296 SHUFELDT, Skeleton of ]V edge-tailed Eagle. [TS^I^rii 



taken into consideration in the |)resent accoimt of the skeleton 

 of the Wedge-tail. 



Judging from certain bones of the skeleton, all of the Ameri- 

 can Eagles examined by me would appear to exceed Uroaetiis 

 audax in the matter of size. It is, moreover, considerably 

 smaller than Pitliccophaga philippiensis, as may be proved by 

 measuring and comjjaring any or all the bones of the skeletons 

 of the two birds. It is also smaller than the Kamchatkan Eagle 

 (Thalassoaetiis pelagicus) — a bird fully one-third or more 

 larger than the Wedge-tail, which latter is again exceeded in size 

 by the Harpy Eagle (Thrasaetos Jiarpyia). In fact, with respect 

 to size, our present subject appears even a trifle smaller than 

 the Golden Eagle (Aquila cJirysaetos), judging from the com- 

 parative lengths of the long bones of the pectoral limbs. Rut 

 little difference is api)arent in the skulls of these two birds. This 

 is likewise true with respect to the White-headed Eagle of 

 America, in which species the bones of the pectoral limb are 

 longer than they are in the Australian bird. 



THE SKULL. 

 (Plates I.-III., Figs 1-6.) 



There is a very considerable amount of uniformity with re- 

 spect to characters in the skulls of all Eagles, in so far as I have 

 examined and compared them, and to this statement the Wedge- 

 tailed Eagle forms no exception. In this matter, however, there 

 is one well-known departure, and that is with respect to the 

 skull of the famous Pithecophac/a philippensis, of the Philij)- 

 l)ines — a bird ha\ing, as I have elsewhere shown, as far as the 

 cranium is concerned, unusual dei)th in the vertical direction, 

 and at the same time extraordinary transverse compression of 

 the mandibles, more especially the upper one. 



As compared with the crania of such species as our ^^'hite- 

 headed Eagle (Haliaetus leucocephalus) and the Golden Eagle 

 {Aquila chrysoactos), it will be noted that the Australian bird 

 belongs in with the .short-faced forms represented by this species, 

 rather than with those with somewhat more elongate crania, as 

 the White-headed s])ecies.* In ])assing it may be noted that 

 PitJjecoplun/a, desi)ite the great de])th of its skull, is more or 

 less rei)resentative of the short-faced forms. Then, too, as is 

 the rule throughout the vertebrata, there is almost invariably 

 ])resent very distinct dififerences. both with respect to form and 

 measurements, among the skulls of Eagles of the same species. 

 This is well exemplified in the skulls at hand of the subject of 

 Ihc i)rescnt pai)er. For example, while the transver.se diameter 

 between the ])ost- frontal proces.ses is the same in each cranium, 

 the .skull of the Eagle from Captain White is notably narrow 

 l)osterior to those processes. 



*Shufeldt, R. W. "Osteology of Birds," State Museum Bull. 130, 

 Albany, N.Y.. 1909, PI. 5. Fip. fi. and PI. 7. Fig. 12. 



