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



connected ; the first carries a large mastigobranchia that projects far into the branchial 

 chamber, but is folded and not produced anteriorly ; the second and third joints are 

 closely associated and form a long concavo-convex plate of considerable tenuity, fringed 

 with hairs, the second being furnished on the outer side with a long biarticulate ecphysis ; 

 the basal joint is longitudinally triangulate, the margin of each angle being fringed 

 with hairs, the second joint is multiarticulate and distally spatuliform ; the fourth 

 joint is short, narrow, curved and tapering. 



The first pair of gnathopoda (/<) is subpediform, six-jointed, the dactylos probably 

 being absent. The coxa carries a long mastigobranchia, to the outer margin of which 

 the podobranchial plume is connected in its entire length ; the second joint carries a 

 biarticulate ecphysis, the basal joint of which is long and subcylindrical, and the 

 terminal is multiarticulate and terminally spatuliform ; the ischium is long and broad, 

 rather more so than figured ; the meros is short and reflexed, the carpos is broad and 

 distally produced on the outer distal angle, and the propodos is small and ovate, the 

 whole of the limb being thickly fringed with hair. 



The second pair of gnathopoda (/) is pediform and seven-jointed. The first or coxal 

 joint is broad, thin, concave below and projecting backwards, supports a long mastigo- 

 branchial plate fixed similarly to the preceding, and is furnished with a branchial plume 

 on the outer surface ; on a small tubercle on the upper surface of the coxa is a fasciculus 

 of very long hairs. The basis or second joint carries a biarticulate ecphysis that resembles 

 that of the first pair of gnathopoda, only it is relatively shorter since it does not reach 

 beyond the distal extremity of the ischium or next succeeding joint : the ischium is 

 long and longitudinally arcuate, the convex surface being below, the upper or concave 

 surface smooth, narrower at the basisal extremity than at the nieral ; the inner margin is 

 serrate with many small blunt cusps. The under surface is fringed within the inner 

 or serrate margin by a row of closely planted fasciculi of hairs, in the median line of the 

 same side is an obtuse carina, furnished with several distantly placed fasciculi of hairs : 

 the meros articulates obliquely at the distal extremity of the ischium, than which it is 

 much narrower ; distally it thickens in width and depth, becoming triangulate at the 

 extremity, where it articulates with the carpos or fifth joint on the inner distal angle, 

 which also increases in diameter distally and articulates with the propodos, which is long, 

 narrow, and ovate, and fringed with hairs on the inner, upper, and lower margins : the 

 dactylos is pointed, tapering, and fringed with hairs, but not unguiculate. 



The first pair of pereiopoda (k) is about two-thirds the length of the animal ; it is 

 chelate, the fingers being subequal in length to the palm ; the propodos is ovate and 

 fringed on the polliciform margin with a double row of longitudinal cusps, and on the 

 dactyloid margin with a single row of six teeth, the posterior of which projects at a 

 right angle and rests against the carpos, and the anterior projects over the dactyloid 

 membranous articulation ; on the under and upper surface corresponding with the articu- 



