328 Swai?ison's Birds of Western Africa. 



Each of these columns are circles ; because Pyrenestes passes into Dertro- 

 ides, just as the tribe of Comrostres passes into that of Scansores. Thus 

 we find that the chief distinctions of each of the tribes of the perchers 

 turn out to be the same as those of the group of Finches before us ; that 

 is, they possess the same characters in addition to others which constitute 

 them finches. It is only upon these principles, in fact, that we can ac- 

 count for the glossy plumage, for instance, of the haw-finches ; their very 

 shot feet, — their broad, although conic bills, — their pointed wings, — their 

 forked tail, — and their migratory habits ; all which, as every one knows, 

 are also the characteristics of the swallow family, and of all Fissirostral 

 birds. Those, on the other hand, which represent the Tenidrostres have 

 the longest bills ; and those, again, which typify the gallinaceous tribe, 

 have the strongest feet and the shortest wings. All the species of Cocco- 

 borus, however diversified in other respects, have a distinct notch (although 

 small, and the tip not hooked, as in the tanagers) in the upper mandible; 

 and this, we all know, is the great distinction which separates the Denti- 

 rostres from the Conirostrcs. Numerous other analogies might be here 

 pointed out, strengthening the accuracy of the above arrangement ; but it 

 is quite needless to proceed further. The clue being now given, the ex- 

 perienced ornithologist will be at no loss in following it up ; while the 

 student will thus have an example he can comprehend, of that systematic 

 order of variation in all animals which the discoveries of every year more 

 and more demonstrate as the fundamental principle of the great plan of 

 creation." 



Strange as it may appear, it does sometimes happen that 

 the experienced ornithologist, having obtained the clue, finds 

 himself suddenly put to the right about whilst following 

 it up ; and, in the identification of columns with circles, the 

 student will find an order of variation, the comprehension of 

 which, if it does nothing more, will at any rate have a tend- 

 ency to strengthen his conceptive faculties. 



Through the entire range of human investigation into the 

 laws of nature, we shall probably not succeed in meeting with 

 so singular an anomaly as the opposite opinions entertained 

 upon those views of natural arrangement first made public by 

 MacLeay, and subsequently sustained by the observations of 

 other naturalists. 



We are told, on the one hand, by men distinguished for 

 zoological attainments of the most solid and comprehensive 

 nature, the greater part of whose lives has been devoted to 

 the investigation of the affinities existing between the subjects 

 of that science ; men whose competency to decide upon the 

 identity or relations of species would never have been ques- 

 tioned, if no system were involved in their decisions, that the 

 quinary distribution is displayed from the highest to the 

 lowest groups of animated beings, and stamped in characters 

 so legible, that little less than wilful blindness is the barrier 

 opposed to its admission as the only true basis of natural 

 systematic arrangement. 



On the other hand, we see individuals who have had 



