REPORT ON THE CRUSTACEA MACRURA. 489 



and the posterior extremity furnished with four hairs. The ventral surface of the pereion 

 and pleon from the oral cavity to the telson is smooth, without any spine or tooth, but a 

 small lobe exists between the second pair of pereiopoda. 



The ophthalmopoda are not large, being well hidden within the orbital cavity ; the 

 surface of the ophthalmus is smooth, destitute of pigment generally and not visibly 

 faceted. 



The first pair of antennas carries on the outer surface a broad thick stylocerite, which 

 springs from the base and reaches to the distal extremity of the first joint, on the under 

 and inner side of which is a short thick tooth ; the second joint is shorter than the 

 first, and the third shorter than the second. The two terminal flagella reach a little 

 beyond the extremity of the scaphocerite of the second parr ; the inner flagellum is a 

 little longer than the outer, and furnished on the inner margin with a fringe of long hairs. 



The second pair of antennae has the scaphocerite, which is ecpal to half the length of 

 the carapace, thick and ridged, with the margins subparallel, the outer terminating in 

 a sharp tooth. The flagellum is broken off near the base in the only specimen procured 

 from this station. 



The second pair of gnathopoda does not reach beyond the distal extremity of the 

 scaphocerite and is furnished with hairs, some of which are smooth and others delicately 

 ciliated. The basecphysis, or branch springing from the basis (the exognathe of Milne- 

 Edwards), is short, reaching, when extended, to nearly the length of the ischium ; the 

 mastigobranchia (epignathe of Milne-Edwards) is reduced to a rudimentary condition. 



The first pair of pereiopoda has the anterior margin of the palm broader than the 

 propodos, incisive, convex, not very oblicpie ; pollex long and sharp ; dactylos smooth 

 and sickle-shaped. The second pair is short and feeble, extending scarcely to the distal 

 extremity of the meros of the first pair ; chela with fingers long, slender, tapering and 

 meeting only at the points. The third pair is long and slender, extending beyond the 

 distal extremity of the scaphocerite of the second pair of antenna?. The fourth and 

 fifth pairs are slender, subecpially long and robust. 



The first pair of pleopoda (p $ , p ¥ ) has the internal branch rather more than half 

 the length of the external, and perfectly free from cilia, but with one or two short spines 

 on the outer side ; the external branch in the male is long, narrow and leaf-bike, and 

 fringed on each side with plumose hairs. In the type specimen all the hairs are rubbed 

 off. The second (<Z £ > <Z ¥ )> third and fourth pairs of pleopoda differ from each other in 

 but a slight degree. Each consists of a pair of nearly equally long, large, ovate, 

 foliaceous plates, fringed with long plumose cilia ; the inner branch carries a stylamblys 

 attached to it. 



The posterior pair, which forms the outer plates of the rhipidura, is rather longer than 

 the telson ; the outer branch has a strong ridge on the outer margin which terminates in 

 a subapical tooth ; the inner branch is longer, narrower, and more pointed. 



(ZOOL. CHALL. EXP. PAET LII. 1887.) Eff 62 



