Of the mammals which made their appearance in Great Britain in recent geological times, _i.e._, during and since the deposition of the Forest-Bed for example, the following species probably came direct from Siberia across the plains of Europe, as already mentioned (p. 95):-- Canis lagopus. Gulo luscus. * Mustela erminea. * " putorius. * " vulgaris. * Sorex vulgaris. Lagomys pusillus. * Castor fiber. Spermophilus Eversmanni. " erythrogenoides. Cricetus songarus. Myodes lemmus. Cuniculus torquatus. * Mus minutus. * Arvicola agrestis. * " amphibius. " arvalis. * " glareolus. " gregalis. " ratticeps. Equus caballus. Saiga tartarica. Ovibos moschatus. Alces latifrons. " machlis. Rangifer tarandus. * Those marked with an asterisk still inhabit Great Britain, or did so within historic times. Of the arrival of many of these in Europe we have geological proof, as they have left their bones in recent pleistocene deposits, and are unknown from older European strata. The remote ancestors of others, such as _Sorex_ and _Lagomys_, no doubt lived in Europe, but the recent species probably had their original homes in Asia. It is evident that in recent geological times there existed no active centre of origin for mammals in Europe, and that our continent was largely dependent on the neighbouring one for the supply of its mammalian fauna. A shifting of the centre of development from Europe to Asia appears to have taken place occasionally, as already mentioned (p. 45). Mr. Lydekker has drawn attention to the fact that though the remote ancestors of the _Elephantidæ_ resided in Europe, neither the latter continent nor North America was the home of the direct ancestor of any of the true Elephants. Similarly, though we have had our _Sorex_ in Europe from the Upper Eocene and _Lagomys_ from the Middle Miocene, the geographical distribution of _Sorex vulgaris_ and _Lagomys pusillus_ does not support the view that they are of European origin and have migrated to Asia. Their absence from most of the European islands indicates either an extremely recent origin or a recent immigration from Asia, and the latter view seems to me much the more probable.