Report on the zoological collections made in the Indo-Pacific Ocean ...

CRUSTACEA. 297peduncles of the antennje are very short, completely concealedbeneath the large basal scales, which reach slightly beyond the antennalpeduncles, narrow to their apices, and have a small spinvdeat the distal ends of their outer margins. The outer maxillipedesare rather robust and elongated, reaching, when thrown forward,almost to the apices of the antennal scales. The first legs are muchshorter than the following, with the joints compressed, the dactyliacute, and the basus and ischium-joints have each a small spine atthe distal ends of their inner margins ; the second and third chelipedesare slender (the hasus-joint of the second legs bears a smallspine) ; the third are longer than the second ; the fourth legs areslender and rarely as long as the third ; the fifth are imperfect.The rami of the iiropoda are narrow, and reach about to the end ofthe terminal segment ; the outer has the lateral margins nearlyparallel ; in the inner ramus they converge very slightly to therounded extremity. Colour (in spirit) purplish beneath the cinereouspubescence. Length about 2 inches 10 lines (72 millim.).The unique example (a female) was obtained at Albany Island in3-4 fms.The palpi of the mandibles are two-jointed ; the joints flattened,dilated, and ciliated, as in Pencms.As the specimen is unique, I have not been able to make a completeexamination of the branchiae ; but I think (as in the trueFencei as restricted by Mr. Hpence Bate) no true podobranchiae arepresent, but merely the epipoditic appendages or " mastibranchise "as he denominates them *.There are, besides, in the collection from Port Denison a specimenclosely allied to Pasipluva and to LeptocJula, Stimpson ;andanother crustacean, perhaps belonging to the Pena^idea, which, beingin very mutilated condition, cannot be described in detail, andwhich I leave for the present iindetermined,* Vide Spence Bate " On the Peufcidea," Aim. & Mag. Nat. Hist. ser. 5, viii.p. 174(1881).In this recent memoir on the Penseidea several new genera and not afew new species have been very briefly characterized, to none of which, Ibelieve, can our new form be referred. The descriptions, however, are insufBcient.From HemvpencBus, which this species resembles in its short and fewtoothedrostrum, it differs in the structure of the flagella of the antennules.Mr. Spence Bate includes in the very insufficiently defined genus PencBopsis theP. styliferus, M.-Edwards, with which he apparently considers P. dohsoni, Miers,to be identical. He has strangely overlooked an important distinction, twicementioned by me in my paper {vide Proc. Zool. See. 1878, pp. 305, 307),namely the absence of lateral marginal spinnles on the terminal postabdorainalsegment. They are absent, I may add, alike in the female and in Prof.Wood-Mason's small male. The existence of these in P. styliferus is mentionedby Milne-Edwards in his original description of that species, and tliey arepresent also in a specimen referred to P. styliferus in the British-Museumcollection.