Microtus

from WordNet (r) 3.0 (2006)

Microtus
    n 1: voles of the northern hemisphere [syn: {Microtus}, {genus
         Microtus}]

from The Collaborative International Dictionary of English v.0.48

Arvicola \Arvicola\ n.
   a genus of mice in some classifications considered synonymous
   with {{Microtus}}.

   Syn: genus {Arvicola}.
        [WordNet 1.5]