Tristan d’Acunha, bright-coloured Pelargonium of, 275 Trochilidæ, 125 Trogons, 105 Tropical vegetation, concluding remarks on, 65 probable causes of its luxuriance and variety, 66 Mr. Belt on, 67 Tropical birds, dull-coloured, 110 coloration of, 110 green, 110 Tropics, limitation of, 3 aspects of animal life in, 121 Trunks, variety of, 31, 33 probable cause of flowering, 34 Twilight, short at equator, 21 Typical colours, 179 V. _Vanda lowii_, 51 Vampyre-bats, 119 Variation, how influenced, 142 Vegetation, equatorial, 27 Vipers, green, 114 Vitality a cause of bright colour, 193 W. Warning Colours, theory of, 189 Wasps and bees, 90 Wave-lengths of coloured rays, 180 Weale, Mr. J. P. Mansel, on plants of Karoo, 223 on _Ajuga ophrydis_, 223 Webber, Mr., on food of humming-birds, 137 West-Indian Islands, large and brilliant butterflies of, 261 peculiarly coloured birds of, 262 Whip-snakes, 114 White animals poisoned where black escape, 265 White colours influencing sense-perception, 265 White colour doubly prejudicial to animals, 266 White tropical birds, 110 Wilson, Dr., on pottery from N. American mounds, 295 Winds, influence of on temperature, 11 direction of near equator, 11, 12 cause of cold near equator, 12, 13 Wolves in England show its union with continent, 305 Woods from equatorial forest-trees, 36 Z. Zebra, possible use of its stripes, 197 Zingiberaceæ, 47 Zoological regions, 314 Zoological regions of the New World, 329 LONDON: R. CLAY, SONS, AND TAYLOR, BREAD STREET HILL. Transcriber's Notes The following changes have been made to the text as printed. 1. Illustrations and footnotes have been located in appropriate paragraph breaks. 2. Obvious typographical errors have been corrected. Other than these and particular changes noted below, inconsistencies in spelling have been retained as printed. 3. Where a word is used repeatedly in the same way, hyphenation has been made consistent, preferring the form most often used in the printed work, or failing that the more usual form in general use at the time of publication. No typographical change has been made within direct quotes from other works. 4. Page 47: "single volcanic mountains" has been changed to "single volcanic mountain". 5. Page 51: "Cælogynes" has been changed to "Cœlogynes". 6. Page 115 and Index: "Dr. Gardiner" has been changed to "Dr. Gardner". (George Gardner, author of "Travels in the Interior of Brazil", London, 1846). 7. Page 221: The chapter heading "CHAPTER VI" has been changed to "VI", consistently with the other chapter headings. 8. Page 259 and footnote: "Euplæa" has been changed to "Euplœa". 9. Page 264 (footnote): "Phlogænas johannœ" has been changed to "Phlogœnas johannæ".