1070 THE VOYAGE OF H.M.S. CHALLENGER. 



finger is broad, the inner margin pectinate and cut into four strong decurrent teeth ; the 

 dorsal cilium near the base is rather long ; there are also some setules at the base of the 

 nail, which is curved and scarcely reaches the extremity of what may be considered as 

 the palm-border. 



Second Gnathopods. — The side-plates deep, wider below than above, the hind margin 

 slightly concave. The branchial vesicles much shorter and narrower than the side-plates. 

 The marsupial plates rather longer than the branchial vesicles, narrow at the basal part, 

 carrying fifteen setae on the lateral margins and apex. The first joint not reaching 

 beyond the side-plate, the convex hind margin having some long seta? at the apex ; the 

 short second joint with an apical group of setse, one long and plumose ; the third joint 

 rather longer than in the first gnathopods, similarly armed ; the wrist much shorter than 

 the hand, broader than long, distally cup-like, with long spines at the front apex and on 

 the narrow hind margin, and some on the lower margin of the inner surface ; the hand 

 broad, between oval and oblong, with a single seta-like spine above the middle of the 

 front margin, a group between that and the apex and another at the apex, these spines 

 being slightly plumose ; the hind margin bordered with more or less pectinate spines, 

 and produced into a tooth at the commencement of the palm, within which the finger 

 closes down against a strong palmar spine ; the palm is obliquely excavate for some 

 distance, bordered with several spines, of which there are also various groups on both 

 surfaces of the hand ; the finger is broad, with five decurrent teeth on the inner margin. 



First Perseopods. — Side-plates rather deeper than the preceding pair, a very little 

 wider below than above, with the front margin convex and the hinder concave. The 

 branchial vesicles narrow, widening a little distally. The marsupial plates as in the 

 preceding segment. The first joint not reaching the end of the side-plate, with four 

 long setse on the lower part of the hind margin, the lowest conspicuously plumose ; near 

 the apex is a shorter plumose seta ; the second joint short, with a long plumose seta at 

 the hinder apex ; the third joint stout, longer than the fourth, its convex margin fringed 

 with about fourteen long plumose setse, the hind margin almost straight, with some 

 setules at the apex ; the fourth joint with a group of setae at the apex of the convex 

 front margin, and some very slender setae or setules at the apex of the straight hind 

 margin ; the fifth joint as long as the third, tapering distally, the convex hind margin 

 with six or seven groups of long slender setse, the straight front margin with a spinule at 

 the apex and another higher up ; the finger curved, rather more than half the length of 

 the fifth joint. 



Second Perseopods. — These in all respects closely resemble the preceding pair ; the 

 side-plates a little broader, and an extra setule perhaps on the hind margin of the fifth 

 joint of the limb. 



Third Perseopods. — Side-plates scarcely less deep aud much broader than the 

 preceding, the front and hind margins both convex, the hind lobe very small. Branchial 



