38 ESSAY ON CLASSIFICATION 



vailing among naturalists respecting the natural limits of faunas; but 

 with the progress of our knowledge these discrepancies cannot fail 

 to disappear. In some respect every island of the Pacific upon which 

 distinct animals are found may be considered as exhibiting a distinct 

 fauna, yet several groups of these islands have a common character 

 which unites them into more comprehensive faunae, the Sandwich 

 Islands, for instance, compared to the Fejees or to New Zealand. 

 What is true of disconnected islands or of isolated lakes is equally 

 true of connected parts of the mainland and of the ocean. 



Since it is well known that many animals are limited to a very 

 narrow range in their geographical distribution, it would be a 

 highly interesting subject of inquiry to ascertain what are the nar- 

 rowest limits within which animals of different types may be cir- 

 cumscribed, as this would furnish the first basis for a scientific con- 

 sideration of the conditions under which animals may have been 

 created. The time is passed when the mere indication of the con- 

 tinent whence an animal had been obtained could satisfy our curi- 

 osity; and the naturalists who, having an opportunity of ascertaining 

 closely the particular circumstances under which the animals they 

 describe are placed in their natural home, are guilty of a gross dis- 

 regard of the interest of science when they neglect to relate them. 

 Our knowledge of the geographical distribution of animals would 

 be far more extensive and precise than it is now, but for this neglect. 

 Every new fact relating to the geographical distribution of well- 

 known species is as important to science as the discovery of a new 

 species. Could we only know the range of a single animal as ac- 

 curately as Alphonse de Candolle has lately determined that of many 

 species of plants, we might begin a new era in Zoology. It is greatly 

 to be regretted that in most works containing the scientific results 

 of explorations of distant countries only new species are described, 

 when the mere enumeration of those already known might have 

 added invaluable information respecting their geogxaphical distri- 

 bution. The carelessness with which some naturalists distinguish 

 species merely because they are found in distant regions, without 

 even attempting to secure specimens for comparison, is a perpetual 

 source of erroneous conclusions in the study of the geographical dis- 

 tribution of organized beings, not less detrimental to the progress 

 of science than the readiness of others to consider as identical ani- 



