IV. 



OF CLASSIFICATION. 



The Animal Kingdom, a term intended to embrace 

 tlie infinite multitude of living beings that people and 

 animate the globe, that fill the air, the earth, and the 

 waters Tvith life, is, by the original laws of its organi- 

 zation, separated into several distinct divisions. In 

 each of these, there prevails a common principle of 

 structure, or unity of composition, variously modified 

 and complicated, wliich pervades all the animals con- 

 tamed within it, and which is independent of, and distinct 

 from, that which governs the composition of the others. 

 The limits and boundaries of the different divisions have 

 not been so thoroughly investigated, as to determine 

 the exact relations wliich obtain among them, or their 

 comparative rank according to the perfection of their 

 organization and functions. Indeed of many of the lower 

 animals very httle is yet known ; but, the constant acces- 

 sions which are daily made to our knowledge of their 

 intimate structure render it certain, that very import- 

 ant modifications of the received opinions in regard to 



