1888.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 227 



Tbe ends of the shortened diapophyses of the first free caudal are 

 usually overlapped by the ilia, but in the next segment these processes 

 are much longer, to be longer still in the third and fourth vertebr;e. 

 In the next two they again become shorter, to be entirely abortive in 

 the ultimate oue. In all they are broad aud depressed. 



Chevron bones are freely articulated between the centra of the last 

 three or four vertebra? of the tail; they are bifid in front and grow 

 gradually smaller as we proceed in that direction. 



The pygostyle is here of considerable size, being an irregular quadri- 

 lateral figure, with its lower margin thickened, and all the others thin 

 and cultrate. 



Of the appendicular skeleton; pectoral limb. — When the skeleton of 

 the upper extremity is in a position of rest alongside the body, we find 

 that the humerus is somewhat longer than the bones of the autibra- 

 chium, and the pinion also projects beyond them behind to the full ex- 

 tent of the last phalanx of index digit. 



The humerus is characterized by a broad, proximal extremity, showing 

 an enormously deep pneumatic fossa, and a distinct trench between the 

 ulnar crest and articular head, running beneath the latter. Its cylin- 

 drical shaft shows the usual sigmoid curves from radial and ancoual 

 views. Nothing unusual marks its distal extremity, where we find the 

 trochlear tubercles for radius and ulna. 



These latter bones are non-pneumatic, in common with the remainder 

 of the skeleton of this limb. The shaft of the radius is straight, whereas 

 it is curved in the ulna, the concavity occurring on the side toward the 

 interosseous space. 



The cylindrical shaft of this latter bone is faintly marked by a double 

 row of papilla? for the secondaries. 



In the carpus we find the two usual segmeuts of forms common to 

 the majority of the class. 



In the pinion the bones are all remarkably well developed. Carpo- 

 metacarpus has its main shaft straight aud of a caliber intermediate 

 between those of the antibrachium, or larger than the shaft of radius 

 and smaller than the shaft of ulna. First metacarpal is short and anchy- 

 losed in the usual manner to shaft of index. The long trihedral pollex 

 phalanx bears a distal joint, w hich is also the case with the second pha- 

 laux of index digit. 



All the bones of the pelvic extremity are non-pneumatic, though the 

 principal long ones have sizable medullary cavities. 



The femur has a very large head, which rises somewhat above the 

 broad articular summit of the shaft, notwithstanding its crown is con- 

 siderably excavated for the ligainentum teres. The axis of its neck 

 makes an angle with the axis of the shaft. 



Trochanter major is suppressed above, while on the anterior aspect 

 its thin edge partly surrounds a sort of fossa, where in other birds the 

 pneumatic orifices occur. Its shaft is rather compressed from side to 



