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Show 608 ON S H E L L S F R O M T H E S O L O M O N ISLANDS. [June 2, Reeve, and some of them exhibit indistinct spotting and reticulation when held up between the light and the eye. The surface of the brown-black epidermis is without gloss, and under the lens appears finely rugose or subgranular. The operculum is rather narrow, with a projection on each side in front of nearly the same length, with a deep rounded sinus between, and the horny portion covers about half the surface. The figure of the operculum of N. cumingiana, given by Martens (Conch.-Cab. ed. 2, pi. 4. fig. 4), somewhat resembles it. N. magnifica, Reeve, and N. scarabaus of the same author, are the same species, but I doubt whether N. sanguisuga also belongs to it. The sculpture of the former is not quite the same, and the surface more glossy. 65. NAVICELLA SUBORBICULARIS, Sowerby. Hab. Faro, Treasury, and Ugi Islands, from streams (Guppy) ; Guadalcanar (J. Macgillivray) ; and San Christoval (Brenchley). Both the varieties described by Martens (Conch.-Cab. ed. 2, p. 31, pi. 6. figs. 5-14), and also figured by Reeve (Conch. Cab. figs. 5, 5a), occur in the Solomon Islands, the black-striped variety being apparently of less frequent occurrence than the more finely reticulated form. 66. UNIO GUPPYI. (Plate XXXVII. figs. 8-8 b.) Shell elongate, very inequilateral, usually a little longer than twice the height, compressed, covered with a blackish-brown epidermis, exhibiting strong lines of growth and very faint radiating substriation, and marked with fine wrinklings at the eroded beaks, which are small and placed quite near the anterior extremity. Dorsal margin behind the umbones almost straight or the least excurved for some distance, then at an obtuse angle becoming oblique before rounding into the extremity, which is a little more sharply curved than the anterior end. Ventral outline either faintly excurved, straight, or the least concave. Interior bluish-white, most iridescent at the hinder extremity, generally stained in parts with olive-brown. Cardinal tooth of the right valve moderately large, four- or five-lobed at the top, situated just in front of the umbo. Between it and the outer margin is a short ridge, the space between the tooth and the ridge receiving the single, smaller, roughened and striated tooth of the left valve. Lateral tooth of the right valve long, obliquely truncate behind, fitting in between two teeth in the opposite valve. * Anterior adductor scar deep, posterior superficial, squarish in front. Pedal scar in both valves under the cardinal tooth very deep. Ligament elongate, prominent. Length 80 m m . ; height 38 ; diameter 21. „ 70 mm.; „ 35 ; „ 18. Hab. From streams in Shortland Island. This species recalls to mind some of the forms from Australia and New Zealand. Its principal features are the elongate compressed form, dark brown colour, wrinkled apices, and coarse incremental |