EVOTOMYS 309 
longer than a hind foot, and thus intermediate between those 
of lemmings and true mice. In their more ordinary hands and 
feet the palms and soles are provided with pads. Voles are 
thus externally less specialised, but cannot be absolutely 
separated from the lemmings, since a few members of either 
group exhibit the characters of the other. The fur is usually 
soft, the colours rarely bright. The skull is comparatively 
slender and lightly built. In the teeth the lower incisors are 
long, and the extremities of their roots lie on the outer sides of 
their ,; the cheek-teeth have the dentine-spaces subequal, 
and their upper crowns become distinctly narrower from front 
to back. 
These are hardy animals, never hibernating, and continuing 
their activity in winter beneath the snow of boreal countries. 
The group is of wide and almost ubiquitous distribution in 
the extra-tropical regions of the Northern Hemisphere, where 
a number of genera have been for the most part recently 
differentiated. There are several British species, which fall into 
three existing genera (Evotomys, Microtus, Arvicola); a single 
extinct genus (J/zmomys); and a genus and _ sub- genus 
(Pitymys and Chzonomys), extinct in Britain, but still existing 
in continental Europe. 
GENUS EVOTOMYS. 
1811. MyopEs, P. S. Pallas, Zoographia Rosso-Asiatica, i., 173, based on Mus 
Zemmus of Linnzeus, hence antedated by LemMus, Link, 1795; de Sélys- 
Longchamps, Etudes de Micromammalogie, 1839, 87, section based on Lemmus 
rubidus of Baillon, 1834 = Mus glareolus of Schreber; Lataste, Le Naturaliste, 
15th October 1883, 349, sub-genus based on Mus rutilus of Pallas=Evotomys 
rutilus. 
1831. HYPUD&US, misprinted Hypupacus (col. 874) and HypupDEvs, (pl. vii.), 
E. Mehlis, Oken’s /szs, viil., based on HZ. hercynicus of Mehlis=Mus glareolus of 
Schreber ; Keyserling and Blasius, Die Wirbelthiere Europa’s, 1840, viii., and 34, 
sub-genus based on JZus glareolus of Schreber; preoccupied by HyPUDUS of 
Illiger, Prodromus Syst. Mamm. et Avium, 1811, 87; the latter based on Jus 
Zemmus of Linnzeus, hence antedated by LEMMUS, Link, 1795. 
1874. Evotomys, Elliott Coues, Proc. Acad. Nat. Sci. (Philadelphia), 186; genus 
based on Mus rutilus of Pallas. 
1900. EvoTomys, Erwin Schultz, Zeztschr. fiir Naturwiss. (Stuttgart), 19th December, 
203 ; Collett. 
