Revieics — Scharff's Origin of the European Fauna. 471 



and other large mammals from the Scandinavian Pleistocene strata, 

 Professor Pohlig expresses the belief that Scandinavia must either 

 have been hardly free from ice during the whole of the Glacial period, 

 or, if free from ice during Interglacial times, it could then only have 

 had an imperfect connection with the Continent. That of these 

 alternatives the former was not the case, and if, as I believe, 

 the bulk of the fauna and flora survived the Glacial period in the 

 country itself from Pre-Glacial times, there is no necessity for 

 supposing that any connection existed between the Continent and 

 Scandinavia in Interglacial times." (p. 468.) 



The Arctic Migration. — " Three of the Irish mammals, one of which, 

 the reindeer, is now extinct, appear to me to have come direct from 

 the north. Several birds, among the most striking of which may be 

 mentioned the grouse (Lagopus scoticas) have formed part of that 

 northern migration. All the Salmonidse have come to us from the 

 north, whilst a still more noteworthy example of a northern migrant 

 is the stickleback (Gasterosteus aculeatus). The land-shells Helix 

 lamellata and Vertigo alpestris, the beetles FelopJiila borealis, Di/tiscus 

 lapponicus, Blethisa malti punctata, and the moth Crymodes exulis, 

 all belong to the same migration. No doubt these and the North 

 American fresh-water sponges, which have been recently discovered 

 on the west coast by the Eoyal Irish Academy Fauna and Flora 

 Committee, have found their way to Ireland along an old land- 

 connection which formerly united that country with the Arctic 

 regions. In the latter may have originated many of these forms, 

 as well as the plants already referred to, and have migrated to both 

 the Old and the New World. Of course, I have selected only a few 

 of the more prominent examples. As our knowledge of the geo- 

 graphical distribution of the species, which is as yet in its infancy, 

 increases, many other of these northern forms will no doubt be 

 discovered in Ireland." 



Arctic Species in Scotland. — " If we cross over to Scotland, we find 

 a very large increase of typically Arctic species of animals and 

 plants ; and as these are absent from England, or confined to the 

 Northern counties, there can be no question as to their having 

 migrated direct from the north to Scotland by a former land- 

 passage. It may be urged that these Arctic species have spread 

 over the plain of Europe, have then entered England from the 

 south, and have subsequently been exterminated except in their 

 most northern stations in the British Islands. But whilst we have 

 only very slender geological evidence that such might have been 

 the case; there is, I think, strong evidence for the belief that, until 

 comparatively recent times, Norway and Scotland were joined, so 

 that animals and plants had no need to migrate by that enormously 

 circuitous route by way of Denmark, Holland, Belgium, and 

 England, and across the many large rivers which would have 

 impeded their journey. In Scandinavia, Arctic animals and plants 

 form a large proportion of the fauna and flora, and as we proceed 

 northward, southern forms become more and more scarce. According 

 to Mr. Peterson, no less than thirteen species of Arctic Lepidoptera 



