148 



p. OMODEO 



accept that the soil of the North American grass and forest land was produced 

 differently from that of other continents. Nor would it be possible to justify 

 the presence in North America of certain higher animals, such as moles, whose 

 diet is made up almost exclusively of earthworms, if none were there. 



To the second question the answer is another: no. More than 200 years 

 ago European earthworms were introduced into central and South America, 

 where they have competed successfully with the indigenous fauna, however, 

 without ever replacing them, even in limited areas. 



Fig. 13. Distribution of Liimbriciis castaneiis and L. rubellus 



W/A £«mt«.. ^.lan 



On the other hand, the European species present in North America do not 

 have the random distribution that would be expected if they had been intro- 

 duced exclusively by the European settlers: they all occur in the northern part 

 of Europe and many do not go beyond the northeastern part of North 

 America (maps, Figs. 12-15). Of course, most of the traffic went on precisely 

 between the northern countries of Europe and New England, but this is not 

 enough to explain the massive presence of these animals in northern localities 

 where farming is very recent. It must be remembered that traffic has been 

 going on between Italy and Sardinia for two millenia and has not yet resulted in 

 the introduction into Sardinia of species that are common on the Italian main- 

 land (and found also in Canada). Table 2 eloquently sums up the situation. 



