Transcriber's Note Italic text has been formatted as _text_ and superscript text as ^{text}. COLOURATION IN ANIMALS AND PLANTS. BY THE LATE ALFRED TYLOR, F.G.S. _Edited by_ SYDNEY B. J. SKERTCHLY, F.G.S., LATE OF H.M. GEOLOGICAL SURVEY. LONDON: PRINTED BY ALABASTER, PASSMORE, AND SONS, FANN STREET, ALDERSGATE STREET, E.C. 1886. IN MEMORY OF A FRIENDSHIP OF MANY YEARS, THIS BOOK IS Affectionately Inscribed TO THE RIGHT HON. GEORGE YOUNG, P.C. 1885. PREFACE. This little book is only a sketch of what its Author desired it to be, and he never saw the completed manuscript. Beginning with the fundamental idea that decoration is based upon structure, he saw that this was due to the fact that in the lower, transparent, animals, colour is applied directly to the organs, and that the decoration of opaque animals is carried out on the same principle--the primitive idea being maintained. Where function changes the pattern alters, where function is localized colour is concentrated: and thus the law of emphasis was evolved. Symmetry was a necessary consequence, for like parts were decorated alike, and this symmetry was carried out in detail apparently for the sake of beauty, as in the spiracular markings of many larvæ. Hence the reason for recognizing the law of repetition. With the developing of these ideas the necessity for recognizing some sort of consciousness even in the lowest forms of life was forced upon the Author, until inherited memory formed part of his scientific faith. This he saw dimly years ago, but only clearly when Mr. S. Butler's remarkable "Life and Habit" appeared, and he was gratified and strengthened when he found Mr. Romanes adopting that theory in his "Mental Evolution." The opening chapters are designedly elementary; for the Author had a wise dread of locking intellectual treasures in those unpickable scientific safes of which "the learned" alone hold keys. Only a very small portion of the vast array of facts accumulated has been made use of, and the Author was steadily working through the animal kingdom, seeking exceptions to his laws, but finding none, when death closed his patient and far-seeing eyes. A few days before the end he begged me to finish this abstract, for I had been at his side through all his labours.