CEUSTACEA OF NEW ZEALAND. 193 



one or two similar setae about the middle and a tuft of fluer setsB at the extremity. The 

 ischium is about three-fourths as long as the basos: it is narrow at the base but con- 

 siderably expanded distally ; the anterior margin is convex, slightly irregular, and bears 

 five spiniform setae, followed by a series of three or four finei- setae towards the extremity ; 

 the posterior margin is nearly straight, bearing five or six small tufts of one or two setae 

 each, and a larger tuft of longer seti:e at the extremity. The meros is about three-fourths 

 as long as the ischium, subtriangular, and produced at the antero-distal angle; the 

 anterior margin is strongly convex, bearing live spiniform setse, with a row of six or seven 

 along the distal end ; the posterior margin straight and fringed with numerous setae. 

 The carpus is somewhat smaller than the meros, similar in shape, but not produced at the 

 antero-distal angle ; the anterior margin convex, with setae toward the extremity only ; 

 posterior margin straight and fringed externally with spiniform setag. The propodos is 

 oblong, slightly longer than the carpus and a little narrowed distally; the anterior 

 margin is slightly convex and bears a few fine setse, chiefly toward the extremity ; the 

 posterior margin straight, bordered with five spiniform setse and a number of finer hairs : 

 at its extremity the propodos is produced alongside the base of the dactylos into a small 

 triangular projection (PL XVII. fig. 5) similar to tliat described by Sars [91, p. 100] in 

 Asellus aqiiaticKS. The dactylos is slender : the end forms a distinct nail with three or 

 four setae on the surface of the dactylos at its base : on the inner margin is a small 

 secondary nail at the base of the large one, with a seta arising in the angle between the 

 two. 



The third appendage of the perceon is almost exactly the same as the second in all 

 respects, and tig. 4, drawn from the second, will equally well delineate the third. 



The fourth appendage of the perceon (figs. 6, 7) is like the second and third in the 

 female, but it is slightly modified in the male to form a grasping-organ, instead of 

 being merely adapted for walking. The whole leg is somewhat shorter than the pre- 

 ceding ; the basos is the same ; the ischium also the same, except that it is shorter than in 

 the preceding legs ; the meros and carpus are much shorter, but otherwise similar, and 

 with the same general arrangement of setoe ; the propodos has the anterior margin very 

 convex, the posterior margin being developed into a slightly concave palm, distinctly 

 defined by a small group of three or four very stout spiniform setse, and occu2)ying 

 nearly three-foiu-ths of the whole margin ; the dacttjlos is rather short, and is considerably 

 curved. 



The first four pairs of appendages to the perseon form an anterior series, differing very 

 considerably in structure from the last three pairs, forming the posterior series. In the 

 anterior series the dactylos is directed backward, while in the posterior pair it is directed 

 forward, as in the majority of the Amphipoda. 



The fiftli, sixth, and seventh appendages of tlie peneoa (figs. 8, 9) are similar to each 

 other, but ditter in size, the sixth being larger than the fifth, and the seventh as 

 much larger than the sixth. I shall describe the sixth, pair only, and it must be under- 

 stood that this pair represents the mean between the fifth and seventh pairs, not in size 

 only, but also in the number and size of the setae found on the various joints. 



The coxa is subtriangular in outline, and fits into a triangular emai'gination in the 



