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



The first pair of antennae is nearly as long as the animal, and carries a sharp-painted 

 stylocerite at the outer side of the base of the first joint, which reaches to the extremity 

 of that joint ; at the base of the stylocerite, on the outer margin, there is a protuberance 

 that is probably of use in retaining the ophthalmopod in position, and protecting the 

 ophthalmus from contact with the sharp point of the antenna! tooth. 



The second pair of antennae is but slightly longer than the first, and about the length 

 of the animal, and carries a scaphocerite that is subequal with the rostrum. 



The mandible has an oblique, smooth, ovate, molar process, and a psalistoma that is 

 smaller at the base than at the serrate extremity ; at the base there is attached a three- 

 jointed synaphipod, the distal joint being flat and spatuliform. 



The first pair of siagnopoda is three-branched ; the outer branch is curved, rigid, and 

 bifid, one process being tipped with a strong spine and the other with several hairs ; the 

 middle branch is broad, flat, and fringed with a series of spines and hairs; the inner 

 branch is curved in a reverse direction to the outer, rapidly tapers to a point, and 

 is fringed with stiff hairs chiefly prominent on the convex margin. 



The second pair of siagnopoda is distinguishable from those of Pandalus by having 

 the mastigobranehial plate short, posteriorly round, and not projecting into the branchial 

 chamber. 



The third pair of siagnopoda bears a close resemblance to those of other species of 

 the genus. 



The first pair of gnathopoda is deeply reflexed and supports a short, thick, mastigo- 

 branehial plate, which carries attached to it a podobranchial plume. 



The second pair of gnathopoda is five-jointed ; the first joint or coxa carries a 

 rudimentary mastigobranehial appendage, at the base of which is a flattened disc-like 

 plate that falls between and separates the base of the first pair of gnathopoda and the 

 branchial plumes, and apparently supports the former appendage in position; the 

 second joint is very short, supports a short, slender ecphysis, and is unyieldingly 

 articulated with the next joint, which is extremely long, slender, and cylindrical ; this 

 is succeeded by one that is about half its length and a little more slender, and by a 

 terminal joint that is subequal with the penultimate and slightly tapers to a rounded apex. 

 The rest of the appendages bear a corresponding resemblance to those of other species. 



The first pair of pereiopoda resembles in form that of the second pair of gnathopoda, 

 hut it is more slender and carries a longer basisal joint and no ecphysis. The second 

 pair has the carpos long, slender, multiarticulate and subequal, the articulations are not 

 well defined, but become more distinct as they approach the propodos, the last articulus 

 equalling in length and thickness the palm of the latter joint. The three j)osterior pairs 

 have the meros long, the anterior pair reaching to about the extremity of the rostrum, 

 and are sparsely armed with long spines ; the carpos is long, the propodos subequal with 

 it, and the dactvlos short. 



