints 

 all short, compact, subequal in length ; the third and the wrist lightly furred 

 behind, the third having scarcely any free front margin, and the triangular, cup-shaped 

 wrist a very small free hind margin ; the hand oblong, thickest near the base, the 

 front margin slightly convex, the hinder margin a little angularly concave, micro- 



1 In Oncsimoides carinaUis in like manner the palp of the left maxilla showed twelve spiue-teeth, that of the right 

 maxilla only nine ; see p. 649. 



