No. 410.] THE EUROPEAN FAUNA. QI 
ptarmigan and snow bunting are also reckoned as invaders 
from the north. Several other animals are mentioned as 
Arctic; thus the various lemmings, though it is not quite clear 
whether he regards these as belonging to the Arctic immigra- 
tion, since they are also included in the animals constituting 
the Siberian contingent. The character of the flora is also 
alluded to as strengthening the theory of an Arctic (7.e., North- 
America- Greenland-Spitsbergen- S linavia-Scotland) route, 
though a postglacial connection between Europe and Green- 
land is not insisted on, as the present flora of that country 
may have survived the glacial period in the Arctic regions. 
Professor Forbes's opinion, that the occurrence of certain 
shore Mollusca, both on the coast of Finmark and Greenland, 
shows that these two countries were not long ago joined, is 
alluded to, and the view that the continental boulder clay is a 
marine deposit is again brought forward as fitting so much 
better with the known facts of distribution. 
The Siberian invasion forms the subject of Chapter V, in 
Which a number of British animals, living and extinct, are 
traced to a Siberian origin, chiefly mammals, and some birds. 
Among many of the lower vertebrates and invertebrates there 
are but few species which in Dr. Scharff's opinion have reached 
England from Siberia. They may have had their original 
homes in the Alps, in eastern Europe, or in central and 
southern Asia, and have joined in their westward course the 
later, more quickly traveling mammals. No less than twenty- 
Six species of the Siberian mammals, according to Scharff, 
penetrated as far west as the British Islands, and nine of these 
still inhabit Great Britain. Some of the remaining seventeen 
species probably lived only for a very short time in England, 
and the rest gradually became extinct one by one. Our author 
enumerates them as follows!: Canis lagopus, Gulo luscus, 
* Mustela erminea, * M. putorius, * M. vulgaris, * Sorex vulgaris, 
Lagomys pusillus, * Castor fiber, Spermophilus eversmannt, $. 
erythrogenoides, Cricetus songarus, Myodes lemmus, Cuniculus 
torquatus, * Mus minutus, * Arvicola agrestis, * A. amphibius, A. 
or did so within 
! Those marked with an asterisk still inhabit Great Britain, 
historic times. 
