_Ungulata._--_Equus_, _Tapirus_, _Dicotyles_, _Auchenia_, _Cervus_, _Leptotherium_, and _Antilope_, are the cave-genera of this order. _Equus_ and _Antelope_ are particularly interesting, as representing groups forming no part of existing South American zoology; while the presence also of _Leptotherium_, an extinct genus of antelopes, shows that the group was fairly represented in South America at this comparatively recent period. _Proboscidea._--A species of _Mastodon_, found also in the Pliocene of La Plata, represents this order. _Rodentia._--These abound. _Dasyprocta_, _Cælogenys_, _Cavia_, _Kerodon_, all living genera of Caviidæ, are represented by {145}extinct species. _Cercolabes_, the 'tree porcupine' (Cercolabidæ) has two species, one as large as a peccary; _Myopotamus_, _Loncheres_, _Carterodon_, are existing genera of spiny rats (Echimyidæ); and there are two extinct genera of the same family, _Lonchophorus_ and _Phyllomys_. _Lagostomus_ (Chinchillidæ), the viscacha of the Pampas, is represented by an extinct species. There is also an extinct species of _Lepus_; several species of _Hesperomys_ and _Oxymycterus_; and a large _Arvicola_, a genus not living in South America. _Edentata._--These, which constitute the great feature of the existing South American fauna, were still more abundant and varied in the Cave period, and it is remarkable that most of them are extinct _genera_. The armadillos are alone represented by living forms, _Dasypus_, and _Xenurus_; _Eurydon_ and _Heterodon_, are extinct genera of the same family, as well as _Chlamydotherium_--huge armadillos the size of a tapir or rhinoceros, and _Pachytherium_, which was nearly as large. The ant-eaters are represented only by _Glossotherium_, an extinct form allied to _Myrmecophaga_ and _Manis_. The sloths were more numerous, being represented by the extinct genera _Cælodon_, _Sphenodon_ and _Ochotherium_, the last of large size. The huge terrestrial sloths--Megatheridæ, also abounded; there being species of _Megatherium_ and _Megalonyx_, as well as the allied _Scelidotherium_, supposed to have some affinity for the African _Orycteropus_. _Marsupials._--No new forms of these appear, but numerous species of _Didelphys_, all closely allied to opossums still living in South America.