CONTENTS. 



CHAPTER PAGE 



I. — From Known to Unknown . . . . . . . . 1 



II. — Review of the Position . . . . . . . . 8 



III.— The Problems Presented 22 



IV. — Initial Variations and Total Experience . . 30 



V.— Method of Proof 36 



VI. — Evidence from Arrangement of Hair . . . . 39 



VII.— The Evolution of Patterns of Hair . . . . 50 



VIII. — Can Muscular Action change the Direction of Hair 



in the Individual ? . . . . . . . . 64 



IX. — Habits and Hair of Ungulates . . . . . . 74 



X. — Habits and Hair of Ungulates . . . . . . 86 



XI. — Habits and Hair of Carnivores . . . . . . 92 



XII. — Habits and Hair of Carnivores . . . . . . 98 



XIII. — Habits and Hair of Primates . . . . . . 103 



XIV. — Miscellaneous Examples 115 



XV.— Experimental 124 



XVI.— First Summary 140 



XVII. — Varieties of Epidermis 145 



XVIII. — Arrangement of the Papillary Ridges . . . . 157 



XIX.— Flexures of the Palm and Sole 170 



XX.— The Evolution of a Bursa 178 



XXL— The Plantar Arch 192 



XXII.— Muscles 200 



XXIII. — Innervation of the Human Skin 218 



XXIV.— The Building of Reflex Arcs 231 



Summary 257 



Index .. .. .. 259 



