Few facts are more remarkable in the history of the progress of human discovery, than that it should have been reserved almost entirely for the researches of the present generation, to arrive at any certain knowledge of the existence of the numerous extinct races of animals, which occupied the surface of our planet, in ages preceding the creation of man. The rapid progress which, during the last half century, has been made in the physical sciences, enables us now to enter into the history of Fossil Organic Remains, in a manner which, till within a very few years, would have been quite impracticable; during these years the anatomy of extinct species of Quadrupeds has been most extensively investigated, and the greatest of comparative anatomists has devoted much of his time and talent to illustrate their organization. Similar inquiries have been carried on also by a host of other enlightened and laborious individuals, conducting independent researches in various countries, since the commencement of the present century; hence our knowledge of the osteology of a large number of extinct genera and species, now rests on nearly the same foundation, and is established with scarcely less certainty, than the anatomical details of those creatures that present their living bodies to our examination.
We can hardly imagine any stronger proof of the Unity of Design and Harmony of Organizations that have ever pervaded all animated nature, than we find in the fact established by Cuvier, that from the character of a single limb, and even of a single tooth or bone, the form and proportions of the other bones, and condition of the entire Animal may be inferred. This law prevails, no less universally, throughout the existing kingdoms of animated nature, than in those various races of extinct creatures that have preceded the present tenants of our planet; hence not only the framework of, the fossil skeleton of an extinct animal, but also the character of the muscles, by which each bone was moved, the external form and figure of the
