Index 
Sexual dimorphism, 51, 297-344 
Sexual selection, theory of, 299-321 
Shaheen, 251 
Shamrock, 274 
Sheathbill, 191 
Sheep, 95, 266, 267, 283, 
Sheldrake, 109, 129 
Shikra, 235, 236 
Shoveler, 290 
Shrew, 180, 216 
Sidgwick, 28 
Sidney, 5, 49 
Sika deer, 120 
Silver-washed fritillary butterfly, 103 
Siskin, 127, 244 
Skua, Arctic, 44, 362 
Skua-gull, 191 
Skunk, 186, 217, 221 
Skylark, 315 
Slug, 49, 185 
Smith, Adam, 28 
Snake, 185, 197, 198, 217, 220, 223- 
6, 247, 356 
Snap-dragon, 268, 272 
Snipe, 69, 327 
Sodium sulphate, 151 
Somatic variations, 106-10. 
“Some Indian Friends and Ac- 
quaintances,” 225, 358 
Sorrel, 274 
Sparrow, 213, 241, 341, 342 
Java, 99, 100 
Sparrow-hawk, 235, 243 
Spatula clypeata, 290 
Spavin, 332 
‘Species and Varieties,” 69, 77, 84, 
87, 118 
Species, definition of, 89 
Species, elementary, 77, 78, 87-9 
Spencer, 3, 15, 16, 28, 38, 151 
Spider, 269, 272 
Sporeginthus amandava, 311 
Sports, 41, 43, 66, 75, 85, 135 
Squirrel, 101, 186, 243 
Stag, 325 
e Irish, 67 
Standfuss, 155 
Stanley crane, 248, 279 
St Hilaire, T. G., 2, 356 
Stick insect, 209 
Stictoptera annulosa, 104 
Stoat, 119, 190, 290 
357, 372 
Stolzmann, 327-9, 342, 343 
Stonechat, 353 
Stork, 247, 282 
“Strand Magazine,” 64 
Strix flammea, 289 
Struggle for existence, 31, 32, 48 
for nourishment, 167 
Suchetet, A., 126, 130 
Sula capensis, 282 
S. serrator, 282 
Sunbird, 324 
Surniculus lugubris, 235, 243 
Survival of the fittest, 32 
Survival value, 33, 34 
Swallow, 250, 251, 279, 361 
Swallow-shrike, 281 
Swallow-tail butterfly, 179 
Swan, 100 
Swift, 243, 250 
Swimming bladder of fishes, 36, 37 
Sycalis flaveola, 244 
Syrphide, 178 
TACHYCINETA LEUCORRHOA, 361 
Tadorna cornuta, 129 
I. tadornoides, 129 
Tails, 62, 64 
Tait, Mr, 356 
Tanager, 281 
Tapir, 42 
Tasmanian devil, 282 
Teal, 290, 316 
Teasel, fuller’s, 58 
Teeth, molar, 105 
Tegetmeier, Mr, 307 
Tern, 62, 278 
Terpsiphone paradisi, 202, 298, 304, 
316, 324 
Tetraogallus, 337 
Tetraonide, 125 
Tetrapteryx paradised, 249 
Tetrao tetrix, 129 
T. urogallus, 129 
Thamnobia cambayensis, 202, 275 
T. fulicata, 202, 378 
Thayer, Mr Abbot, 184-7 
Thompson, Seton, 354 
Thomson, 103, 136, 145, 166, 306, 
326, 340 
Throat disease, 353 
“‘ Through Southern Mexico,” 197, 
24 . 
“e Through the Heart of Patagonia,” 
359 
399 
