[STERNBERG] PANOPLOSAURUS M I RUS 97 



roughly oval in cross-section and has a well-defined articular face, 

 which conforms to the articular face of the diapophysis of the axis. 

 Contrary to the arrangement of the second rib of Stegosaurus the 

 main articulation is with the diapophysis and the articulation with 

 the parapophysis was by ligament or cartilage. The distal end of the 

 rib is convex on the outer side and flat on the inner. 



Length of first cervical rib 70 mm. 



Proximal breadth of first cervical rib 35 " 



Length of second cervical rib 83 " 



All the larger ribs preserved were found disarticulated and 

 scattered, so it is not possible to definitely place them, though it is 

 thought that all pertain to the anterior dorsal region. None of those 

 present show any indication of ankylosing with the vertebrae as in 

 the posterior dorsals of Ankylosauriis. The ribs are long and moder- 

 ately stout, with well-developed capitulum and tuberculum placed 

 well apart. 



The tuberculum is sessile, with the articular face looking inward 

 at about the same angle as the curvature of the upper part of the rib. 

 The capitular process does not form a sharp angle but is the con- 

 tinuation of the gently rounded curve of the upper part of the rib. 

 This would throw the rib, when articulated, well up, making a flat 

 back and broad body cavity as in Ankylosauriis. The distal end, 

 where preserved, shows a thickened, rounded end, rather than a 

 spatulate extremity. 



Coraco-scapida. — -The coracoid and scapula (Plate II, Figure 1) 

 are firmly co-ossified, the suture being indicated only by a slight 

 thickening of the bone. 



The scapula is moderately short and small except where it unites 

 with the coracoid and contributes in part to the formation of the 

 glenoid cavity, where it is greatly expanded and thickened. It is 

 thickest and broadest at the superior border of the glenoid cavity. 



The blade curves strongly downward proximo-distally and the 

 inner face is strongly concave. Both the downward curvature and the 

 inner concavity are continued throughout the length of the coracoid. 

 This curvature would throw the coracoid in the articulated skeleton 

 well in front of the chest as in Slegosaiinis, Triceratops and Hadro- 

 saiirus. The thickness of the blade is approximately the same 

 throughout the upper half of its length, but from midlength to its 

 union with the coracoid it gradually thickens. The expansion at the 

 proximal end is only slïghtly greater than at midlength. The upper 

 end is gently rounded as in Ankylosauriis and has a very slightly 



