36 ESSAY ON CLASSIFICATION. 



correspondence, in their structure and in the combination 

 of their families, which shows them to have belonged to 

 contemporaneous faunce. It would, therefore, seem that, 

 even where metamorphic rocks prevail, the traces of the 

 earliest inhabitants of tin's globe have not been entirely 

 obliterated. 



SECTION VIII. 



THE GRADATION OF STRUCTURE AMONG ANIMALS. 



There is not only variety among animals and plants, 

 but they differ also as to their standing, their rank, their 

 superiority or inferiority, when compared one to another. 

 But this rank is difficult to determine ; for, while in some 

 respects all animals are equally perfect, since they perform 

 completely the part assigned to them in the general 

 economy of nature, 1 there are in other respects such 

 striking differences between them, that their very agree- 

 ment in certain features points at their superiority or 

 inferiority in regard to others. 



This being the case, the question first arises, Do all 

 animals form one unbroken series, from the lowest to the 

 highest 1 Before the animal kingdom had been studied 

 so closely as it has been of late, many able writers really 

 believed that all animals formed but one simple, conti- 

 nuous series, the gradation of which Bonnet was particu- 

 larly industrious in trying to ascertain. 2 At a later period, 

 Lamarck 3 endeavoured to show further, that, in the com- 



1 EHRENBERG (C. G.), Das Natur- 2 vols. 8vo. Contemplations de la 

 reich des Menschen, oder das Reich Nature; Amsterdam, 1764-65, 2 vols. 

 der willensfreien beseelten Naturkor- 8vo. Palingenesie philosophique ; 

 per, in 29 Classen iibersichtlich ge- Geneve, 1769, 2 vols. 8vo. 



ordnet; Berlin, 1835 (folio), 1 sheet. 3 LAMARCK (J. B. DE), Philoso- 



2 BONNET (Cn.), Considerations sur phie zoologique; Paris, 1809, 2 vols. 

 les corps organises ; Amsterdam, 1762, Svo. 



