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



and the extremity rounded and like the inner margins fringed with ciliate hairs, and 

 armed on the outer distal extremity with a strong tooth ; the second joint of the 

 peduncle is furnished at the outer angle with a sharp tooth. 



The mandibles (fig. Id) are short, robust, and have neither synaphipod nor molar pro- 

 cess ; the psalistoma is prominent and sharp ; behind it on the margin are several minute 

 teeth or spinules. 



The first pair of siagnopoda is three-branched ; the two basal branches are broad and 

 foliaceous, and the distal narrow ; all supporting a few spine-like hairs. 



The second pair of siagnopoda (fig. If) is four-lobed ; the two basal on the inner side 

 are bilobed, and tipped with long simple hairs, the distal is narrow and furnished with hairs 

 on the inner side and at the tip, the outer side being smooth ; the fourth or outer lobe is 

 broad, projects anteriorly and posteriorly beyond the others, and is fringed with hairs, of 

 which a few at the posterior margin are extremely long and directed backwards, the others 

 fringe the margin from the posterior extremity to the anterior, gradually increase in size, 

 and are directed forwards. 



The third pair of siagnopoda (fig. lg) or maxillipedes consists of two foliaceous plates 

 on the inner surface fringed with hairs, of which the distal is narrow and the basal broad, 

 and on the outer side a long and slender ramus distally tipped with a few hairs. 



The first pair of gnathopoda is short and pediform ; the ischial and meral joints are 

 broad, concavo-convex, and fringed with hairs ; the basisal joint carries an ecphysis that 

 is double the length of the leg, and the coxa supports a divided mastigobranchia. 



The second pair of gnathopoda is longer and more robust than the first, it terminates 

 in a sharply pointed dactylos, and is furnished with a very long and slender multiarti- 

 culate basecphysis, and the coxa carries an undivided mastigobranchia. 



The first pair of pereiopoda is long, cylindrical, and pediform ; the coxa and basis are 

 long, the latter carrying an ecphysis that is subequal in length with the leg ; the meros 

 is long, the carpos short, the propodos longer, and the dactylos tapering, and terminating 

 in a styliform unguis. The other pereiopoda correspond in form but gradually increase 

 in length until the posterior pair, which is slightly shorter. 



The pleopoda are biramose and smooth, as if not yet fully developed. The posterior 

 pair is more advanced, is subequally biramose, fringed with hairs, and the outer margin 

 near the distal extremity is armed with a strong tooth. 



The branchiae consist of five pairs, one to each pair of pereiopoda ; these represent as 

 many pleurobranchise, all of which are comparatively large and well developed. 



One of the specimens showed the nerve-ganglia very distinctly through the dermal 

 structure, and it appeared as if the several somites of the pereion were connected by one 

 large neural mass, while those of the pleon consisted of large globular ganglia, situated 

 near the posterior extremity of each successive somite, connected together by a fine cord. 



Observations. — The specimens taken were of different sizes, that described being 



