394 MURID^— LEMMUS 



of the prehistoric fauna, having been identified also from 

 Forest of Dean, Gloucestershire ; Ightham, Kent ; Langwith, 

 Derbyshire; and Dog Holes, Warton Crag, Lancashire. It 

 was probably present at Hoe Grange Quarry, Longcliffe, 

 Derbyshire, as well as (with Dicrostonyx) in the earlier brick- 

 earth of Erith, in the Thames Valley (see Newton, Geol. Mag., 

 October 1890, 455).^ 



In Ireland it is known only from Doneraile Cave, Co. Cork, 

 where it was discovered by Ussher in 1904 [Journ. Cork Hist, 

 and Arch. Soc, xvii., 92, 123; Irish Naturalist, 1904, 237 and 

 248, also 1 9 10, 42), along with mammoth, bear, reindeer, wolf, 

 and a large hare (true Lepus). 



Some of its remains have such a fresh appearance that the 

 animal may well have survived until prehistoric or historic 

 times. Those from Portugal included the entire dried skins 

 and ligaments of two complete individuals. 



H in ton concludes that the lemmings, helped by their well- 

 known migratory habits, reached Ireland, with the ancestor of 

 the Irish Hare, during the latter part of the pleistocene period, 

 at which time the land stood high enough to lay bare the bed 

 of the North Sea to a latitude somewhere north of the Dogger 

 Bank. The meagre Irish fauna shows that the connection 

 between Ireland and England could only have been inconsider- 

 able or temporary, probably between Carnarvonshire and 

 Wicklow. 



The absence of L. lemmus from Siberia, from the south- 

 west and south of Sweden, and from the late glacial deposits of 

 Denmark (Winge, Vidensk. Meddel. Naturh. For., Kjobenhavn, 

 1904, 3, 223) caused Stejneger to suggest {Smiths. Misc. 

 Coll., 4th May 1907, 478), with much probability that, 

 with the Varying Hare of Norway, it reached Skandinavia 

 from Scotland by means of a land bridge across the 

 North Sea. 



No ancestral forms of Lemmus occur in Britain, whither it 

 probably came from the East. Its absence from eastern North 

 America and Greenland seems to indicate an Old World origin, 



^ Hinton {Proc. Geol. Ass., 3rd June 1910, 496) believes that remains from Uphill 

 Cave, Weston-super-Mare, Somersetshire, represent a second species as yet un- 

 described. 



