3 68 
INDEX. 
River systems of Africa, 34. 
Rocky Mountains, 33, 36. 
Ruchuru river, fauna of, 139. 
Rudolph lake, fauna of, 132. 
,, ,, , fresh-water fauna of, 328. 
Rukwa, fauna of, 127. 
,, , molluscs of, 19. 
,, , sandstones of, 52, 62. 
Rusisi, fauna, 139. 
„ river, 83. 
,, valley, geology of, 82. 
Ruwenzori, 33. 
SALINITY OF THE SEA, 28, 29. 
Salt, effects of, on fresh-water organisms, 
23. 24- 
,, , experiments of Herbert, 25. 
,, ,, Loeb, 25. 
,, ,, Vernon, 25. 
,, , increase of, in the sea, 26, 27, 28, 
29, 326. 
,, ,, , in Shirwa, 22. 
Sandstone deposits, 65, 66, 68, 85. 
,, of Karagwe, Gregory', 66. 
,, of Mwero, 62, 65. 
,, of Nyassa, 61, 62. 
,, , old African, 81. 
,, of Rukwa, 62, 65. 
,, scarps on Nyassa, 42. 
,, of Tanganyika, 48, 62, 65, 
66, 80. 
Saracin Brothers, investigations of, 239. 
Scarps, gigantic, on Tanganyika, 80. 
Scenery', artificial aspect of, 108. 
Schilbe mystus, 128. 
Scott Elliott, 34, 79, 102. 
Sea, ancient, of Western Africa, 343. 
,, , changes of salinity in, 21, 26, 27, 28, 
326. 
,, , former extent of, over Africa, 68. 
,, , ,, extension over Congo, 140. 
,, „ ,, Nyassa, 72, 74. 
,, ,, ,, Tanganyika, 3. 
,, , probable date of separation from Tan* 
ganyika, 74. 
,, , the Red, 79. 
Seasons, wet and dry, on Tanganyika, 301. 
Secondary' fresh-water faunas, 15, 30. 
Section through North Nyassa and great 
central ridge, 142. 
,, ,, South Nyassa and great 
central ridge, 140. 
,, ,, Rukwa, 45. 
Semliki valley, 94. 
,, , fauna of, 139. 
Semper and Sollas, investigations of, 12. 
Serranidse, 135, description of, 168. 
,, of Lake Rudolf, 132. 
Shales on Tanganyika, 48. 
Shells of Tanganyika, 220. 
,, ,, brought back by 
various travellers, 
218, 220. 
,, ,, , marine appearance 
of the, 219. 
,, ,, , remarkable facies 
of, 344. 
Shiri, fauna of, 139. 
Shirwa lake, 21, 26. 
,, ,, , fauna of, 3, 126. 
» >. , geology of, 57. 
,, ,, , lake deposits of, 58. 
,, ,, , salt in, 22, 126. 
Siluridie, 341, 135. 
,, description of, 160. 
,, of Mwero, 125. 
,, of Nyassa, 124. 
Simochromis diagramma, description of, 
198. 
Sinking of floor of Nyassa, 44. 
Snow line on Mountains of the Moon, 101. 
Sollas and the solution of fresh-water 
fauna problem, 15. 
Spatha kirkii, 125. 
,, nyassensis, 125. 
,, trapezia, 1 31. 
Spathodus erythrodon, description of, 212. 
Species, number of, in proportion to size 
of lake, 146, 147, 150. 
Speke, shells brought from Tanganyika by, 
1, 218. 
Spekia, affinities of, 218, 250, 256, 258, 
259, 260, 267, 274, 349. 
,, , description of, 256. 
