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Show 604 MR. E. A. S M I T H O N S H E L L S [June 2, &c, in a marshy district in the interior of the Shortland Islands, Bougainville Straits ; also from a stream in Choiseul Bay, and from the vicinity of Star Harbour on the south-east coast of San Christoval, found living on the trunks of trees 300 feet above the sea and about 150 feet above an adjacent stream. The majority of the specimens from the above localities are very like Reeve's figure (Conch. Icon. f. 7a). One specimen, however, from a stream in Choiseul Bay, is worthy of special notice on account of its extraordinary size. It is as large as the shell figured by Gould (Wilkes's Explor. Exped. pi. xi. fig. 1K5) from Fiji, and, like it, has the edge of the columella furnished with about a dozen small denticles, agreeing in this respect with N. subsulcata. The portion of the specimen which equals an average-sized example is quite normally painted; but the rest or aftergrowth is mostly of a sombre olive-brown, with only very faint indications of the spiral mottled black zones. The operculum is quite similar to that of other specimens, but much thickened with flesh-red callus on the inner surface. The distribution of this species has already been given by Von Martens in his monograph of the genus. In addition to the localities there enumerated, I may mention that in the British Museum there are specimens from Amboyna and the Admiralty Islands collected by the Challenger Expedition; and others from Guadalcanar, San Christoval, and Ysabel Islands of the Solomon group, presented by J. Macgillivray, Esq., and J. Brenchley, Esq. 51. NERITINA SUBSULCATA, Sowerby. Hab. Streams in Treasury and Faro Islands, and at Choiseul Bay ; also found living in numbers on the stems of tree-ferns, betel-nut palms & c , in a marshy district in the interior of the Shortland Islands ; also from a stream in the vicinity of Star Harbour on the south-east coast of San Christoval; from a stream in the middle of the island of San Christoval 3-4 miles from the coast; from the sides of a freshwater stream, found at an elevation of 500 feet above the sea at Cape Keibeck, San Christoval, and finally from a stream in Ugi Islands. Mr. Guppy informs me that this is the most widely distributed species of the genus which occurs in the Solomon group, and that when first picked off the rock it ejects a watery fluid possessing a powerful musky odour. Some of the specimens are considerably eroded, and the erosion is always greatest in non-calcareous districts, where the carbonic-acid gas of the rain is not previously expended as a dissolving agent of limestone rocks. Although this species very closely approaches N. cornea, it may, I think, be held distinct on account of its difference in coloration, the crenulated and straighter margin of the columella, and the slightly finer sculpture on the outer surface of the operculum, especially towards the outer curved margin. |
