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Show 290 MR. E. A. SMITH ON SHELLS FROM [Feb. 15, 28. LANISTES PURPUREUS, Jonas. Ampullaria purpurea, Jonas, Archiv f. Naturgesch. 1839, p. 342, pi. 10. f. 1 ; Philippi, Conch.-Cab. p. 22, pi. 6. fig. 1. Bulimus tristis, Jay, Cat. Shells, p. 121, pi. 7. fig. 1. Meladomus olivaceus, H. & A. (non Paludina olivacea, Sowerby), Genera, vol. i. p. 349, vol. iii. pi. 37. f. 6-6 b. Meladomus bulimoides, Swainson, Treatise on Malacology, 1840, p. 340 (probably). Hab. Lake Nyassa, and between it and the east coast (Thomson). One specimen from the lake differs from the normal form of the species in having the whorls flatter and the lines of growth somewhat puckered beneath the suture. Another shell, found further eastward, has a very unusually conical form, with the volutions also exceptionally flat. The species appears to be very abundant at Zanzibar, and has also been found in many localities further south, in Mozambique. 29. LANISTES AFFINIS, Smith. (Plate XXXIV. fig. 23.) Lanistes affinis, Smith, Proc. Zool. Soc. 1877, p. 716, pi. 74. fig. Hab. Lake Nyassa {Simons & Thomson). When I described this species I had but a single shell before me, which now proves to be only a small example of it. The series brought home by Mr. Thomson show that it attains a considerably larger size. The finest specimen is 60 millims. in length, and has a considerable part of the surface strongly mal-leated, which, judging from the rest of the specimens, appears to be quite an exceptional feature. But one constant character, which may serve to part it from its congeners, is the narrow orange-yellow line which borders the volutions immediately beneath the suture. L. ovum, Peters, has a more elevated spire and smaller aperture; and L. ellipticus, Martens, appears to be (judging from the figure, Novitates Conchol. vol. ii. pi. 70. figs. 9, 10) more narrowly umbilicated, with the last whorl and aperture considerably narrower at the base. The penultimate whorl, too, of the latter is very narrow in proportion to the body-whorl. The operculum is very thin, pale, horny, and considerably smaller than the aperture. The odontophore extracted from the dried remains of an animal agrees exactly with that of L. ovum (Troschel, • Gebiss der Schnecken', vol. i. p.*90, pi. 6. fig. 11). 30. LANISTES, sp., jun. Hab. Lake Tanganyika {Thomson). Only a single immature specimen of a species of this genus was found. This is the first record of its occurrence in the lake. The specimen has a depressed spire, but not so flattened as L nyassanus, is rather widely umbilicated, and consists of three whorls. It closely resembles the apical portion of L. solida described by me from Lake Nyassa. |