n. A rodent quadruped of the family Muridæ, subfamily Arvicolinæ, and one of the genera Myodes, Cuniculus, and Synaptomys (see these terms).n. The North American lemmings, 8 or 10 species of which are now recognized, have been divided into two genera, Lemmus and Dicrostonyx, and the species once familiar as Myodes obensis is now Lemmus alascensis. The black-footed lemming, L. nigripes, is peculiar to St George Island, Bering Sea. The common northeastern species is D. hudsonius.