OSTEOLOGY OF BIRDS 



12^ 



that follow, which are of about equal length. The middle anterior 

 toe (3d) also has rather a short .basal joint, and the one just be- 

 yond it is most decidedly so. Second digit has likewise a short 

 basal phalanx, and the basal joint of hallux is broadened and verti- 

 cally compressed. In fact it may be said that there is more or less 

 of a shortening of all the basal joints to the three anterior toes, 

 and the distal ones just posterior to the claws are long. All the 

 various points about these phalangeal joints are strong, powerfully 

 produced and massive. 



The claw joints themselves are peculiar in that they are very 

 smooth, beautifully curved, taper gradually to a sharp apex, are 

 elliptical upon section, the major axis of the ellipse being vertical, 

 and finally are characterized by a conspicuous basal tubercle upon 

 their plantar aspects. 



Pandion has a very unusual form of patella at its kneejoint. I 

 know at present of no other hawk that has one anything like it. 

 It is long and oblong, rather narrow, curved for its entire length 

 from above downwards, the convexity being in front, where it is 

 likewise marked below its middle by the oblique groove for the 

 tendon of the ambiens muscle. 



LENGTHS OF THE BONES OF THE PELVIC LIMB 

 Centimeters and their fractions 



Femur 8.1 Patella 2.0 



Tibiotarsus 12.7 Tarsometatarsus 5.6 



Fibula 11.6 Accessory metatarsal 1.7 



LENGTHS OF PHALANGEAL JOINTS OF TOES 



First joint is the basal one; second joint is one next beyond the basal one, 



and so on. 



TOES 



BASAL 

 JOINT 



SECOND 



THIRD 



FOURTH 



CHORD OF 

 CLAW 



First toe or hallux , 



Second toe 



Third toe 



Fourth or outside toe. . . . 



2 .4 

 1 .0 

 1.6 



0. 7 



2 .0 

 0.9 

 0.5 



2.5 

 0.4 



2 . 1 



2.8 

 2.8 

 2 . 7 

 2.9 



In taking the chord of the claw the measurement was made from 

 the most proximal point of the bone on its dorsal aspect, to the apex. 



OSTEOLOGICAL CHARACTERS OF THE UNITED STATES 

 ACCIPITRES SYNOPTICALLY ARRANGED 



Our studies now have carried us through the consideration of the 

 skeletology of all the vultures of this country, as well as the vast 



