1020 THE VOYAGE OF H.M.S. CHALLENGER. 



groups of setas on the margins and surface, and on one side near the base a group of 

 spines; the fifth joint elongate, without the spines, but otherwise furnished like the 

 preceding ; the flagellum scarcely as long as the peduncle, of about seventeen joints, with 

 apical groups of setae, the first joint the longest, with marginal as well as apical seta3. 



Upper Lip broad and deep, the distal margin rounded, closely ciliated, with the 

 slightest central emargination, as narrow as it is shallow. 



Mandibles. — Cutting plate with a smooth or faintly denticulate edge between a tooth 

 at the top and two or three at the lower end ; the secondary plate of the left mandible 

 distally widened, divided into five teeth ; on the right mandible the secondary plate is 

 weaker, distally bifid, with a small process on the front margin near the base ; the front 

 tooth the stronger, with six or seven denticles along the edge, the hinder tooth with one 

 minute denticle ; the spine-row of three denticulate spines longer in our specimen on the 

 right than on the left mandible ; the molar tubercle very robust, with strongly dentate 

 crown and plumose seta ; a small process projects close to the base of the palp ; palp 

 slender and feeble, the first joint nearly three times as long as broad, the second longer 

 than the first, with three setiform spines at the distal end, and one a little lower 

 down; third joint -nearly as long as the first and second together, with two setiform 

 spines, longer than the joint itself, at the apex, a shorter one beside them, and three on 

 the margin just below. 



Lower Lip. — Principal lobes rather dehiscent, the inner and distal margins thickly 

 furred, and, in addition to the cilia, having on each lobe a pair of very short, blunt- 

 headed spines, one on each side of the inner distal corner ; the inner lobes rather thick, 

 oval, distally narrowed ; the mandibular processes very long, subacute, very divergent. 



First Maxillse. — Inner plate with three, not very long, plumose setas on the apex ; 

 outer plate with only seven spines on the truncate, slightly oblique, and rather narrow 

 distal margin, the two outermost spines the strongest, with a single tooth just below the 

 apex, the two next with two teeth so placed, the next with three short denticles, the next 

 with three long ones, and the innermost with five or six that are minute ; the dentation 

 not exactly alike in both maxillse ; the first joint of the palp not more than half the 

 length of the second, carrying a small spine at the outer apex ; the second joint with a 

 double row of rather long slender spines, sixteen in number, round the apex and oblique 

 distal portion of the inner margin. 



Second Maxillse. — Plates elongate, the inner narrower and a little shorter than the 

 outer, fringed round the sloping apex with many long pectinate spines, the row continued 

 by plumose setae on the distal part of the inner margin ; the outer plate having its apex 

 fringed with longer spines, this apical border sloping outwards, while that of the inner 

 plate slopes inwards ; the outer plate has some small setae near the base of its outer 



rgin. 



Maxillipeds. — The inner plates not reaching so far as the distal end of the first joint 



