n. <古生>始祖马

[ noun ]
earliest horse; extinct primitive dog-sized four-toed Eocene animal
<noun.animal>

Hyracotherium \Hyracotherium\ n.
An extinct horse genus, formerly called genus {Eohippus}.

Syn: genus {Hyracotherium}.
[WordNet 1.5]

eohippus \eo*hip"pus\ ([=e]`[-o]*h[i^]p"p[u^]s), n. [Gr. 'hw`s
dawn + "ipposhorse.]
an extinct primitive dog-sized 4-toed Eocene mammal, the
earliest horse known in the line of descent of the modern
horse. It is classed in the extinct genus {Hydracotherium}.
Called also {dawn horse}.

Syn: dawn horse.
[WordNet 1.5 +PJC]