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If we proceed to consider the orders or subdivisions of the class of hoofed animals, and examine what modifications the general conditions undergo, or rather what particular conditions are conjoined with them, according to the respective characters of these orders, the reasons of these subordinate conditions begin to appear less obvious. We can still easily conceive, in general, the necessity of a more complicated system of digestive organs in those species which have a more imperfect masticatory system; and hence we may presume, that these latter must be rather ruminating animals, in which there is wanting such or such an order of teeth; and may also deduce from the same consideration, the necessity of a certain form of the œsophagus, and of corresponding forms in the vertebræ of the neck, &c. But I doubt whether it would have been discovered, independently of actual observation, that the ruminating animals should all have cloven hoofs, and that they should be the only animals having them; that there should be horns on the fore-head in this class alone; or that such of them as have sharp canine teeth, should, in general, have no horns.