198 THE FIRST PRINCIPLES OF HEREDITY 



Reproduction, 6, 10, 50 



asexual, 1 1 



sexual, 18 

 Reptile. 35, 49 



Reversion, 54, 81, 84, 86, 138 

 Rheumatism, no, 112 

 Ritchie, D. G., 176 

 Rotifer, 24, 90, 91 

 Roux, W., yj' 78 



Sagitta-worm, 60 

 Saturation hypothesis, 87 

 Scatulation, 47 

 Schleiden, 28 

 Schwann, 28 

 Sea-anemone, 9 

 Sea-plants, 10 1 

 Sea-squirt, 1 1, 22 

 Sea-urchin, 45 

 Segmentation, 49, 78 

 equal, 49 

 superficial, 49 

 unequal, 49 

 Segregation, 126, 127, 130 

 Selection, genetic, 166 



germinal, 79, 80, 95. 99. 100 

 natural, 80, 93, 94. 95. 99. 

 100, 106, 107, 117, 140, 

 143, 144, 174, 175, 176. 

 See also Survival of the 

 fittest 

 rational, 176, 181 

 Seminal fluid, 29 

 Serum treatment, 116 

 Sex, determination of, 89 

 Short-sightedness, 100 

 Smallpox, 116 

 Snail, 9, 24 

 Social Science, 2, 173 

 Solidago virgaurea, 99 

 Somatogenic, 96, 97 

 Spencer, Herbert, 10, 51, 52, 53, 



73> 94, 96, 100, 104. 106 

 Spermatogenesis, 41 

 Spermatophore, 23 

 Spermatozoon, 22, 23, 29, s^, 

 43. 87, 91, 109. See also 

 Sperm-cell 



Sperm-cell, 89. See also Sper- 

 matozoon 

 Sponge, 14, 22, 24, 34, 49 

 Spore, 26 

 Sporulation, 16 

 Stamen, 21 



Standard deviation, 154 

 Star-fish, 9, 34 

 Statistics, 142, 167 

 Stature, 165 

 Sterility, 165 



Stigmatic bands, 150, 166 

 Stirp, 56 



theory, 51, 55 

 Stocks, 132 

 Survival of the fittest, 93, 176. 



See also Natural selection 

 Sweet-pea, 132, 137, 138 

 Syllis ramosa, 14 

 Symmetrical curve, 151, 152 

 Syphilis, 109 



Tadpole, 90 



Talent, 177 



Telegony, 86 



Testes, 29 



Thomson, J. A., 90, 96, 105, 109, 



140, 141, 181 

 Tobacco, 114 

 Triton, 9 

 Trophoplasm, 57 

 Tschermak, 120 

 Tuberculosis, 109, no, in, n2. 



See also Consumption 

 Tunicates, n, 14 

 Traits, congenital, 98 

 individual, 74, 75 

 Twins, 92 

 Type, 154, 166 



Unicellular organisms, 96, 97 

 Unit, constitutional, 52 

 organic, 51 

 physiological, 52, 53 

 Unit-characters, 139 

 Use-inheritance, 94, 100. See 

 also Lamarckism 



