tSRIMSON NUT-CRACKER. 161 



is natural ; that is, whether it will bear the test of 

 comparison with the orders of birds and the tribes 

 of the Insessores. The usual mode we have always 

 adopted for this purpose is to place the genera in a 

 column which corresponds to those which contain 

 the groups represented, thus : 



SUB-FAMILY COCCOTHRAUSTIN^E. 



1. TYPICAL. 

 Pyrewstes ......... The most perfectly conic bills... Conirostres. 



2. SUB-TYPICAL. 

 Coccoborus ......... Bill notched at the tip ............ Dentirostrei. 



3. ABERRANT. 



. . . Bill most lengthened ............... Tenuirostres. 



( "Wings short, feet large, veryl 

 Dertroides ...... -c strong, upper mandible curv- > Scansores. 



( ed above ........................ j 



Each of these columns are circles; because Py- 

 renestes passes into Dertroides^ just as the tribe of 

 Conirostres passes into that of Scansores. Thus w* 

 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 pos- 

 sess the same characters in addition to others which 

 constitute them Finches. It is only upon these 

 principles, in fact, that we can account for the 

 glossy plumage, for instance, of the haw-finches; 

 their very short feet, their broad, although conic 

 bills, their pointed wings, their forked tail, and 



