XXX INTRODUCTION. 



proportions of tlie wing primaries, or even in that of a 

 single primary, as in Acrocephalas brunescens of India, 

 compared with A. arundinaceus of Europe ; or, in the 

 relative sizes of the ear-tufts, as in Otocompsa jocosa of 

 India and of Burmah ; or in the length of the lower tail- 

 coverts, as in Irena puella and I. iudica. 



In many cases sundry of the foregoing differences are 

 variously combined. 



Classification may be said to be the grouping of o1)jects 

 according to their affinities, and their arrangement into 

 divisions of various degrees of magnitude. Its object is to 

 bring together those beings that most resemble each other, 

 and to separate those that differ. By some it has been 

 regarded simply as a convenient method of arrangement 

 for shortening the labor of the naturalist, who, by its 

 means, instead of studying all the characters which each 

 specimen presents, is enabled, by knowing its general 

 position, to confine his attention to a few of the minor 

 details of structure. His labour is thus simplified by the 

 union into one group of all the animals which agree 

 in the most important and essential characters. The 

 Philosophic naturalist has, however, a higher aim, aud 

 his object is to discover the natural system, in other words, 

 to endeavour to develop the general plan on which the 

 Creator has formed and arranged the numberless species of 

 natural objects. 



On comparing certain species with others, we find 

 various degrees of resemblance of structure and general 

 appearance. Those, which are nearest and most close, 

 are called affinities, and the more distant resemblances, 

 analogies ; and these are of every degree of nearness or 

 remoteness. The affinities of species may be said to 

 point out their order of succession in nature, and are easily 



