16 Introduction. 



ascending ; of this the Wood-peckers are examples. The fourth 

 and last tribe is composed of the ' Fissirostres,' or ' wide-billed' 

 so called from their enormous width of gape ; these have usually 

 very small feet, and take their food principally on the wing ; 

 everyone will readily perceive how well the Swallows answer to- 

 this description. 



Having now reached the point at which the four tribes of 

 perchers are on an equality with the remaining four entire 

 orders, we come to subdivide these several classes into 'Families/ 

 The word 'families' describes itself at once : these, it will clearly 

 be perceived, are groups of birds belonging to the same order 

 and tribe, and having still nearer affinities one to another, not 

 shared by members of another family, though belonging to the 

 same order and tribe. Thus, for example, the tribe ' tooth- 

 billed' is composed of a number of families the thrushes, the 

 warblers, the titmice, etc. all resembling one another in the 

 formation of their beak, and other characteristics of the tribe ; 

 but each family containing distinctive marks, separating them 

 from the remaining families, and uniting them in a closer 

 alliance to one another. 



When we have mastered the classification of birds up to this 

 point, we have attained no slight knowledge of their arrange- 

 ment ; but again we must pursue our inquiries a little further, 

 and subdivide these families into 'Genera.' Of these each family 

 contains a certain number, some more, some less, the members 

 of each genus having still further points of resemblance between 

 them than with those of other genera, though of the same family. 

 Thus to take, for example, the warblers, sylviadce : in this 

 family there is the genus curruca, containing the ' whitethroats ;' 

 the genus regulus, containing the 'golden-crested wrens;' the 

 genus saxicola,' containing the 'chats.' Thus, again, of the 

 family of grouse, there is the genus tetrao, containing the real 

 ' grouse ;' the genus lagopus, containing the ' ptarmigans ;' the 

 genus perdix, containing the ' partridges.' 



And so again in like manner, to come to the last subdivision, 

 which concludes the arrangement of birds according to scientific 



