SHUFELDT : OSTEOLOGY OF THE STEGANOPODES 199 



turned epicoracoidal process. On the posterior side at the mesial angle there is a 

 prominent jutting flange bearing an articular facet upon its entire under surface for 

 articulation with the sternum. The inner two thirds of the inferior border is also 

 for articulation with the same bone. The head is more or less massive, being ob- 

 liquely compressed above. Well below this, anteriorly, is a non-elevated, circular 

 facet for the os furcula. Above the large glenoid concavity, between it and the 

 summit of the bone, is a deep valley passing downwards and forwards from the pos- 

 terior aspect. Pneumatic foramina occur in it, as they do also on the mesial aspect 

 of the shaft in an elongated group below the coracoidal head. The facet for the 

 articulation with the scapula is a deep circumscribed concavity, and in front of it a 

 conspicuous scapular process is developed, but it never reaches the os furcula in 

 articulation when the bones are in situ. Below the open valley for the tendons, 

 the shaft, is pierced by a foramen, a character often seen in birds of other groups. 



A scapula is small in proportion for the size of the bird, thick, narrow and 

 short. It is bent neither right nor left, but moderately curved, its convexity being 

 along its dorsal aspect. It has a distinct ellipsoidal raised facet for articulation with 

 the above-described pit in the coracoid, while the surface it offers for the glenoid 

 cavity is small. Its most striking character is the very much elongated process at its 

 antero-mesial angle. This acromial process does, not meet the clavicle in articula- 

 tion. On the dorsal aspect of the blade, near its middle, is a distinct tubercle for 

 muscular attachment, that is quite noticeable. 



Of the Appendicular Skeleton. 

 (See Plate XXVIL, Figs. 31-34, 38 and 39.) 



In the pectoral limb the humerus is a very long, large bone showing the usual 

 double sigrnoidal curvature in its shaft, which for its middle third is subcylindrical 

 in form. (See PL XXVIL, Fig. 34.) 



The radial crest is but moderately developed, while a peculiar tuberous enlarge- 

 ment is found on the ulnar border of the bone, just distad to the pneumatic cavity. 

 It is stopped abruptly immediately before we come to the shaft, by a distinct 

 though very narrow notch. The ulnar tuberosity is not very prominent, only parti- 

 ally overhanging the pneumatic fossa. Between it and the true humeral head is a 

 distinct notch or valley. At the distal end of the shaft, the oblique and radial 

 tubercles stand out with considerable prominence ; the olecranon fossa is pretty well 

 marked, otherwise we find only the usual ornithic characters here. The humerus 

 has an extreme length of about 27 centimeters. 



