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Show 1900.] FROM THE FALKLAND ISLANDS. 551 6-jointed, shorter than peduncle of second, first joint nearly as broad as long, second shorter and much narrower, third about half as long as second ; flagellum small, its middle joint longest. Second antennae apparently with a minute rudiment of a process on the third joint, carrying 2 spinules, sixth joint of peduncle a little longer than 5th; flagellum sometimes nearly twice as long as peduncle, attaining to 25 joints (20-30 are given for I. hargeri). Upper lip with rounded or somewhat flattened apical margin. Under lip with rather strong setules on the obtuse apices. First maxillae.-Inner plate not linear, its margins convex, the apex carrying 4-5 setae; outer plate much broader, apex fringed with 11 spines in two series. Second maxillae.-Inner plate moderately broad, with numerous setae on apex; outer plates narrow, each with 4 apical setae, longer than those on inner plate. Maxillipeds.-First joint short, the epipod irregularly oblong or oval, not reaching beyond first joint of the palp ; second joint broad, its terminal plate nearly as long as the base and more than half as broad, with one or two coupling spines on inner margin, and several spinules fringing the apex; first joint of palp short, second rather broad, scarcely longer than broad, third much shorter and narrower, distally narrow ed, fourth as long as second but narrower even than third, fifth much shorter than fourth. Limbs of peraeon all nearly alike. First pair (gnathopods) are a little shorter than the others, and, so far as I could discern, are without the triangular prolongation of the sixth joint seen on the other pairs. In all, the second joint is little broader than the fifth and little longer than the sixth, the fourth is shorter than the third, the fifth is decidedly broader than the sixth, but scarcely so long. The short finger has a broadly oval base, from which issues a strongly curved nail on the outer side of the apex, and on the inner side two similar but shorter nails ; between these and the longer nail a curved spine may sometimes be seen protruding. The two smaller nails are placed so close together that they often look like a single two-pointed nail. Over the broad part of the finger the apex of the sixth joint is produced in a triangular process. In the female, the operculum of the pleon is broadly rounded, with a produced obtuse apical point. The uropods are rather more (or slightly less, Bovallius) than a fourth of the caudal shield. The outer ramus is as long as the peduncle, and has several setae on the truncate but narrowed apex, with one or two setules near the middle ; the inner has a basal part as long as, but broader than, the outer, with a narrower and much shorter apical portion, separated as it were by a fringe of spinules and tipped with long setae. The specimens were of various sizes (including young with the seventh pair of trunk-legs undeveloped). All the adults seemed to be females, tbe largest scarcely exceeding 2-5 m m. Locality. Falkland Islands. On Exosphceroma gigas. |