The Origin of the Fittest: Essays on Evolution

acceleration adaptation adult Amblypoda animals Anura aorta aorta-root appear Artiodactyla automatic Batrachia bones brain Bunodonts Carnivora carot cells Cetacea characters complex condition consciousness Coryphodon Creodonta dentition derived descent Digitigrade digits Dipnoi direction division doctrine embryonic energy Eocene evidence evolution exact parallelism exhibit existence extinct fact force forms genera genus geologic groups growth growth-force habits higher homologous human identical incisors increase individuals inexact inferior intelligence jaws known latter less limbs lower Mammalia mammals mental metamorphosis mind modification molar movements natural selection Naturalist nutrition observed organs origin paleontology period Perissodactyla Phenacodus physical plantigrade plants possess posterior present primitive probably produced progress protoplasm Quadrumana regarded relation repetition represented reptiles Reptilia result rudimental sectorial segments Selenodont skull species stages structure succession superior molar teeth Teleostomi theory tion tissue tooth true tubercles Uintatherium unconscious ungulate vertebral Vertebrata