Survival of the fittest, 129.
Systems,
respiratory, excretory, circulatory, 17;
organic, reproductive, 18;
nervous, 256, 257;
blood-vascular, respiratory and excretory, 257;
ethical, 286;
religious, 288.
Tadpole, 58, 59, 60;
larvæ, 64.
Tapeworm, a relative of simple worms, 50; 123.
Tapir, 41;
Moeritherium, 97.
Thorndike, 209;
heredity of mental qualities, 232.
Tidal waves, 85.
Tigers, 101.
Tirawa, 301.
Tissue-cells, 28.