"We analyze the interrelationships of the several groups of hornless ruminants and show which of them lie nearest the higher ruminants. The phylogenetic progression within Ruminantia proceeds from Hypertragulidae through Tragulidae to Leptomerycidae to Gelocidae to Moschidae and thence to the horned ruminants. Archaeomeryx of the late Eocene is recognized as a primitive member of the Leptomerycidae; the living Tragulidae actually represent a more primitive ruminant stock. We introduce the name Moschina for the Gelocidae and the Moschidae and the term Eupecora for the higher ruminant groups bearing horns, antlers, and ossicones. We also propose Neoselenodontia, above the subordinal level, to include both the Ruminantia and their sister group, the Tylopoda. The stratigraphic records of the five lower ruminant families appear relatively complete with the exception of the Tragulidae, which are poorly known prior to the Miocene. The exclusively North American distribution of the family Hypertragulidae and many of the Tylopoda suggests that the Ruminantia may have originated in North America. The Tragulidae, exclusively Old World and predominantly subtropical, presumably originated by colonization and isolation in the Old World. Thereafter ruminant evolution centered in the Old World, but representatives of every major group reached North America"--P. 121.