North- American Kites. 229 



Archibuteo and Halia'etns, and finally with examples of two 

 species of Polyborus and of Pandion. 



In so far as their osteological characters are concerned, 

 our Kites differ most markedly among themselves. As for 

 instance, with respect to this part of its structure, Ictinia 

 mississippiensis might almost at once be dismissed by saying 

 that in all essential particulars its skeleton is buteonine in 

 character — it is a miniature Buteo, such as, for example, 

 Buteo lineatus. In it, however, the basipterygoid processes 

 are hardly discernible, or most often quite absent, while it 

 presents the rather remarkable character in that the short 

 basal joint of the second toe permanently fuses with the 

 joint next beyond it. This latter condition I have also found 

 to exist in Haliaetus leucocephalus ; it is never present in 

 any typical Buteo or in any of the other Kites. 



All these Kites generally have the osseous nasal septum en- 

 tire, but the superior osseous mandible is not laterally toothed. 



Passing to Elanoides forficatus, we find its skeleton entirely 

 different from the corresponding parts in Ictinia; and we 

 are struck with the unusual number of important skeletal 

 characters it holds in common with no less a distantly related 

 form than Pandion. Elanoides agrees very closely with 

 'Pandion in the pattern of its sternum ; in its having a complete 

 fibula (a very unusual character) ; in its having the supraor- 

 bital parts of the lacrymals much reduced and the accessory 

 piece in either bone absent (?); in its having a similar hypo- 

 tarsus to its tarso-metg.tarsus (a still more uncommon feature) , 

 and in other minor points. 



It is to be noted here that, although the supraorbital 

 process of the lacrymal is short in Elanoides, with a probable 

 absence of the terminal accessory piece, such is not the case in 

 either Ictinia or Elanus, where it is long and has the accessory 

 piece well developed, especially so in Elanus. The descending 

 portion of a lacrymal does not articulate with the outer 

 border of the pars plana in Elanoides, while it does so in 

 Elanus. All have the vomer present, varying somewhat in 

 form. 



Elanoides agrees with Ictinia iu being desmognathous much 



