All the preceding types of hoofed animals, the horses, tapirs, peccaries, llamas, deer, antelopes and †mastodons were migrants from the north, and four of these, tapirs, peccaries, llamas and deer, were able to gain a permanent footing in South America and are more or less abundant there to-day, while the horses, antelopes and †mastodons failed to do so and died out. In addition to these, there were the indigenous types, which are now extinct and have never been found outside of the Neotropical region. An extremely peculiar creature, _†Macrauchenia_, was the last surviving member of an order, the †Litopterna, which for ages played a very important rôle in South America. _†Macrauchenia_ was a large animal, somewhat larger and of much heavier build than a camel, to which it had a considerable, though entirely superficial, resemblance. The head was relatively small and must have had quite a long proboscis; the neck was very long, suggesting that the animal browsed upon trees, which is also indicated by the character of the teeth; the legs were long and stout, the feet short and each provided with three toes. Another curious creature was _†Typotherium_, from which is named the group of the †Typotheria, which some authorities regard as a suborder, while others assign to it a full ordinal rank. [Illustration: FIG. 120.—A Pampean †Litoptern (_†Macrauchenia patachonica_). Restored from a skeleton in the Museum of La Plata.] The †Typotheres throughout the Tertiary period were among the most abundant and characteristic of the South American hoofed animals, and the genus _†Typotherium_ was the last of a very long series and was an animal of moderate size, with chisel-shaped incisor teeth so like those of the rodents that the genus was long referred to that order. Finally, we have _†Toxodon_, type of the order †Toxodontia, a ponderous beast, as large as a rhinoceros, which, there is some reason to think, was largely aquatic in its habits. The first species of this extraordinary creature was found by Charles Darwin, who says of it: “Perhaps one of the strangest animals ever discovered; in size it equalled an elephant or megatherium, but the structure of its teeth, as Mr. Owen states, proves indisputably that it was intimately related to the Gnawers [_i.e._ Rodentia] ... in many details it is allied to the Pachydermata: judging from the position of its eyes, ears, and nostrils, it was probably aquatic, like the Dugong and Manatee, to which it is also allied.”[4] Modern views concerning the relationships of _†Toxodon_ are very different from those advanced by Darwin, but he gives a vivid picture of its diverse likenesses. Neither _†Macrauchenia_, _†Typotherium_ nor _†Toxodon_ has been found in the Brazilian caverns, but this is no doubt due to the accidents of preservation, for the latter animal ranged north to Nicaragua. [Illustration: FIG. 121.—A Pampean †Toxodont (_†Toxodon burmeisteri_). Restored from a skeleton in the La Plata Museum.]