xlviii INTRODUCTORY OBSERVATIONS 



now been devoted, almost unceasingly, to this investigation ; and 

 although I have found it impossible in every instance to enter into 

 details, I now venture to lay the results before the world, considering 

 that a more appropriate channel for such communication could not be 

 chosen than this : being the first zoological work ever published under 

 the immediate authority of the British Government. 



The object of the introductory observations to each family of the 

 order Insessores, is to demonstrate the following peculiarities in 

 natural arrangement. These I shall briefly state as propositions. 



1. Every natural series of beings, in its progress from a given point, either actually 



returns, or evinces a tendency to return, again to that point, thereby forming 

 a Circle. 



2. The contents of such a Circle or Group are symbolically represented by the 



contents of all other Circles in the same class of animals ; this resemblance 

 being strong or remote, in proportion to the proximity or the distance of the 

 groups compared. 



3. The primary divisions of every natural Group, of whatsoever extent or value, 



are three, each of ivhich forms its own Circle. 



1. Little need be said on the first proposition, since it is in com- 

 plete accordance with the theory supported by MM. Macleay, Fries, 

 Agardh, Oken, &c. I have merely modified it for the purpose of 

 showing that, strictly speaking, every group is not a circle, since in 

 many which, by the theory of representation, can be proved to be 

 natural, the circle is incomplete, either by the extinction or by the 

 non-discovery of certain types. The aberrant group of the class Aves, 

 of the order Raptores, and of the family of Picidce, are all striking 

 examples of this truth. 



2. This, which may be termed the theory of representation, was 



this order. But it should not have been concealed that the merit of having first united the Passeres 

 and the Piece belongs to M. Vieillot, and not to the writer in the Linna?an Transactions. So far 

 back as the year 1816, M. Vieillot named this order Sylvicolce. See his Analyse Orn., p. 25. 



