TRANSACTIONS OF SECTION E. 825 



suggest that tlie earth on the treeless plains contains too much salt or too little 

 organic matter to be favourable to the growth of trees. No one, so far as I know, 

 has suggested a climatic explanation of the circumstance. Want of drainage may 

 produce a swamp and the deficiency of rainfall may cause a desert, both conditions 

 being fatal to forest growth, but no one can mistake either of these treeless dis- 

 tricts for a steppe or prairie. The 



ANTHROPOLOGY 



of the Polar Basin presents many points of interest. On the American coasts of 

 the Arctic Ocean the Eskimo lives a very similar life to the Lapp in Norway and 

 the Samoyede in the tundras of Siberia. These races of men resemble each other 

 very much in their personal appearance, and still more so in their habits. Their 

 straight black hair, with little or no beard, their dark and obliquely set eyes, their 

 high cheek bones and flat noses, and their small hands and feet testify to their 

 3Iongoloid origin. They are all indebted to the reindeer for their winter dress 

 and for much of their food, and they all have dogs ; but the Eskimo travel only with 

 dogs, and the Lapp only with reindeer, whilst the Samoyede uses both dog sledges 

 and reindeer sledges. They all lead a nomadic life, trapping fur-bearing animals 

 in winter and fishing in summer ; they resemble each other in many other customs 

 and beliefs, but they are nevertheless supposed to have emigrated to the Arctic 

 regions from independent sources, and many characters in which they resemble 

 each other are supposed to have been independently acquired. 



The various races which inhabit the Polar Basin below the limit of forest 

 growth are too numerous to be considered in detail. 



Most zoologists divide the Polar Basin into two zoological regions, or, to be 

 strictly accurate, they include the Old World half of the Polar Basin in what 

 they call the Palsearctic region, and the New World half in the Nearctic region ; 

 but recent investigations have shown that these divisions are unnatural and can- 

 not be maintained. Some writers unite the two regions together under the name 

 of the Holarctic region, whilst others recognise a circumpolar Arctic region above 

 the limit of forest growth, and unite in a second region the temperate portions of 

 the northern hemisphere. In the opinion of the last-mentioned writers the circum- 

 polar Arctic region differs more from tlie temperate regions of the northern hemi- 

 sphere than the American portion of the latter does from the Eurasian portion. 



The fact is that 



LIFE AEEAS, 



or zoo-geographical regions, are more or less fanciful generalisations. The geo- 

 graphical distribution of animals, and probably also that of plants, is almost entirely 

 dependent upon two factors, climate and isolation, the one playing quite as im- 

 portant a part as the other. The climate varies in respect of rainfall and temper- 

 ature, and species are isolated from each other by seas and mountain ranges. The 

 geographical facts which govern the zoological provinces consequently range 

 themselves under these four heads. It is at once obvious that the influences which 

 determine the geographical distribution of fishes must be quite different from those 

 which determine the distribution of mammals, since the geographical features which 

 isolate the species in the one case are totally different from those which form im- 

 passable barriers in the other. It is equally obvious that the climatic conditions 

 which influence the geographical range of mammals must include the winter cold as 

 well as the summer heat, whilst those which determine the geographical distribution 

 of birds, most of which are migratory in the Arctic regions, is entirely independent 

 of any amount of cold which may descend upon their breeding grounds during the 

 months which they spend in their tropic or sub-tropic winter quarters. 



Hence all attempts to divide the Polar Basin into zoological regions or pro- 

 vinces are futile. Nearly every group of animals has zoological regions of its own, 

 determined by geographical features peculiar to itself, and any generalisations 

 from these different regions can be little more than a curiosity of science. The 

 mean temperature or distribution of heat can be easily ascertained. It is easy to 

 generalise so as to arrive at an average between the summer heat and the winter 

 cold, because they can be both expressed in the same terms. When, however, we 



