INDEX 



211 



Skeletons of unicellular organisms, 32, 

 PL 21 ; of arm of vertebrates, 92. 



Skin muscles in man, 94. 



Skunk, 133, 134, PL 12. 



Skunk-cabbage, 154. 



Slavonia, fossil Paludina, 107. 



Small pox, 171. 



Smelting ore, 176. 



Smerinlhus til ice, PI. 55; ocellata, 142. 



Snail, development of pond, 97. 



Snails of Oahu, segregation, 63. 



Snakes, aggressive color, 126; behavior of 

 poisonous, 143; hind limbs, 93, 94; 

 mimicry, 139, PL 79; protective color, 

 120. 



Snipe protective color, 119. 



Snow grouse seasonal color change, 121, 

 PL 57- 



Snowy owl, 126. 



Socialism, control of marriage, 182; nature 

 socialistic, 187. 



Social progress, an end in itself, 176; 

 vs.. evolution, 173-177. 



Soil, relation to segregation, 63. 



Solea concolor, 89, po, 91. 



Soma y distinguished from germ cells, 70; 

 relation to processes of reproduction, 74. 



Sparrow, aggressive color, 126; protective 

 color, 1 1 8, PI. 49. 



Spathura solstitialis, PI. 26. 



Species, mean, 19; meaning of, 88; preser- 

 vation of species, not of individual, 

 secured by natural selection, 187. 



Spermophile, protective color, PL 53. 



Sphinx convolvuli, PL 55- 



Spiders, aggressive coloration, 126, PL 75; 

 aggressive mimicry of ants, 145 ; ene- 

 mies of, 121 ; protective coloration, !2O y 

 PL 75, PL 8$; protective resemblances, 

 124, PL 64; resembling bird excre- 

 ment, 127; sexual coloration, PL 85; 

 sexual selection, 50, PL 28. 



Spilomyia hamifera, PL 74. 



Spinal column, curvature in man and apes, 

 166, PL 99. 



Spizella, pusilla, PL 49. 



Sports, 19, 39, 46. 



Sprouts, Brussels, PL 7. 



Squirrel, confusing coloration, 148. 



Stability of certain species, 9. 



Staghorn beetle, 51, PL 29. 



Starfish, birth-rate, 13, 17. 



Stearns, PI. 3. 



Sterility, domestic races not mutually 



sterile, 31; of crosses between certain 

 individuals, 66; of crosses between 

 species, 31; of hybrids, 31, 41; of 

 soma cells, 71; of worker bees, recently 

 acquired, 77; starting-point in forma- 

 tion of species, 32. 



Stick-like insects, 122, PL 61 ; spider, PL 64. 



Stridulating organs, 51, PL 29. 



Struggle for existence, 10-18; between near 

 relatives, 25; man, 169. 



Summary, of Part I, 82 ; of color in animals, 



W- 



Supernaturalism, Intro, ix, x. 

 Superstition, Intro, ix. 

 Survival of the fittest, 15, 18. 

 Swamping of varieties by cross-breeding, 



40-47. 



Swedish turnip, PL J. 

 Synageles picata, PL 28. 



Tadpole, of salamander, 98. 



Tail, vestigial muscles in man, 165, PL 95. 



Taxonomy, 88. 



Teeth, deterioration of human, 170; man 



and gorilla, 164, PL 92. 

 Tegetmeier, PI. 12-15, p l- l8 > P1 - T 9> PI- 2 4- 

 Tendency, inherent, in evolution, 188; in 



variat'on, 40. 



Terrifymg attitude, 139, 140, 142, PL 78. 

 Tetragnatha grallator, 120; laboriosa, PL 85. 

 "Thierleben" (Brehm), 4, 22, 31, 133, PI. 



24, PL 30, PL 33, PL 62, PL 99. 

 Thomisidce, 129. 

 Thompson, J. A., 189. 

 Thyroidopteryx ephemerijormis y 21. 

 Tiger, aggressive coloration, 129, PL 68. 

 Timor, friar-bird and oriole, 144. 

 Timor Laut, friar-bird and oriole, 144. 

 Toad, aggressive coloration, 126, 133, 



PL 66; rejects noxious insects, 130. 

 Tody, green, protective coloration, 119. 

 Tortoise, embryos, PL 38. 

 Trailing arbutus, odor, 154; variation, 7. 

 Transparency of pelagic animals, 117. 

 Tree-frogs, protective coloration, 725, PL 66. 

 Tree-hopper, mimicry of leaf-cutting ants, 



137, PI- 75- 



Trends in evolution, 40, 188, 189, 192. 

 Trillium grandiflorum, PL 2. 

 Triton cristatus, 52, PL 33; punctatus, 52. 

 Trochilium apijorme, PL 70. 

 Tropidorhynchus, 144. 

 Tunicates, transparency of pelagic, 117. 

 Turkey cock, 49, PL 27. 



