V. Rhinocerotidæ. True Rhinoceroses.
†Trigonias, low. Oligo. †Cænopus, Oligo. and low. Mioc. †Diceratherium, up. Oligo. and low. Mioc. †Aphelops, mid. Mioc. to low. Plioc. †Teleoceras, mid. Mioc. to low. Plioc.
VI. †Hyracodontidæ. †Hyracodonts and †Amynodonts, cursorial and aquatic Rhinoceroses.
†Hyrachyus, low. and mid. Eoc. †Triplopus, mid. and up. Eoc. †Colonoceras, mid. Eoc. †Hyracodon, low. Oligo. †Amynodon, up. Eoc. †Metamynodon, low. Oligo.
Suborder †ANCYLOPODA. †Clawed Perissodactyls
VII. †Chalicotheriidæ. Chalicotheres.
†Moropus, up. Oligo. and low. Mioc. ?†Schizotherium, low. Oligo. †Eomoropus, mid. Eoc.
The earliest perissodactyls of which we have any knowledge are found in the older part of the lower Eocene (Wasatch stage) of Europe and North America, into which they must have migrated from some other region yet unknown, for no probable ancestors of the group are found in the Paleocene of either continent.