---- epidermal 72 ---- following structure 83, 91 ---- hypodermal 53, 73 ---- nature of 25 ---- of day-and-night flying insects 47, 69 ---- opaque 53 ---- perception of 5, 23, 25, 32 ---- uniform, why rare 28 Colouration 3 ---- laws of 21, 51 ---- of desert animals 4 ---- of arthropoda 85 ---- of coelenterata 51, 59 ---- of insects 68 ---- of invertebrata 49 ---- of molluscs 85 ---- of plants 94 ---- of protozoa 51 ---- of spiders 82 ---- of vertebrata 88 ---- sexual 5 ---- varieties of 3 Contour feathers 91 _Conus_ 86 _Coppinia arcta_ 60 _Corallium rubrum_ 54 Corals 54 Correlation of teeth and hair 94 _Corynida_ 52 Cowries 86 Crab, shore 4 Croton 46 Cuttle-fishes 19, 87 _Cyllo leda_ 45 _Cynthia cardui_ 68 _Cypræa_ 86 _Cyrtidosphæra_ 57 Dallas, W. S., on butterflies 71 _Danais_ 72 ---- niavius 30, 80 Darwin, C. 1, 2, 5, 9, 11, 14, 45, 47, 94 Darwin, Dr. E., cited 37 Deer 92 Deformity, antipathy to 32 _Deilephila Euphorbiæ_ 81 ---- _galii_ 81