Fig. 71. — Dicrostonyx. 



Crown views of upper molars : 



1. Dicrostonyx lorquatus Pallas (Miller Coll., B.M., No. 7.7.7.3621). Eight )?;•, m', and m'. 



2. Same specimen. Left m' and »?i'. 



3. Dicrostonyx groe^ilandicus Traill. Discovery Bay (B.M., Xo. 77.8.6.5a). Eight m', m', 



and ni'. 



4. Dicrostonyx giilielmi Sanford. Pleistocene; Hutton Cave, Somersetshirs. Upper 



molars, right and left, of the typical skull (Taunton Museuiii), 



5. Dicrostonyx gulielmi Sanford. Pleistocene ; Kesh Caves, Co. Sligo. Eight m} and m' 



(Dublin Museum, C.K. 12). 



6. Dicrostcmyx gulielmi Sanford. Pleistocene; Dog Holes, Warton Crag, Lancashire. 



Eight ?«' and m' (B.M. ; presented by J. Wilfrid Jacksmi). 



7. Dicrostonyx hudsmmis Pallas. Labrador. Lett ni", m', and m' (B.M., No. 61.2.4.1). 



8. Dicrostonyx henseWRiniaa. Pleistocene ; Ightham Fissures, Kent. Left »i', m% and m'. 



9. Dicrostonyx henstli Hinton. Pleistocene; Doneraile Caves. 9. Left m', m', and »«' ; 



a. right m' ; b. and c. right m' (Dublin Museum'). 

 10. Dicrostoni/x torquatus ungulatus v. Baer. Novaya Zemlya. Eight m', m*, and m' of a 

 young individual (B.M., No. 80.3.29.2). 



