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Show 1887.] MOLLUSKS OF THE VITI ISLANDS. 177 lunate ; peristome simple, straight above, acute, at the base with callus. Major diam. 15, height 6-7 millim. As compared with T. ludersi it is smaller, differs in the groundcolour, the umbilicus is not so large, and the bands are wider and only two in number. 11. TROCHOMORPHA SUBTROCHIFORMIS. Helix trochiformis, Gould (not of Ferussac), Expl. Exp., Shells, p. 61. Helix eurydice, Mousson (not of Gould), Journ. de Conch. 1865, p. 170. Trochomorpha subtrochiformis, Mousson, Journ. de Conch. 1869, p. 335, pl. 4. fig. 6 ; 1870, var. albo-striata, p. 122; Pease, Proc. Zool. Soc. 1871, p. 474. Helix subtrochiformis, Schmeltz, Cat. Mus. Godeff. p. 95 ; Pfeiffer, Mon. Hel. vii. p. 289. Mousson's var. albo-striata inhabits Kanathia, one of the Windward Islands, and the type is a Samoan species. The variety, which is unknown to me, is described as follows :- " Spira fusco-nigrescens, strigis transversis, albis, imperfectis, eleganter ornata, ad basin fulvescens, cum zona peripherica fusca." (Mousson.) It is probably distinct from the Samoan type. 12. TROCHOMORPHA THEMIS, sp. nov. Trochomorpha (Discus) ludersi, Mousson (not of Pfeiffer), Journ. de Conch. 1870, p. 122 (part.). I obtained numerous specimens of this species at Vanua Balavo, where they were found adhering to the trunks of trees. It is also recorded from Oneata Island. Shell with a narrow umbilicus, solid, sublenticular, not shining; striae very fine, oblique and crowded; whitish horn-colour, with a single dorsal and basal submarginal chestnut-brown line; spire depressedly conoid, obtuse; suture with a depressed white margin; whorls 5|, depressedly convex, slowly and regularly increasing, last one not deflected in front, acutely and compressedly carinated, keel white ; base convex ; umbilicus about one eighth the major diameter of the shell; aperture and peristome the same as in T. corallina. Major diam. 14, height 6 millim. As compared with T. ludersi it is smaller, paler, has only half so many linear bands, striae finer and the umbilicus much smaller. T. corallina is of a fulvous colour (very rarely whitish), the bands are wider and paler and the suture has not got the white margin ; it is also a little larger and smoother, and lives in a different station. 13. TROCHOMORPHA KANTAVUENSIS, sp. nov. Shell widely umbilicated, thin, fragile, pellucid, depressed, lenticular, smooth, shining; incremental striae fine, crowded, oblique; PROC. ZOOL. Soc-1887, No. XII. 12 |
