Report on the zoological collections made in the Indo-Pacific Ocean ...

MOLLUSCA.Illparticularly conspicuous at the pallial line, where they terminate.The muscular scars are large, well defiued by a line radiating from theumbones. Hinge-teeth rather numerous, minute in the centre,considerably larger at both ends. In the type there are forty, anda specimen about half-grown has thirty-five. The ligament isnarrow, but very coarsely striated transversely. The epidermis isthinnish and somewhat fibrous near the margins, especially posteriorly.59. Area (Barlbatia) symmetrica.Area symmetrica, Reeve, Conch. Icon, sp, 117, and fig. 120.? Var. = Area zebuensis, Reeve, I. c. fig. 117, sp. 120.Hah. Port Molle, Queensland, 12-20 fms. (Copjpinger) ; Bay ofManila {Cuminy).In the Conchologia ' Iconica ' the numbers of the figures 120and 117 should be reversed. The specimens of A. symmetricawhich were described by Reeve are of a greenish tint, and not sooblique as' A. zebuensis. The sculpture in both consists of fineradiating lirse, rendered minutely granular by the concentric linesof growth. The liras vary but little in thickness, with the exceptionof a few finer intermediate ones here and there and those onthe posterior extremity, which are a trifle stouter. A. zebuensisdiffers, in addition to its extra obliquity before referred to, resultingfrom the less central position of the umbones, in being a trifle morefinely lirate. One of the specimens from Port Molle is somewhatintermediate in form, being more oblique than A. symmetrica andless so than A. zebuensis. The measurements of two specimens willindicate to what extent the form and proportions may vai'y —:No. 1. Height 7^ millim., length 11, diameter 8,No, 2, „ 6i „ „ 11, „ 6|.Area tortuosa, Linn.60, Area (Trisis) tortuosa.Hah. Singapore and Malacca {^Cuming'); North-west Australia{Du Boiday) and China {Beeves), in Brit, Mus, ; Port Curtis in11 fms., sand and shell bottom (Cojjjnnyer).The right valve of this well-known and remarkable shell alwaysappears to retain more of the epidermis than the left. The foot andmouth of the animal, as might be expected, are at the narrow endof the shell. The foot (in spirit) is small, narrow, and groovedbeneath, retaining a small byssus.61. Leda darwini. (Plate VII. figs. L-L2.)Shell a little inequilateral, rather convex, transversely irregularlyovate, acuminate posteriorly, thinnish, glossy, moderately coarselyconcentrically ridged and sulcate throughout, except upon the lunuleand area, the ridges being finer and the sulci broader on a slightlydepressed portion of the surface down the posterior side, which is of