I have made a few alterations and corrections in some of the papers, so as to bring the statements into closer accordance with scientific accuracy. At the same time, I should like to add that I have intentionally simplified the scientific facts as far as possible. Thus, instead of saying that the groundsel is a composite, I have said that it is a daisy by family; and instead of saying that the ascidian larva belongs to the sub-kingdom Chordata, I have said that it is a first cousin of the tadpole. For these simplifications, I hope technical biologists will pardon me. After all, if you wish to be understood, it is best to speak to people in words whose meanings they know. Definite and accurate terminology is necessary to express definite and accurate knowledge; but one may use vague expressions where the definite ones would convey no ideas. I have to thank the kindness of my friend the Rev. E. PURCELL, of Lincoln College, Oxford, for the clever and appropriate design which appears upon the cover. G. A. CONTENTS. PAGE A BALLADE OF EVOLUTION 1 I. MICROSCOPIC BRAINS 3 II. A WAYSIDE BERRY 16 III. IN SUMMER FIELDS 25 IV. A SPRIG OF WATER CROWFOOT 36 V. SLUGS AND SNAILS 48 VI. A STUDY OF BONES 59 VII. BLUE MUD 67 VIII. CUCKOO-PINT 77 IX. BERRIES AND BERRIES 87 X. DISTANT RELATIONS 96 XI. AMONG THE HEATHER 105 XII. SPECKLED TROUT 114 XIII. DODDER AND BROOMRAPE 124 XIV. DOG'S MERCURY AND PLANTAIN 133 XV. BUTTERFLY PSYCHOLOGY 142 XVI. BUTTERFLY ÆSTHETICS 153 XVII. THE ORIGIN OF WALNUTS 161 XVIII. A PRETTY LAND-SHELL 172 XIX. DOGS AND MASTERS 181 XX. BLACKCOCK 189 XXI. BINDWEED 198 XXII. ON CORNISH CLIFFS 207 _A BALLADE OF EVOLUTION._ In the mud of the Cambrian main Did our earliest ancestor dive: From a shapeless albuminous grain We mortals our being derive. He could split himself up into five, Or roll himself round like a ball; For the fittest will always survive, While the weakliest go to the wall.