662 



PROF. H. Cr. SEELE I ON THE REPTILE 



cimen is 18| centim. The length of the posterior margin to the 

 humeral articulation is about 15 centim., the length of the chord of 

 the arc of the posterior curvature is 13| centim., and the abscissa 

 is about 28 millim. ; so that the curvature is much less than in the 

 large species. The posterior margin is also more inflated ; it is 

 similarly sharp at its distal end ; but the bone thickens steadily 

 towards the humeral end, where it rapidly expands, chiefly on the 

 inner side, to form the humeral articular surface. The posterior 

 margin is more rounded on the external than on the internal sur- 

 face, giving the effect of an obscure ridge along the visceral border 

 of this outline of the bone. The anterior border is also well rounded 

 and thicker than the posterior border, the thickness in the middle of 

 the blade being about 12 millim. The outline divides itself into a 

 proximal part, which is concave, and a distal part, which is straight. 

 The middle convexity of the outline is much less pronounced than in 

 the larger species. The concavity towards the proximal end is due 

 to the prolongation forward of the comparatively thin process for 

 union with the coracoid. The middle part of the anterior margin is 

 marked with fine parallel muscular ridges ; and from this region 

 the spine of the scapula is prolonged downward obliquely across the 

 bone, so that it terminates at about the middle of the proximal end 

 of the bone, which is 9 centim. wide. The least width of the blade in 

 the middle of the concavity on the anterior side of the margin is less 

 than 5 centim. The width at the origin of the spine of the scapula 

 is about 53 millim.; and the width at the distal end, as preserved, is 

 6| centim. The spine is remarkably straight ; and even the length 

 to its acromial termination is nearly 10 centim. ; it does not so 

 much suggest the form of spine in a mammalian scapula as that of 

 Hatteria, existing as a broad rounded ridge, which divides the 

 proximal end of the external surface of the bone into two areas, 

 which are both concave in length, though the outer subtriangular 

 area is rather wider and shallower. The acromial process is imper- 

 fectly preserved proximally ; and hence the spine appears to termi- 

 nate in a rounded ridge which is about 2 centim. high and ap- 

 proaches to within a centim. and. a half of the humeral articulation. 

 The thickness of the bone from the internal to the external surface 

 at the worn or eroded termination of the spine of the scapula is 4 

 centim. The width of the process is less than 1^ centim. ; and the 

 measurement from its outer border to the anterior coracoid margin 

 is about 5 centim., or over 4 centim. from its inner margin to the 

 posterior humeral articulation. The visceral surface is remarkably 

 flat ; but beneath the region occupied by the spine the base was 

 somewhat concave. The humeral articular surface obliquely trun- 

 cates the inner half of the proximal end. It is much roughened and 

 grooved with the marks of a cartilaginous epiphysis, and was broader 

 in proportion to its length than in the larger species. It shows 

 some sign of crushing, and is fully 4 centim. wide and 47 millim. 

 long. Its posterior outline is much broader than in the larger spe- 

 cies ; and the axis of the articular surface was not materially different 

 from the plane of the blade. The thickness of the anterior coracoid 



