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



margin with about a dozen long plumose setae, and also with spines not reaching quite 

 so far down the margin as the setse ; the outer plate bordered with spines on the upper 

 half of its inner margin and on the apex. 



Maxillijoeds. — The inner plates not reaching as far as the apex of the first joint of 

 the paljj, widening distally, the outer margin very convex, the apical border very large, 

 concave, produced at the outer corners ; ten plumose setse passing from the inner margin 

 at once obliquely across to the outer apex ; in the concavity of the apical border three 

 little nodulous teeth at intervals, at the outer extremity three setse, the longer inner- 

 most ; just below the innermost nodule a longer spine-tooth is placed, as it were crossing 

 swords with the corresponding tooth of the opposite plate ; outer plates very broad and 

 long, reaching as far forward as the second joint of the palp ; on the inner border some 

 thirteen denticles are spaced, on the apex three or four spines successively increase in 

 size, and pass over into long feathered setse which fringe the outer margin more than 

 half-way down ; near the inner border is a row of some nine or ten spinules on the surface 

 of the plate; the second joint of the palp is considerably longer than the first, which 

 is nearly equal in length to the third ; all the three joints have setiform spines on the 

 inner margins and outer apices, the thii-d joint having also three groups, and the second 

 joint one group, on the outer margin below the apex ; the finger is rather slender, with a 

 line of pectination near the inner margin, a very small nail and some cilia near it, and a 

 dorsal cilium midway between the nail and the hinge. 



First Gnathopods. — The side-plates very small, narrowed below. The first joint 

 much longer than the side-plate, narrow, of even width throughout, smooth ; second joint 

 very long, though shorter than the first joint or the wrist, with one or two cilia-like spines 

 upon it ; third joint much shorter than the second, with scarcely any free front margin, 

 having a group of setiform spines on the hind border near the produced acute apex ; 

 the wrist long and narrow, a little shorter than the first joint, a little longer than 

 the hand, with a few setiform spines about the centre and at the apex ; the hand long 

 and narrow, tapering, with setse on lioth edges, these edges, however, representing those 

 of the hinder surface of the hand rather than those of the hand as usually viewed later- 

 ally ; the finger slender, with some cilia near the nail. 



Second Gnathopods. — Side-plates quite small, rounded in front, with two or three 

 cilia-like spines on the lower margin. Branchial vesicle long, simple. First joint of limb 

 long, slender, smooth, scarcely dilated below and a little curved ; second joint much longer 

 than the third but shorter than the wrist ; third joint with but little free margin in front, 

 behind furred, having one small spine high up, three longer near the pointed apex ; the 

 wrist very long and narrow, not dilated, furred on both sides, with five groups of setiform 

 spines on the hinder margin ; hand much shorter than wrist, but still comparatively long 

 and narrow, furred both back and front, with numerous groups of spines on both borders 

 as well as some on the surface ; the spines show but little curve, the pectination, as 



