1022 THE VOYAGE OF H.M.S. CHALLENGER. 



contracting a^ain distally, its length once and a half the greatest breadth, the front 

 margin rather sinuous, almost unarmed, the shorter hind margin fringed with 

 a continuous brush of very long setae, which also cover a large part of the inner 

 surface, and are continued along the palm ; the palm begins with a small tooth-process, 

 runs almost in a continuation of the hind margin obliquely to a larger tooth-process, 

 which is followed by a small cavity and then by a bulky process armed with short spines 

 and groups of seta? ; over this the finger closes with a finely crenulate inner margin, 

 making a bend over the cavity, touching the central tooth-process by the angular 

 projection of its own inner margin, and with its point reaching the palm near the 

 smaller tooth, its own curved outer margin being bent almost at a right angle. 



First Perseopods. — Side-plates oblong, rather longer than the preceding pair, lower 

 margin convex. Branchial vesicles with a narrow neck, distally of great breadth, longer 

 than the first joint. First joint reaching much beyond the side-plate, curved a little 

 backwards, with many setae and setules on both margins ; second joint short, with an 

 apical groirp of setse behind ; third joint much thicker than fourth, longer than either 

 fourth or fifth, with spines at four points in front, groups of setse at five points of the 

 nearly straight, slightly serrate, hind margin ; fourth joint shorter than fifth, with spines 

 at seven points of the hind margin, two apical setules on the front margin, and one 

 minute one high up on the same ; the fifth joint slightly curved, with nine groups of 

 spines on the serrate hind margin, an apical group of setules on the front, and a small 

 setule below its centre ; the finger short, broad, more than half the length of the fifth 

 joint, the inner margin forming an angle at the base of the short curved nail, with three 

 setules shorter than the nail implanted at that point ; the dorsal cilium very small, near 

 the base of the finger. 



Second Perseopods. — Side-plates broad, narrowly excavate. The limb as in the 

 preceding pair. 



Third Perseopods. — Side-plates not very deep. Limb as in the following pair, but 

 on a smaller scale. 



Fourth Perseopods. — First joint rounded oblong rather than oval, with a group of setse 

 at the top of the front margin, and spines at eleven points along it, the hind margin more 

 convex, serrate, the serration continued on the rounded lower margin ; the short second 

 joint a little overlapped behind, carrying an apical group of spines in front ; the third 

 joint broad and strong, expanding distally, and distally a little decurrent before and 

 behind, with spines at five poiuts of the serrate hind margin, and a group fringing the 

 truncate apex, mixed groups of spines and setse at five points of the serrate front margin ; 

 the fourth joint widened distally, with mixed groups of spines and setse at four points of 

 the serrate front margin, a similar group on the apex of the hinder, and some setules and 

 spinules higher up ; the fifth joint equal in length to the third, not so broad as the 

 fourth, but still stoutly built, with seven groups on the serrate front margin, five (chiefly 



