REPORT ON THE AMPHIPODA. 653 



narrower across the back than the wide distally squared dorsum of the third segment ; 

 the first three segments of the pleon large, the remainder small, the contrast between the 

 two portions when viewed from above being especially conspicuous. 



Eyes not observed. 



Ujiper Antenme. — First joint of the peduncle shorter than the head, much longer 

 than thick, upper margin convex, with a slight depression nenr the base ; second joint 

 longer than third, and longer than the first joint of the flagellum ; flagellum of seven 

 joints, the first equal in length to the two following, all the joints carrying filamentary 

 cylinders ; secondary flagellum of four joints, the first as long as the first of the primary, 

 the other three shorter than the next three of the primary. 



Lower Antennie. — Gland-cone prominent ; third joint not very short, fourth longer 

 than fifth, widening distally, both fourth and fifth with some slender lateral spines ; 

 flagellum of eight articulations, of which the first is the longest, each with a distal tuft 

 of cilia. 



Mandibles. — The cutting edge very slightly convex, with the upper tooth sharply 

 produced downwards and the lower' tooth bifid, produced upwards and outwards, the 

 secondary plate of the left mandible small, spiniform, placed low down ; both spine-row 

 and molar tubei'cle seemed to be wanting ; the palp set far forward, the first joint short, 

 the second with six or eight spines at the upper end, the third joint little shorter than 

 the second, with six or seven spines at and near the upper end, and numerous adpressed 

 cilia on the surface projecting beyond the inner margin. The figures in the Plate show 

 the mandibles as they appear with their edges somewhat bent in ; the enlarged figure of 

 the left mandible shows the true outline of its cutting edge ; that of the right mandible 

 is probably similar, but it could not be made out with certainty. 



First Maxilla?. — Inner plate very short, rounded at the top, carrying a single seta ; 

 outer plate showing a minute serration with four minute spine-teeth at the upper part 

 of the inner margin, and apically two powerful bent teeth, the outer much the larger 

 and over-arching the inner, but whether these two teeth consist of prominences sur- 

 mounted by spines or constitute simple processes of the margin, could not be definitely 

 made out ; the second joint of the palp widens greatly from the base, and on the broad 

 truncate apex carries four or five little spine-teeth, the outermost larger than the others ; 

 on the inner liorder it has four or five slender spines. 



Second Maxillie. — The outer plate seemingly much longer than the inner, with seven 

 spines dispersed along the upper part of the inner margin and the apex ; the inner plate, 

 so far as made out, with few spines. 



Maxillipeds extremely slender ; inner plates minute, slender, not reaching even to 

 the base of the first joint of the palp ; the apical margin produced into a tooth-like point 

 on the inner side, near the much lower outer side carrying a long spine, the only 

 armature of the plate ; the outer plates slender, reaching but little beyond the first joint 



