REPORT ON THE CRUSTACEA MACRURA. 643 



The mandible (fig. Id) consists of a broad apophysis supporting a long, narrow, 

 subcylindrical, molar process, a distinct narrow, flattened, and slightly curved psalistoma, 

 and a triarticulate synaphipod. 



The first pair of siagnopoda (fig. le) is three-branched, the central branch being 

 broad and disc-like. 



The second pair (fig. 1/) is two-branched, the inner branch being bilobed, and each 

 lobe fringed with short spicules; the second branch is short and tapering, and on the 

 outer side, attached to the coxal joints, is a mastigobranchial plate produced as a broad 

 foliaceous plate, anteriorly beyond the extremity of the inner branches, and posteriorly 

 but little beyond the coxal joint, and fringed with hairs directed centrifugally to the 

 front. 



The third pair of siagnopoda (fig. lg) is three-branched, and carries a mastigobranchia 

 of two plates ; the inner branch is broad and fringed with hair on the inner margin, 

 the second is slender, cylindrical, and tipped with hairs, the third consists of a broad 

 foliaceous plate, from the inner margin of which springs a long and slender flagellum 

 fringed with small hairs, and on the outer margin attached to the coxal joint are two 

 membranous plates springing from a common base, the one anteriorly, the other 

 posteriorly. 



The first pair of gnathopoda (fig. lh) is six-jointed and subpediform ; the coxal joint 

 carries a mastigobranchial plate and an arthrobranchial plume ; the basis supports a long 

 ecphysis, and the two succeeding joints are subcylindrical and subequal in length, the 

 two terminal being reflexed against the preceding, and fringed on the inner margin with 

 closely packed hairs. 



The second pair of gnathopoda is long, slender, and pediform, terminating in a long 

 and tapering propodal joint, the dactylos being absent, and carries an ecphysis or branch 

 attached to the basisal joint. 



The pereiopoda are all slender, but not remarkably long ; the carpos is about half the 

 length of the meros, the posterior distal portion of which is dentated with spine-like 

 points, and about the same length as the propodos, which terminates in a short and 

 slightly curved dactylos. 



The pleopoda are moderately long, except the first pair, which is short, one branch 

 being much shorter than the other. The rest have the rami long, narrow, and subfoliaceous ; 

 in both sexes the posterior and inner branch carries a stylamblys that has the distal 

 extremity oblicme and armed with numerous cincinnuli. The posterior or sixth pair 

 forms the lateral plates of the rhipidura ; these are longer than the telson, and the outer 

 plate carries a well-defined diaeresis. 



Observations. — The two specimens, a male and a female, belong, I think, to the same 

 species ; but had they been taken at separate stations, the variations between them might 

 have appeared sufficient to justify their separation as distinct species. These are, the 



