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Show 1868.] MR. C. SPENCE BATE ON NEW FRESHWATER PRAWNS. 365 pair of pereiopoda half as long again as the animal, having the carpus longer than the meros and as long as the propodos, excepting the digital process; digital process curved slightly inwards, fringed with a row of hairs, and furnished with two dental tubercles within the centre. Dactylus curved; the apex crossing the extremity of the digital process of the propodos, and impinging against it through the entire length, fringed with a row of hairs and with a single tubercle. The entire appendage covered with small, yellow, transparent, spinous denticles. Last three pairs of pereiopoda moderately robust, and furnished with numerous small denticles along the inferior margin. Posterior pair of pleopoda roughened with small spines, as also the telson, which carries a small fasciculus of hairs near the base, and two small sublateral spines beyond the middle. The length of this species is about 4 inches. It has recently been taken and brought home by Dr. Collingwood, who procured it from the River Tamsuy, in the Island of Formosa. MACROBRACHIUM GANGETICUM, sp. nov. (The Chingra.) This species appears closely to resemble the preceding. I only know it through a drawing given to me by the late Colonel Hamilton Smith, who obtained it from a friend at Patna, a distance of 250 miles from Calcutta, where it was used as food, and was known under the name of " Chingra," the Hindostanee, I believe of " shrimp." Its length is about 6 inches, and the colour a bluish grey. MACROBRACHIUM LONGIDIGITUM, sp. nov. (Plate XXXI. fig. 2.) Carapace, including rostrum, nearly half as long as the animal. Rostrum about half as long as the carapace; upper surface armed with eight teeth, two only of which are behind the orbital margin. The teeth are widely separated from each other, and a few hairs are situated immediately anterior to each denticle. The lower margin armed with five teeth and a copious fringe of hair. First pair of antennae having the peduncle one-third shorter than the rostrum, the first joint of which is about half the length of the peduncle, concave upon the upper surface, and armed with a sharp distal tooth on the outer angle, and without conspicuous cilia along the margin. The smallest branch of the flagella attached to the largest for about one-fourth of an inch from the base. Second pair of antennae as long as the animal, the peduncle being about half the length of the peduncle of the upper pair. Squamiform appendage not reaching to the extremity of the rostrum, and armed subapically with a small, sharp tooth, that does not reach beyond the cilia that thickly fringe the distal and internal margin. First pair of pereiopoda long and slender, having the carpus longer than the meros, and three times as long as the propodos. Second pair of pereiopoda not quite as long as the animal, having the carpus a little longer than the meros, and the propodos, inclusive of the digital process, as long again as the carpus, the dactylus being half the length of the propodos, being pointed and curved at the apex, |