294 
AVES. 
distal tuberosit}^, which is not the case in the Golden Eagle. The distal 
external tubercles are less marked than in that bird, while the internal one 
is similar, but not so median, being near the posterior superior margin of 
the condyle. The anterior ligamentous bridge is similarly oblique, and 
spans a deep fossa. The inner plane of the distal end is not parallel to the 
exterior, diverging backward and inward. The condylar surface is uninter¬ 
rupted. The proximal end of the fibula differs from that of the A. chrysaetos 
in the greater transverse width and the obliquity of the articidar face out¬ 
ward. The tarso-metatarsus presents a prominent ala along the interior 
margin, which is recurved posteriorly, as is also the posterior margin of the 
flat external side. Of the three distal condyles, the internal has less trans¬ 
verse extent than the corresponding one in the A. clirysaMos, being but little 
wider than the median condyle. It terminates in the usual posterior acumi- 
nation. The internal free metatarsus is like that of the species just 
mentioned, but is one-third smaller. The proximal phalange of the third 
digit is a little longer than the corresponding one in the Golden Eagle, and 
much more slender; the penultimate phalange is more slender and is shorter. 
Of the fourth digit, the first phalange is a little longer, and much more 
slender; the second is relatively longer than the first, while the third is of 
the same length as in the Golden Eagle, but not more than half the diameter. 
The lateral condylar fossrn are not strong, excepting in the second and third 
phalanges of the fourth digit. The proximal end of the first of these 
presents the usual oblique articular face. 
Measurements of the posterior Umh. 
Diameter of the proximal end of the femur J autero posterioV ',!!! ! 
Transverse diameter of the shaft of the femur 0“.045 from the distal extremity 
Antero posterior diameter of the shaft of the femur at the same point. 
r transverse. 
Diameter of the distal end > ,,„tero posterior ! . . 
Diameter of the proximal end of the ‘iWa{ 
Transverse diameter of the shaft 0“.04 from the proximal end. 
Antero-posterior diameter of the shaft at the same point. . 
M. 
0.021 
0.017 
0. 010 
0. on 
0. 022 
0. 014 
0. 020 
0. 020 
0. 017 
0.012 
0. 007 
