50 Philippine Journal of Science 1919 



slenderer. We are also to notice that the papillse on the shaft 

 of the latter are closer together. Ten pairs of them appear to 

 be present, and the ulna in this bird has an extreme length of 

 24.3 centimeters. 



America's golden eagle departs from others examined, in that 

 the humerus and the -femur are the only pneumatic bones of the 

 pelvic and pectoral limbs. 



Unfortunately, I have not at hand the skeleton of manus either 

 in the case of the harpy or of the species here being osteologically 

 considered ; so that a description of these parts will have to be 

 undertaken by someone else, when such material falls into the 

 hands of science. Very likely, in other published papers of 

 mine, descriptions of these parts of the skeleton in other species 

 of eagles will be found, either of fossil or existing species. 



The pelvic limb.— Plate VII, fig. 1 ; and Plates IX, X, and XL 

 Pithecophaga jefferyi possesses a big femur, which is permeated 

 by air in all of its parts. There is an extensive group of pneu- 

 matic foramina in the deep popliteal concavity, and. another 

 large opening on the proximal end of the bone anteriorly, at the 

 termination of the trochanter major; it is bounded internally 

 by the linea aspera. Caput femoris is sessile, with an extensive 

 pit for the ligamentum teres. The summit is smooth and convex 

 from before backward, and concave from head to the trochanter, 

 which latter rises above the summit of the bone. It is very broad 

 and rough on its external surface. Passing to the shaft, we 

 find that to be very stout and uniformly arched, the convexity 

 being in front. For its middle third it is subcylindrical in form 

 and very slightly roughened throughout. 



Distally the condyles of this femur are enormous with very 

 prominent articular surfaces. The side of the inner condyle is, 

 for the most part, flat and smooth, while the outer one is slightly 

 roughened and presents a conspicuous tuberosity. As usual, this 

 condyle is vertically divided posteriorly, in that it may articulate 

 with the head of the fibula of the leg. This femur has an extreme 

 length of about 13.2 centimeters, or 2 millimeters more than the 

 length of the femur of a harpy eagle; but the little that the 

 harpy lacks in length in this bone it amply makes up in stout- 

 ness; and, apart from this general stoutness, there is no specific 

 difference worthy of notice or description. 



The femur of the golden eagle is of about the same length as 

 the two just noticed ; but it is a far slenderer bone, with the ellip- 

 tical pneumatic foramen at its proximal end very conspicuous, 

 and the muscular lines on the shaft are likewise so. The poplit- 



