Page:The naturalist on the River Amazons 1863 v1.djvu/228

One of the principal points of distinction from other families is the strong, blunt form of the claws, which in one of the forms (the Capybara) are very broad, and approximate in shape to the hoofs of the Pachydermata. On this account the family is named by some authors Subungulati; the great division of mammalian animals to which the Pachydermata belong being called, in the classifications of the best authors, Ungulata, after the hoofed feet, which are considered their leading character. It is an interesting fact that the pachydermatous animal most nearly allied to the Rodents is also American, although found only in the fossil state, namely, the Toxodon, which Professor Owen states resembled the Rodentia in its dentition. The Toxodon, on the other hand, was nearly related to the Elephant, of which the same distinguished zoologist says, "Several particulars in its organization indicate an affinity to the Rodentia." These facts impart a high degree of interest to these semi-hoofed American Rodents, because they make it probable that these animals are the living representatives, albeit somewhat modified, of a group which existed at a former distant epoch in the world's history, and which possessed a structure partaking of the characters of the two great orders, Rodentia and Pachydermata, now so widely distinct in the majority of their forms. I believe that no remains of the order Toxodontia, or of the Rodent family Subungulati, have been found fossil in any other part of the world besides America. In this sort of question it is very unsafe to found generalizations on negative evidence; but does not this tend to show that