458 
Protozoa, 104. 
Ptarmigan, 317, 318. 
Plerodactyl, wing of, 56. 
Purpose, Darwin's use of the word, 
281, 340, 
Puss moth, larva of, 325, 326. 
Python, 66, 67. 
Q. 
Quadrumana, musclesof, 76, 82, 83; 
perforations of humeri of, 94, 
95; hair on phalanges of, g1. 
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. 
Naia radiata, and batts, 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, 110; 
foreshadowing of, sexual in uni- 
cellular organisms, 115-117. 
Reptiles, wing of flying. 56; rudi- 
mentary limbs of, 67; nictitating 
membrane of, 75; branchial 
arches of, 150; embryology of, 
152; paleontology of, 163, 165, 
178-180; brain of, 194-197; 
distribution of, 224-240. 
Rhinoceros, foot of, 186. 
Robinson, Dr. L., on grasping 
power of an infant’s hands, So-S2, 
Rudimentary organs, 65-97. 
Ruminants, palzontology of, 167, 
168, 
S. 
Sacrum of man, compared with 
that of apes, 82-84. 
Sagitla, 138. 
Salamander, young of terrestrial, 
L[hdex. 
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- 
319. 
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, 379-2913 crilicisms 
of, 391-400; includes law of 
battle with that of charming, 
385. 386; in relation to religious 
thought,411—418; Tylor’stheory 
substituted for, by Wallace, 449, 
459. A 
Shark, eye of, 75; man-eating. 
149; and pilot-fish, 289. 
Sheep, limb-bones of, 176, 1773 
portraits of, 310. 
Shells, of crabs, 62-64; palzon- 
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, paleontology 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 
