INDEX. 
Mutation—Continued. 
Denies Effect of Individual Variation, 71-77. 
Reached by Selection of Fluctuating Varia- 
tions, 77. 
: Natural Species: 
Evolution of, 23-36, 212-240 
Unity and Diversity, 23-29. 
Unity Through Community of Descent, 
23-26. 
Diversity not Always Through Diversity of 
Environments, 23-29. 
Selection May Help Unity or Diversity, 25, 29. 
May Lose Plasticity and Become Extinct, 
Pa 
Varieties are Incipient Species, 213. 
Illustration of Intergrading Species, Plate 
III, 43. 
Reference to Intergrading Species, 214. 
Utility of Specific Characters, 255-261. 
If All Men were Left-handed no Loss, 256- 
25s 
Many Examples of Asymmetry, 257. 
Cockerell’s Letter on Utility of Specific Char- 
acters, 260. 
Osborn, H. F., 45; also Preface. 
Packard, A. S., ‘‘Lamarck; His Life and Work,’’7. 
Recognizes Importance of Isolation, 7. 
Partition: 
Need of Such a Term, 51. 
Defined, 53. 
Industrial, illustrated, 67. 
Reflexive, 81-114. 
Conjunctional, 82-83. 
Institutional, 82, 114. 
Family 83, 86. 
Social, 83-85. 
Environal, 115, 129. 
Endonomic, 115, 129. 
Industrial, 115, 129. 
Migrational, 115, 129. 
Heteronomic, 115, 129. 
Transportational, 115, 129. 
Geological, 115, 129 
Artificial, 115, 129. 
Pearson, Karl: 
“The Chances of Death,’’ 16, 92-95, 113-114. 
“‘Grammar of Science,’’ 51, 92—94. 
Statistical Methods, 154. 
Physiological— 
Isolation, 95—96. 
Selection, 96. 
Plate A, Map of Hawaiian Islands, between 42, 43. 
Plate I, Eight Genera of Achatinellida, 42. 43. 
Explanation of, 37. 
Plate B, Map of Oahu, 42, 43. 
Explanation of, 43. 
Plate II, Twenty-five Species of Achatinella, 42, 
43, : 
Explanation of, 39. 
Plate III, Variation and Intergrading of Buli- 
mella, 42, 43. 
Explanation of, 41. 



267 
Radius of Distribution Varies— 
Directly as the Power for Migrating, 220. 
Inversely as the Power for Variation, 220. 
Rats of Arboreal Habits, as Illustrating Coépera- 
tion of Positive and Negative Segregation, 
101-103. 
Reflexive— 
Mode of Influence, 80-114. 
Selection, 81-114, 151. 
Isolation, 81-114. 
Election, 81-114. 
Partition, 81-114. 
Regressive— 
Mode of the Four Principles, 80, 129. 
Selection, 129, 131. 
Election, 129. 
Isolation, 130. 
Partition, 130. 
Reid, G. A., Increasing Difficulty of Childbirth, 
86. 
Riley, C. V., Bul. No. 8, Divis. Entomology, U. S$. 
Department Agriculture, 229-232. 
Romanes, G. J., 192. 
“Darwin and After Darwin,’’ 51 52. 
‘Physiological Isolation,’ 52. 
On Cessation of Natural Selection, 198, 254. 
“Mental Evolution in Animals,’ 237-238. 
Scott, William E. D., How Red-winged Blackbird 
Learned to Crow, 84. 
Segregate Adaptation, 87, 170. 
Association, 48; also Preface. 
Segregate Generation, 47; also Preface. 
A Condition of Allogamic Evolution, 79. 
Segregate— 
Survival, 95—96, 108. 
Union, 95—96. 
Vigor, 87, 170. 
Escape from Enemies, 87, 171. 
Illustrated by Arboreal Rats, 101-103. 
Fecundity, 87, 170. 
How Accumulated, 262. 
Freedom from Competition, 87, 171. 
Illustrated by Arboreal Rats, 101-103. 
Segregation: 
Its Causes and Effects, 6-8. 
The Fundamental Process in Evolution, 8, 
22 WATS VS 1 
Through Transformation During Isolation, 8. 
Initial, Through Isolation, 22. . 
Intensive, Through Transformation, 22. 
The Four Segregative Principles, 45-78. 
Industrial, 45. 
Racial, 45, 47, 151. 
Social or Habitudinal, 45, 48-49, 151, 153. 
Without it Differences Would Cease, 47. 
Interaction of Racial and Social, 49. 
Four Principles of, 45-145. 
Interaction of the Four Principles, 55—78. 
Intensive, and Headley’s Criticism, 55—56. 
Importance of Each of the Principles, 56-58. 
Impregnational, illustrated, 68—70. 
Positive, 98-101, 163. 
Negative. 98-101. 163-164. 
