CHAPTER XVI.. Conclusions.

CONCLUSIONS.

We have now, more or less fully, examined into the system of colouration in the living world, and have drawn certain inferences from the facts observed.

It appears that colouration began--perhaps as a product of digestion--by the application of pigment to the organs of transparent creatures. Supposing that evolution be true--and, if we may not accept this theory there is no use in induction whatever--it must follow that even the highest animals have in the past been transparent objects. This was admirably illustrated by Prof. Ray Lankester in a lecture on the development of the eyes of certain animals, before the British Association meeting at Sheffield, in which it was shown that the eyes commenced below the surface, and were useful even then, for its "body was full of light."

Granting this, it follows that the fundamental law of decoration is a structural one. Assuming, as we do, that memory has played a most important part in evolution, it follows that all living matter has a profound experience in decorating its organs--it is knowledge just as anciently acquired, and as perfectly, as the power of digestion. This colour was produced under the influence of light--so it is even in opaque animals.

With a knowledge so far reaching, we might expect that even in opaque animals the colouring would still follow structural lines, and there should still be traces of this, more or less distinct.

This is precisely what we do find; and, moreover, we sometimes get a very fair drawing of the important hidden parts, even where least expected, as in a cat's head, a snake's body, a dragon-fly's thorax, a spider's abdomen, a bird's skull.

But if animals thus learned to paint themselves in definite patterns, we might expect that when called upon to decorate for the sake of beauty certain parts not structurally emphatic, they would adopt well-known patterns, and hence arose the law of repetition.

But with wider experience came greater powers, and the necessity for protection arising, the well-known patterns were enlarged, till an uniform tint is produced, as in the Java pig, or some repeated at the expense of others, as in the civets. But so ingrained is the tendency to structural decoration that even where modification has reached its highest level, as in the leaf-butterflies, some trace of the plan that the new pattern was founded on is recognisable, just as the rectangular basis can be traced in the arabesque ornaments of the Alhambra.

The pointing out of this great fact has seemed to us a useful addition to the great law of evolution. It supplements it; it gives a reason why.

Could he who first saw these points have read these final pages, it would have lightened the responsibility of the one upon whom the completion of the work has fallen. But he died when the work was nearly finished. The investigation is of necessity incomplete, but nothing bears such misstatements as truth, and though specialists may demur to certain points, the fundamental arguments will probably remain intact.

GLOSSARY.

ACETABULA. Lat. acetabulum, a little vessel. Sucking discs as on the tentacles of Physalia.

AORTA. Gr. The chief artery.

CEPHALOTHORAX. Gr. kephale, head; thorax, chest. The anterior division of the body in Crustacea and Arachnida, composed of the amalgamated segments of the head and thorax.

CILIA. Lat. cilium, an eyelash. Microscopic filaments having the power of vibratory movement.

CNOSARC. Gr. Koinos, common; sarx, flesh. The common stem uniting the separate animals of compound hydrozoa, &c.

CORPUSCLE. Lat. corpusculum, a little body. Small coloured bodies, as in the endoderm of hydra, p. 59.

DIFFERENTIATED. Modified into definite organs, or parts; as distinct from structureless protoplasm.

ECTODERM. Gr. ektos, outside; derma, skin. The internal layer or skin of the Coelenterata.

EFFERENT. Lat. effero, to carry out. A vessel which carries fluids out of the body is said to be efferent.

ENDODERM. Gr. endon, within; derma, skin. The inner layer or skin of Coelenterata. See ECTODERM.

ENDOSARC. Gr. endon, within; sarx, flesh. The inner layer of sponges.

EPIDERMAL. Gr. epi, upon; derma, skin. Relating to the outer layer of skin. As applied to colour, surface pigment as distinct from hypodermal, or deep-seated colour.

GASTROVASCULAR CANAL. Gr. gaster, belly; Lat. vasculum, a little vessel. The canals or vessels in the umbrella (manubrium) of hydrozoa.

GONIDIA. Gr. gonos, offspring; oidos, like. Reproductive bodies in Sea-anemones.

HYDRANTH. Gr. hudor, water; anthos, flower. The bodies or polypes of hydroids which exercise nutritive functions. They were called polypites by Huxley.

HYDROPHYLLIA. Gr. hudor and phyllon, a leaf. Leaf-like organs protecting the polypites of hydrozoa.

HYDROSOMA. Gr. hudor and soma, body. The entire organism of a hydrozöon.

HYPODERMAL. Gr. hypo, beneath; derma, skin. In colour, such as lies beneath the surface, as distinct from epidermal.

LYTHOCYSTS. Gr. lythos, stone, kystis, a bladder. Sense organs in hydroids, consisting of transparent capsules inclosing round transparent concretions.

MANUBRIUM. Lat. a handle. The central polypite suspended from the interior of the umbrella of hydroids.

MESODERM. Gr. mesos, intermediate; derma, skin. The middle layer of sponges, &c.

MESOTHORAX. Gr. mesos and thorax. The middle division of the thorax in insects, carrying the second pair of legs.

PERISTOME. Gr. peri, about; stoma, a mouth. The area surrounding the mouth in sea-anemones.

PNEUMATOCYST. Gr. pneuma, air; kystis a bladder. The air-sac contained in the pneumatophore, see below.

PNEUMATOPHORE. Gr. pneuma; phero, to carry. The float of certain hydrozoa (Physophoridæ.)

POLYPITE. Gr. polus, many; pous, foot. The separate animal or zöoid of a hydrozöon. See HYDRANTH.

PROTOPLASM. Gr. protos, first; plasso, I mould. The jelly-like matter which forms the basis of all tissues. It is identical with the sarcode or flesh of protozoa.

SAC. Lat. saccus, a bag, a small cell.

SARCODE. Gr. sarx, flesh; eidos, form. The protoplasm of protozoa, &c., which see.

SPADIX. Lat. spadix, a broken palm branch. In zoology a hollow process occupying the axis of the generative buds of hydrozoa.

SPOROSAC. Gr. spora, a seed, and sac. The body containing the ova of hydrozoa.

SOMATIC FLUID. Gr. soma, the body. The fluid which contains digested food, and taking the place of blood, circulates through the body of hydrozoa.

TENTACLES. Lat. tentaculus, a little arm. The arms or prehensile organs of Sea-anemones, &c.

THREAD CELLS. Cells containing an extensible microscopic thread, possessing stinging properties, common among the Coelenterata.

THORAX. Gr. a breastplate. The chest.

INDEX.

PAGE

Abyla 63

Acanthometra 57

Actinea Cari, varieties of 66

---- mesembryanthemum 54

Acanthostratus 57

Actinozoa 51, 52

Æschna 77

Agalma breve 64

Agrion puella 77

Aiptasia mutabilis 67

Albinism in butterflies 79

Alcyonariæ 54

Allman, Prof., on Hydroids 59, 60

"Alps and Sanctuaries" quoted 36

Amoeba 56

Amphibia 89

Amphilonche 57

Andres, Dr., on Hydrozoa 65

Anemonia sulcata 67

Anemones, Sea 52

Animals and Plants, origin of 36

---- classification of 49

Anoechtochilus 95

Anteater 93

Anthocaris belemia 41

---- belia 42

---- cardamines 41, 42

---- euphemoides 43

---- eupheno 42

---- simplonia 42

Apatura iris 46

---- larvæ of 81

Arachnida 82

Araschnia Levana 43, 45

---- porima 43, 45, 79

---- prorsa 43, 45

Arctia 69

Arachnocorys 57

Argus Pheasant 6, 39, 91

Argynnis Lathonia 69

Armadillo 84

Arthropoda, colouration of 85

Ascidians 35

Automatic habits 9

Arthorybia rosacea 64

Badger 93

Begonia 95

Birds, colouration of 89

---- of Paradise 90

Biston betularia 79

Black and White, production of 28

Blackwell, J., on British Spiders 82

Blatta 14

Bougainvillea 16

Bower Birds 5

Bunodes crassicornis 54

---- gemmaceus, varieties of 66

---- rigidus 67

Burnet Moths 5, 69

Butler S., on inherited memory 9, 10, 11, 15

---- on origin of animals and plants 36

Butterflies, albinism in 79

---- classification of 74

---- sense organs of 30

---- varieties of 77

Caladium 95

Calathea 96

Calycophoridæ 63

Carcinus moenas 4

Carpocanium 57

Cats, colouration of 17, 92

---- recognising form 32

Caterpillars, colours of 81

---- spiracular markings 22

Cephalopoda 87

Cerithium 86

Char 88

Chlorophyll in hydra 59

Cicada 77

Cladococeus 57

Classification of animals 49

---- of butterflies 74

Coelenterata 20

---- colouration in 51

Coelodendrum 57

Coenonympha davus 79

---- pamphilus 79

Coenosarc 55

Coleus 95

Colour and form 32

---- and transparency 53

---- 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

Descent with modification 1

Desert animals, colour of 4

Dictyoceras 57

Dictyophimus 57

Diphyes 63

Disease, markings in 39, 44

Distant, W. L., on Malayan butterflies 80

Distinctive Colouration 3

Dogs recognising portraits 32

Dracæna ferrea 96

Elephant, increase of 2

Engelmann on Euglena 34

Epidermal colour 72

Eresus cinnabarinus 82

Eucecryphalus 57

Eucrytidium 57

Euglena viridis 34

Evolution 1-98

Eye-spots 45, 47

Fayrer, Sir W., on snakes 89

Feathers 91

Fishes, colours of 88

Foal, stripes on 46

Foraminiferæ 56

Fuller, W. J., on aquatic larvæ 77

Gamopetalous flowers 96

Gegenbaur's "Comparative Anatomy" cited 82

General colouration 3

Gloxinia 96

Gomphina 77

Gonepteryx Cleopatra 41, 42

---- rhamni 40, 42

Gonophores 52

Grapta interrogationis 79

Gregarinidæ 56

Guinea-fowl 91

Haagen, Dr., on colour 53, 72

Habits 8

Haeckel, Prof., on Radiolaria 57

Hair and teeth, correlation of 94

Hawk moths 69

Hebrides, colours of insects in 80

Heredity 2

Herpes 40, 93

Heteromorphism 78

Higgins, Rev. H. H. 39

Hoverer flies 84

Humming birds 90, 92

Hutchinson, Mr., on herpes 40

Huxley, Prof., on hydrozoa 63

Hydra viridis 59

Hydrida 59

Hydrozoa 51, 59

Hypodermal colour 53, 72

Identity of offspring and parent 11

Identity, personal 10

Inherited memory 8

Insects, colour in 68, 75

John Dory 89

Kallima inachus 30, 80

Kentish Glory Moth 30

Lamium galeobdolon 96

Lankester, Prof. Ray, on development of eyes 97

Large Copper Butterfly 68

Larvæ, colours of 45, 81

Laws of emphasis 21

---- exposure 18

---- heredity 2

---- multiplication 2

---- repetition 21, 22

---- structure 18

---- variation 2

Leaf-butterfly 16, 30

Leidy, Prof., on Rhizopoda 56

Leopard 17, 92

Leucophasia diniensis 41

---- sinapis 41

"Life and Habit" cited 9

Light, reflected 26

---- sensibility to 33

---- waves 25

Liminitis sibilla 43

Lion 17, 92

---- stripes on young 46

Lithocysts of hydroids 62

Lucernaria auricula 65

Lycæna dispar 68

Lycosa agretyca 83

---- allodroma 83

---- andrenivora 83

---- cambria 84

---- campestris 83

---- latitans 84

---- picta 84

---- piratica 84

---- rapax 83

Mackerel 88

Mactra 86

---- stultorum 87

Madrepores 54

Mammalia, colouration in 92

Margarita catenata 87

Measles 39

Medusæ 52, 65

Melanism in insects 79

Meldola, Prof. R., on Melanism 79

Melitæa artemis 43

---- athalia 43

Mimicry 3, 4

Mollusca 21

---- colouration in 85

Monstrosities, antipathy to 32

Morphinæ 72

Morpho 4

Murex 86

Muscles of insects 71

Nectarinea chloropygea 90

Newman, Mr., on varieties of butterflies 77

Newts 89

Nitzsch on feather-tracts 91

Nudibranchs 85

Nymphalidæ 74

Oak Egger Moth 30

Ocelli 47

Ocelot 93

Oliva 86

Opaque colouring 53

Organ-pipe coral 54

Origin of animals and plants 36

---- -- species 1

Orthopoecilism 78

Oxen 94

Painted Lady Butterfly 68

Pangenesis 12

Papilio Ajax 79

---- machaon 43, 68, 76, 78

---- ---- larva of 81

---- merope 30, 76, 80

---- nireus 14

---- podalirius 43

Paradisea Papuana 90

---- regia 90

---- speciosa 90

---- Wallacei 90

---- Wilsoni 90, 91

Pavetta Borbonica 96

Pecten 86

Pelargonium 96

Perch 88

Personal identity 10

Physalia 63

---- caravilla 64

---- pelagica 64

---- utriculus 64

Physophoridæ 63

Plaice 88

Plants and animals, origin of 36

---- colour in 95

Pneumatophores 63

Portuguese Man o' War 63

Protective resemblance 3

Protista 34

Protozoa 20

---- colouration in 51, 56

Python 89

Radiolaria 57

Rarity of uniform colour 28

Ray Lankester, Prof., on Ascidians 35

Red Admiral Butterfly 29

Repetition, effects of 8

Reptilia, colouration in 89

Resemblance, Protective 3

Rhizophora filiformis 64

Rhizopoda 56

Rhododendron 96

Ringlet Butterflies, eye-spots of 47

Roach 88

Romanes, Prof., cited 33, 34

Satyrus hyperanthus 79

Scales of insects, structure of 72

Scarlet Tiger Moth 5

Sea anemones 52

---- ---- colours of 67

Seasonal dimorphism 70

Sea squirts 35

Segestria senoculata 83

Selection, sexual 5

Self-coloured flowers 28

Sense organs of Butterflies 30

Sertularidæ 63

Sexual colours 4

---- selection 5

---- dimorphism 70

Shell, Structure of 85

Shore Crab 4

Simple variation in Butterflies 77

Siphonophora 63

Small pox 39

Snakes, patterns of 89

Sollas, Prof., on Sponges 58

Soles 88

Sparassus smaragdulus 82

Species, origin of 1

Sphæronectes 63

Sphingidæ 45, 69

Spiders, structure and colour of 82

Spiracles of larvæ 22

Spondylus 86

Sponges 57

Spongida 57

Spongocyclia 57

Spots and Stripes 39

Stephanomia amphitridis 63

Struggle for existence 2

Sun-birds 90

Sus vittatus 46, 94

Sutton, Mr. Bland, on Herpes 40

Swallow-tailed Butterflies 68

Syncoryne pulchella 62

Systems of colouration 51

Teeth and Hair, correlation of 94

Thomisus cinereus 82

---- floricolens 82

Thomisus luctuosus 84

---- trux 82

Thrush, increase of 2

Tiger 17, 92

---- Moths 69

Tipula 33

Toucans 90, 92

Transparency and colour 53

Trigonia 86

Tubipora musica 54

Tubularida 59

Tylor, A., on Specific change 10

Vanessa Antiopa 76

---- atalanta 29, 43, 69

---- urticæ 77

Variation in insects 70

---- law of 2

---- simple, in Butterflies 77

Velella 52, 65

Vertebrata, colouration of 88

Viverridæ 94

Wallace, A. R., on sexual selection 5, 6, 14, 15

---- on colour 29

---- on abnormal structures 94

Warning colours 4

Wasps 84

Weir, J. Jenner, on variation in insects 78

Weismann, Dr., on Caterpillars 81

Wing of Butterfly, typical 70

---- patterns of 76

Woodpecker 91

Yellow Archangel 96

Zebra 92

Zygæna 69

Transcriber's Notes:

Variations in spelling, punctuation and hyphenation have been retained except in obvious cases of typographical error.

"Haeckel" and "Hæckel" were used interchangeably and have been standardized to "Haeckel".

Image tags interrupting paragraphs have been moved.

Footnotes have been moved to end of chapters.