Social life and gregariousness, 410.--Communal life, 411.--Commensalism, 413.--Parasitism, 415. XXXI.--COLOR AND PROTECTIVE RESEMBLANCES. Use of color, 424.--General, variable, and special protective resemblance, 426.--Warning colors, terrifying appearances, and mimicry, 430.--Alluring coloration, 433. XXXII.--THE DISTRIBUTION OF ANIMALS. Geographical distribution, 435.--Laws of distribution, 437.--Modes of migration and distribution, 437.--Barriers to distribution, 438.--Faunæ and zoogeographic areas, 440.--Habitat and species, 441.--Species-extinguishing and species-forming, 442. APPENDICES EQUIPMENT AND METHODS APPENDIX I.--EQUIPMENT AND NOTES OF PUPILS. Equipment of pupils, 447.--Laboratory drawings and notes, 447.--Field observations and notes, 448. APPENDIX II.--LABORATORY EQUIPMENT AND METHODS. Equipment of laboratory, 450.--Collecting and preparing material for use in the laboratory, 451.--Obtaining marine animals, microscopic preparations, etc., 453.--Reference-books, 454. APPENDIX III.--REARING ANIMALS AND MAKING COLLECTIONS. Live cages and aquaria, 457.--Making collections, 461.--Collecting and preserving insects, 463.--Collecting and preserving birds, 466.--Collecting and preserving mammals, 470.--Collecting and preserving other animals, 472. PART I STRUCTURE, FUNCTIONS, AND DEVELOPMENT OF ANIMALS CHAPTER I THE STUDY OF ANIMALS AND THEIR LIFE