Index. 



Protozoa, 104. 

 Ptarmigan, 317, 318. 

 Pterodactyl, wing of, 56. 

 Purpose, Darwin's use of the word, 



281, 3-fO. 



Puss moth, larva of, 325, 326. 

 Python, 66, 67. 



Quadrumana, muscles of, 76, 82, 83; 

 perforations of humeri of, 94, 

 95 ; hair on phalanges of, 91. 



R. 



Rabbit, embryology of, 153 ; mul- 

 tiplication of. in Australia, 286 ; 

 portraits of wild and domesticated 

 breeds of, 308 ; protective colour- 

 ing of, 319, 320. 



Radiate form, beauty of, 408, 409. 



Raid radiata, and batis, 367-371. 



Rats, species of, restricted to Old 

 and New Worlds, 212; British 

 and Norwegian, 285, 286. 



Rattle-snake, tail of, 289. 



Recognition marks, 271-273. 



Religion, in relation to Darwinism, 

 401-418. 



Reproduction, different methods of, 

 106-117 ; essence of sexual, no; 

 foreshadowing of sexual in uni- 

 cellular organisms, 115-1 1 7- 



Reptiles, wing of flying, 56 ; rudi- 

 mentary limbs of, 67; nictitating 

 membrane of, 75 ; branchial 

 arches of, 150 ; embryology of, 

 152 ; palseontology of, 163, 165, 

 178-180; brain of, 194-197; 

 distribution of, 324-240. 



Rhinoceros, foot of, 186. 



Robinson, Dr. L., on grasping 

 power of an infant'shands, 80-82. 



Rudimentary organs, 65-97. 



Ruminants, palseontology of, 167, 

 168. 



a 



Sacrum of man, compared with 



that of apes, 82-84. 

 Sagitta, 138. 

 Salamander, young of terrestrial, 



living in water, 102; embryo- 

 logy of, 152. 



Sandwich Islands, 234-237. 



Science, method of, 1-9. 



Sclater, W. L., on a case of 

 mimicry, 331, 332. 



Scorpion in Silurian formation, 

 163. 



Sea, lamprey, 148; destructive 

 agency of the, 423, 424. 



Seal, 51, 52, 75. 



Seasonal changes of colour, 317- 



3 ! 9- 



Selection, value, 275 ; by physical 

 processes, 282, 283, 335. See 

 also Natural selection, Artificial 

 selection, Sexual selection, Phy- 

 siological selection. 



Sentiency, in relation to the 

 theory of evolution, 417. 



Sex, difference of, restricted to 

 Metazoa and Metaphyta, 105. 



Sexual reproduction, see Repro- 

 duction. 



Sexual selection, theory of, 277, 

 378-410; statement and evi- 

 dences of, 379- .',9 1 ; criticisms 

 of, 391-400 ; includes law of 

 battle with that of charming, 

 385.386; in relation to religious 

 thonght,4i 1-41 8 ; Tylor'stheory 

 substituted for, by Wallace, 449, 

 450. 



Shark, eye of, 75 ; man-eating, 

 149 ; and pilot-fish, 289. 



Sheep, limb-bones of, 176, 177; 

 portraits of, 310. 



Shells, of crabs, 62-64 ; palseon- 

 tology of mollusk's, 199-203 ; 

 land on oceanic islands, 224- 

 240. 



Silliman's Journal, on fauna of the 

 Mammoth Cave, 70. 



Skate, electric organ of, 364~373- 



Skull, palaeontology of, 194-199; 

 of bull-dog compared with that 

 of deer-hound, 307. 



Slavonia, Tertiary deposits of, 

 18, 19. 



Species, not eternal, but either 

 created or evolved, 13 ; named 

 as such through absence of 



