LIASSIC DINOSAURS. Ill 



humeral articulation (PI. 50, h). So mucli as is exposed of this surface is slightly 

 concave transversely, slightly undulating in the opposite direction, 2 inches in 

 breadth. The articulation (e) with the coracoid (PI. 49, 52') is a straight 

 harmonia. At the upper part of the humeral articular process there is an oblong 

 notch, with slightly raised borders. The left scapula (PI. 50, 5I) has yielded 

 in two places to the external pressure, but without separation of the broken 

 parts. It gives the same indication of the triangular muscular surface on the 

 outside of its distal end as does the right scapula, the apex being defined by a 

 better preseiwed, slightly raised, obtuse border. The fore part of the acromial 

 end of the scapula (a), though fractured like that on the right side, is here 

 better preserved, and gives a breadth of nearly 6 inches to this end of the bone. 

 The humeral articulation (/,) measures 2 inches 6 lines, the coracoid one (c) 

 4 inches. A small, oval, dermal bone (rf), 1 inch 6 lines by 1 inch 3 lines, overlies 

 the fore part of the scapulo-coracoid harmonia. It is flattened, slightly convex 

 externally, like some others that seem to have defended the skin of the under 

 surface of the trunk. 



The coracoid (ib., 52) is an almost circular, flattened, discoid bone, 5 inches in 

 antero-posterior diameter and 4J inches in transverse diameter; the margin is 

 most modified where it is expanded in two inches of its extent to contribute the 

 coi'acoid portion ( ^ ) of the humeral joint. The scapular articular border ( « ) pre- 

 sents less thickness. The mesial or sternal border ( m ), continuing the circular 

 curve, touches its fellow ( 52) by only a small part of its circumference. The average 

 thickness of the coracoid plate is 7 lines. About 1 inch 3 lines from the 

 scapular surface there is a foramen, 5 lines in diameter. The free border of the 

 entire coracoid appears to be raised, but this may be due to the included surface 

 having been crushed in and cracked by external pressure. 



In the hinder intersjjace of the coracoids there is a flattened mass of a rhom- 

 boidal form, composed of scattered portions of thin, dark, osseous substance, 

 cemented together by matrix, which is discoloured by carbonaceous material. No 

 part shows the continuous roughened, but compact, structure of the dermal bones. 

 It appears rather to be the remains of some partially ossified element of the endo- 

 skeleton. In its position it corresponds with the sternum. There is a fainter 

 trace of the same kind of material, or discoloration of the matrix, at the anterior 

 interspace of the coracoids. 



The humerus, which is preserved on the left side (PI. 50, 53 ), has been singularly 

 crushed and flattened ; the side of the middle of the shaft being broken away, ex- 

 poses a small medullary cavity. The distal end ( rf ) is broken off, and slightly over- 

 lapped by the shaft (53). The length of the humerus is 11 inches 3 lines. It pre- 

 sents a sigmoid flexure, the distal end slightly bent downward or forward ; the 

 proximal articulationj moderately convex, is 3 inches 8 lines in the long diameter ; 



