XI. 



CETEOSAURUS. 



269 



relations of the scapulo-sternal arch would be as below, giving 

 36 inches as the space between the lower ends of the scapulae. 



Sternum. 



The mode of implantation, or rather of apposition, of the ribs 

 to prominences on the posterior border, is like what occurs in 

 iguana : the fewness of the side rib-junctions (two on each side, 

 or possibly three) reminds us of the monitors and crocodiles, which 

 have two, rather than of iguana, which has four. The transversely- 

 elliptical figure of the whole bone is without example among living 

 reptiles . 



There is a portion of a second sternum, smaller than that above 

 mentioned, and apparently agreeing in magnitude with the middle- 

 sized femur made known by Mr. Strickland. 



Coracoids. A pair of these bones occurred at Enslow Rocks, and 

 but for the awkward position in which they lay, and the thinness 

 of some parts, might have been extracted entire. In Diagram 

 XCVIII. the least injured is represented, and a dotted outline is 

 added to complete the figure. It is supposed to be seen internally, 

 the 'arrow flying from the head. On this aspect it is largely 

 concave, with a prominent convex wave directed backward and 

 outward. The articulating surface making part of the glenoid 

 cavity is rough and deep ; the borders are thickened all round, and 

 against the sternum bevelled to 70 or 75, but against the scapula 

 nearly square. There is a deep, smooth sinuosity behind the glenoid 

 articulation, but no perforation of the disk of these coracoids. On 

 the opposite surface of the bone a broad convexity corresponds to 



o The admirable volume on the Shoulder-girdle and Sternum, by W. K. Parker, 

 F.R.S., issued by the Kay Society, may here be consulted with advantage. 



