156 POLAR PROBLEMS 



This view of the north pole as a zoogeographical center was later 

 taken up and elaborated by others, and some years afterwards there 

 appeared two papers, one by Wilhelm Haacke,- the other by Canon 

 H. B. Tristram.^ Haacke's idea was that all the larger groups of 

 animals originated on the polar continent. He argued more partic- 

 ularly from the distribution of the struthious birds, the monotremes, 

 marsupials, lemurs, edentates, and insectivores, the older forms being 

 supposed to have been pushed southwards in widening circles by the 

 forms evolved subsequently. Hence, he concluded, we find at the 

 present time the ancient types crowded farthest off to the south end 

 of the continental masses, while the more modern ones occur nearer 

 the north pole. He did not touch upon the role of the Glacial Period, 

 nor did he discuss the presence or the absence of land bridges between 

 the Old and the New Worlds, for the simple reason that he was willing 

 to concede the possibility of the looo-fathom line having formed the 

 original coast line, which of course — according to the knowledge of 

 that time — would outline a solid circumpolar continent of tremendous 

 proportions. Tristram's hypothesis is in many ways similar, but he 

 goes into more detail and attributes the southward push from the 

 pole to the gradual advance of the Glacial Period. "The polar con- 

 tinent continued to cool, the accumulation of snow and ice over its 

 whole surface became so enormous from the precipitation of frozen 

 vapour as to equal the present deposits on the southern polar conti- 

 nent."^ This enormous accumulation of ice finally depressed the 

 continent to such an extent that when the ice melted the oceanic 

 waters of the Atlantic and Pacific gained access to the more deeply 

 depressed portions of the area. 



This idea of a once elevated polar continent depressed into a 

 shallow sea between Eurasia and America by the weight of the ice 

 cap was finally disposed of by Nansen's drift in the Fram and his 

 demonstration of the fact that the Arctic Basin is of truly oceanic 

 nature. From this time on the discussion of the north polar area as a 

 center of zoogeographical distribution assumed a somewhat different 

 aspect. 



The Arctic Not a Faunal Center of Origin 



It is not the place here to discuss the distribution of land and water 

 in the circumpolar area during geological periods previous to the 

 origin of the present polar fauna or all the theories which have been 

 advanced since the demolition of the hypothesis of a central polar 

 continent with a subsequent enormous ice cap, but it is the intention 



2 Der Nordpol als Schopfungszentrum der Landfauna, Biol. Centralhlalt, Vol. 6, i886, pp. 363-370. 

 s The Polar Origin of Life in Its Bearing on the Distribution and Migration of Birds, Ihis, 

 Ser. 5, Vol. 5, 1887, pp. 236-242; and Vo\. 6, 1888, pp. 204-216. 

 * op. cit.. Vol. 6, p. 206. 



