290 



INDEX 



Children, effect of class size, 

 143; in wartime, 230 



China, population, 226; racial 

 vigor, 232 



Cladocera, sex determination, 



257 

 Class size, effect on rate of 



learning, 142 



Cleveland, L. R., 269 



Cockroaches, effect of num- 

 bers on rate of learning, 

 149; related to termites, 

 265, 269 



Coe, W. R., 252 



Collias, N., 185 



Colloidal silver, mass protec- 

 tion from, 53, 56 



Colonial organisms, 41 



Community, ecological, 38 



Confusion effect, 139 



Conditioned water, 64, 92 



Co-operation, history, 23, 31; 

 ecological, 40; voluntary, 

 42; evidence for, 49, 50; un- 

 conscious, 88, 133; con- 

 scious, 209; principle of, 

 209, 211, 242, 243 



Copepods, 35 



Crepidula, 253 



Crowding, harmful effects, 31, 



50 

 Ctenophores, 35 

 Czechoslovakia, population, 



227 

 Cyprinodon, learning, 164 



Daphnia, mass protection, 57, 

 139; food for fish, 137; sex 

 determination, 257 



Darling, E. Fraser, 111, 260 



Deegener, P., 28 

 Deer, 48, 248, 259, 260 

 Despotism, 185, 208 

 Dionne quintuplets, 201, 207 

 Disease in wartime, 224, 225, 



228, 230, 231 

 Division of labor, 32, 247, 251 

 Dominance, qualities causing, 



190; relation to breeding 



cycle, 194 

 Drosophila, effect of numbers 



on rate of reproduction, 



103 



Eggs, sea-urchin, 69 



Elephants, minimal popula- 

 tion, 108 



Ellis, Havelock, 24 



Emigration, 122, 126, 131 



Empedocles, 23 



England, population trend, 

 219, 223, 226, 227 



Espinas, A. V., 25, 28 



Euglena, 34 



Evans, Gertrude, 73, 92 



Evolution, course of, 86, 87; 

 effect of numbers on rate 

 of, 118; Lamar ckian, 118 



Family, as origin of society, 

 47, 244, 248 



Finkel, Asher, 92 



Fish, schools, 48; mass pro- 

 tection, 53, 56, 68; effect of 

 crowding on growth, 92; on 

 amount of food taken, 136; 

 on learning, 158; leader- 

 ship, 166; imitation, 170 



Fischel, W., 196 



