asinus onager

from The Collaborative International Dictionary of English v.0.48

Onager \On"a*ger\, n.; pl. L. {Onagri}, E. {Onagers}. [L.
   onager, onagrus, Gr. ?.]
   1. (Rom. Antiq.) A military engine acting like a sling, which
      threw stones from a bag or wooden bucket, and was operated
      by machinery. --Fairholt.
      [1913 Webster]

   2. (Zool.) A wild ass of central Asia, especially the
      {koulan} ({Equus hemionus} syn. {Equus hemippus} syn.
      {Equus onager}, formely {Asinus onager}).
      [1913 Webster +PJC]

from The Collaborative International Dictionary of English v.0.48

Koulan \Kou"lan\, n. [Native name.] (Zool.)
   A wild horse ({Equus onager} or {Asinus onager}) inhabiting
   the plains of Central Asia; -- called also {gour}, {khur},
   and {onager}. [Written also {kulan}.]
   [1913 Webster]

   Note: It is sometimes confounded with the dziggetai, to which
         it is closely related. It is gray in winter, but
         fulvous in summer. It has a well defined, dark, dorsal
         stripe, and a short, erect mane. In size, it is
         intermediate between the horse and ass.
         [1913 Webster]