1512 THE VOYAGE OF H.M.S. CHALLENGER. 



front margin a little produced, with rounded apex, the hind margin pectinate except near 

 the base, the triangular distal process rather broad, not quite so long as the hand, with 

 the inner margin pectinate as well as the outer ; the hand similar to that of the first pair* 

 but a little larger, and with the whole of the hind margin distinctly pectinate ; the finger 

 rather less than half the length of the hand, slightly curved ; there are numerous gland- 

 cells in the first four joints of these and the preceding gnathopods. 



First Perseopods with scarcely any perceptible armature ; the first joint narrowest 

 near the base and a little narrowed distally ; the second joint short ; the third shorter 

 than the fourth, widening from a narrow neck, the front apex rounded, not produced ; 

 the 'fourth widest near the base, narrowing distally ; the fifth narrower than the fourth, 

 scarcely longer, apically narrowed ; the finger slender, curved, about a third, the length 

 of the fifth joint. 



Second Perseopods very similar to the first, but with a much longer third joint, 

 this being longer than the fourth ; the fourth joint is rather narrower than in the 

 preceding pair, shorter than the fifth. 



Third Perseopods. — Side-plates narrowed in front. First joint oblong, about twice as 

 long as broad, not nearly so long as the following joints together, the front margin 

 descending a little below the hinder, and with some shallow serration of the lower part ; the 

 angles are not very strongly rounded; the second joint short, yet long enough to reach 

 below the front margin of the first joint ; the third joint longer than the fourth, finely 

 pectinate along the front and apical margins ; the fourth joint more strongly pectinate 

 than the third, except close to the apex, where the pectination becomes very fine on 

 one surface and ceases on the other; the fifth joint slightly curved, longer than the third, 

 more strongly pectinate than the fourth, the hind margin having an apical spine ; the 

 finger slender, about a third of the length of the fifth joint, a little bulbous at the base. 



Fourth Perseopods. — First joint very large, broadly pear-shaped, longer than all the 

 following joints together, the front margin a little sinuous, the hind margin extremely 

 convex above, reaching nearly as far down as the front, the short distal margin straight, 

 with rounded corners, the front one serrate with four or five indents ; the second joint 

 very short ; the third as long as the fourth and fifth together, strongly pectinate along 

 the front margin, and produced for three-quarters of the length of the fourth joint ; 

 the fourth joint more than half the length of the fifth, the front margin pectinate, not 

 produced ; the fifth joint slightly curved, with pectinate front margin, and a spine at the 

 apex of the convex hind margin ; the finger about a third of the length of the fifth joint. 



Fifth Perseopods. — The first joint smooth, pear-shaped, not twice as long as the 

 breadth at the upper part ; the second (terminal) joint about a quarter as long as the 

 first, oval, the neck narrow. 



Pleopods. — Peduncles stout ; coupling spines small ; cleft spine apparently with the 

 dilated arm longer than the other, the dilatation narrow ; the first joint of the inner 



