THE ZOOLOGY OF THE VOYAGE OF H. M. S. BEAGLE, UNDER THE COMMAND OF CAPTAIN FITZROY, R.N., DURING THE YEARS 1832 TO 1836. _PUBLISHED WITH THE APPROVAL OF THE LORDS COMMISSIONERS OF HER MAJESTY’S TREASURY_. Edited and Superintended by CHARLES DARWIN, ESQ. M.A. F.R.S. SEC. G.S. NATURALIST TO THE EXPEDITION. PART I. FOSSIL MAMMALIA: BY RICHARD OWEN, ESQ. F.R.S. PROFESSOR OF ANATOMY AND PHYSIOLOGY TO THE ROYAL COLLEGE OF SURGEONS IN LONDON; CORRESPONDING MEMBER OF THE INSTITUTE OF FRANCE, ETC. ETC. LONDON: PUBLISHED BY SMITH, ELDER AND CO. 65, CORNHILL. MDCCCXL. LONDON: PRINTED BY STEWART AND MURRAY, OLD BAILEY. CONTENTS. Page GEOLOGICAL INTRODUCTION 3 TOXODON PLATENSIS, Description of Cranium 16 of Lower Jaw and Teeth 29 MACRAUCHENIA PATACHONICA, Cervical Vertebræ 35 Lumbar Vertebræ 40 Scapula 43 Antibrachium and Fore-foot 44 Femur 48 Tibia, Astragalus, and Metatarsal Bone 50 GLOSSOTHERIUM, Fragment of Cranium 57 MYLODON DARWINII, Lower Jaw and Teeth 63 SCELIDOTHERIUM LEPTOCEPHALUM, Cranium and Teeth 73 Vertebral Column 84 Bones of the Extremities 88 MEGALONYX JEFFERSONII, Lower Jaw 99 MEGATHERIUM CUVIERI, Cranium and Teeth 100 TESSELATED ARMOUR AND BONES, large Edentata 106 MASTODON ANGUSTIDENS, Cuv. (?) 108 EQUUS, Molar Teeth 108 CTENOMYS PRISCUS, and a large Rodent 109 Geological contemporaneity of preceding extinct Mammalia 111 LIST OF PLATES.