270 FIKST PRINCIPLES OF NATURAL CLASSIFICATION. 



animal^ the vegetable, and the mineral. These divi- 

 sions are palpable ; and our belief in them is not to be 

 disturbed by the subtleties of philosophy or the argu- 

 ments of metaphysicians. From this point, therefore, 

 if we wish to pursue the synthetic mode of investi- 

 gation, we may start, as from an incontrovertible truth. 

 The animal kingdom is admitted to be a circular group : 

 its first divisions are, therefore, into sub-kingdoms. 

 Vertebra ted animals form one of these sub-kingdoms ; 

 and annulose animals, or insects, generally speaking, 

 another. These are next divided naturally into classes, 

 of which description are quadrupeds, birds, fishes, rep- 

 tiles, and Amphibia in one ; and winged insects, apter- 

 ous insects, barnacles (Cirripeda), &c. in the other. 

 So far we can have no doubt as to the kingdom, sub- 

 kingdom, or class to which an animal, whose rank we 

 wish to ascertain, belongs ; and we will suppose this to 

 be the common-bearded titmouse (Parus biarmicus}. 

 Every one sees that this is a bird not formed either for 

 swimming, wading, or running upon the ground : we 

 consequently conclude that it perches, and refer it at 

 once to the division of birds named, from this circum- 

 stance, Insessores ; and by this means arrive at its 

 order. Its perfect and well-proportioned feet guide us 

 to the particular tribe of Insessores which is distin- 

 guished by these characters ; and we then proceed, by 

 still further examining its structure, to refer it to the 

 family of warblers, and to the sub-family of titmice 

 (Parlance)* The sharp conic bill, and other minute 

 peculiarities of structure, show that it belongs to the 

 genus of Parus ; and to that little group, or sub-genus, 

 which contains the most typical examples, or Pari 

 proper. But even a sub- genus, as we have already 

 seen, contains in its own little circle, when perfect, a 

 representation of all the types of nature ; and thus the 

 bird before us, as representing the natatorial or aquatic 

 type, inhabits the marshy borders of lakes and rivers, 



* Northern Zoology, vol. ii. p. 203. 



