REPORT ON THE CRUSTACEA MACRURA. 771 



has the posterolateral angle rounded, but that of the fifth is produced to a sharp angle, 

 and above, just below the articulation of this somite with the sixth, is a projecting tooth. 

 The sixth somite is longer than the preceding two and subecpial with the third, gradually 

 narrows posteriorly, is subcylindrical, and has the posterior margin produced to a sharp 

 point between the sixth pair of pleopoda and the telson. 



The telson tapers to a truncated apex that is fringed with fine hairs ; the dorsal 

 surface is flattened, the lateral margin depressed, and the longitudinal angle thus 

 produced is furnished with five short spinules on each side. 



The ophthalmopoda are short and supported at the extremities of the ophthalmic 

 somite, which is partially protected by a projection of the metope that is produced 

 to an obtuse point in the median line. The ophthalmus is large and reniform and the 

 peduncle is reduced to a minimum ; there is no distinct ocellus, but on the outer margin 

 of the ophthalmus there is a projection of the pigment from the margin of the ophthalmus 

 that looks like a rudimentary or obsolete organ of this kind. 



The first pair of antennae has the first joint long, broad, deeply excavate, and 

 furnished with a stjdocerite that is strong, sharp, and reaches beyond the distal 

 extremity of the joint ; the second joint is short and cylindrical, and the third, which is 

 still shorter, supports two flagella that are subequal in length and reach a little beyond 

 the apex of the rostrum. 



The second pair of antennae carries a scaphocerite that reaches beyond the peduncle 

 of the first pair, but not to the extremity of the rostrum ; it is broad and rounded 

 distally, foliaceous on the inner and ridged on the outer margin, which terminates in a 

 small sharp tooth ; the flagellum is flexible and subecpial in length to the animal. 



The mandibles are strong and have the molar process connected with the psalistoma, 

 the former being triangulate and the latter serrate, and having at the base a biarticulate 

 synaphipod, the first joint of which is long and the second short and fringed with hairs. 



The first pair of siagnopoda is three-branched ; the two branches at the base are broad, 

 foliaceous, and fringed with strong hairs, the third is curved, slender, tapering, and 

 bifid at the extremity, the inner lobe supporting a long, stout, and strong hair, and the 

 outer having several long, slender, and ciliated hairs. 



The second pair of siagnoj>oda consists of two branches and a mastigobranchial plate ; 

 the branch nearest the base is broad, flat, and two-lobed, the inner margin being fringed 

 with stiff hairs ; the second branch is broad at the base and narrow at the apex, short 

 and smooth ; on the outer side is a long mastigobranchial plate, it projects anteriorly 

 beyond the central branch and also projects posteriorly, gradually tapering to a point that 

 is fringed with long hairs furnished with slender cilia that exist mostly towards their 

 distal extremities. 



The third pair of siagnopoda consists of a broad, foliaceous, concavo-convex plate, the 

 margins of which are fringed with hairs, the inner being rigid and distally produced to a 



