Vol. 69.] SKELETON OF ORNITHOD&SMUS L ATI DENS. 385 



The Appendicular Skeleton. 



The Pectoral Girdle. 



The scapula and coracoid are strong bones. The former is shorter 

 than the latter. The scapula is fused to the coracoid ; the line of 

 suture is horizontal, and both bones here are truncated. Only the 

 preaxial half of the proximal end of the scapula is in union with the 

 coracoid, and here it is bulbous ; whereas the free portion is com- 

 pressed dorso-ventrally, and set at right angles to the glenoid cavity. 

 Its articular surface looks downwards, and forms an extra glenoidal 

 surface (PL XXXVIII, fig. 7, ad.ar.sur.). The articular surface of 

 the fused portion is oblique. The glenoid cavity is saddle-shaped. 

 The dorsal surface is convex and the ventral flat, but both become 

 •concave near the glenoid cavity. The bone here shows a quad- 

 rangular section. The preaxial border immediately behind the 

 glenoid cavity is deeply emarginate, followed by a strong convexity 

 (the acromion process), and that again by a concavity to the distal 

 end. The postaxial border is very concave over its whole length. 

 The distal extremity is considerably expanded ; the vertebral margin 

 has a concave facet, apparently for articulation with the notarium. 

 The postaxial border of the proximal end of the coracoid is bent 

 downwards into a kind of lip with a convex aiticular surface. The 

 coracoid is moderately curved. It is expanded at both ends pre- 

 postaxially and compressed in the central region of the shaft, the 

 preaxial edge traversing postaxially across the bone, until at the 

 sternal end it is iu the centre of its ventral surface, which gives 

 the appearance of a twist to' the bone. Its sternal articular face is 

 •concave pre-postaxially, with its preaxial border ^produced distallj'' 

 more than the postaxial. Anterior to the glenoid surface of the 

 coracoid there is a triangular inarticular portion, the apex forming 

 the border of the bone. It is produced into a tubercle, between 

 which and the scapula is a groove, which leads into a pit or pneu- 

 matic foramen, situated at the base of this triangular area, near 

 •the articulation. 



The Humerus. 



The proximal condyle of the humerus is of the usual Ornitho- 

 saurian character, feebly convex on its articular surface, and 

 crescent-shaped in outline, with the horns well splayed out. Near 

 the dorsal border of the preaxial side of the articular surface of 

 ■the condyle is a strong ridge. The deltoid crest is remarkably 

 developed. It springs powerfully from the preaxial border, at 

 some distance below the head, and curves spirally round the bone 

 until its apex is over the middle of the ventral surface of the shaft. 

 This spiral curve commences 40 mm. from the proximal condyle, 

 and terminates 125 mm. from it. Along its outer curve it measures 

 75 mm. At its distal end it is 27 mm. above the surface of the 

 shaft. This extremity is claw-like, the point directed postaxially, 



