82 Classification of Birds. 



contains the true Falcons, distinguished by a single tooth on the 

 upper mandible, with an incipient festoon or sinuation behind it ; 

 next to it he places the subgenus Harpagus, (the Bidens of Spix), 

 with two small teeth in the upper mandible, the wings more rounded, 

 and the scutellation of the tarsi different from that of Falco. The 

 passage between Harpagus and Falco is effected by the F. cazru- 

 lescens of Linnaeus. The third group is marked by F. lopholes 

 of Temminck, evidently an aberrant form, and probably the rasorial 

 type. The fourth is his subgenus Aviceda, a bird with which we 

 are not acquainted; and the fifth he thinks may probably prove to 

 be the Gampsonyx Swainsonii of Vigors, which in some respects 

 seems to unite the characters of Buteo and Falco. The circle of 

 the genus, or division Accipiter, he commences with Ictinia, Vieill. 

 as a form connecting Lopholes with the accipitrine falcons : this is 

 followed by the typical subgenus Accipiter, well characterized by 

 the sparrowhawk. The third is that of Astur, or goshawk group, 

 and as a fourth form belonging to it, he proposes the Pondicherry 

 eagle, {Aquila Pondicerianus, auct.) a bird which, in our estima- 

 tion, has a nearer affinity to the aquiline group. The fifth form has 

 not yet been recognized. 



The genus Aquila, the first of the aberrant groups of the Falco- 

 nidfe, contains four types, represented by Pandion, Harpyia, Aquila, 

 and lbycter, the second and third being the typical and subtypical 

 groups, while Pandion represents the aquatic or fissirostral type, 

 and lbycter the rasorial : the fifth, or tenuirostral form, he thinks, 

 may possibly be represented by Asturina, Vieill. 



The Milvine or kite division, represented by the genus Cymindis, 

 he enters by means of Polyborus, an American group nearly related 

 to lbycter ; this is followed by the genus Cymindis, the pre-emi- 

 nent type, all the members of which belong to South America. Next 

 to it he thinks it likely that the genus Elanus will take its place, 

 and this view we are inclined to adopt, looking at specimens of 

 species now before us. The bill we perceive is as much hooked, and 

 similar in form to that of Cymindis. The characters of the feet are 

 peculiar, the interior toe being longer than the exterior, and the 

 hinder toe shorter than either: the claws are sharp and strong, and 

 all of them rounded beneath, as in Pandion ; the under one in addi- 

 tion has a sharp projecting edge on its inner side. The wings are 

 long, the feathers broad, with the first quill emarginate near the 

 tip. The tail is nearly even, or very slightly forked. This form is 

 immediately followed by Vigors's genus, Nauclerus, represented by 

 the fork-tail kite of America, which, from its swallow like form and 



