The Collaborative International Dictionary of English v.0.48:

Micromyx \Micromyx\ prop. n.
   A genus of Old World harvest mice.

   Syn: genus Micromyx.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Micromyx
    n 1: Old World harvest mice [syn: Micromyx, genus Micromyx]