a small,herbivorous,extinct mammal of the genus Hyracotherium(or Eohippus) from the Eocene Epoch of the western United States,having four-toed front feet and three-toed hind feet and related ancestrally to the horse是什么意思_a small,herbivorous,extinct mammal of the genus Hyracotherium(or Eohippus) from the Eocene Epoch of the western United States,having four-toed front feet and three-toed hind feet and related ancestrally to the horse在线翻译_英语_读音_用法_例句