our duty to explain, again and again, the foundation of our belief, in the hope and assurance that we shall at length remove the erroneous opinions of persons whose scepticism arises from their imperfect acquaintance with the subject. It has been insisted upon by those whose views are limited to the present state of the globe, that the supposition of the earth having been peopled by other creatures before the existence of the human race is incompatible with the evident design of the Creator, and derogatory from the dignity of Man, for whose pleasure and necessities they assume ail living things were created. But this inference is at variance with what we know of the living world around us: everywhere we see forms of animated existence utterly unconscious of the presence of Man, and endowed with faculties and sensations wholly dissimilar from our own. Thus, while in the beautiful language of Scripture we are told that not a sparrow falls to the ground without our heavenly Father's notice, a philosophical examination of the present constitution of nature would alike condemn such vanity and presumption. For my own part, feeling, as I do, the most profound reverence and the deepest gratitude to the Eternal Being, who has given unto me this reasoning intellect, however feeble it may be,—and believing that the gratification and delight experienced in the contemplation of the Wonders of Creation here are but a foretaste of that inexpressible felicity which, in a higher state of existence, will be our portion hereafter, I cannot but think that the minutest living atom, which the aided eye of man is able to explore, is designed for its own peculiar sphere of enjoyment, and is alike the object of His mercy and His care, as the most stu pendous and exalted of His creatures.

"Le même Dieu créa la mousse et l' Univers."

In nothing, perhaps, are we more mistaken than in our estimate of the happiness enjoyed by other beings; to em

ploy the beautiful simile of a distinguished author,—“ As the moon plays upon the waves, and seems to our eyes to favour with a peculiar beam one long track amidst the waters, leaving the rest in comparative obscurity, yet all the while she is no niggard in her lustre; for, although the rays that meet not our eyes seem to us as though they were not, yet she, with an equal and unfavouring loveliness, mirrors herseif on every wave; even so, perhaps, happiness falls with the same power and brightness over the whole expanse of veing, althougn to our limited perceptions it seems only to rest on those billows from which the rays are reflected back upon our sight."* And if we admit, as all must admit who for one moment consider the marvels which Astronomy has unfolded to us, that there are countless worlds around us, inhabited by intelligences of whose nature we can form no just conception, surely the discoveries of Geology ought not to be rejected because they instruct us, that ere man was called into existence this planet was the object of the Almighty's care, and teeming with life and happiness.

Thus Geology reveals the sublime truth, that through periods of incalculable duration, our globe was the abode of myriads of living creatures, enjoying all the blessings of existence, and which at the same time were the destined instruments for the elaboration of the materials, by which the surface of the earth was rendered, in the course of innumerable ages, a fit temporary abode for intellectual and immortal beings! †

* Sir E. B. Lytton's "Eugene Aram."

+ See M'Cosh and Dickie's "Typical Forms and Special Ends in Creation," 1856, for some interesting remarks on the adaptations of both fossil and recent animals and plants to their functions and conditions, and a brief notice of the evidences of a long preparation for the advent of man upon the earth (p. 345).

LECTURE VI.

ON ZOOPHYTA AND CRINOIDEA.

1. Introductory. 2. Organic and Inorganic Bodies. 3. Distinction between Animals and Vegetables. 4. Nervous System and Sensation. 5. Diversity of Animal Forms. 6. Zoophytes. 7. Animal nature of Zoophytes. 8. Cilia, or vibratile organs. 9. Hydræ, or Fresh-water Polypes. 10. Elementary organic structure. 11. Analogy not Identity. 12. The Bryozoa. 13. Food of Zoophytes. 14. Nature of Zoophytes. 15. Corals or Polypifera. 16. Sertularian Zoophytes. 17. Actinoidea or Corallaria. 18. Caryophyllia and Turbinolia. 19. Madrepore. 20. Fungia. 21. Astræa, Pavonia, &c. 22. Mæandrina cerebriformis. 23. Alcyonarian Zoophytes: Gorgonia. 24. The Red Coral. 25. Tubipora. 26. Geographical Distribution of Corals. 27. Appearance of living Corals. 28. Coral Reefs. 29. Coral Reef of Loo-Choo. 30. Coral Islands. 31. Formation of Coral Islands. 32. Montgomery on Coral Islands. 33. Fossil Zoophytes. 34. Ventriculites. 35. Zoophytes of the Oolite and Lias. 36. Corals of the Paleozoic Formations. 37. Coralline Marbles. 38. The Crinoidea. 39. Structure of the Crinoidea. 40. Encrinites and Pentacrinites. 41. Derbyshire Encrinital Marble. 42. The Lily-Encrinite. 43. Pear-Encrinite of Bradford. 44. Pentacrinites and Actinocrinites. 45. Pentremites and Cystidea. 46. Concluding Remarks.

1. INTRODUCTORY.-In many of the deposits of the Secondary formations reviewed in the last discourse, a large proportion of the fossils were seen to consist of those interesting types of animal organization, the Polypifera and Crinoidea: some of the Oolitic strata, as for example the Coral-rag, being wholly made up of Corals; while many of the limestones and shales of the Lias equally abound in Pentacrinites and other forms of the Crinoidea. In the more ancient paleozoic formations, to the examination of which our attention will hereafter be directed, we shall find these organisms in still greater profusion: entire mountain-chains consisting of the consolidated remains of corals, and vast tracts of limestones composed of the mineralized skeletons of the Lily-shaped animals.

To enable the unscientific reader to comprehend the ori

gin and formation of these ancient fossiliferous rocks, I therefore purpose devoting the present Lecture to a general view of the natural history of some of the recent animals of these classes, and a brief notice of the most characteristic fossil species.

2. ORGANIC AND INORGANIC BODIES. The beautiful world in which we are placed is everywhere full of objects presenting innumerable varieties of form and structure, of action and position; some of them being inanimate or inorganic, and others possessing organization or vitality. The organic kingdom of nature, in like manner, is separated into two grand divisions, the animal and the vegetable. The differences between organic and inorganic bodies are numerous and manifest; but it will suffice for my present purpose to mention a few obvious and familiar characters.

All the parts of an inorganic body enjoy an independent existence; if I break off a crystal from this mass of calcareous spar, the specimen does not lose any of its properties, it is still a group of crystals as before: but if a branch be separated from a tree, or a limb from an animal, each is rendered imperfect, and the parts removed suffer decomposition,—the branch withers, and the limb undergoes putrefaction. If crystals, which may be considered the most perfect models of inorganic substances, be formed, they will remain unchanged, unless acted upon by some external force of a chemical or mechanical nature: within, every particle is at rest, nor do they possess the power to alter, increase, or diminish: they can enlarge by external additions only, and decrease but by the removal of portions of their mass. *

* These remarks must be taken in a general sense only, since various experiments have demonstrated that the molecules of inorganic matter undergo modification by the slightest action of light and variation of temperature.

"Prismatic crystals of zinc are changed in a few seconds into octahedrons by the heat of the sun. We are led from the mobility of fluids to expect great changes in the relative positions of their molecules, which must be in perpetual motion even in the stillest water or calmest air; but we were not prepared to find motion to such an extent in the interior of solids. We knew that their particles were brought nearer by cold or

But organic bodies have characters of a totally different nature; they possess definite forms and structures, which are capable of resisting for a time the ordinary laws by which the changes of inorganic matter are regulated, while internally they are in constant mutation. From the first moment of the existence of the plant or animal to its dissolution there is no repose; youth follows infancy,-maturity precedes age; it is thus with the moss and the oak,-the monad and the elephant,-life and death are common to them all.

Animals and vegetables also require a supply of food and air, and a suitable temperature, for the continuance of their existence; and they are nourished by fluids elaborated by appropriate organs, and transmitted through suitable vessels. In the germ of an animal or a vegetable there is a vital principle in action, by which are developed in succession the ordained phenomena of its existence. By this power the germ is able to attract towards it particles of inanimate matter, and bestow on them an arrangement widely different from that which the laws of chemistry or mechanics could produce. The same power not only attracts these particles, and preserves them in their new situations, but is continually engaged in removing those which might by their presence prevent or derange its operations; and, on the other hand, so soon as the vital principle deserts the body which it has animated, the latter immediately becomes subjected to the agencies which act on inorganic matter: "in obedience to the power of gravitation the pliant twig hangs down, and the slender stem bends. In animals the body falls to the ground; the pressure of the upper parts flattens those on which the others rest; the skin stretches out; and the graceful rotundity of life is exchanged for the oblateness of death." * The laws of chemistry then begin to operate,

pressure, or removed farther from one another by heat; but it could not have been anticipated that their relative positions could be so entirely changed as to alter their mode of aggregation. It follows from the low temperature at which these changes are effected, that there is probably no portion of inorganic matter that is not in a state of relative motion. Prismatic crystals of sulphate of nickel exposed to the summer heat, in a close vessel, had their internal structure completely altered, so that when broken open they were composed internally of octahedrons, with square bases. The original aggregation of the internal particles had been dissolved, and a disposition given to arrange themselves in a crystalline form."-Mrs. Somerville, On the Connexion of the Sciences, p. 171, * Dr. Fleming; Philosophy of Zoology, vol. i. p. 39.