192 ZOOLOGY. 



nothing is It-It in the same group but the different individual* 

 of the same species. 



Clas.-itiratioii. tlifii, is & sort of catalogue raisonne", in 

 which all beings are arranged according to a certain order, 

 and reunited into groups, recognisable by determinate cha- 

 racters, which in their turn are reunited into other groups of 

 a still more elevated place. 



361. The practical utility of such classifications is easily 

 seen by comparing it with the address of a letter. So it is 

 with the naturalist, who, by his zoological classifications, 

 arrives speedily to the groups to which the animal belongs. 

 If, for example, he was desirous to define a hare, without 

 resorting to such means he would be forced to compare his 

 description to that of more than one hundred thousand dif- 

 ferent animals. But if he says that the hare is a vertebrate 

 animal of the class mammals, of the order rodents, of the 

 genus lepus, by the first he excludes all invertebrates from 

 his comparison ; by the second, he excludes all reptiles, fishes, 

 and birds ; by the third, he distinguishes the hare from nine- 

 tenths of these mammals ; and having thus arrived at the 

 genus to which it belongs, a very few distinguishing cha- 

 racters in addition will enable him to characterize the species 

 for certainty. 



362. Artificial and Natural Classifications. Zoolo- 

 gical classifications are of two kinds, ortijir'ntl and natural. 



In the artificial classification of animals, the divisions 

 are based on modifications which certain parts of the 

 bodies present, and which are chosen arbitrarily; in the 

 natural classification, on the contrary, the whole of the or- 

 ganization of each being is taken into consideration, and then 

 arranged accordingly. 



363. An artificial system is generally of easy appli- 

 cation, but it often gives us no important information hut 

 the name of the object. Suppose we take the number 

 of the limbs as a base for classification, we should place in 

 the division quadrupeds, the ox, the frog, the li/.ard. A..-.. 

 thus violently separating animals from their natural alhnities. 

 and grouping together those which have none. 



364. By the natural method, the divisions and subdi- 

 visions of the animal kingdom are founded on the whole of 

 the characters furnished hy each animal, arranged according 

 to their degree of respective importance; thus, in knowing 

 the place which the animal occupies, we also know the re- 



