300 ON SHELLS FROM LAKE TANGANYIKA, ETC. [Feb. 15, 



from the other species of the genus known as inhabiting the lake, 

 and is easily recognized by its form and thin lamellar teeth. U. bakeri, 

 H. Adams, from Lake Albert Nyanza, approaches the present 

 species, but is much longer and much more corrugated upon the 

 surface. 



EXPLANATION OF THE PLATES. 

 Plate XXXII. 



Fig. 1, la. Cyclostoma insular e, vara., p. 277. 



2, 2 a, 2 0. Helix (Isanina ?) ni/assana, p. 278. 



3, 3 a. Helix {Trovhoncmina) mozambicensis, var., p. 279. 



4, 4 a. Strq^taxis gigas, p. 279. 



5, 5 a. craveni, p. 280. 



6, 6(7. mozambicensis, p. 280. 



6 *. Ennea IcBvigata, p. 281. 



7, 7 a, 7 b,7 c. Bulimus (Rkachis) bratinsii, p. 281. 



8, Bulimus notabilis, p. 282. 



9, (Bulimimis) kirki, p. 282. 



10, Achatina hctmillei, p. 282. 



Plate XXXIII. 



Fig. 11. Achatina craveni, p. 283. 



12, thomsoni, p. 283. 



13, {Limicolaria) caillaudi, p. 284. 



14, 14 a. Achatina [Limicolaria) rectistrigctta, p. 284 



15, Subulina lenta, p. 284. 



1 6, solidiuscula, p. 285. 



17, 17 a, 17 b. Limnotrochus thomsoni, p. 285. 



18, 18 a, 18 b. kirJci, p. 286. 



19, Lithoglyphus neritinoides, p. 287. 



20, 20 a. Lithoglyphus rufofilosus, p. 288. 



21, 21 a, 21 b. Syrnolojisis lacitstris, p. 288. 



22, 22 a. Ampullaria gradata, p. 289. 



Plate XXXIV. 



Fig. 23. Lanistes affinis, p. 290. 



24. Melania {Sermyla) admirabilis, p. 291. 



25. tanganyicensis, p. 291. 



26. 26 a, 26 b. Melania (Melanella) nassa, p. 292. 



27. Melania horci, p. 292. 



28. Tiphobia horei, operculum, p. 293. 



29. Fahidomus fcrriigineus, p. 294. 



30. 30 a, 30 b. Segmentina (Planorbula) alexandrina, var. tan- 



ganyicensis, p. 294. 



31. 31 a. Pleiodon spekei, p. 296. 



32. Spiatha tanqanyiccnsis, p. 296. 

 S3, 33 a, 33 b. 'Unw Imrtoni, p. 297. 



34. 34 a, b. TJnio nyassacnsis, p. 298. 



35. Unio tanganyicensis, p. 298. 



36. thomsoni, p. 299. 



37. horei, p. 299. 



