also Mutations)

Sanders, experiments on Vanessa by, 65

Savigny, 249

Schelling, 4, 5, 200, 201

Schleiden and Schwann, Cell-theory of, 147

Schoetensack, on _Homo heidelbergensis_, Foot Note 118

Schuett, 23

SCHWALBE, G., on _The Descent of Man_, 111-145

Seeck, O., Foot Note 240

Segregation, 97, 98

Selection, artificial, 24, 25, 26, 41, 45, 120, 269-272
--germinal, 35, 36, 46-52, 64

Selection, natural (see Natural Selection)
--organic, 53, 171, 172
--sexual, 55-64, 117, 118
--social and natural, 271
--23-86, 103, 129, 130

Selenka, 131

Semnopithecus, 132

Semon, R., 28, 153

Sergi, 138, 143

Sex, recent investigations on, 99, 100

Sibbern, 201

_Smerinthus ocellata_, 38

_Smerinthus populi_, 38

_S. tiliae_, 38

Smith, A., 200

Sociology, Darwinism and, 264-280
--History and, 255

Sollas, W. J., 134

Sorley, W. R., 217

Species and varieties, 100

Spencer, H., on evolution, 204-209
--on the theory of Selection, 41

Spencer, H., on Sociology, 268
--on the transmission of acquired characters, 149
--on Weismann, 41, 150
--2, 17, 217, 231, 268

Sphingidae, variation in, 37

Spinoza, 153, 206

Standfuss, 82

Stephen, L., 217

Sterility in hybrids, 104-106

Sterne, C, Foot Note 10

Struggle for existence, 25, 26, 272-274

Sutton, A. W., Foot Note 73

Synapta, calcareous bodies in skin of, 38-41

Syrphus, 75

Tarde, G., 279

Tennant, F. R., Foot Note 218

Tetraprothomo, 138, 144

THOMSON, J. A., on _Darwin's Predecessors_, 1-22
--150
--and P. Geddes, 276

Treschow, 201

Treviranus, 8, 14, 15

Turgot, 249

Turner, Sir W., 150

Tylor, 267

Tyndall, W., 267

Tyrrell, G, Foot Note 222

Uhlenhuth, on blood reactions, 135

Use and disuse, 28, 41-43, 48-54, 94, 95, 119, 149

Vanessa, 63

_V. levana_, 31

_V. polychloros_, 82

_V. urticae_, 65, 82

Variability, Darwin's attention directed to, 24
--W. Bateson on, 87-110
--causes of, 200

Variation, Darwin's views as an evolutionist, and as a systematist, on, 212
--and heredity, 87-110
--minute, 28-32
--in relation to species, 100, 101

Varigny, H. de, 6, 19

Verworn, 136

_Vestiges of Creation_, Darwin on _The_, 15

Virchow, his opposition to Darwin, 157, 158
--on the transmission of acquired characters, 149

Vogt, 137

Voltaire, 248

VRIES, H. de, the Mutation theory of, 31, 101, 151, 213

WAGGETT, Rev. P. N., on _The Influe