condyle of the jaw bone, will not be so confined a hinge as in carnivorous animals, but must be flattened, corresponding to a more or less flattened facette of the temporal bone; and the temporal fosse, having to receive but a small muscle, will be narrow and of little depth. All these things flow from one another, according as they are more or less general; some being essential and exclusively appropriated to animals with hoofs; and others though equally necessary to them, but not peculiar, being found likewise in some other animals, where the rest of the conditions permit. Had not observation informed us, we should not probably have divined, that all ruminating animals have a cloven foot, and they alone. It is moreover doubtful, if we should have inferred a priori, that none but animals of this class would have horns on their forehead; and that those of them which had sharp canine teeth, would be the only ones without horns. Yet since these relations are uniform, they must have a sufficient cause; but as we do not know it, observation must supply the deficiencies of theory. We thereby establish empirical laws which become almost as certain as rational ones, when they repose on observations often enough repeated. Whoever at the present day sees the print of a cloven foot, may safely conclude that the animal which left that impression, chews the cud; a conclusion as certain indeed as any in physical or moral science.

This single foot-print, then, affords to the observer, at once the form of the teeth, the form of the jaws, the form of the vertebræ, and the form of

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all the bones of the legs, the thighs, the shoulders, and the pelvis of an animal which has merely walked past without being seen.

That there are secret reasons, however, of all these relations, observation alone can suggest, independently of general philosophy. In forming a tabular view of these relations, we recognise not only a constancy of specific characters, so to speak, between such a form of such an organ, and such another form of a different organ; perceive at the same time a constancy in the classic characters, and a correspondent gradation in the development of these two organs, which display almost to demonstration, their mutual influence.

but we

numerous

For example, the dental system, of non-ruminant hoofed animals, is in general more complete than that of ruminant animals with cloven feet; because the former have either incisor or canine teeth in both jaws. The structure of their foot is in general more complex, because they have more toes, or have nails (hoofs) which leave the phalanges more free, or a greater number of distinct bones in the metacarpus and metatarsus, or more tarsal bones, or a fibula, more distinct from the tibia, or lastly because all these circumstances are often combined. It is impossible to give reasons for these relations; but they are clearly not the result of chance, because whenever a cloven-footed creature shows, in the arrangement of its teeth, some tendency to approach to the animals under consideration, it exhibits a similar tendency in the conformation of its feet. Thus the camels possessing canine teeth, and even two or four incisors in the upper

jaw, have an additional bone in the tarsus, because their scaphoid bone is not firmly adherent to the cuboid; and they have very small hoofs, with corresponding ungual phalanges. The musk animals, in which the canine teeth are strongly developed, have a distinct fibula along the whole length of their tibia, while the other cloven-footed kind, have, instead of a fibula, merely a small bone articulated to the lower end of the tibia. Hence a constant harmony subsists between two organs apparently quite alien to each other; and the gradations of their forms have an uninterrupted correspondence, even in cases where we can see no reason for their relations.

By adopting, in this manner, observation as a supplementary means when theory fails, we arrive at results calculated to astonish. The least facette of a bone, the smallest apophysis (bony process) has a determinate character, relative to the class, order, genus, and species, to which it belongs, so that whenever we get merely an extremity of a bone in good preservation, we can, by diligent application, and by availing ourselves with a little address of analogy, and careful comparison, determine all those things as certainly, as if we had the whole animal under our hands. M. Cuvier has often verified this method on portions of well known animals, before bestowing confidence on it, with regard to fossil species; and it has afforded him such infallible success, as to leave no doubt of the certainty of its results.

He enjoyed indeed every desirable co-operation. His fortunate appointment as superintendent of the

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Museum of Natural History, joined to an assiduous research for more than 25 years, furnished him with skeletons of all the genera and sub-genera of quadrupeds, with many species of certain genera, and several individuals of some species. With such resources, it became easy for him to multiply his comparisons, and to verify in all their details the applications which he made of his laws.

In this way, he has determined and classed the remains of nearly 100 quadrupeds, mammiferous or oviparous. Considered in reference to species, upwards of 70 of these animals were previously quite unknown to naturalists; 10 or 12 have so perfectly resembled known species, that no doubt can remain of their identity; the others present many kindred features with known species, but the comparison has not hitherto been made in a sufficiently scrupulous manner to remove all ambiguity. Viewed in reference to the genera, out of these 70 unknown species there are nearly 40 animals which belong to genera that are new.

The other species are referrible to genera or sub-genera.

It may be useful also to consider these animals with respect to the classes and orders to which they belong.

Of the hundred species, about one-fourth part are oviparous quadrupeds, and the rest are mammiferous. Among the latter, more than one-half belong to non-ruminant hoofed animals. It would, however, be premature to establish onthese numbers, any conclusions relative to the theory of the earth, because they are not in a necessary ratio with the numbers of the genera or species which may be

buried in our strata. Thus there have been collected many bones of the large species, which are most obvious to the quarriers, while those of small species are usually neglected, unless accident should make them fall into the hands of a naturalist, as was the case at the Kirkland cave, with Professor Buckland; or unless some peculiarity, as their extreme abundance in certain places, should attract the attention of the vulgar.

That the extinct species are not varieties of the living species, M. Cuvier has proved by an ample induction of facts. A species comprises all the individuals which descend from one another, or from common parents, and those which resemble them as much as they resemble each other. Hence the varieties of a species are merely breeds more or less different, which may issue from them by generation. Our observations on the differences between ancestors and descendants, constitute therefore our only rational rule; for every other would fall under the head of hypotheses devoid of proofs. Although the wolf and the fox inhabit every country from the torrid to the icy zone, they experience in this immense interval, hardly any other change, than a little variation in the beauty of their fur. M. Cuvier compared the skulls of foxes from the north of Europe, and from Egypt, with those of France, and he found no individual differences.

The varieties of the wild animals which are restricted to more limited spaces, differ still less, especially the carnivorous. A more bushy mane forms all the difference between the hyæna of Persia and Morocco.