342 



EVOLUTION OF TO-DAY. 



R 



Race-horses, 31 



Rats on the island of Formosa, 25 



Reciprocal crosses, 39 



Relation of the present animals 



to the past, 171 

 Religion, 314 

 Return to the original condition 



of domestic animals becoming 



feral, 43 

 Revelation, 17 

 Reversions, 47 



Rhyncophora of St. Helena, 197 

 Ritta, I So 

 Rodents, 66 

 Romanes, 302, 303, 320 

 Rudimentary organs, 78, 267, 291 



Schmankewitsch, experiments on 

 artemia, 26 



Scorpions, 95 



Sea-urchins, fossils, 112 



Separation of the sub-kingdoms 

 from gastrula, 158 



Serial homology, 72 



Sexual selection, 210 



Significance of the parallel be- 

 tween embryology and paleon- 

 tology, 140 



Silurian animals all marine, 107 



Similarity of independently ac- 

 quired organs, 231 



Sirenia, 66 



Slowness of modification by natu- 

 ral selection, 215 



Specialized fauna of the Silurian, 

 loo 



Species not definable, 32 



Spencer, 5, 15, 73, 315 



Spontaneous generation, 4, 7 



Steinheim Lake deposit, 46 



Sterile insects, 237 



Sterility, a variable quantity, 39 ; 



explanation of, 40 

 St. Helena, 196 

 Summary of all the evidence, 20, 



203, 232 



Supernatural, 315 

 Synthetic types few in number of 



individuals, 102 



Tapir, 188 



Teeth of ungulates, 268 



Theistic evolution, 17 



Thrush-tit, 180 



Tortoises of the Galapagos 

 islands, 195 



Transitional varieties wanting in 

 most cases, 217 



Tree- like arrangement of rela- 

 tions, 58 



Trochosphere stage of mollusks 

 and worms, 62 



Tsetze fly, 166 



Tyndall and spontaneous genera- 

 tion, 7 



Types, number of, 60 



Ungulates, 66, 268 



Unity of the organic world, 58 



Unspecialized, doctrine of the, 

 330 



Use and effort, 262, 263 



Uselessness of many characteris- 

 tics, 219 



W 



Wagner, theory of migration, 247 

 Weissmann, theory of heredity 



269 



Zoological regions, 176 



