34 ESSAY ON CLASSIFICATION. Part I. 



associations of organized beings extending over a wider or narrower area are called 

 Faunce when the animals alone are considered, and Fhrw when the plants alone are 

 regarded. Their natural limits are far from being yet ascertained satisfactorily 

 everywhere. As the works of Schow and Schmarda may suffice to give an approxi- 

 mate idea of their extent,^ I would refer to them for further details, and allude here 

 ovAj to the unequal extent of these different faunae, and to the necessity of limiting 

 them in different ways, according to the point of view vmder which they are con- 

 sidered, or rather show that, as different groups have a wider or more limited range, 

 in investigating their associations, or the faunre, we must distinguish between zoologi- 

 cal realms, zoological provinces, zoological counties, zoological fields, as it were ; that 

 is, between zoological areas of unequal value over the ■widest of which range the 

 most extensive types, while in their smaller and smaller divisions, we find more and 

 more hmited types, sometimes overlapping one another, sometimes placed side by 

 side, sometimes concentric to one another, but always and everywhere impressing a 

 special character upon some jiart of a wider area, which is thus made to differ from 

 that of any other part within its natural limits. 



These various combinations of smaller or wider areas, equally well defined in 

 different types, has given rise to the conflicting views prevailing among naturalists 

 respecting the natural limits of faun* ; but with the progress of our knowledge 

 these discrepancies cannot fail to disaj^pear. 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 faunte, the Sandwich Islands for instance, com- 

 pared 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 suljject of inquiry 

 to ascertain what are the narrowest limits within which animals of different types 

 may be circumscribed, as this would furnish the first basis for a scientific consid- 

 eration of the conditions under which animals may have been created. The time 

 is passed when the mere indication of the continent whence an animal had been 

 obtained, could satisfy our curiosity ; and the naturalists who, having an opportunity 

 of ascertaining closely the particular circumstances under which the animals they 

 describe are j^laced in their natural home, are guilty of a gross disregard of the 

 interest of science when they neglect to relate them. Our knowledge of the geo- 

 graphical distribution of animals would be far more extensive and precise than it 



' I would also refer to a sketch I have pub- Types of Mankind, Philadelphia, 1854, 4to., accom- 

 lished of the Faunie in Nott's and Gliddox's panied with a map and illustrations. 



