290 MR. E. A. SMITH ON SHELLS FROM [Feb. 1 T, 



28. Lanistes purpurexjs, 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. 



Meladotmis 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 some- 

 what 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. 7. 



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 Concho), vol. ii. pi. 70. figs. 9, 10) more narrowly umbi- 

 licated, with the last whorl and aperture considerably narrower at 

 the base. The penultimate whorl, too, of the latter is vepy 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 re- 

 mains of an animal agrees exactly with that of L. ovum (Troschel, 

 • Gebiss der Schnecken', vol. i. p. 90, pi. 6. fig. 1 1). 



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 de- 

 scribed by me from Lake Nyassa. 



