=Vestigial Organs.=—_See_ Rudimentary organs, =Xenia.=—_See_ p. 141. INDEX. A. Acquired characters, definition of, 5; inheritance of, 6, 15, 49, 57, 60, 67, 69, 71, 81, 83-84, 93-96, 104, 107, 110-111, 127, 173, _et seq._; Galton on inheritance of, 62, 106. Adaptive development, Weismann on, 19. Algae, De Vries on the chromatophores of, 83, 111. Amphigony, the cause of individual hereditary variation, 91, 100-101. Amphimixis, _see_ Sexual propagation. Ancestral germ-plasm, 123. Atavism, 3, 91, 105. B. =Bary, De=, on Weismann’s theory, 152. Basidiomycetes, 90. Begonia, regeneration in, 4, 52. Biophores, 123. Body-cells, and germ-cells, 29. =Brooks=, theory of heredity, 2. Bud-variation, 90, 94, 96, 98-99; Weismann on, 95, 97, 161; Fritz Müller on, 95. Butterflies, climatic varieties of and Weismann’s theory, 67-68, 127-128. C. =Candolle, De=, on inheritance of acquired characters in plants, 93. “Carriers of Heredity,” 32, 38, 70, 78, 122. Cessation of Selection, _see_ Panmixia. Chromatophores, of Algae, 83, 111. Compositae, pollen of, 5. Congenital variations, definition of, 5; inheritance of, 6, 110; sexual propagation, the cause of, 11; Darwin on, 13; origin of, 23, 25, 100, 102; nutritive congenital changes, 64; examples of, 64; specialized congenital changes, 65; representative congenital changes, 65; Galton on, 134. Continuity of germ-plasm, _see_ Germ-plasm. Crustacea, and the inheritance of acquired characters, 94. Cuttings, and bud-variation, 98. _Cytisus adami_, grafting of, 127. D. =Darwin, Charles=, and Pangenesis, 2, 26; arguments in favour of pangenesis, 3, 59; on the cause of congenital variations, 13; comparison of his theory of heredity with that of Weismann, 52, 55, 73, 92, 105-106, 115, 133, 173 _et seq._; on germ and somatic-cells, 76; on the influence of pollen upon somatic tissues, 79-80; on graft-hybridization, 83; on bud-variation, 95; on the causes of variation, 102, 161; on the inheritance of acquired characters, 107, 111-112; on Xenia, 144; on sexual union, 154. Death, Weismann on the origin of, 8, 10; in plants, 10. Determinants, 123. Direct action of environment, on unicellular organisms, 15, 23. E. =Elsberg=, theory of heredity, 2. Environment, direct action of on Protozoa, 15. Evolution, _see_ Organic evolution. F. =Flint, Prof. Austin=, on Telegony, 204. =Focke=, on Xenia, 141, 144. “Formative material,” and germ-plasm, 56. Fungi, Prof. Vines on Basidiomycetes, 90. G.