298 SHUFELDT, Skeleton of Wedge-taUed Eofile. K^l^rii 



margin to the bone, it being at right angles to the keel. On the 

 other hand, in the Captain White sjjecimen, there is a consider- 

 able foramen on the right side, well within the postero-external 

 angle, and the hinder margin of this sternum is markedly con- 

 cave, the convexity being directed anteriorly. In some species 

 of Eagles, as will be seen further on in this paper, the sternal 

 foramina are \'ery large. 



Returning to the consideration of the skull, and viewing it 

 upon its dorsal or superior aspect, it is to be noted in such Eagles 

 as are at my hand at this writing; that is to say, in addition to 

 Uroaettts, the Philippine bird {Pithecophaga), the White-headed, 

 the Oolden, and the Kamchatkan, there is invariably a more or less 

 e\ident median concavity at the ])oint where the nasal processes 

 of the premaxillary are lost from sight posteriorly. This con- 

 cavity possesses no defined borders, being simply a median de- 

 pression in the region of the locality designated as the "facial 

 hinge" in some birds when a certain degree of mobility exists 

 there. Usually, in the Eagles here being compared, the sutures 

 between the premaxillary and the bones in contact with it are 

 readily made out, especially should the bird be a subadult indi- 

 vidual, when they are very clearly defined, as in the case of the 

 skull of a White-headed Eagle at hand (No. 19926). Posterior 

 to this concavity, the interorbito- frontal region is broad and 

 generally flat, with the extensive orbital margin on either side 

 rather sharp and thin. The external vault of the cranium is like- 

 wise broad and smooth, presenting a uniform convexity through- 

 out its extent. Anteriorly and mesially it occasionally possesses, 

 as pointed out above, a shallow, median groove in the frontal 

 region. 



Tn these characters, as thus far enumerated, all these Eagles 

 practically agree, the cranial region merely being relatively some- 

 what broader in the Wedge-tailed Eagle than it is in any of the 

 other species under consideration. 



All true Eagles have very large lacryinal bone.:, and either one 

 of these articulate with a free, subtriangular piece of consider- 

 able size at its outer, free margin — n llat. thin bone, generally 

 designated as the aceessory lacrymal. Apparently, in subadult 

 Eagles, as for example in the White-headed Eagle (Xo. 19926, 

 U.5^. Nat. Mus. Coll.). the free. ])osteri()r margin of a lacrvmal 

 is rounded, and the ligamentary attachment of the accessory 

 piece is feeble in character, and readily comes away in the prepa- 

 ration of the skeleton. Tn other S|)ecimens, where ihe bnxls are 

 adult, the attachment is much fiimer and coextensive with the 

 long, straight edge of the outer uiargin of the lacrvmal. ( PI. ii.. 

 Fig. 5.) 



In the big Krunchatkan Eagle the horizontal ])orti()n of either 

 lacrymal is very small, both relatively and actually as compared 

 with the size of the bird and the skull it has. On the other 

 hand, the descending part of the bone in this species is massive 



