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



spines, many of which are strongly pectinate ; the series is continued some way down the 

 inner margin with spines that are partly pectinate, partly plumose ; the outer plates are 

 narrower and longer than the inner ; there are many long pectinate spines on the narrow 

 apex, and a little way down the inner margin, besides four or five more slender than the 

 rest down the outer margin. 



Maxillipeds. — The inner prismatic plates very long, fringed far down the inner margin 

 with a series of fifteen plumose setae, this margin ending in a small apical point, the distal 

 margin not broad, but set with two rows of strongly pectinate spines of different lengths, 

 two near the inner apex comparatively short, but still too long to be regarded as spine- 

 teeth ; two or three slender spines pass down the outer margin. The outer plates scarcely 

 larger than the inner, not reaching the distal end of the palp's second joint, the inner 

 margin in its upper part fringed with feathered setae, near the rather pointed apex 

 becoming serrate and carrying pectinate spines ; four or five feathered setae pass down 

 the outer margin ; the three joints of the palp are rather narrow, the first a little longer 

 than the second, with a few setae on the inner margin and outer apex, the second with 

 several long setae near and at the apex of the inner margin ; the third about as long as 

 the second, with numerous setae along the upper half of the inner mai'gin, and at least 

 one long pectinate spine at the apex ; no trace of a finger could be perceived among the 

 parasites which beset the apical setae. 



First Gnathopods. — The side-plates have the narrowed distal portion divided into 

 two large acute processes, of which the hinder curves slightly forwards, and has a small 

 denticle on its front or inner margin ; the front process has a small denticle on the front 

 margin, below winch it slopes slightly backwards. The limb closely resembles the first 

 gnathopods of Iphimcdia pacifica, but the specimen being larger some of the details are 

 more easily observed ; thus the tip of the thumb has a small spine, against which the hooked 

 tip of the finger impinges ; at the base of the thumb there are three or four pectinate setaa 

 and two long ones on its inner margin, the finger having two dorsal setae, one near the 

 base, the other near the tip, the pectination of these setae being turned backwards in the 

 limb as mounted for the microscope, but this is perhaps accidental ; besides the strong- 

 apical hook, the finger has at least one retroverted tooth on the inner margin. 



Second Gnathopods. — The side-plates similar to the preceding pair, but narrower, a 

 little longer, with the hinder process rather more produced in comparison with the front 

 one. The limb is very like that of the second gnathopods in Iphimedia pacifica; the 

 first joint widens a little distally, is as long as the wrist and hand united, and much 

 broader than either ; the second joint is longer than the third ; the wrist has six groups 

 of setae along the distal half of the hind margin ; there are seventeen or eighteen groups 

 of long setae along the distal two-thirds of the hand's hind margin, and eight groups 

 alone; the distal half of the front margin. 



First Per&opods. — The side-plates similar to those of the preceding pair, a little 



