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Show 1884.] OF T H E ' C H A L L E N G E R ' E X P E D I T I O N . 267 cations of spiral striae on the under surface. Spire shortly obtuse at the apex, with almost straight lateral outlines. Aperture moderately large, yellow within, subsemicircular. Peristome semi-pellucid, slightly expanded and thickened, generally margined externally with a whitish stripe. Columellar side of the aperture oblique, coated over the umbilical region with a glossy yellow callosity, slightly channelled at the base. Greatest diameter 6 millim., smallest 5, height 5. Operculum thin, slightly concave externally, minutely rugose, yellowish on the straight or columellar side, brownish or reddish brown towards the outer edge, which is very finely carinate. Hab. Wild Island and Pigeon Island. This species is very like H. modesta, Pfr., from the island of Tanra, but has a slightly larger mouth, a yellow basal callus instead of a whitish one, and a different operculum, that of H. modesta being thicker, more shelly, concave in the centre, with a broad flattened raised rim all round the convex side and a raised but not flattened margin on the straight side. 10. PYTHIA SCARAB^EUS, Linn. Hab. Wild Island. A large number of specimens were brought home from this locality. They are, as a rule, rather larger than those obtained by the Expedition at the Ke Islands, having an average length of about 29 millim. and a width of 17- They vary in colour, some being painted like typical variegated forms, and others more uniformly tinted like P. pollex, Hinds, and P. albivaricosa, Pfeiffer, which might be regarded as local varieties apparently offering no structural differences. 11. MELANIA ARTHURII, var. ? Hab. Wild Island, Admiralty Islands. As far as I can ascertain, no species of Melania has been recorded from these islands. The single shell at hand, which had been seized upon by a Pagurus, approaches so closely to M. arthurii (Brot) that I think it will probably prove only a variety of that species. It is decollated above, four and a half whorls only remaining, of which the two uppermost, however, show the longitudinal costae occurring in that species. The rest of the surface is spirally densely striated and sculptured with rather elevated lines of growth. It is of a dark brown tint, slightly paler at the margina-tion below the suture, beneath which there is a series of oblique dark oblong spots. The whorls are slightly convex, and somewhat contracted just below the upper marginate edge. 12. NERITINA CORNEA. Hab. Wild Island. The two specimens correspond to the form figured by Martens in his Monograph (Conchyl.-Cab. pi. 12. f. 15). |