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



Maxillipeds. — Inner plates reaching nearly to the apex of the first joint of the palp, 

 the apical border sloping back towards the outer, and occupied by five long plumose 

 setae ; the inner plates long and narrow, reaching slightly beyond the second joint of the 

 palp, having on the straight inner margin five setse, followed by nine rather long spine- 

 teeth in a scries which does not q^uite reach the apex ; there is also on the surface a row 

 of eight setse beginning a little lower than the row of spine-teeth ; the first joint of the 

 palp is short, the second much longer, its inner margin bordered with long setaj except 

 close to the base and for a space distally ; the third joint longer than the first, with setse 

 or spines only on the apical part ; the finger short, with a long slender nail accompanied 

 by some cilia. 



First Ghiathopods. — Side-plates very small, directed forwards. The narrow first 

 joint extending much beyond the side-plate, with some long setse at a few points on 

 each margin, the lower half of the joint a little expanded ; the second joint narrow, 

 longer than the third, as long as the hand ; the third joint not long, bent, the hind 

 margin being much longer than the front, and carrying a single cilium near the apex ; the 

 wrist long and slender, but not equal in length to the two preceding joints united, with a 

 group of setae near the apex behind ; the hand with the closed finger forming a long oval, 

 the front margin of the hand being much shorter than the hinder, the extremities of the 

 two being joined by a very oblique palm, in antagonism with which the finger and nail 

 form a complete chela, capable of gaping widely ; at the apex of the front margin there is 

 a group of setae, some of which are longer than the finger ; there are two groups of setge 

 on the hind margin not far from the apex, a small spine at the apex, and setules along 

 part of the palm-border ; the finger shows some cilia about the base of the nail. The 

 skin is extremely transparent. 



Second Gnathopods. — Side-plates small, with an excavation behind, not at the top but 

 above the middle, the first joint of the limb being attached at this point, a long seta and 

 two cilia being set in the margin lower down. Branchial vesicles of slight structure, 

 larger than the side-plates, tapering below. The limb constructed on the same plan as 

 in the first gnathopod, but all the joints except the finger longer, the slender wrist being 

 longer than the two preceding joints and as long as the first joint, the hand longer in 

 proportion to its breadth, and with less difference between the lengths of the front and 

 hind margins, so that the finger antagonises with a shorter palm, and is itself shorter 

 to correspond. 



First Per^eopods. — Side-plates not large, with a long seta at the lower front angle. 

 Branchial vesicles longer and larger than the side-plates ; marsupial plates narrow, longer 

 than the first joint of the limb, with half a dozen long setae on the hinder margin and 

 apex. First joint of the limb reaching much beyond the side-plate, with three long setae 

 on the lower part of its hinder margin; second joint short; third longer and broader than 

 any of those which follow, expanded downwards, not decurrent, with setae along much of 



