| PAGE |
| STROMNESS AND ITS ASTEROLEPIS.—THE LAKE OF STENNIS | [21] |
| THE DEVELOPMENT HYPOTHESIS, AND ITS CONSEQUENCES | [37] |
| THE RECENT HISTORY OF THE ASTEROLEPIS.—ITS FAMILY | [48] |
| CEREBRAL DEVELOPMENT OF THE EARLIER VERTEBRATA.—ITS APPARENT PRINCIPLE | [62] |
| THE ASTEROLEPIS.—ITS STRUCTURE, BULK, AND ASPECT | [94] |
| FISHES OF THE SILURIAN ROCKS, UPPER AND LOWER.—THEIR RECENT HISTORY, ORDER, AND SIZE | [130] |
| HIGH STANDING OF THE PLACOIDS.—OBJECTIONS CONSIDERED | [147] |
| THE PLACOID BRAIN.—EMBRYONIC CHARACTERISTICS NOT NECESSARILY OF A LOW ORDER | [160] |
| THE PROGRESS OF DEGRADATION.—ITS HISTORY | [181] |
| EVIDENCE OF THE SILURIAN MOLLUSCS.—OF THE FOSSIL FLORA.—ANCIENT TREE | [205] |
| SUPERPOSITION NOT PARENTAL RELATION.—THE BEGINNINGS OF LIFE | [230] |
| LAMARCKIAN HYPOTHESIS OF THE ORIGIN OF PLANTS.—ITS CONSEQUENCES | [243] |
| THE TWO FLORAS, MARINE AND TERRESTRIAL.—BEARING OF THE EXPERIENCE ARGUMENT | [262] |
| THE DEVELOPMENT HYPOTHESIS IN ITS EMBRYONIC STATE.—OLDER THAN ITS ALLEGED FOUNDATIONS | [277] |
| FINAL CAUSES—THEIR BEARING ON GEOLOGIC HISTORY—CONCLUSION | [303] |
| | PAGE |
| 1. | Internal ridge of hyoid plate of Asterolepis | [31] |
| 2. | Shagreen of Raja clavata:—of Sphagodus | [54] |
| 3. | Scales of Acanthodes sulcatus:—shagreen of Scyllium stellare | [55] |
| 4. | Scales of Cheiracanthus microlepidotus:—shagreen of Spinax Acanthias | [56] |
| 5. | Section of shagreen of Scyllium stellare:—of scales of Cheiracanthus microlepidotus | [56] |
| 6. | Scales of Osteolepis microlepidotus:—of an undescribed species of Glyptolepis | [57] |
| 7. | Osseous points Of Placoid Cranium | [65] |
| 8. | Osseous centrum of Spinax Acanthias:—of Raja clavata | [67] |
| 9. | Portions of caudal fin of Cheiracanthus:—of Cheirolepis | [69] |
| 10. | Upper surface of cranium of Cod | [72] |
| 11. | Cranial buckler of Coccosteus | [74] |
| 12. | Cranial buckler of Osteolepis | [75] |
| 13. | Upper surface of head of Osteolepis | [77] |
| 14. | Under surface of head of Osteolepis | [79] |
| 15. | Head of Osteolepis, seen in profile | [80] |
| 16. | Cranial buckler of Diplopterus | [81] |
| 17. | Ditto | [82] |
| 18. | Palatal dart-head, and group of palatal teeth, of Dipterus | [83] |
| 19. | Cranial buckler of Dipterus | [85] |
| 20. | Base of cranium of Dipterus | [86] |
| 21. | Under jaw of Dipterus | [87] |
| 22. | Longitudinal section of head of Dipterus | [88] |
| 23. | Section of vertebral centrum of Thornback | [92] |
| 24. | Dermal tubercles of Asterolepis | [95] |
| 25. | Scales of Asterolepis | [96] |
| 26. | Portion of carved surface of scale | [96] |
| 27. | Cranial buckler of Asterolepis | [98] |
| 28. | Inner surface of cranial buckler of Asterolepis | [99] |
| 29. | Plates of cranial buckler of Asterolepis | [102] |
| 30. | Portion of under jaw of Asterolepis | [103] |
| 31. | Inner side of portion of under jaw of Asterolepis | [104] |
| 32. | Portion of transverse section of reptile tooth of Asterolepis | [105] |
| 33. | Section of jaw of Asterolepis | [106] |
| 34. | Maxillary bone? | [108] |
| 35. | Inner surface of operculum of Asterolepis | [109] |
| 36. | Hyoid plate | [110] |
| 37. | Nail-like bone of hyoid plate | [111] |
| 38. | Shoulder plate of Asterolepis | [112] |
| 39. | Dermal bones of Asterolepis | [113] |
| 40. | Internal bones of Asterolepis | [114] |
| 41. | Ditto | [115] |
| 42. | Ischium of Asterolepis | [116] |
| 43. | Joint of ray of Thornback:—of Asterolepis | [117] |
| 44. | Coprolites of Asterolepis | [118] |
| 45. | Hyoid plate of Thurso Asterolepis | [124] |
| 46. | Hyoid plate of Russian Asterolepis | [127] |
| 47. | Spine of Spinax Acanthias:—fragment of Onondago spine | [143] |
| 48. | Tail of Spinax Acanthius:—of Ichthyosaurus tenuirostris | [172] |
| 49. | Port Jackson Shark (Cestracion Phillippi) | [177] |
| 50. | Tail of Osteolepis | [195] |
| 51. | Tail of Lepidosteus osseus | [196] |
| 52. | Tail of Perch | [197] |
| 53. | Altingia excelsa (Norfolk-Island Pine) | [212] |
| 54. | Fucoids of the Lower Old Red Sandstone | [216] |
| 55. | Two species of Old Red Fucoids | [217] |
| 56. | Fern (?) of the Lower Old Red Sandstone | [219] |
| 57. | Lignite of the Lower Old Red Sandstone | [221] |
| 58. | Internal structure of lignite of Lower Old Red Sandstone | [223] |
When engaged in prosecuting the self-imposed task of examining in detail the various fossiliferous deposits of Scotland, in the hope of ultimately acquainting myself with them all, I extended my exploratory ramble, about two years ago, into the Mainland of Orkney, and resided for some time in the vicinity of Stromness.