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Show 1893.] SHELLS FROM BRITISH CENTRAL AFRICA. 633 tution has been indebted on previous occasions for valuable collections trom the Cameroons and the neighbourhood of Mount Kilimanjaro. The most interesting specimens of the present collection are those obtained at Lake Mweru, a locality from which no Mollusca have as yet been recorded. This lake lies to the south-west of Lake Tanganyika, with which, however, it has no connection, as would be presumed by the difference of the Molluscan faunas so tar as they are at present known. All the species from Lake Mweru are undescribed with one exception, and this appears to be a dead worn example of Lanistes ovum. The other species include two forms of Viviparus, two Cleopatrce, three Melanice, a very remarkable winged Unio, and examples of two or three other species of that genus, but represented by specimens too young or too worn to be determined. Forms of all these genera occur in Tanganyika, aud one of the species belongs to that group of Viviparus which, characterized by the aperture being somewhat effuse anteriorly and the outer lip smuated, was described by the writer in these ' Proceedings' for 1880 as a new genus from Tanganyika, under the name^of Neoihauma. 1. ENNEA JOHNSTONI. (Plate LIX. fig. 1.) Testa elongatee, cylindracea, crassiuscula, rimata, flavo-viridis, parum nitida; anfractus 6, convexiusculi, oblique fortiter striati, superiores quatuor regulariter crescentes, ultimus et penultimus longe majores, ultimus elongatus, supra aperturam Icevior et sub-complanatus, primo peroblique descendens, sed ad labrum breviter ascendens; spira obtusissima; sutura mediocriter profunda; apertura subovata, intus sordide cdbida, longit. totius j paulo superans, clenticulo unico parietali munita; peristoma album, incrassatum, anguste reflexum, marginibus callo crassmsculo junctis. Longit. 20 millim., diam. 10; apertura 8 longa, 5 | lata. Hab. Fort Johnston, Upper Shire River (A. Whyte). This interesting shell is quite unlike any other known species, but recalls the form of some of the Mauritian Gonospirce, e. g! G. modiolus, Ferussac, although the relative proportion of the whorls is quite different. The oblique striae are distinct and thread-like, but less observable upon the body-whorl above the aperture, where the surface has a faintly flattened appearance. With this species I have associated the name of H . H. Johnston, Esq., the spirited Commissioner of this Country in British Central Africa, and the donor to the Museum of the specimens. 2. ENNEA KARONGANA. (Plate LIX. fig. 2.) Testa cylindracea, rimata, cdba, nitida ; anfractus 7, lente accrescentes, leaves, leviter convexiusculi, sutura profunda vix obliqua sejuncti; spira cylindrica, ad apicem obtuse conica; anfr. ultimus antice haud descendens vel ascendens, pone labrum profunde, 43* |
