Chemotaxis, 264 Chick, 255 Chimaeroids, 119 Chimpanzee, 33, 270, 314, 323 Chin, 319, 320, 328; may be accentuated by a mutation, 320; prominence in Spy No. 1, 328; recessive, 320; recessiveness of the, 319; recessiveness and protuberance of, 320; recessiveness, an acquired adaptation, 320; receding, acquired, 328 China, 110, 337 Chinless mandible, not sloping backward, 332 Chlorophyll, 62, 145, 147, 148, 149, 151, 154; chromogen group of, 148; chromogen complex, 148; colloidal solution of, 145; not a “sensitizer” like Eosin, 147, 148; regenerated from H₂O and CO₂, 147, 148; “sensitizer,” 145 Chondriosomes, 140 Christianity, 359 Chromatin, 138, 139 Chromiole, 138 Chromosomes, 17, 21, 27, 44, 45, 139, 141, 157, 158, 159; diploid number normal, 159; diploid number of, 157, 158, 159; duplication of, 17, 21, 44, 45; haploid number of, 157, 158, 159; homologous, 17, 21; random assortment of, 27 Chronology, 98; lithic, 98; principles of, 98 Chronometer, palæontological, 135 Chrysothrix, 274 Cidaris, 119 Ciliate, 163 Circumstances, environmental, 250-252 Civilization, old, destruction of, 336 Classes, 37 Classification, taxonomic, not historical, 112 Clays, Pleistocene, 289 Cleavage, 154, 159 Cloaca, 281 Coccyx, alleged rudiment of former tail, 297; serves purpose, 298 Cockroaches, 115 Coelenterates, 78, 118 Coexistence of impressions, not a companion of them, 208 Cognitive intellect, 220, 221 Colloid systems, aggregates, not units, 168 Colloidal, 141, 170; substances, 141; systems not analogous to organisms, 170 Colloids, 166-169; hydrophilic, 168, 169 Columns, continental and submarine, 114 Commanchian period, 72 Commensal, 46 Commensalism, 52 Common stock, 39 Comparative anatomy, 279, 304 Complexity, “Law” of, 166, 167 Components, 138, 139, 141, 142, 168; cytoplasmic and nuclear, 138, 139; of cell, 141 —self-perpetuating, 168; of protoplasmic system, 141 Compounds, organic, 142 Concepts, 219, 220, 221, 247; abstract and general, 220, 247; rational, 247 Conceptual thought, 219, 222, 223; concerned with the reality of essence, 219; excludes materiality from its specific agent and receptive subject, 222; not communicated to organism, 223; subject in soul alone, 223 Conduction path, 265 Condyles, occipital, 272 Conformity, 105, 107, 110; “deceptive,” 105, 110; normal significance of, 105; “upside-down,” 107 Conjugation, 157, 161