y 



THE ARCTIC FAUNAV. O*J^ 1 87 



SUMMARY OF CHAPTER IV. 



The fauna of the Arctic Regions is much poorer than that of the 

 other regions which are dealt with in this work. In some groups, 

 such as Reptiles and Amphibia, there are no representatives at all, 

 but no doubt a larger number of species existed there in earlier 

 Tertiary times. At least we have fossil evidence that during 

 the Miocene Epoch plants of many families flourished in Green- 

 land of which no vestige is now left in the Polar area. Climatic 

 conditions must therefore have changed, as in Europe. A 

 gradual refrigeration took place, owing probably to the slow 

 withdrawal of the current which supplied the Arctic Sea with 

 warmth. Greenland and Europe were then connected, and 

 the Arctic Ocean was separated from the Atlantic. This land- 

 connection is supposed to have lain far north between Scan- 

 dinavia, Spitsbergen, and Greenland, and must have persisted 

 until towards the end of the Glacial period. 



As the temperature decreased and the land-area available in 

 the north diminished, the surplus population, consisting of 

 animals and plants, and possibly also of human beings, moved 

 southward. We have traces in Europe, and especially in the 

 British Islands, of a very early migration from the north in the 

 so-called American plants and in the freshwater sponges. The 

 geographical distribution of some of the Arctic species of mam- 

 mals is referred to in greater detail, to show how the relative 

 age of their entry into Europe can be determined. Two forms 

 of Reindeer, resembling the Barren-ground and Woodland 

 varieties, have been met with in European deposits, but only 

 the former occurs in Ireland and the south of France, whilst 

 eastward the other becomes more common, and finally is the 

 only one found. It is believed that the Barren-ground is the 

 older form as far as Europe is concerned, and that it came to 

 us with the Arctic migration, and that the other Reindeer 

 reached Europe much later from Siberia, when Ireland had 

 already become detached from England. The range of the 



