On the Groups of the Falconidce. 317 



group that precedes it. I thus enter upon every group at the 

 point where it joins that from which I have parted : I thence gra- 

 dually ascend to the most typical division of it, which thus be- 

 comes placed in the centre ; and thence I finally descend in order 

 to the other extreme. In pursuing this uniform mode of proceed- 

 ing, when I find a group complete in its general outlines, or con- 

 sisting of five subdivisions returning into themselves, the subdivision 

 which I call the 1st, naming it such only with reference to the 

 order in which I examine it, is always that which is united with the 

 group that went before : the 3rd contains the type par excellence : 

 and the 4th is that which forms the link of connexion between the 

 present group and that which succeeds. The 2nd and 3rd will 

 thus be the normal subdivisions; the 4th, 5th and 1st the aber- 

 rant. In the more extensive groups of natural history which I 

 have examined with respect to their affinities, and in which natural 

 character is sufficiently strong to afford sure grounds for distribu- 

 tion, this disposition invariably appears to me to prevail. This 

 therefore is the order in which I shall observe upon the birds at 

 present before us, and to which, for the sake of uniformity, I 

 shall adhere in my future examinations. 



§. 1. Siirps Aquilina. Eagles. 



The long bills of the Vultures, straight at the base, and hooked 

 only at the apex, are carried on to the Falconidce, from which they 

 are separated by the sufficiently distinctive external character of 

 having the head, neck, and cheeks more or less naked. As how- 

 ever the extremes of every group participate in some measure in the 

 characters of those that approach it, we must not be surprised at 

 finding species appertaining to each of these two families, which it 

 is difficult to arrange decidedly on either side. The naked cheeks 

 of the Vultures are thus observable in a few Birds of Prey, which 

 have been almost universally allowed to belong to the Eagles, and 

 have particularly been ranked as such by their earlier describers, 

 who having had the opportunity of observing their living manners 

 may be supposed to have been the best judges of their natural affi- 

 nities. In these extreme cases every naturalist takes that side of 



