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Show 24 MR. E. J. MIERS ON CRUSTACEA FROM [Jan. 14, OREGONIA HIRTA ? ? Oregonia hirta, Dana, Amer. Journ. Sci. and Arts (ser. 2), p. 270 (1851); U.S. Expl. Exp. xiii., Crust, i. p. 107, pi. iii. fig. 3 (1852). Two specimens of an Oregonia were collected, both females, the larger and mature example densely overgrown with sea-weed. These agree in almost every respect with specimens of Oregonia hirta, from California (Puget's Sound), in the collection; but the legs are rather more robust, and the branchial regions more convex. The examination of males might show that they belong to a distinct species; for the present, however, they cannot be regarded as distinct. Japan, Cape Blunt, lat. 41° 41' N., long. 141° 0' E. (depth 35 fathoms). P L E I S T A C A N T H A , gen. nov.1 Carapace triangular, convex, and spinose. Rostrum long and slender, composed, as in Oregonia, of two spines, which are in contact with one another to near their extremities. Eyes laterally projecting. Orbits not defined, the inferior walls wanting, the superior and posterior represented by two or three spines. Antennules long; interantennulary septum with a prominent spine projecting downward. Antennae with the basal joint extremely slender and armed with three spines ; the flagellum long, reaching almost to the extremity of, and visible in a dorsal view at, the side of the rostrum. Ischium (or second) joint of the outer maxillipeds longer than the merus-joint, which has a short spine at its antero-external angle ; the exognath very slender. Legs, as in Egeria, very long; the anterior pair robust, with the fingers acute and meeting near their apices along their inner margins, but leaving an hiatus at base when closed. The ambulatory legs are slender, and diminish successively in length to the last pair; their terminal joints are long, slender, and densely hairy. The male postabdomen is 6-jointed, the inflexed portion oblong, the terminal joint transverse and rounded at its distal extremity. This genus must be placed near Oregonia, with which it is nearly allied in the structure of the rostrum and orbital and antennal region; but it differs in the convex and spinose carapace and greatly elongated legs, which gives it more the aspect of Egeria, and would necessitate its being placed among the Macropodiens in Milne-Edwards's arrangement. From Egeria it differs in the structure of the orbital and antennal region, &c. PLEISTACANTHA SANCTI-JOHANNIS, sp. n. (Plate I. fig. 1.) Carapace covered with very numerous small spines of uniform size; interspersed with these are longer spines, of which three are placed in a transverse series on the front and one at the back of the gastric region, two on the cardiac, two on the intestinal and about three on each branchial region; there are also several longer spines placed behind the eyes and on the sides of the branchial regions. Rostrum 1 7r\er<rro9, superl. of iroXis, many; and aicavGa, a spine. |