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CHAPTER XL 



CONCLUSION. 



The map which accompanied the first volume of 

 this series * was on Mercator's projection, and was 

 intended to exhibit the distribution of summer and 

 winter mean temperatures over the European area. 

 When, however, in any branches of natural history 

 the subject of distribution is treated by division of 

 " Zones " or of " Provinces," it is of the utmost im- 

 portance that relative proportions should be pre- 

 served j a projection, such as Mercator's, not only 

 does not suggest any correct views as to the rela- 

 tions of zoological provinces, but may be said to 

 prevent those relations being understood and ap- 

 preciated. 



A map to illustrate the natural history of the 

 European seas has to embrace an area from the 

 whole of the Arctic basin, as far south as Cape 

 Verde, so as to include the South Lusitanian pro- 

 vince. The American coasts have to be introduced 

 for the purpose of showing along what extent the 

 Western Atlantic has a molluscous fauna identical 



* The Vegetation of Europe. 



