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Show 176 MR. A. D. MICHAEL ON AN [Mar. 5, Colour orange-scarlet, varying in different parts of the body in shades from orange to scarlet. Chitinous plates on the dorsal and ventral surfaces and the legs lemon-yellow ; spines on the legs yellow tipped with scarlet. Form oblong, corners rounded ; compressed dorso-ventrally; dorsal surface flat, concave in young specimens. Texture.-The whole cuticle of the body, where it is not chitinized, is covered by conspicuous rounded papillae, having an average diameter of about -005 to '008 m m . The dorsal and ventral surfaces are, however, mostly occupied by numerous porous chitinized plates sunk in the cuticle; the epimera, sternal plate, legs, palpi, and maxillary lip are all chitinized and pierced by pores averaging about 150 to the millimetre on the epimera and sternum, and about 250 to the millimetre on the legs and palpi; while the actual pores themselves have an average diameter of about -003 in the former, and '001 in the latter situations. 'Eyes crimson, placed at the antero-lateral angles of the body; the two eyes in each pair quite distinct. I cannot find any trace of a fifth median eye. Maxillary lip (fig. 4).-This, as usual, forms a deep trough, slightly narrowed toward the anterior end, which is sharply truncated and slightly bifid. Palpi (fig. 5) have tbe second joint the thickest, the fourth much the longest, the fifth a blunt claw. They are what is known as the Hydrophantes-ns\\)WS, i. e. the dorsal part of the fourth joint projects considerably parallel to the fifth, so that the fourth and fifth form a sort of chela. Mandibles (figs. 3, 21) almost straight; the chitinous wall of the dorsal half of the first joint much longer than that of the ventral. There is a membranous anterior projection (mdp.) overhanging the second joint, which joint is hook-like, movable, and serrated on its upper (concave) edge. Dorsal surface (fig. 1).-This is mostly covered by chitinous plates sunk in the cuticle, and which are usually at the bottom of small depressions ; these depressions are formed partly by the drying up and often entire rubbing off of the portion of the external layer of the cuticle which overlies the plate, and partly by these plates giving points of attachment for the powerful dorso-ventral and other muscles, by which they are drawn downward (into the body) a little. These plates are of two kinds : one consists of large, or comparatively large, plates thickly and irregularly pierced by areolations of various sizes and shapes, but so large and numerous that the holes cover a larger area than the chitin; a small portion of one of these plates is shown at fig. 11. The second kind consists of quite small plates, mostly having some approach to the round or square form, and mostly with an almost circular opening in the middle and the rest of the plate pierced by fine pores more regularly placed than those on the larger plates. Each smaller plate bears a small hollow colourless hair or spine close to the central hole, if there be one, but the hair is always present; such hairs do |
