WEALDEN FORMATIONS. 15 



' Geological Transactions,' produced a similar appearance, and led to the belief that 

 the Megalosaurus resembled those Lacertians, in having both the scapular and 

 episternal processes of the coracoid. 



Not fewer than three entire or almost entire coracoids of the Megalosaurus have 

 since been obtained, and are now in the British Museum, two of which show the true 

 contour of the anterior part of the bone, as represented in T. VI, fig. 1, c , s. The Mega- 

 losaurus, therefore, resembled the Scincoid Lizards and the Crocodiles, in having only the 

 scapular process in its coracoid j approaching, however, to those Lizards and the Lacer- 

 tians generally in the great breadth of the bone, but more resembling the Crocodiles 

 in the greater development of the scapular process as compared with that in the 

 Scincoids. The glenoid cavity of the coracoid of the Megalosaurus, T. VI, fig. 2, m , 

 is deeper and larger than in recent Saurians, or than in the Iguanodon. The 

 longitudinal diameter of its outlet is 8 inches in the largest of the three coracoids (pur- 

 chased by the British Museum of Mr. Stone, from Stonesfield) ; the greatest transverse 

 diameter of the cavity is 4 inches 4 lines : the internal (central) border of the cavity 

 is moderately sharp and entire ; the external (peripheral) border becomes thicker as it 

 recedes from the scapular process, and ends abruptly in an oblong tuberosity ; the rest 

 of the outer border beyond this part is thick and rounded, and is continued upon the 

 obtuse process, I, forming the hinder boundary of the cavity. This process projects 

 beyond the sharp, almost straight, outer border of the hinder part of the coracoid, 

 which terminates in the hinder angle of the bone. 



A strong ridge, like the spine of a scapula, begins to rise from the outer surface of 

 the coracoid, about four inches behind the tubercular termination of the fore and 

 outer part of the glenoid border : it is, at first, thick and rounded, but gradually 

 becomes thinner and more prominent, and is bent outwards and backwards, rapidly 

 subsiding near the hinder angle of the coracoid, and forming the external wall of a 

 wide and deep groove ; the internal wall of which is formed by the proper outer and 

 hinder border of the coracoid, fig. 2, l. The large proportion of the exterior surface of 

 the coracoid between this process and the anterior border of the bone is slightly con- 

 cave ; the opposite or inner surface being in a less degree convex, or nearly flat. 

 Except a low thick ridge extending from within about four inches of the glenoid 

 cavity to near the lower angle, enlarging as it approaches thereto, the inner surface, 

 fig. 1, is even and almost smooth. Coarse stria? radiate from the articular part of the 

 coracoid to its free expanded border. There is no foramen in any part of the 

 coracoid ; none certainly at the base of the scapular process or between this and the 

 glenoid cavity, where such perforation, Cuvier states, may be found in all existing 

 Lizards. If the scapula, T. V, above described should actually belong to the Mega- 

 losaurus, the notch or foramen at e, fig. 1, may fulfil the function of that which, in 

 the Iguanodon, exists in the coracoid itself. 



