342 BRITISH FOSSIL REPTILES. 



which form part of Mr. Holmes's instructive collection, it is possible that the blade- 

 bone in question may belong to that genus ; but I insert the description of it here with 

 a full sense of the inadequacy of our present evidence for the precise determination of 

 the scapula of the Megalosaurus. 



The body of the bone is an oblong flattened plate, proportionally broader and 

 shorter than in the Iguanodon ; with the base rounded, not truncate as in the Hylaeo- 

 saurus ; and with the anterior border at first, as it descends, straight and then concave, 

 not convex, as in the Hylseosaurus. The body of the scapula slightly decreases in breadth 

 as it approaches the articular end, near which there is continued from the anterior 

 border a long and slender process, at least three fourths the length of the entire bone, 

 but the precise proportions of which cannot be determined in this specimen, because the 

 extremity of the process is broken ofl". Near the base of the process a tuberous pro- 

 jection is developed, which touches the anterior angle of the articular end of the 

 scapula, circumscribing an elliptical vacuity probably for the transmission of vessels. 

 The thickened articular extremity shows indications of a division into two surfaces, 

 one for the coracoid, the other for the humerus. 



The coracoid. PI. 28. 



The coracoid is a long and large semioval plate of bone, 2 feet 6 inches in length, 

 I foot 4 inches in greatest breadth ; with the inner (mesial) border thin and regularly 

 but very slightly convex, the upper border thin and strongly convex, the outer (lateral) 

 border thick and made irregular by the development of processes, grooves, and 

 articular surfaces. The latter are two in number : the largest and deepest, fig. 1, o,l, 

 for the head of the humerus, the smallest and shallowest, o, o, for junction with the 

 scapula. 



This surface, which is hollowed out, groove-wise, chiefly in one direction, is 

 supported by a very strong, thick, three-sided process, «, o, a little expanded towards 

 its free end, and contributing by its hinder surface, o' to the formation of the glenoid 

 cavity, in front of which it projects to meet the blade-bone. The length of this process 

 is about 6 inches : its circumference is 13 inches; the length of the scapular articular 

 surface, fig. 2, o, is 6 inches. A deep oblique notch, fig. 1, «, divides the scapular 

 process, o, from the thin anterior part of the coracoid, c, s, the convex border of which 

 is entire. 



In some existing Lacertians, e, g, the Monitor and Iguana, a second process is sent 

 off from this part, for articulation through the medium of an epicoracoid cartilage with 

 the episternum ; and the mutilated state of the first-discovered specimen of coracoid of 

 the Megalosaurus, figured by Dr. Buckland in pi. xliii, fig. 3, vol. i, 2d series of the 



