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Show 294 MR. G. S. BRADY ON EUROPEAN CYPRIDINIDAE. [Apr. 4, The male of this species is already sufficiently well known ; but the female has not heretofore been described, unless, indeed, the form figured by Mr. Norman in the 'Annals and Magazine of Natural History' for 1861 may be supposed to belong to that sex. Mr. Norman's description, however, so far as the structure of the antennae is concerned, applies only to the male. Externally the male is easily distinguished by its more elongated and angular form, and by the want of spinous armature at the posterior extremity, the lower angle of which is produced into a blunt subangular prominence; the upper angle, however, occasionally bears a small tooth. 7. PHILOMEDES FOLINII, nov. sp. (Plate XXVII.) Female. Carapace as seen from the side subrhomboidal; greatest height situated in the middle and equal to at least two-thirds of the length ; anterior extremity very prominent in the middle, beak broad and blunt, notch wide and rather shallow ; posterior produced at the ventral angle into a broad triangular projection ; superior margin boldly and evenly arched, inferior also distinctly but somewhat less strongly convex. Seen from above the outline is subhexagonal, with nearly parallel sides, which converge suddenly and angularly towards the extremities; anterior extremity truncate, notched in the middle, posterior very broadly and bluntly mucronate; greatest width equal to rather more than half the length: the end view is irregularly heptagonal, the nearly parallel lateral margins ending above and below in prominent rounded angles, the two superior margins converging into an irregular arch, the basal margin nearly flat. The surface of the shell is irregularly undulated and closely set throughout with rounded or subangular sharply cut pittings of moderate size and depth, and is strengthened by several strongly projecting rounded ribs, which are disposed as follows : one commencing immediately below the antennal notch, in a conspicuous angular projection, is continued round the interior part of the shell and terminates in the posteal spine; a second (which is irregularly nodulated at the hinder extremity) rises in the posteal spine, runs upwards within the posterior margin, and then strikes somewhat obliquely across the valve, terminating in a long and sharp beak, which forms the anterior margin of the antennal notch: these two ridges are connected behind the notch by a short transverse prolongation, which gives off from near its middle a third long and rather flexuous rib running parallel with and midway between those already described, but losing itself before quite reaching the posterior margin ; just within the antero-superior border a fourth but much more feebly developed rib runs backwards to the* middle of the superior margin, where it joins an encircling dorsal ridge of about equal development. Length T l r inch. Male. The shell of the male (possibly a young specimen) is altogether smaller, but comparatively much more elongated, the height being equal to only half the length; the shell-structure is similar in character to that of the female, but very feebly developed. Length 1^ inch. The secondary branch of the lower antenna, in the female |